pylast.py

# -*- coding: utf-8 -*-
#
# pylast - A Python interface to Last.fm (and other API compatible social networks)
#
# Copyright 2008-2010 Amr Hassan
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# http://code.google.com/p/pylast/

__version__ = '0.5'
__author__ = 'Amr Hassan'
__copyright__ = "Copyright (C) 2008-2010  Amr Hassan"
__license__ = "apache2"
__email__ = 'amr.hassan@gmail.com'

import hashlib
from xml.dom import minidom
import xml.dom
import time
import shelve
import tempfile
import sys
import collections
import warnings

def _deprecation_warning(message):
    warnings.warn(message, DeprecationWarning)

if sys.version_info[0] == 3:
    from http.client import HTTPConnection
    import html.entities as htmlentitydefs
    from urllib.parse import splithost as url_split_host
    from urllib.parse import quote_plus as url_quote_plus
    
    unichr = chr

elif sys.version_info[0] == 2:
    from httplib import HTTPConnection
    import htmlentitydefs 
    from urllib import splithost as url_split_host
    from urllib import quote_plus as url_quote_plus

STATUS_INVALID_SERVICE = 2
STATUS_INVALID_METHOD = 3
STATUS_AUTH_FAILED = 4
STATUS_INVALID_FORMAT = 5
STATUS_INVALID_PARAMS = 6
STATUS_INVALID_RESOURCE = 7
STATUS_TOKEN_ERROR = 8
STATUS_INVALID_SK = 9
STATUS_INVALID_API_KEY = 10
STATUS_OFFLINE = 11
STATUS_SUBSCRIBERS_ONLY = 12
STATUS_INVALID_SIGNATURE = 13
STATUS_TOKEN_UNAUTHORIZED = 14
STATUS_TOKEN_EXPIRED = 15

EVENT_ATTENDING = '0'
EVENT_MAYBE_ATTENDING = '1'
EVENT_NOT_ATTENDING = '2'

PERIOD_OVERALL = 'overall'
PERIOD_7DAYS = "7day"
PERIOD_3MONTHS = '3month'
PERIOD_6MONTHS = '6month'
PERIOD_12MONTHS = '12month'

DOMAIN_ENGLISH = 0
DOMAIN_GERMAN = 1
DOMAIN_SPANISH = 2
DOMAIN_FRENCH = 3
DOMAIN_ITALIAN = 4
DOMAIN_POLISH = 5
DOMAIN_PORTUGUESE = 6
DOMAIN_SWEDISH = 7
DOMAIN_TURKISH = 8
DOMAIN_RUSSIAN = 9
DOMAIN_JAPANESE = 10
DOMAIN_CHINESE = 11

COVER_SMALL = 0
COVER_MEDIUM = 1
COVER_LARGE = 2
COVER_EXTRA_LARGE = 3
COVER_MEGA = 4

IMAGES_ORDER_POPULARITY = "popularity"
IMAGES_ORDER_DATE = "dateadded"


USER_MALE = 'Male'
USER_FEMALE = 'Female'

SCROBBLE_SOURCE_USER = "P"
SCROBBLE_SOURCE_NON_PERSONALIZED_BROADCAST = "R"
SCROBBLE_SOURCE_PERSONALIZED_BROADCAST = "E"
SCROBBLE_SOURCE_LASTFM = "L"
SCROBBLE_SOURCE_UNKNOWN = "U"

SCROBBLE_MODE_PLAYED = ""
SCROBBLE_MODE_LOVED = "L"
SCROBBLE_MODE_BANNED = "B"
SCROBBLE_MODE_SKIPPED = "S"

class _Network(object):
    """
        A music social network website that is Last.fm or one exposing a Last.fm compatible API
    """
    
    def __init__(self, name, homepage, ws_server, api_key, api_secret, session_key, submission_server, username, password_hash,
                    domain_names, urls):
        """
            name: the name of the network
            homepage: the homepage url
            ws_server: the url of the webservices server
            api_key: a provided API_KEY
            api_secret: a provided API_SECRET
            session_key: a generated session_key or None
            submission_server: the url of the server to which tracks are submitted (scrobbled)
            username: a username of a valid user
            password_hash: the output of pylast.md5(password) where password is the user's password
            domain_names: a dict mapping each DOMAIN_* value to a string domain name
            urls: a dict mapping types to urls
            
            if username and password_hash were provided and not session_key, session_key will be
            generated automatically when needed.
            
            Either a valid session_key or a combination of username and password_hash must be present for scrobbling.
            
            You should use a preconfigured network object through a get_*_network(...) method instead of creating an object
            of this class, unless you know what you're doing.
        """
        
        self.name = name
        self.homepage = homepage    
        self.ws_server = ws_server
        self.api_key = api_key
        self.api_secret = api_secret
        self.session_key = session_key
        self.submission_server = submission_server
        self.username = username
        self.password_hash = password_hash
        self.domain_names = domain_names
        self.urls = urls
        
        self.cache_backend = None
        self.proxy_enabled = False
        self.proxy = None
        self.last_call_time = 0
        self.limit_rate = False
        
        #generate a session_key if necessary
        if (self.api_key and self.api_secret) and not self.session_key and (self.username and self.password_hash):
            sk_gen = SessionKeyGenerator(self)
            self.session_key = sk_gen.get_session_key(self.username, self.password_hash)
    
    """def __repr__(self):
        attributes = ("name", "homepage", "ws_server", "api_key", "api_secret", "session_key", "submission_server",
            "username", "password_hash", "domain_names", "urls")
        
        text = "pylast._Network(%s)"
        args = []
        for attr in attributes:
            args.append("=".join((attr, repr(getattr(self, attr)))))
        
        return text % ", ".join(args)
    """
    
    def __str__(self):
        return "The %s Network" %self.name
    
    def get_artist(self, artist_name):
        """
            Return an Artist object
        """
        
        return Artist(artist_name, self)
    
    def get_track(self, artist, title):
        """
            Return a Track object
        """
        
        return Track(artist, title, self)
    
    def get_album(self, artist, title):
        """
            Return an Album object
        """
        
        return Album(artist, title, self)
    
    def get_authenticated_user(self):
        """
            Returns the authenticated user
        """
        
        return AuthenticatedUser(self)
    
    def get_country(self, country_name):
        """
            Returns a country object
        """
        
        return Country(country_name, self)
    
    def get_group(self, name):
        """
            Returns a Group object
        """
        
        return Group(name, self)
    
    def get_user(self, username):
        """
            Returns a user object
        """
        
        return User(username, self)
    
    def get_tag(self, name):
        """
            Returns a tag object
        """
        
        return Tag(name, self)
    
    def get_scrobbler(self, client_id, client_version):
        """
            Returns a Scrobbler object used for submitting tracks to the server
            
            Quote from http://www.last.fm/api/submissions:
            ========
            Client identifiers are used to provide a centrally managed database of 
            the client versions, allowing clients to be banned if they are found to 
            be behaving undesirably. The client ID is associated with a version 
            number on the server, however these are only incremented if a client is 
            banned and do not have to reflect the version of the actual client application.

            During development, clients which have not been allocated an identifier should 
            use the identifier tst, with a version number of 1.0. Do not distribute code or
            client implementations which use this test identifier. Do not use the identifiers
            used by other clients.
            =========
            
            To obtain a new client identifier please contact:
                * Last.fm: submissions@last.fm
                * # TODO: list others
            
            ...and provide us with the name of your client and its homepage address. 
        """
        
        _deprecation_warning("Use _Network.scrobble(...), _Network.scrobble_many(...), and Netowrk.update_now_playing(...) instead")
        
        return Scrobbler(self, client_id, client_version)
    
    def _get_language_domain(self, domain_language):
        """
            Returns the mapped domain name of the network to a DOMAIN_* value
        """
        
        if domain_language in self.domain_names:
            return self.domain_names[domain_language]
    
    def _get_url(self, domain, type):
        return "http://%s/%s" %(self._get_language_domain(domain), self.urls[type])
    
    def _get_ws_auth(self):
        """
            Returns a (API_KEY, API_SECRET, SESSION_KEY) tuple.
        """
        return (self.api_key, self.api_secret, self.session_key)

    def _delay_call(self):
        """
            Makes sure that web service calls are at least 0.2 seconds apart.
        """

        # delay time in seconds from section 4.4 of http://www.last.fm/api/tos
        DELAY_TIME = 0.2
        now = time.time()

        if (now - self.last_call_time) < DELAY_TIME:
            time.sleep(now - self.last_call_time - DELAY_TIME)

        self.last_call_time = now

    def create_new_playlist(self, title, description):
        """
            Creates a playlist for the authenticated user and returns it
                title: The title of the new playlist.
                description: The description of the new playlist.
        """
        
        params = {}
        params['title'] = title
        params['description'] = description
        
        doc = _Request(self, 'playlist.create', params).execute(False)
        
        e_id = doc.getElementsByTagName("id")[0].firstChild.data
        user = doc.getElementsByTagName('playlists')[0].getAttribute('user')
        
        return Playlist(user, e_id, self)

    def get_top_tags(self, limit=None):
        """Returns a sequence of the most used tags as a sequence of TopItem objects."""
        
        doc = _Request(self, "tag.getTopTags").execute(True)
        seq = []
        for node in doc.getElementsByTagName("tag"):
            tag = Tag(_extract(node, "name"), self)
            weight = _number(_extract(node, "count"))
            
            seq.append(TopItem(tag, weight))
        
        if limit:
            seq = seq[:limit]
        
        return seq

    def enable_proxy(self, host, port):
        """Enable a default web proxy"""
        
        self.proxy = [host, _number(port)]
        self.proxy_enabled = True

    def disable_proxy(self):
        """Disable using the web proxy"""
        
        self.proxy_enabled = False

    def is_proxy_enabled(self):
        """Returns True if a web proxy is enabled."""
        
        return self.proxy_enabled

    def _get_proxy(self):
        """Returns proxy details."""
        
        return self.proxy

    def enable_ratelimit(self):
        """Enables rate limiting for this network"""
        self.limit_rate = True

    def disable_ratelimit(self):
        """Disables rate limiting for this network"""
        self.limit_rate = False

    def is_rate_limited(self):
        """Return True if web service calls are rate limited"""
        return self.limit_rate
        
    def enable_caching(self, file_path = None):
        """Enables caching request-wide for all cachable calls.
        
        * file_path: A file path for the backend storage file. If 
        None set, a temp file would probably be created, according the backend.
        """
        
        if not file_path:
            file_path = tempfile.mktemp(prefix="pylast_tmp_")
        
        self.cache_backend = _ShelfCacheBackend(file_path)
            
    def disable_caching(self):
        """Disables all caching features."""

        self.cache_backend = None

    def is_caching_enabled(self):
        """Returns True if caching is enabled."""
        
        return not (self.cache_backend == None)

    def _get_cache_backend(self):
        
        return self.cache_backend
        
    def search_for_album(self, album_name):
        """Searches for an album by its name. Returns a AlbumSearch object.
        Use get_next_page() to retreive sequences of results."""
        
        return AlbumSearch(album_name, self)

    def search_for_artist(self, artist_name):
        """Searches of an artist by its name. Returns a ArtistSearch object.
        Use get_next_page() to retreive sequences of results."""
        
        return ArtistSearch(artist_name, self)

    def search_for_tag(self, tag_name):
        """Searches of a tag by its name. Returns a TagSearch object.
        Use get_next_page() to retreive sequences of results."""
        
        return TagSearch(tag_name, self)

    def search_for_track(self, artist_name, track_name):
        """Searches of a track by its name and its artist. Set artist to an empty string if not available.
        Returns a TrackSearch object.
        Use get_next_page() to retreive sequences of results."""
        
        return TrackSearch(artist_name, track_name, self)

    def search_for_venue(self, venue_name, country_name):
        """Searches of a venue by its name and its country. Set country_name to an empty string if not available.
        Returns a VenueSearch object.
        Use get_next_page() to retreive sequences of results."""

        return VenueSearch(venue_name, country_name, self)
        
    def get_track_by_mbid(self, mbid):
        """Looks up a track by its MusicBrainz ID"""
        
        params = {"mbid": mbid}
        
        doc = _Request(self, "track.getInfo", params).execute(True)
        
        return Track(_extract(doc, "name", 1), _extract(doc, "name"), self)

    def get_artist_by_mbid(self, mbid):
        """Loooks up an artist by its MusicBrainz ID"""
        
        params = {"mbid": mbid}
        
        doc = _Request(self, "artist.getInfo", params).execute(True)
        
        return Artist(_extract(doc, "name"), self)

    def get_album_by_mbid(self, mbid):
        """Looks up an album by its MusicBrainz ID"""
        
        params = {"mbid": mbid}
        
        doc = _Request(self, "album.getInfo", params).execute(True)
        
        return Album(_extract(doc, "artist"), _extract(doc, "name"), self)
    
    def update_now_playing(self, artist, title, album = None, album_artist = None, 
            duration = None, track_number = None, mbid = None, context = None):
        """
            Used to notify Last.fm that a user has started listening to a track. 
            
            Parameters:
                artist (Required) : The artist name
                title (Required) : The track title
                album (Optional) : The album name.
                album_artist (Optional) : The album artist - if this differs from the track artist.
                duration (Optional) : The length of the track in seconds.
                track_number (Optional) : The track number of the track on the album.
                mbid (Optional) : The MusicBrainz Track ID.
                context (Optional) : Sub-client version (not public, only enabled for certain API keys)
        """
            
        params = {"track": title, "artist": artist}
        
        if album: params["album"] = album
        if album_artist: params["albumArtist"] = album_artist
        if context: params["context"] = context
        if track_number: params["trackNumber"] = track_number
        if mbid: params["mbid"] = mbid
        if duration: params["duration"] = duration
        
        _Request(self, "track.updateNowPlaying", params).execute()
    
    def scrobble(self, artist, title, timestamp, album = None, album_artist = None, track_number = None, 
        duration = None, stream_id = None, context = None, mbid = None):
        
        """Used to add a track-play to a user's profile.
        
        Parameters:
            artist (Required) : The artist name.
            title (Required) : The track name.
            timestamp (Required) : The time the track started playing, in UNIX timestamp format (integer number of seconds since 00:00:00, January 1st 1970 UTC). This must be in the UTC time zone.
            album (Optional) : The album name.
            album_artist (Optional) : The album artist - if this differs from the track artist.
            context (Optional) : Sub-client version (not public, only enabled for certain API keys)
            stream_id (Optional) : The stream id for this track received from the radio.getPlaylist service.
            track_number (Optional) : The track number of the track on the album.
            mbid (Optional) : The MusicBrainz Track ID.
            duration (Optional) : The length of the track in seconds.
        """
        
        return self.scrobble_many(({"artist": artist, "title": title, "timestamp": timestamp, "album": album, "album_artist": album_artist,
            "track_number": track_number, "duration": duration, "stream_id": stream_id, "context": context, "mbid": mbid},))
        
    def scrobble_many(self, tracks):
        """
            Used to scrobble a batch of tracks at once. The parameter tracks is a sequence of dicts per
            track containing the keyword arguments as if passed to the scrobble() method.
        """
        
        tracks_to_scrobble = tracks[:50]
        if len(tracks) > 50:
            remaining_tracks = tracks[50:]
        else:
            remaining_tracks = None
        
        params = {}
        for i in range(len(tracks_to_scrobble)):
            
            params["artist[%d]" % i] = tracks_to_scrobble[i]["artist"]
            params["track[%d]" % i] = tracks_to_scrobble[i]["title"]
            
            additional_args = ("timestamp", "album", "album_artist", "context", "stream_id", "track_number", "mbid", "duration")
            args_map_to = {"album_artist": "albumArtist", "track_number": "trackNumber", "stream_id": "streamID"}  # so friggin lazy
            
            for arg in additional_args:
                
                if arg in tracks_to_scrobble[i] and tracks_to_scrobble[i][arg]:
                    if arg in args_map_to:
                        maps_to = args_map_to[arg]
                    else:
                        maps_to = arg
                    
                    params["%s[%d]" %(maps_to, i)] = tracks_to_scrobble[i][arg]
        
        
        _Request(self, "track.scrobble", params).execute()
        
        if remaining_tracks:
            self.scrobble_many(remaining_tracks)
    
class LastFMNetwork(_Network):
    
    """A Last.fm network object
    
    api_key: a provided API_KEY
    api_secret: a provided API_SECRET
    session_key: a generated session_key or None
    username: a username of a valid user
    password_hash: the output of pylast.md5(password) where password is the user's password
    
    if username and password_hash were provided and not session_key, session_key will be
    generated automatically when needed.
            
    Either a valid session_key or a combination of username and password_hash must be present for scrobbling.
    
    Most read-only webservices only require an api_key and an api_secret, see about obtaining them from:
    http://www.last.fm/api/account
    """
    
    def __init__(self, api_key="", api_secret="", session_key="", username="", password_hash=""):
        _Network.__init__(self,
            name = "Last.fm",
                    homepage = "http://last.fm",
                    ws_server = ("ws.audioscrobbler.com", "/2.0/"),
                    api_key = api_key,
                    api_secret = api_secret,
                    session_key = session_key,
                    submission_server = "http://post.audioscrobbler.com:80/",
                    username = username,
                    password_hash = password_hash,
                    domain_names = {
                        DOMAIN_ENGLISH: 'www.last.fm',
                        DOMAIN_GERMAN: 'www.lastfm.de',
                        DOMAIN_SPANISH: 'www.lastfm.es',
                        DOMAIN_FRENCH: 'www.lastfm.fr',
                        DOMAIN_ITALIAN: 'www.lastfm.it',
                        DOMAIN_POLISH: 'www.lastfm.pl',
                        DOMAIN_PORTUGUESE: 'www.lastfm.com.br',
                        DOMAIN_SWEDISH: 'www.lastfm.se',
                        DOMAIN_TURKISH: 'www.lastfm.com.tr',
                        DOMAIN_RUSSIAN: 'www.lastfm.ru',
                        DOMAIN_JAPANESE: 'www.lastfm.jp',
                        DOMAIN_CHINESE: 'cn.last.fm',
                        },
                    urls = {
                        "album": "music/%(artist)s/%(album)s",
                        "artist": "music/%(artist)s",
                        "event": "event/%(id)s",
                        "country": "place/%(country_name)s",
                        "playlist": "user/%(user)s/library/playlists/%(appendix)s",
                        "tag": "tag/%(name)s",
                        "track": "music/%(artist)s/_/%(title)s",
                        "group": "group/%(name)s",
                        "user": "user/%(name)s",
                        }
                )
    
    def __repr__(self):
        return "pylast.LastFMNetwork(%s)" %(", ".join(("'%s'" %self.api_key, "'%s'" %self.api_secret, "'%s'" %self.session_key, 
            "'%s'" %self.username, "'%s'" %self.password_hash)))
    
    def __str__(self):
        return "LastFM Network"

def get_lastfm_network(api_key="", api_secret="", session_key = "", username = "", password_hash = ""):
    """
    Returns a preconfigured _Network object for Last.fm
    
    api_key: a provided API_KEY
    api_secret: a provided API_SECRET
    session_key: a generated session_key or None
    username: a username of a valid user
    password_hash: the output of pylast.md5(password) where password is the user's password
    
    if username and password_hash were provided and not session_key, session_key will be
    generated automatically when needed.
            
    Either a valid session_key or a combination of username and password_hash must be present for scrobbling.
    
    Most read-only webservices only require an api_key and an api_secret, see about obtaining them from:
    http://www.last.fm/api/account
    """
    
    _deprecation_warning("Create a LastFMNetwork object instead")
    
    return LastFMNetwork(api_key, api_secret, session_key, username, password_hash)

class LibreFMNetwork(_Network):
    """
    A preconfigured _Network object for Libre.fm
    
    api_key: a provided API_KEY
    api_secret: a provided API_SECRET
    session_key: a generated session_key or None
    username: a username of a valid user
    password_hash: the output of pylast.md5(password) where password is the user's password
    
    if username and password_hash were provided and not session_key, session_key will be
    generated automatically when needed.
    """
    
    def __init__(self, api_key="", api_secret="", session_key = "", username = "", password_hash = ""):
        
        _Network.__init__(self,
                    name = "Libre.fm",
                    homepage = "http://alpha.dev.libre.fm",
                    ws_server = ("alpha.dev.libre.fm", "/2.0/"),
                    api_key = api_key,
                    api_secret = api_secret,
                    session_key = session_key,
                    submission_server = "http://turtle.libre.fm:80/",
                    username = username,
                    password_hash = password_hash,
                    domain_names = {
                        DOMAIN_ENGLISH: "alpha.dev.libre.fm",
                        DOMAIN_GERMAN: "alpha.dev.libre.fm",
                        DOMAIN_SPANISH: "alpha.dev.libre.fm",
                        DOMAIN_FRENCH: "alpha.dev.libre.fm",
                        DOMAIN_ITALIAN: "alpha.dev.libre.fm",
                        DOMAIN_POLISH: "alpha.dev.libre.fm",
                        DOMAIN_PORTUGUESE: "alpha.dev.libre.fm",
                        DOMAIN_SWEDISH: "alpha.dev.libre.fm",
                        DOMAIN_TURKISH: "alpha.dev.libre.fm",
                        DOMAIN_RUSSIAN: "alpha.dev.libre.fm",
                        DOMAIN_JAPANESE: "alpha.dev.libre.fm",
                        DOMAIN_CHINESE: "alpha.dev.libre.fm",
                        },
                    urls = {
                        "album": "artist/%(artist)s/album/%(album)s",
                        "artist": "artist/%(artist)s",
                        "event": "event/%(id)s",
                        "country": "place/%(country_name)s",
                        "playlist": "user/%(user)s/library/playlists/%(appendix)s",
                        "tag": "tag/%(name)s",
                        "track": "music/%(artist)s/_/%(title)s",
                        "group": "group/%(name)s",
                        "user": "user/%(name)s",
                        }
                    )
        
    def __repr__(self):
        return "pylast.LibreFMNetwork(%s)" %(", ".join(("'%s'" %self.api_key, "'%s'" %self.api_secret, "'%s'" %self.session_key, 
            "'%s'" %self.username, "'%s'" %self.password_hash)))
    
    def __str__(self):
        return "Libre.fm Network"

def get_librefm_network(api_key="", api_secret="", session_key = "", username = "", password_hash = ""):
    """
    Returns a preconfigured _Network object for Libre.fm
    
    api_key: a provided API_KEY
    api_secret: a provided API_SECRET
    session_key: a generated session_key or None
    username: a username of a valid user
    password_hash: the output of pylast.md5(password) where password is the user's password
    
    if username and password_hash were provided and not session_key, session_key will be
    generated automatically when needed.
    """
    
    _deprecation_warning("DeprecationWarning: Create a LibreFMNetwork object instead")
    
    return LibreFMNetwork(api_key, api_secret, session_key, username, password_hash)

class _ShelfCacheBackend(object):
    """Used as a backend for caching cacheable requests."""
    def __init__(self, file_path = None):
        self.shelf = shelve.open(file_path)
    
    def get_xml(self, key):
        return self.shelf[key]
    
    def set_xml(self, key, xml_string):
        self.shelf[key] = xml_string
    
    def has_key(self, key):
        return key in self.shelf.keys()
    
class _Request(object):
    """Representing an abstract web service operation."""
    
    def __init__(self, network, method_name, params = {}):
        
        self.network = network
        self.params = {}
        
        for key in params:
            self.params[key] = _unicode(params[key])
        
        (self.api_key, self.api_secret, self.session_key) = network._get_ws_auth()
        
        self.params["api_key"] = self.api_key
        self.params["method"] = method_name
        
        if network.is_caching_enabled():
            self.cache = network._get_cache_backend()
        
        if self.session_key:
            self.params["sk"] = self.session_key
            self.sign_it()
    
    def sign_it(self):
        """Sign this request."""
        
        if not "api_sig" in self.params.keys():
            self.params['api_sig'] = self._get_signature()
    
    def _get_signature(self):
        """Returns a 32-character hexadecimal md5 hash of the signature string."""
        
        keys = list(self.params.keys())
        
        keys.sort()
        
        string = ""
        
        for name in keys:
            string += name
            string += self.params[name]
        
        string += self.api_secret
        
        return md5(string)
    
    def _get_cache_key(self):
        """The cache key is a string of concatenated sorted names and values."""
        
        keys = list(self.params.keys())
        keys.sort()
        
        cache_key = str()
        
        for key in keys:
            if key != "api_sig" and key != "api_key" and key != "sk":
                cache_key += key + _string(self.params[key])
        
        return hashlib.sha1(cache_key).hexdigest()
    
    def _get_cached_response(self):
        """Returns a file object of the cached response."""
        
        if not self._is_cached():
            response = self._download_response()
            self.cache.set_xml(self._get_cache_key(), response)
        
        return self.cache.get_xml(self._get_cache_key())
    
    def _is_cached(self):
        """Returns True if the request is already in cache."""
        
        return self.cache.has_key(self._get_cache_key())
        
    def _download_response(self):
        """Returns a response body string from the server."""
        
        # Delay the call if necessary
        if self.network.limit_rate:
            self.network._delay_call()
        
        data = []
        for name in self.params.keys():
            data.append('='.join((name, url_quote_plus(_string(self.params[name])))))
        data = '&'.join(data)
        
        headers = {
            "Content-type": "application/x-www-form-urlencoded",
            'Accept-Charset': 'utf-8',
            'User-Agent': "pylast" + '/' + __version__
            }        
        
        (HOST_NAME, HOST_SUBDIR) = self.network.ws_server
        
        if self.network.is_proxy_enabled():
            conn = HTTPConnection(host = self._get_proxy()[0], port = self._get_proxy()[1])
            
            try:
                conn.request(method='POST', url="http://" + HOST_NAME + HOST_SUBDIR, 
                    body=data, headers=headers)
            except Exception as e:
                raise NetworkError(self.network, e)
                
        else:
            conn = HTTPConnection(host=HOST_NAME)
            
            try:
                conn.request(method='POST', url=HOST_SUBDIR, body=data, headers=headers)
            except Exception as e:
                raise NetworkError(self.network, e)
        
        try:
            response_text = _unicode(conn.getresponse().read())
        except Exception as e:
            raise MalformedResponseError(self.network, e)
        
        self._check_response_for_errors(response_text)
        return response_text
        
    def execute(self, cacheable = False):
        """Returns the XML DOM response of the POST Request from the server"""
        
        if self.network.is_caching_enabled() and cacheable:
            response = self._get_cached_response()
        else:
            response = self._download_response()
        
        return minidom.parseString(_string(response))
    
    def _check_response_for_errors(self, response):
        """Checks the response for errors and raises one if any exists."""
        
        try:
            doc = minidom.parseString(_string(response))
        except Exception as e:
            raise MalformedResponseError(self.network, e)
            
        e = doc.getElementsByTagName('lfm')[0]
        
        if e.getAttribute('status') != "ok":
            e = doc.getElementsByTagName('error')[0]
            status = e.getAttribute('code')
            details = e.firstChild.data.strip()
            raise WSError(self.network, status, details)

class SessionKeyGenerator(object):
    """Methods of generating a session key:
    1) Web Authentication:
        a. network = get_*_network(API_KEY, API_SECRET)
        b. sg = SessionKeyGenerator(network)
        c. url = sg.get_web_auth_url()
        d. Ask the user to open the url and authorize you, and wait for it.
        e. session_key = sg.get_web_auth_session_key(url)
    2) Username and Password Authentication:
        a. network = get_*_network(API_KEY, API_SECRET)
        b. username = raw_input("Please enter your username: ")
        c. password_hash = pylast.md5(raw_input("Please enter your password: ")
        d. session_key = SessionKeyGenerator(network).get_session_key(username, password_hash)
    
    A session key's lifetime is infinie, unless the user provokes the rights of the given API Key.
    
    If you create a Network object with just a API_KEY and API_SECRET and a username and a password_hash, a
    SESSION_KEY will be automatically generated for that network and stored in it so you don't have to do this
    manually, unless you want to.
    """
    
    def __init__(self, network):        
        self.network = network
        self.web_auth_tokens = {}
    
    def _get_web_auth_token(self):
        """Retrieves a token from the network for web authentication.
        The token then has to be authorized from getAuthURL before creating session.
        """
        
        request = _Request(self.network, 'auth.getToken')
        
        # default action is that a request is signed only when
        # a session key is provided.
        request.sign_it()
        
        doc = request.execute()
        
        e = doc.getElementsByTagName('token')[0]
        return e.firstChild.data
    
    def get_web_auth_url(self):
        """The user must open this page, and you first, then call get_web_auth_session_key(url) after that."""
        
        token = self._get_web_auth_token()
        
        url = '%(homepage)s/api/auth/?api_key=%(api)s&token=%(token)s' % \
            {"homepage": self.network.homepage, "api": self.network.api_key, "token": token}
        
        self.web_auth_tokens[url] = token
        
        return url

    def get_web_auth_session_key(self, url):
        """Retrieves the session key of a web authorization process by its url."""
        
        if url in self.web_auth_tokens.keys():
            token = self.web_auth_tokens[url]
        else:
            token = ""    #that's gonna raise a WSError of an unauthorized token when the request is executed.
        
        request = _Request(self.network, 'auth.getSession', {'token': token})
        
        # default action is that a request is signed only when
        # a session key is provided.
        request.sign_it()
        
        doc = request.execute()
        
        return doc.getElementsByTagName('key')[0].firstChild.data
    
    def get_session_key(self, username, password_hash):
        """Retrieve a session key with a username and a md5 hash of the user's password."""
        
        params = {"username": username, "authToken": md5(username + password_hash)}
        request = _Request(self.network, "auth.getMobileSession", params)
        
        # default action is that a request is signed only when
        # a session key is provided.
        request.sign_it()
        
        doc = request.execute()
        
        return _extract(doc, "key")

TopItem = collections.namedtuple("TopItem", ["item", "weight"])
SimilarItem = collections.namedtuple("SimilarItem", ["item", "match"])
LibraryItem = collections.namedtuple("LibraryItem", ["item", "playcount", "tagcount"])
PlayedTrack = collections.namedtuple("PlayedTrack", ["track", "playback_date", "timestamp"])
LovedTrack = collections.namedtuple("LovedTrack", ["track", "date", "timestamp"])
ImageSizes = collections.namedtuple("ImageSizes", ["original", "large", "largesquare", "medium", "small", "extralarge"])
Image = collections.namedtuple("Image", ["title", "url", "dateadded", "format", "owner", "sizes", "votes"])
Shout = collections.namedtuple("Shout", ["body", "author", "date"])

def _string_output(funct):
    def r(*args):
        return _string(funct(*args))
        
    return r

def _pad_list(given_list, desired_length, padding = None):
    """
        Pads a list to be of the desired_length.
    """
    
    while len(given_list) < desired_length:
        given_list.append(padding)
    
    return given_list

class _BaseObject(object):
    """An abstract webservices object."""
    
    network = None
    
    def __init__(self, network):
        self.network = network
    
    def _request(self, method_name, cacheable = False, params = None):
        if not params:
            params = self._get_params()
            
        return _Request(self.network, method_name, params).execute(cacheable)
    
    def _get_params(self):
        """Returns the most common set of parameters between all objects."""
        
        return {}
    
    def __hash__(self):
        return hash(self.network) + \
            hash(str(type(self)) + "".join(list(self._get_params().keys()) + list(self._get_params().values())).lower())

class _Taggable(object):
    """Common functions for classes with tags."""
    
    def __init__(self, ws_prefix):
        self.ws_prefix = ws_prefix
    
    def add_tags(self, tags):
        """Adds one or several tags.
        * tags: A sequence of tag names or Tag objects.
        """
        
        for tag in tags:
            self.add_tag(tag)
    
    def add_tag(self, tag):
        """Adds one tag.
        * tag: a tag name or a Tag object.
        """
        
        if isinstance(tag, Tag):
            tag = tag.get_name()
        
        params = self._get_params()
        params['tags'] = tag
        
        self._request(self.ws_prefix + '.addTags', False, params)
    
    def remove_tag(self, tag):
        """Remove a user's tag from this object."""
        
        if isinstance(tag, Tag):
            tag = tag.get_name()
        
        params = self._get_params()
        params['tag'] = tag
        
        self._request(self.ws_prefix + '.removeTag', False, params)

    def get_tags(self):
        """Returns a list of the tags set by the user to this object."""
        
        # Uncacheable because it can be dynamically changed by the user.
        params = self._get_params()
        
        doc = self._request(self.ws_prefix + '.getTags', False, params)
        tag_names = _extract_all(doc, 'name')
        tags = []
        for tag in tag_names:
            tags.append(Tag(tag, self.network))
        
        return tags
    
    def remove_tags(self, tags):
        """Removes one or several tags from this object.
        * tags: a sequence of tag names or Tag objects.
        """
        
        for tag in tags:
            self.remove_tag(tag)
    
    def clear_tags(self):
        """Clears all the user-set tags. """
        
        self.remove_tags(*(self.get_tags()))
    
    def set_tags(self, tags):
        """Sets this object's tags to only those tags.
        * tags: a sequence of tag names or Tag objects.
        """
        
        c_old_tags = []
        old_tags = []
        c_new_tags = []
        new_tags = []
        
        to_remove = []
        to_add = []
        
        tags_on_server = self.get_tags()
        
        for tag in tags_on_server:
            c_old_tags.append(tag.get_name().lower())
            old_tags.append(tag.get_name())
        
        for tag in tags:
            c_new_tags.append(tag.lower())
            new_tags.append(tag)
        
        for i in range(0, len(old_tags)):
            if not c_old_tags[i] in c_new_tags:
                to_remove.append(old_tags[i])
        
        for i in range(0, len(new_tags)):
            if not c_new_tags[i] in c_old_tags:
                to_add.append(new_tags[i])
        
        self.remove_tags(to_remove)
        self.add_tags(to_add)
        
    def get_top_tags(self, limit=None):
        """Returns a list of the most frequently used Tags on this object."""
        
        doc = self._request(self.ws_prefix + '.getTopTags', True)
        
        elements = doc.getElementsByTagName('tag')
        seq = []
        
        for element in elements:
            tag_name = _extract(element, 'name')
            tagcount = _extract(element, 'count')
            
            seq.append(TopItem(Tag(tag_name, self.network), tagcount))
        
        if limit:
            seq = seq[:limit]
        
        return seq
        
class WSError(Exception):
    """Exception related to the Network web service"""
    
    def __init__(self, network, status, details):
        self.status = status
        self.details = details
        self.network = network

    @_string_output
    def __str__(self):
        return self.details
    
    def get_id(self):
        """Returns the exception ID, from one of the following:
            STATUS_INVALID_SERVICE = 2
            STATUS_INVALID_METHOD = 3
            STATUS_AUTH_FAILED = 4
            STATUS_INVALID_FORMAT = 5
            STATUS_INVALID_PARAMS = 6
            STATUS_INVALID_RESOURCE = 7
            STATUS_TOKEN_ERROR = 8
            STATUS_INVALID_SK = 9
            STATUS_INVALID_API_KEY = 10
            STATUS_OFFLINE = 11
            STATUS_SUBSCRIBERS_ONLY = 12
            STATUS_TOKEN_UNAUTHORIZED = 14
            STATUS_TOKEN_EXPIRED = 15
        """
        
        return self.status

class MalformedResponseError(Exception):
    """Exception conveying a malformed response from Last.fm."""
    
    def __init__(self, network, underlying_error):
        self.network = network
        self.underlying_error = underlying_error
    
    def __str__(self):
        return "Malformed response from Last.fm. Underlying error: %s" %str(self.underlying_error)

class NetworkError(Exception):
    """Exception conveying a problem in sending a request to Last.fm"""
    
    def __init__(self, network, underlying_error):
        self.network = network
        self.underlying_error = underlying_error
    
    def __str__(self):
        return "NetworkError: %s" %str(self.underlying_error)

class Album(_BaseObject, _Taggable):
    """An album."""
    
    title = None
    artist = None
    
    def __init__(self, artist, title, network):
        """
        Create an album instance.
        # Parameters:
            * artist: An artist name or an Artist object.
            * title: The album title.
        """
        
        _BaseObject.__init__(self, network)
        _Taggable.__init__(self, 'album')
        
        if isinstance(artist, Artist):
            self.artist = artist
        else:
            self.artist = Artist(artist, self.network)
        
        self.title = title
    
    def __repr__(self):
        return "pylast.Album(%s, %s, %s)" %(repr(self.artist.name), repr(self.title), repr(self.network))

    @_string_output
    def __str__(self):
        return _unicode("%s - %s") %(self.get_artist().get_name(), self.get_title())
    
    def __eq__(self, other):
        return (self.get_title().lower() == other.get_title().lower()) and (self.get_artist().get_name().lower() == other.get_artist().get_name().lower())
    
    def __ne__(self, other):
        return (self.get_title().lower() != other.get_title().lower()) or (self.get_artist().get_name().lower() != other.get_artist().get_name().lower())
    
    def _get_params(self):
        return {'artist': self.get_artist().get_name(), 'album': self.get_title(), }
    
    def get_artist(self):
        """Returns the associated Artist object."""
        
        return self.artist
    
    def get_title(self):
        """Returns the album title."""
        
        return self.title
    
    def get_name(self):
        """Returns the album title (alias to Album.get_title)."""
        
        return self.get_title()
    
    def get_release_date(self):
        """Retruns the release date of the album."""
        
        return _extract(self._request("album.getInfo", cacheable = True), "releasedate")
    
    def get_cover_image(self, size = COVER_EXTRA_LARGE):
        """
        Returns a uri to the cover image
        size can be one of:
            COVER_EXTRA_LARGE
            COVER_LARGE
            COVER_MEDIUM
            COVER_SMALL
        """
        
        return _extract_all(self._request("album.getInfo", cacheable = True), 'image')[size]
    
    def get_id(self):
        """Returns the ID"""
        
        return _extract(self._request("album.getInfo", cacheable = True), "id")
    
    def get_playcount(self):
        """Returns the number of plays on the network"""
        
        return _number(_extract(self._request("album.getInfo", cacheable = True), "playcount"))
    
    def get_listener_count(self):
        """Returns the number of liteners on the network"""
        
        return _number(_extract(self._request("album.getInfo", cacheable = True), "listeners"))
    
    def get_top_tags(self, limit=None):
        """Returns a list of the most-applied tags to this album."""
        
        doc = self._request("album.getInfo", True)
        e = doc.getElementsByTagName("toptags")[0]
        
        seq = []
        for name in _extract_all(e, "name"):
            seq.append(Tag(name, self.network))
        
        if limit:
            seq = seq[:limit]
        
        return seq

    def get_tracks(self):
        """Returns the list of Tracks on this album."""
        
        uri = 'lastfm://playlist/album/%s' %self.get_id()
        
        return XSPF(uri, self.network).get_tracks()
    
    def get_mbid(self):
        """Returns the MusicBrainz id of the album."""
        
        return _extract(self._request("album.getInfo", cacheable = True), "mbid")
        
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the album page on the network. 
        # Parameters:
        * domain_name str: The network's language domain. Possible values:
            o DOMAIN_ENGLISH
            o DOMAIN_GERMAN
            o DOMAIN_SPANISH
            o DOMAIN_FRENCH
            o DOMAIN_ITALIAN
            o DOMAIN_POLISH
            o DOMAIN_PORTUGUESE
            o DOMAIN_SWEDISH
            o DOMAIN_TURKISH
            o DOMAIN_RUSSIAN
            o DOMAIN_JAPANESE
            o DOMAIN_CHINESE
        """
        
        artist = _url_safe(self.get_artist().get_name())
        album = _url_safe(self.get_title())
        
        return self.network._get_url(domain_name, "album") %{'artist': artist, 'album': album}
    
    def get_wiki_published_date(self):
        """Returns the date of publishing this version of the wiki."""
        
        doc = self._request("album.getInfo", True)
        
        if len(doc.getElementsByTagName("wiki")) == 0:
            return
        
        node = doc.getElementsByTagName("wiki")[0]
        
        return _extract(node, "published")
    
    def get_wiki_summary(self):
        """Returns the summary of the wiki."""
        
        doc = self._request("album.getInfo", True)
        
        if len(doc.getElementsByTagName("wiki")) == 0:
            return
        
        node = doc.getElementsByTagName("wiki")[0]
        
        return _extract(node, "summary")
    
    def get_wiki_content(self):
        """Returns the content of the wiki."""
        
        doc = self._request("album.getInfo", True)
        
        if len(doc.getElementsByTagName("wiki")) == 0:
            return
        
        node = doc.getElementsByTagName("wiki")[0]
        
        return _extract(node, "content")

class Artist(_BaseObject, _Taggable):
    """An artist."""
    
    name = None
    
    def __init__(self, name, network):
        """Create an artist object.
        # Parameters:
            * name str: The artist's name.
        """
        
        _BaseObject.__init__(self, network)
        _Taggable.__init__(self, 'artist')
        
        self.name = name
    
    def __repr__(self):
        return "pylast.Artist(%s, %s)" %(repr(self.get_name()), repr(self.network))
    
    @_string_output
    def __str__(self):
        return self.get_name()
    
    def __eq__(self, other):
        return self.get_name().lower() == other.get_name().lower()
    
    def __ne__(self, other):
        return self.get_name().lower() != other.get_name().lower()
    
    def _get_params(self):
        return {'artist': self.get_name()}
    
    def get_name(self, properly_capitalized=False):
        """Returns the name of the artist.
        If properly_capitalized was asserted then the name would be downloaded
        overwriting the given one."""
        
        if properly_capitalized:
            self.name = _extract(self._request("artist.getInfo", True), "name")
        
        return self.name
    
    def get_cover_image(self, size = COVER_MEGA):
        """
        Returns a uri to the cover image
        size can be one of:
            COVER_MEGA
            COVER_EXTRA_LARGE
            COVER_LARGE
            COVER_MEDIUM
            COVER_SMALL
        """
        
        return _extract_all(self._request("artist.getInfo", True), "image")[size]
    
    def get_playcount(self):
        """Returns the number of plays on the network."""
        
        return _number(_extract(self._request("artist.getInfo", True), "playcount"))

    def get_mbid(self):
        """Returns the MusicBrainz ID of this artist."""
        
        doc = self._request("artist.getInfo", True)
        
        return _extract(doc, "mbid")
        
    def get_listener_count(self):
        """Returns the number of liteners on the network."""
        
        if hasattr(self, "listener_count"):
            return self.listener_count
        else:
            self.listener_count = _number(_extract(self._request("artist.getInfo", True), "listeners"))
            return self.listener_count
    
    def is_streamable(self):
        """Returns True if the artist is streamable."""
        
        return bool(_number(_extract(self._request("artist.getInfo", True), "streamable")))
    
    def get_bio_published_date(self):
        """Returns the date on which the artist's biography was published."""
        
        return _extract(self._request("artist.getInfo", True), "published")
    
    def get_bio_summary(self, language=None):
        """Returns the summary of the artist's biography."""

        if language:
            params = self._get_params()
            params["lang"] = language
        else:
            params = None
        
        return _extract(self._request("artist.getInfo", True, params), "summary")
    
    def get_bio_content(self, language=None):
        """Returns the content of the artist's biography."""
        
        if language:
            params = self._get_params()
            params["lang"] = language
        else:
            params = None
        
        return _extract(self._request("artist.getInfo", True, params), "content")
    
    def get_upcoming_events(self):
        """Returns a list of the upcoming Events for this artist."""
        
        doc = self._request('artist.getEvents', True)
        
        ids = _extract_all(doc, 'id')
        
        events = []
        for e_id in ids:
            events.append(Event(e_id, self.network))
        
        return events
    
    def get_similar(self, limit = None):
        """Returns the similar artists on the network."""
        
        params = self._get_params()
        if limit:
            params['limit'] = limit
        
        doc = self._request('artist.getSimilar', True, params)
        
        names = _extract_all(doc, "name")
        matches = _extract_all(doc, "match")
        
        artists = []
        for i in range(0, len(names)):
            artists.append(SimilarItem(Artist(names[i], self.network), _number(matches[i])))
        
        return artists

    def get_top_albums(self):
        """Retuns a list of the top albums."""
        
        doc = self._request('artist.getTopAlbums', True)
        
        seq = []
        
        for node in doc.getElementsByTagName("album"):
            name = _extract(node, "name")
            artist = _extract(node, "name", 1)
            playcount = _extract(node, "playcount")
            
            seq.append(TopItem(Album(artist, name, self.network), playcount))
        
        return seq
        
    def get_top_tracks(self):
        """Returns a list of the most played Tracks by this artist."""
        
        doc = self._request("artist.getTopTracks", True)
        
        seq = []
        for track in doc.getElementsByTagName('track'):
            
            title = _extract(track, "name")
            artist = _extract(track, "name", 1)
            playcount = _number(_extract(track, "playcount"))
            
            seq.append( TopItem(Track(artist, title, self.network), playcount) )
        
        return seq
    
    def get_top_fans(self, limit = None):
        """Returns a list of the Users who played this artist the most.
        # Parameters:
            * limit int: Max elements.
        """
        
        doc = self._request('artist.getTopFans', True)
        
        seq = []
        
        elements = doc.getElementsByTagName('user')
        
        for element in elements:
            if limit and len(seq) >= limit:
                break
                
            name = _extract(element, 'name')
            weight = _number(_extract(element, 'weight'))
            
            seq.append(TopItem(User(name, self.network), weight))
        
        return seq

    def share(self, users, message = None):
        """Shares this artist (sends out recommendations). 
        # Parameters:
            * users [User|str,]: A list that can contain usernames, emails, User objects, or all of them.
            * message str: A message to include in the recommendation message. 
        """
        
        #last.fm currently accepts a max of 10 recipient at a time
        while(len(users) > 10):
            section = users[0:9]
            users = users[9:]
            self.share(section, message)
        
        nusers = []
        for user in users:
            if isinstance(user, User):
                nusers.append(user.get_name())
            else:
                nusers.append(user)
        
        params = self._get_params()
        recipients = ','.join(nusers)
        params['recipient'] = recipients
        if message:
            params['message'] = message
        
        self._request('artist.share', False, params)
    
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the artist page on the network. 
        # Parameters:
        * domain_name: The network's language domain. Possible values:
          o DOMAIN_ENGLISH
          o DOMAIN_GERMAN
          o DOMAIN_SPANISH
          o DOMAIN_FRENCH
          o DOMAIN_ITALIAN
          o DOMAIN_POLISH
          o DOMAIN_PORTUGUESE
          o DOMAIN_SWEDISH
          o DOMAIN_TURKISH
          o DOMAIN_RUSSIAN
          o DOMAIN_JAPANESE
          o DOMAIN_CHINESE 
        """
        
        artist = _url_safe(self.get_name())
        
        return self.network._get_url(domain_name, "artist") %{'artist': artist}
    
    def get_images(self, order=IMAGES_ORDER_POPULARITY, limit=None):
        """
            Returns a sequence of Image objects
            if limit is None it will return all
            order can be IMAGES_ORDER_POPULARITY or IMAGES_ORDER_DATE.
            
            If limit==None, it will try to pull all the available data.
        """
        
        images = []
        
        params = self._get_params()
        params["order"] = order
        nodes = _collect_nodes(limit, self, "artist.getImages", True, params)
        for e in nodes:
            if _extract(e, "name"):
                user = User(_extract(e, "name"), self.network)
            else:
                user = None
                
            images.append(Image(
                            _extract(e, "title"),
                            _extract(e, "url"),
                            _extract(e, "dateadded"),
                            _extract(e, "format"),
                            user,
                            ImageSizes(*_extract_all(e, "size")),
                            (_extract(e, "thumbsup"), _extract(e, "thumbsdown"))
                            )
                        )
        return images

    def get_shouts(self, limit=50):
        """
            Returns a sequqence of Shout objects
        """
        
        shouts = []
        for node in _collect_nodes(limit, self, "artist.getShouts", False):
            shouts.append(Shout(
                                _extract(node, "body"),
                                User(_extract(node, "author"), self.network),
                                _extract(node, "date")
                                )
                            )
        return shouts
    
    def shout(self, message):
        """
            Post a shout
        """
        
        params = self._get_params()
        params["message"] = message
        
        self._request("artist.Shout", False, params)
        

class Event(_BaseObject):
    """An event."""
    
    id = None
    
    def __init__(self, event_id, network):
        _BaseObject.__init__(self, network)
        
        self.id = event_id
    
    def __repr__(self):
        return "pylast.Event(%s, %s)" %(repr(self.id), repr(self.network))
    
    @_string_output
    def __str__(self):
        return "Event #" + self.get_id()
    
    def __eq__(self, other):
        return self.get_id() == other.get_id()
    
    def __ne__(self, other):
        return self.get_id() != other.get_id()
    
    def _get_params(self):
        return {'event': self.get_id()}
    
    def attend(self, attending_status):
        """Sets the attending status.
        * attending_status: The attending status. Possible values:
          o EVENT_ATTENDING
          o EVENT_MAYBE_ATTENDING
          o EVENT_NOT_ATTENDING 
        """
        
        params = self._get_params()
        params['status'] = attending_status
        
        self._request('event.attend', False, params)
    
    def get_attendees(self):
        """
            Get a list of attendees for an event
        """
        
        doc = self._request("event.getAttendees", False)
        
        users = []
        for name in _extract_all(doc, "name"):
            users.append(User(name, self.network))
        
        return users
        
    def get_id(self):
        """Returns the id of the event on the network. """
        
        return self.id
    
    def get_title(self):
        """Returns the title of the event. """
        
        doc = self._request("event.getInfo", True)
        
        return _extract(doc, "title")
    
    def get_headliner(self):
        """Returns the headliner of the event. """
        
        doc = self._request("event.getInfo", True)
        
        return Artist(_extract(doc, "headliner"), self.network)
    
    def get_artists(self):
        """Returns a list of the participating Artists. """
        
        doc = self._request("event.getInfo", True)
        names = _extract_all(doc, "artist")
        
        artists = []
        for name in names:
            artists.append(Artist(name, self.network))
        
        return artists
    
    def get_venue(self):
        """Returns the venue where the event is held."""
        
        doc = self._request("event.getInfo", True)
        
        v = doc.getElementsByTagName("venue")[0]
        venue_id = _number(_extract(v, "id"))
        
        return Venue(venue_id, self.network)
    
    def get_start_date(self):
        """Returns the date when the event starts."""
        
        doc = self._request("event.getInfo", True)
        
        return _extract(doc, "startDate")
        
    def get_description(self):
        """Returns the description of the event. """
        
        doc = self._request("event.getInfo", True)
        
        return _extract(doc, "description")
    
    def get_cover_image(self, size = COVER_MEGA):
        """
        Returns a uri to the cover image
        size can be one of:
            COVER_MEGA
            COVER_EXTRA_LARGE
            COVER_LARGE
            COVER_MEDIUM
            COVER_SMALL
        """
        
        doc = self._request("event.getInfo", True)
        
        return _extract_all(doc, "image")[size]
    
    def get_attendance_count(self):
        """Returns the number of attending people. """
        
        doc = self._request("event.getInfo", True)
        
        return _number(_extract(doc, "attendance"))
    
    def get_review_count(self):
        """Returns the number of available reviews for this event. """
        
        doc = self._request("event.getInfo", True)
        
        return _number(_extract(doc, "reviews"))
    
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the event page on the network. 
        * domain_name: The network's language domain. Possible values:
          o DOMAIN_ENGLISH
          o DOMAIN_GERMAN
          o DOMAIN_SPANISH
          o DOMAIN_FRENCH
          o DOMAIN_ITALIAN
          o DOMAIN_POLISH
          o DOMAIN_PORTUGUESE
          o DOMAIN_SWEDISH
          o DOMAIN_TURKISH
          o DOMAIN_RUSSIAN
          o DOMAIN_JAPANESE
          o DOMAIN_CHINESE 
        """
        
        return self.network._get_url(domain_name, "event") %{'id': self.get_id()}

    def share(self, users, message = None):
        """Shares this event (sends out recommendations). 
          * users: A list that can contain usernames, emails, User objects, or all of them.
          * message: A message to include in the recommendation message. 
        """
        
        #last.fm currently accepts a max of 10 recipient at a time
        while(len(users) > 10):
            section = users[0:9]
            users = users[9:]
            self.share(section, message)
        
        nusers = []
        for user in users:
            if isinstance(user, User):
                nusers.append(user.get_name())
            else:
                nusers.append(user)
        
        params = self._get_params()
        recipients = ','.join(nusers)
        params['recipient'] = recipients
        if message:
            params['message'] = message
        
        self._request('event.share', False, params)

    def get_shouts(self, limit=50):
        """
            Returns a sequqence of Shout objects
        """
        
        shouts = []
        for node in _collect_nodes(limit, self, "event.getShouts", False):
            shouts.append(Shout(
                                _extract(node, "body"),
                                User(_extract(node, "author"), self.network),
                                _extract(node, "date")
                                )
                            )
        return shouts
    
    def shout(self, message):
        """
            Post a shout
        """
        
        params = self._get_params()
        params["message"] = message
        
        self._request("event.Shout", False, params)
        
class Country(_BaseObject):
    """A country at Last.fm."""
    
    name = None
    
    def __init__(self, name, network):
        _BaseObject.__init__(self, network)
        
        self.name = name
    
    def __repr__(self):
        return "pylast.Country(%s, %s)" %(repr(self.name), repr(self.network))
    
    @_string_output
    def __str__(self):
        return self.get_name()
    
    def __eq__(self, other):
        return self.get_name().lower() == other.get_name().lower()
    
    def __ne__(self, other):
        return self.get_name() != other.get_name()
    
    def _get_params(self):
        return {'country': self.get_name()}
    
    def _get_name_from_code(self, alpha2code):
        # TODO: Have this function lookup the alpha-2 code and return the country name.
        
        return alpha2code
    
    def get_name(self):
        """Returns the country name. """
        
        return self.name
    
    def get_top_artists(self):
        """Returns a sequence of the most played artists."""
        
        doc = self._request('geo.getTopArtists', True)
        
        seq = []
        for node in doc.getElementsByTagName("artist"):
            name = _extract(node, 'name')
            playcount = _extract(node, "playcount")
        
            seq.append(TopItem(Artist(name, self.network), playcount))
        
        return seq
    
    def get_top_tracks(self):
        """Returns a sequence of the most played tracks"""
        
        doc = self._request("geo.getTopTracks", True)
        
        seq = []
        
        for n in doc.getElementsByTagName('track'):
            
            title = _extract(n, 'name')
            artist = _extract(n, 'name', 1)
            playcount = _number(_extract(n, "playcount"))
            
            seq.append( TopItem(Track(artist, title, self.network), playcount))
        
        return seq
    
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the event page on the network. 
        * domain_name: The network's language domain. Possible values:
          o DOMAIN_ENGLISH
          o DOMAIN_GERMAN
          o DOMAIN_SPANISH
          o DOMAIN_FRENCH
          o DOMAIN_ITALIAN
          o DOMAIN_POLISH
          o DOMAIN_PORTUGUESE
          o DOMAIN_SWEDISH
          o DOMAIN_TURKISH
          o DOMAIN_RUSSIAN
          o DOMAIN_JAPANESE
          o DOMAIN_CHINESE 
        """
        
        country_name = _url_safe(self.get_name())
        
        return self.network._get_url(domain_name, "country") %{'country_name': country_name}


class Library(_BaseObject):
    """A user's Last.fm library."""
    
    user = None
    
    def __init__(self, user, network):
        _BaseObject.__init__(self, network)
        
        if isinstance(user, User):
            self.user = user
        else:
            self.user = User(user, self.network)
        
        self._albums_index = 0
        self._artists_index = 0
        self._tracks_index = 0
    
    def __repr__(self):
        return "pylast.Library(%s, %s)" %(repr(self.user), repr(self.network))
    
    @_string_output
    def __str__(self):
        return repr(self.get_user()) + "'s Library"
    
    def _get_params(self):
        return {'user': self.user.get_name()}
    
    def get_user(self):
        """Returns the user who owns this library."""
        
        return self.user
    
    def add_album(self, album):
        """Add an album to this library."""
        
        params = self._get_params()
        params["artist"] = album.get_artist.get_name()
        params["album"] = album.get_name()
        
        self._request("library.addAlbum", False, params)
    
    def add_artist(self, artist):
        """Add an artist to this library."""
        
        params = self._get_params()
        params["artist"] = artist.get_name()
        
        self._request("library.addArtist", False, params)
    
    def add_track(self, track):
        """Add a track to this library."""
        
        params = self._get_params()
        params["track"] = track.get_title()
        
        self._request("library.addTrack", False, params)
    
    def get_albums(self, artist=None, limit=50):
        """
        Returns a sequence of Album objects
        If no artist is specified, it will return all, sorted by playcount descendingly.
        If limit==None it will return all (may take a while)
        """
        
        params = self._get_params()
        if artist:
            params["artist"] = artist
        
        seq = []
        for node in _collect_nodes(limit, self, "library.getAlbums", True, params):
            name = _extract(node, "name")
            artist = _extract(node, "name", 1)
            playcount = _number(_extract(node, "playcount"))
            tagcount = _number(_extract(node, "tagcount"))
            
            seq.append(LibraryItem(Album(artist, name, self.network), playcount, tagcount))
        
        return seq
    
    def get_artists(self, limit=50):
        """
        Returns a sequence of Album objects
        if limit==None it will return all (may take a while)
        """
        
        seq = []
        for node in _collect_nodes(limit, self, "library.getArtists", True):
            name = _extract(node, "name")
            
            playcount = _number(_extract(node, "playcount"))
            tagcount = _number(_extract(node, "tagcount"))
            
            seq.append(LibraryItem(Artist(name, self.network), playcount, tagcount))
        
        return seq

    def get_tracks(self, artist=None, album=None, limit=50):
        """
        Returns a sequence of Album objects
        If limit==None it will return all (may take a while)
        """
        
        params = self._get_params()
        if artist:
            params["artist"] = artist
        if album:
            params["album"] = album
        
        seq = []
        for node in _collect_nodes(limit, self, "library.getTracks", True, params):
            name = _extract(node, "name")
            artist = _extract(node, "name", 1)
            playcount = _number(_extract(node, "playcount"))
            tagcount = _number(_extract(node, "tagcount"))
            
            seq.append(LibraryItem(Track(artist, name, self.network), playcount, tagcount))
        
        return seq
            

class Playlist(_BaseObject):
    """A Last.fm user playlist."""
    
    id = None
    user = None
    
    def __init__(self, user, id, network):
        _BaseObject.__init__(self, network)
        
        if isinstance(user, User):
            self.user = user
        else:
            self.user = User(user, self.network)
        
        self.id = id
    
    @_string_output
    def __str__(self):
        return repr(self.user) + "'s playlist # " + repr(self.id)
        
    def _get_info_node(self):
        """Returns the node from user.getPlaylists where this playlist's info is."""
        
        doc = self._request("user.getPlaylists", True)
        
        for node in doc.getElementsByTagName("playlist"):
            if _extract(node, "id") == str(self.get_id()):
                return node
    
    def _get_params(self):
        return {'user': self.user.get_name(), 'playlistID': self.get_id()}
    
    def get_id(self):
        """Returns the playlist id."""
        
        return self.id
    
    def get_user(self):
        """Returns the owner user of this playlist."""
        
        return self.user
    
    def get_tracks(self):
        """Returns a list of the tracks on this user playlist."""
        
        uri = _unicode('lastfm://playlist/%s') %self.get_id()
        
        return XSPF(uri, self.network).get_tracks()
    
    def add_track(self, track):
        """Adds a Track to this Playlist."""
        
        params = self._get_params()
        params['artist'] = track.get_artist().get_name()
        params['track'] = track.get_title()
        
        self._request('playlist.addTrack', False, params)
    
    def get_title(self):
        """Returns the title of this playlist."""
        
        return _extract(self._get_info_node(), "title")
    
    def get_creation_date(self):
        """Returns the creation date of this playlist."""
        
        return _extract(self._get_info_node(), "date")
    
    def get_size(self):
        """Returns the number of tracks in this playlist."""
        
        return _number(_extract(self._get_info_node(), "size"))
    
    def get_description(self):
        """Returns the description of this playlist."""
        
        return _extract(self._get_info_node(), "description")
    
    def get_duration(self):
        """Returns the duration of this playlist in milliseconds."""
        
        return _number(_extract(self._get_info_node(), "duration"))
    
    def is_streamable(self):
        """Returns True if the playlist is streamable.
        For a playlist to be streamable, it needs at least 45 tracks by 15 different artists."""
        
        if _extract(self._get_info_node(), "streamable") == '1':
            return True
        else:
            return False
    
    def has_track(self, track):
        """Checks to see if track is already in the playlist.
        * track: Any Track object.
        """
        
        return track in self.get_tracks()

    def get_cover_image(self, size = COVER_EXTRA_LARGE):
        """
        Returns a uri to the cover image
        size can be one of:
            COVER_MEGA
            COVER_EXTRA_LARGE
            COVER_LARGE
            COVER_MEDIUM
            COVER_SMALL
        """
        
        return _extract(self._get_info_node(), "image")[size]
    
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the playlist on the network. 
        * domain_name: The network's language domain. Possible values:
          o DOMAIN_ENGLISH
          o DOMAIN_GERMAN
          o DOMAIN_SPANISH
          o DOMAIN_FRENCH
          o DOMAIN_ITALIAN
          o DOMAIN_POLISH
          o DOMAIN_PORTUGUESE
          o DOMAIN_SWEDISH
          o DOMAIN_TURKISH
          o DOMAIN_RUSSIAN
          o DOMAIN_JAPANESE
          o DOMAIN_CHINESE 
        """
        
        english_url = _extract(self._get_info_node(), "url")
        appendix = english_url[english_url.rfind("/") + 1:]
        
        return self.network._get_url(domain_name, "playlist") %{'appendix': appendix, "user": self.get_user().get_name()}
        

class Tag(_BaseObject):
    """A Last.fm object tag."""
    
    # TODO: getWeeklyArtistChart (too lazy, i'll wait for when someone requests it)
    
    name = None
    
    def __init__(self, name, network):
        _BaseObject.__init__(self, network)
        
        self.name = name
    
    def __repr__(self):
        return "pylast.Tag(%s, %s)" %(repr(self.name), repr(self.network))
    
    @_string_output
    def __str__(self):
        return self.get_name()
    
    def __eq__(self, other):
        return self.get_name().lower() == other.get_name().lower()
    
    def __ne__(self, other):
        return self.get_name().lower() != other.get_name().lower()
    
    def _get_params(self):
        return {'tag': self.get_name()}
    
    def get_name(self, properly_capitalized=False):
        """Returns the name of the tag. """
        
        if properly_capitalized:
            self.name = _extract(self._request("tag.getInfo", True), "name")
        
        return self.name

    def get_similar(self):
        """Returns the tags similar to this one, ordered by similarity. """
        
        doc = self._request('tag.getSimilar', True)
        
        seq = []
        names = _extract_all(doc, 'name')
        for name in names:
            seq.append(Tag(name, self.network))
        
        return seq
    
    def get_top_albums(self):
        """Retuns a list of the top albums."""
        
        doc = self._request('tag.getTopAlbums', True)
        
        seq = []
        
        for node in doc.getElementsByTagName("album"):
            name = _extract(node, "name")
            artist = _extract(node, "name", 1)
            playcount = _extract(node, "playcount")
            
            seq.append(TopItem(Album(artist, name, self.network), playcount))
        
        return seq
        
    def get_top_tracks(self):
        """Returns a list of the most played Tracks by this artist."""
        
        doc = self._request("tag.getTopTracks", True)
        
        seq = []
        for track in doc.getElementsByTagName('track'):
            
            title = _extract(track, "name")
            artist = _extract(track, "name", 1)
            playcount = _number(_extract(track, "playcount"))
            
            seq.append( TopItem(Track(artist, title, self.network), playcount) )
        
        return seq
    
    def get_top_artists(self):
        """Returns a sequence of the most played artists."""
        
        doc = self._request('tag.getTopArtists', True)
        
        seq = []
        for node in doc.getElementsByTagName("artist"):
            name = _extract(node, 'name')
            playcount = _extract(node, "playcount")
        
            seq.append(TopItem(Artist(name, self.network), playcount))
        
        return seq
    
    def get_weekly_chart_dates(self):
        """Returns a list of From and To tuples for the available charts."""
        
        doc = self._request("tag.getWeeklyChartList", True)
        
        seq = []
        for node in doc.getElementsByTagName("chart"):
            seq.append( (node.getAttribute("from"), node.getAttribute("to")) )
        
        return seq
    
    def get_weekly_artist_charts(self, from_date = None, to_date = None):
        """Returns the weekly artist charts for the week starting from the from_date value to the to_date value."""
        
        params = self._get_params()
        if from_date and to_date:
            params["from"] = from_date
            params["to"] = to_date
        
        doc = self._request("tag.getWeeklyArtistChart", True, params)
        
        seq = []
        for node in doc.getElementsByTagName("artist"):
            item = Artist(_extract(node, "name"), self.network)
            weight = _number(_extract(node, "weight"))
            seq.append(TopItem(item, weight))
        
        return seq
    
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the tag page on the network. 
        * domain_name: The network's language domain. Possible values:
          o DOMAIN_ENGLISH
          o DOMAIN_GERMAN
          o DOMAIN_SPANISH
          o DOMAIN_FRENCH
          o DOMAIN_ITALIAN
          o DOMAIN_POLISH
          o DOMAIN_PORTUGUESE
          o DOMAIN_SWEDISH
          o DOMAIN_TURKISH
          o DOMAIN_RUSSIAN
          o DOMAIN_JAPANESE
          o DOMAIN_CHINESE 
        """
        
        name = _url_safe(self.get_name())
        
        return self.network._get_url(domain_name, "tag") %{'name': name}

class Track(_BaseObject, _Taggable):
    """A Last.fm track."""
    
    artist = None
    title = None
    
    def __init__(self, artist, title, network):
        _BaseObject.__init__(self, network)
        _Taggable.__init__(self, 'track')
        
        if isinstance(artist, Artist):
            self.artist = artist
        else:
            self.artist = Artist(artist, self.network)
        
        self.title = title
    
    def __repr__(self):
        return "pylast.Track(%s, %s, %s)" %(repr(self.artist.name), repr(self.title), repr(self.network))

    @_string_output
    def __str__(self):
        return self.get_artist().get_name() + ' - ' + self.get_title()

    def __eq__(self, other):
        return (self.get_title().lower() == other.get_title().lower()) and (self.get_artist().get_name().lower() == other.get_artist().get_name().lower())
    
    def __ne__(self, other):
        return (self.get_title().lower() != other.get_title().lower()) or (self.get_artist().get_name().lower() != other.get_artist().get_name().lower())
    
    def _get_params(self):
        return {'artist': self.get_artist().get_name(), 'track': self.get_title()}
            
    def get_artist(self):
        """Returns the associated Artist object."""
        
        return self.artist
    
    def get_title(self, properly_capitalized=False):
        """Returns the track title."""
        
        if properly_capitalized:
            self.title = _extract(self._request("track.getInfo", True), "name")
        
        return self.title
    
    def get_name(self, properly_capitalized=False):
        """Returns the track title (alias to Track.get_title)."""
        
        return self.get_title(properly_capitalized)
    
    def get_id(self):
        """Returns the track id on the network."""
        
        doc = self._request("track.getInfo", True)
        
        return _extract(doc, "id")
    
    def get_duration(self):
        """Returns the track duration."""
        
        doc = self._request("track.getInfo", True)
        
        return _number(_extract(doc, "duration"))
    
    def get_mbid(self):
        """Returns the MusicBrainz ID of this track."""
        
        doc = self._request("track.getInfo", True)
        
        return _extract(doc, "mbid")
        
    def get_listener_count(self):
        """Returns the listener count."""
        
        if hasattr(self, "listener_count"):
            return self.listener_count
        else:
            doc = self._request("track.getInfo", True)
            self.listener_count = _number(_extract(doc, "listeners"))
            return self.listener_count
    
    def get_playcount(self):
        """Returns the play count."""
        
        doc = self._request("track.getInfo", True)
        return _number(_extract(doc, "playcount"))
    
    def is_streamable(self):
        """Returns True if the track is available at Last.fm."""
        
        doc = self._request("track.getInfo", True)
        return _extract(doc, "streamable") == "1"
    
    def is_fulltrack_available(self):
        """Returns True if the fulltrack is available for streaming."""
        
        doc = self._request("track.getInfo", True)
        return doc.getElementsByTagName("streamable")[0].getAttribute("fulltrack") == "1"
        
    def get_album(self):
        """Returns the album object of this track."""
        
        doc = self._request("track.getInfo", True)
        
        albums = doc.getElementsByTagName("album")
        
        if len(albums) == 0:
            return
        
        node = doc.getElementsByTagName("album")[0]
        return Album(_extract(node, "artist"), _extract(node, "title"), self.network)
    
    def get_wiki_published_date(self):
        """Returns the date of publishing this version of the wiki."""
        
        doc = self._request("track.getInfo", True)
        
        if len(doc.getElementsByTagName("wiki")) == 0:
            return
        
        node = doc.getElementsByTagName("wiki")[0]
        
        return _extract(node, "published")
    
    def get_wiki_summary(self):
        """Returns the summary of the wiki."""
        
        doc = self._request("track.getInfo", True)
        
        if len(doc.getElementsByTagName("wiki")) == 0:
            return
        
        node = doc.getElementsByTagName("wiki")[0]
        
        return _extract(node, "summary")
        
    def get_wiki_content(self):
        """Returns the content of the wiki."""
        
        doc = self._request("track.getInfo", True)
        
        if len(doc.getElementsByTagName("wiki")) == 0:
            return
        
        node = doc.getElementsByTagName("wiki")[0]
        
        return _extract(node, "content")
    
    def love(self):
        """Adds the track to the user's loved tracks. """
        
        self._request('track.love')
    
    def ban(self):
        """Ban this track from ever playing on the radio. """
        
        self._request('track.ban')
    
    def get_similar(self):
        """Returns similar tracks for this track on the network, based on listening data. """
        
        doc = self._request('track.getSimilar', True)
        
        seq = []
        for node in doc.getElementsByTagName("track"):
            title = _extract(node, 'name')
            artist = _extract(node, 'name', 1)
            match = _number(_extract(node, "match"))
            
            seq.append(SimilarItem(Track(artist, title, self.network), match))
        
        return seq

    def get_top_fans(self, limit = None):
        """Returns a list of the Users who played this track."""
        
        doc = self._request('track.getTopFans', True)
        
        seq = []
        
        elements = doc.getElementsByTagName('user')
        
        for element in elements:
            if limit and len(seq) >= limit:
                break
                
            name = _extract(element, 'name')
            weight = _number(_extract(element, 'weight'))
            
            seq.append(TopItem(User(name, self.network), weight))
        
        return seq
    
    def share(self, users, message = None):
        """Shares this track (sends out recommendations). 
          * users: A list that can contain usernames, emails, User objects, or all of them.
          * message: A message to include in the recommendation message. 
        """
        
        #last.fm currently accepts a max of 10 recipient at a time
        while(len(users) > 10):
            section = users[0:9]
            users = users[9:]
            self.share(section, message)
        
        nusers = []
        for user in users:
            if isinstance(user, User):
                nusers.append(user.get_name())
            else:
                nusers.append(user)
        
        params = self._get_params()
        recipients = ','.join(nusers)
        params['recipient'] = recipients
        if message:
            params['message'] = message
        
        self._request('track.share', False, params)
    
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the track page on the network. 
        * domain_name: The network's language domain. Possible values:
          o DOMAIN_ENGLISH
          o DOMAIN_GERMAN
          o DOMAIN_SPANISH
          o DOMAIN_FRENCH
          o DOMAIN_ITALIAN
          o DOMAIN_POLISH
          o DOMAIN_PORTUGUESE
          o DOMAIN_SWEDISH
          o DOMAIN_TURKISH
          o DOMAIN_RUSSIAN
          o DOMAIN_JAPANESE
          o DOMAIN_CHINESE 
        """
        
        artist = _url_safe(self.get_artist().get_name())
        title = _url_safe(self.get_title())
        
        return self.network._get_url(domain_name, "track") %{'domain': self.network._get_language_domain(domain_name), 'artist': artist, 'title': title}
    
    def get_shouts(self, limit=50):
        """
            Returns a sequqence of Shout objects
        """
        
        shouts = []
        for node in _collect_nodes(limit, self, "track.getShouts", False):
            shouts.append(Shout(
                                _extract(node, "body"),
                                User(_extract(node, "author"), self.network),
                                _extract(node, "date")
                                )
                            )
        return shouts
        
class Group(_BaseObject):
    """A Last.fm group."""
    
    name = None
    
    def __init__(self, group_name, network):
        _BaseObject.__init__(self, network)
        
        self.name = group_name
    
    def __repr__(self):
        return "pylast.Group(%s, %s)" %(repr(self.name), repr(self.network))
    
    @_string_output
    def __str__(self):
        return self.get_name()
    
    def __eq__(self, other):
        return self.get_name().lower() == other.get_name().lower()
    
    def __ne__(self, other):
        return self.get_name() != other.get_name()
    
    def _get_params(self):
        return {'group': self.get_name()}
    
    def get_name(self):
        """Returns the group name. """
        return self.name
    
    def get_weekly_chart_dates(self):
        """Returns a list of From and To tuples for the available charts."""
        
        doc = self._request("group.getWeeklyChartList", True)
        
        seq = []
        for node in doc.getElementsByTagName("chart"):
            seq.append( (node.getAttribute("from"), node.getAttribute("to")) )
        
        return seq
    
    def get_weekly_artist_charts(self, from_date = None, to_date = None):
        """Returns the weekly artist charts for the week starting from the from_date value to the to_date value."""
        
        params = self._get_params()
        if from_date and to_date:
            params["from"] = from_date
            params["to"] = to_date
        
        doc = self._request("group.getWeeklyArtistChart", True, params)
        
        seq = []
        for node in doc.getElementsByTagName("artist"):
            item = Artist(_extract(node, "name"), self.network)
            weight = _number(_extract(node, "playcount"))
            seq.append(TopItem(item, weight))
        
        return seq

    def get_weekly_album_charts(self, from_date = None, to_date = None):
        """Returns the weekly album charts for the week starting from the from_date value to the to_date value."""
        
        params = self._get_params()
        if from_date and to_date:
            params["from"] = from_date
            params["to"] = to_date
        
        doc = self._request("group.getWeeklyAlbumChart", True, params)
        
        seq = []
        for node in doc.getElementsByTagName("album"):
            item = Album(_extract(node, "artist"), _extract(node, "name"), self.network)
            weight = _number(_extract(node, "playcount"))
            seq.append(TopItem(item, weight))
        
        return seq

    def get_weekly_track_charts(self, from_date = None, to_date = None):
        """Returns the weekly track charts for the week starting from the from_date value to the to_date value."""
        
        params = self._get_params()
        if from_date and to_date:
            params["from"] = from_date
            params["to"] = to_date
        
        doc = self._request("group.getWeeklyTrackChart", True, params)
        
        seq = []
        for node in doc.getElementsByTagName("track"):
            item = Track(_extract(node, "artist"), _extract(node, "name"), self.network)
            weight = _number(_extract(node, "playcount"))
            seq.append(TopItem(item, weight))
        
        return seq
        
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the group page on the network. 
        * domain_name: The network's language domain. Possible values:
          o DOMAIN_ENGLISH
          o DOMAIN_GERMAN
          o DOMAIN_SPANISH
          o DOMAIN_FRENCH
          o DOMAIN_ITALIAN
          o DOMAIN_POLISH
          o DOMAIN_PORTUGUESE
          o DOMAIN_SWEDISH
          o DOMAIN_TURKISH
          o DOMAIN_RUSSIAN
          o DOMAIN_JAPANESE
          o DOMAIN_CHINESE 
        """
        
        name = _url_safe(self.get_name())
        
        return self.network._get_url(domain_name, "group") %{'name': name}
    
    def get_members(self, limit=50):
        """
            Returns a sequence of User objects
            if limit==None it will return all
        """
        
        nodes = _collect_nodes(limit, self, "group.getMembers", False)
        
        users = []
        
        for node in nodes:
            users.append(User(_extract(node, "name"), self.network))
        
        return users

class XSPF(_BaseObject):
    "A Last.fm XSPF playlist."""
    
    uri = None
    
    def __init__(self, uri, network):
        _BaseObject.__init__(self, network)
        
        self.uri = uri
    
    def _get_params(self):
        return {'playlistURL': self.get_uri()}
    
    @_string_output
    def __str__(self):
        return self.get_uri()
    
    def __eq__(self, other):
        return self.get_uri() == other.get_uri()
    
    def __ne__(self, other):
        return self.get_uri() != other.get_uri()
    
    def get_uri(self):
        """Returns the Last.fm playlist URI. """
        
        return self.uri
    
    def get_tracks(self):
        """Returns the tracks on this playlist."""
        
        doc = self._request('playlist.fetch', True)
        
        seq = []
        for n in doc.getElementsByTagName('track'):
            title = _extract(n, 'title')
            artist = _extract(n, 'creator')
            
            seq.append(Track(artist, title, self.network))
        
        return seq

class User(_BaseObject):
    """A Last.fm user."""
    
    name = None
    
    def __init__(self, user_name, network):
        _BaseObject.__init__(self, network)
        
        self.name = user_name
        
        self._past_events_index = 0
        self._recommended_events_index = 0
        self._recommended_artists_index = 0
    
    def __repr__(self):
        return "pylast.User(%s, %s)" %(repr(self.name), repr(self.network))
    
    @_string_output
    def __str__(self):
        return self.get_name()
    
    def __eq__(self, another):
        return self.get_name() == another.get_name()
    
    def __ne__(self, another):
        return self.get_name() != another.get_name()
    
    def _get_params(self):
        return {"user": self.get_name()}
        
    def get_name(self, properly_capitalized=False):
        """Returns the nuser name."""
        
        if properly_capitalized:
            self.name = _extract(self._request("user.getInfo", True), "name")
        
        return self.name
    
    def get_upcoming_events(self):
        """Returns all the upcoming events for this user. """
        
        doc = self._request('user.getEvents', True)
        
        ids = _extract_all(doc, 'id')
        events = []
        
        for e_id in ids:
            events.append(Event(e_id, self.network))
        
        return events
    
    def get_friends(self, limit = 50):
        """Returns a list of the user's friends. """
        
        seq = []
        for node in _collect_nodes(limit, self, "user.getFriends", False):
            seq.append(User(_extract(node, "name"), self.network))
        
        return seq
    
    def get_loved_tracks(self, limit=50):
        """Returns this user's loved track as a sequence of LovedTrack objects
        in reverse order of their timestamp, all the way back to the first track.
        
        If limit==None, it will try to pull all the available data.
        
        This method uses caching. Enable caching only if you're pulling a
        large amount of data.
        
        Use extract_items() with the return of this function to
        get only a sequence of Track objects with no playback dates. """
        
        params = self._get_params()
        if limit:
            params['limit'] = limit
        
        seq = []
        for track in _collect_nodes(limit, self, "user.getLovedTracks", True, params):
                
            title = _extract(track, "name")
            artist = _extract(track, "name", 1)
            date = _extract(track, "date")
            timestamp = track.getElementsByTagName("date")[0].getAttribute("uts")
                
            seq.append(LovedTrack(Track(artist, title, self.network), date, timestamp))
        
        return seq
    
    def get_neighbours(self, limit = 50):
        """Returns a list of the user's friends."""
        
        params = self._get_params()
        if limit:
            params['limit'] = limit
        
        doc = self._request('user.getNeighbours', True, params)
        
        seq = []
        names = _extract_all(doc, 'name')
        
        for name in names:
            seq.append(User(name, self.network))
        
        return seq
        
    def get_past_events(self, limit=50):
        """
        Returns a sequence of Event objects
        if limit==None it will return all
        """
        
        seq = []
        for n in _collect_nodes(limit, self, "user.getPastEvents", False):
            seq.append(Event(_extract(n, "id"), self.network))

        return seq
                
    def get_playlists(self):
        """Returns a list of Playlists that this user owns."""
        
        doc = self._request("user.getPlaylists", True)
        
        playlists = []
        for playlist_id in _extract_all(doc, "id"):
            playlists.append(Playlist(self.get_name(), playlist_id, self.network))
        
        return playlists
    
    def get_now_playing(self):
        """Returns the currently playing track, or None if nothing is playing. """
        
        params = self._get_params()
        params['limit'] = '1'
        
        doc = self._request('user.getRecentTracks', False, params)
        
        e = doc.getElementsByTagName('track')[0]
        
        if not e.hasAttribute('nowplaying'):
            return None
        
        artist = _extract(e, 'artist')
        title = _extract(e, 'name')
        
        return Track(artist, title, self.network)


    def get_recent_tracks(self, limit = 10):
        """Returns this user's played track as a sequence of PlayedTrack objects
        in reverse order of their playtime, all the way back to the first track.
        
        If limit==None, it will try to pull all the available data.
        
        This method uses caching. Enable caching only if you're pulling a
        large amount of data.
        
        Use extract_items() with the return of this function to
        get only a sequence of Track objects with no playback dates. """
        
        params = self._get_params()
        if limit:
            params['limit'] = limit
        
        seq = []
        for track in _collect_nodes(limit, self, "user.getRecentTracks", True, params):
            
            if track.hasAttribute('nowplaying'):
                continue    #to prevent the now playing track from sneaking in here
                
            title = _extract(track, "name")
            artist = _extract(track, "artist")
            date = _extract(track, "date")
            timestamp = track.getElementsByTagName("date")[0].getAttribute("uts")
                
            seq.append(PlayedTrack(Track(artist, title, self.network), date, timestamp))
        
        return seq
    
    def get_id(self):
        """Returns the user id."""
        
        doc = self._request("user.getInfo", True)
        
        return _extract(doc, "id")
    
    def get_language(self):
        """Returns the language code of the language used by the user."""
        
        doc = self._request("user.getInfo", True)
        
        return _extract(doc, "lang")
    
    def get_country(self):
        """Returns the name of the country of the user."""
        
        doc = self._request("user.getInfo", True)
        
        return Country(_extract(doc, "country"), self.network)
    
    def get_age(self):
        """Returns the user's age."""
        
        doc = self._request("user.getInfo", True)
        
        return _number(_extract(doc, "age"))
    
    def get_gender(self):
        """Returns the user's gender. Either USER_MALE or USER_FEMALE."""
        
        doc = self._request("user.getInfo", True)
        
        value = _extract(doc, "gender")
        
        if value == 'm':
            return USER_MALE
        elif value == 'f':
            return USER_FEMALE
        
        return None
    
    def is_subscriber(self):
        """Returns whether the user is a subscriber or not. True or False."""
        
        doc = self._request("user.getInfo", True)
        
        return _extract(doc, "subscriber") == "1"
    
    def get_playcount(self):
        """Returns the user's playcount so far."""
        
        doc = self._request("user.getInfo", True)
        
        return _number(_extract(doc, "playcount"))
        
    def get_top_albums(self, period = PERIOD_OVERALL):
        """Returns the top albums played by a user. 
        * period: The period of time. Possible values:
          o PERIOD_OVERALL
          o PERIOD_7DAYS
          o PERIOD_3MONTHS
          o PERIOD_6MONTHS
          o PERIOD_12MONTHS 
        """
        
        params = self._get_params()
        params['period'] = period
        
        doc = self._request('user.getTopAlbums', True, params)
        
        seq = []
        for album in doc.getElementsByTagName('album'):
            name = _extract(album, 'name')
            artist = _extract(album, 'name', 1)
            playcount = _extract(album, "playcount")
            
            seq.append(TopItem(Album(artist, name, self.network), playcount))
        
        return seq
    
    def get_top_artists(self, period = PERIOD_OVERALL):
        """Returns the top artists played by a user. 
        * period: The period of time. Possible values:
          o PERIOD_OVERALL
          o PERIOD_7DAYS
          o PERIOD_3MONTHS
          o PERIOD_6MONTHS
          o PERIOD_12MONTHS 
        """
        
        params = self._get_params()
        params['period'] = period
        
        doc = self._request('user.getTopArtists', True, params)
        
        seq = []
        for node in doc.getElementsByTagName('artist'):
            name = _extract(node, 'name')
            playcount = _extract(node, "playcount")
            
            seq.append(TopItem(Artist(name, self.network), playcount))
        
        return seq
    
    def get_top_tags(self, limit=None):
        """Returns a sequence of the top tags used by this user with their counts as TopItem objects. 
        * limit: The limit of how many tags to return. 
        """
        
        doc = self._request("user.getTopTags", True)
        
        seq = []
        for node in doc.getElementsByTagName("tag"):
            seq.append(TopItem(Tag(_extract(node, "name"), self.network), _extract(node, "count")))
        
        if limit:
            seq = seq[:limit]
        
        return seq
    
    def get_top_tracks(self, period = PERIOD_OVERALL):
        """Returns the top tracks played by a user. 
        * period: The period of time. Possible values:
          o PERIOD_OVERALL
          o PERIOD_7DAYS
          o PERIOD_3MONTHS
          o PERIOD_6MONTHS
          o PERIOD_12MONTHS 
        """
        
        params = self._get_params()
        params['period'] = period
        
        doc = self._request('user.getTopTracks', True, params)
        
        seq = []
        for track in doc.getElementsByTagName('track'):
            name = _extract(track, 'name')
            artist = _extract(track, 'name', 1)
            playcount = _extract(track, "playcount")
            
            seq.append(TopItem(Track(artist, name, self.network), playcount))
        
        return seq
    
    def get_weekly_chart_dates(self):
        """Returns a list of From and To tuples for the available charts."""
        
        doc = self._request("user.getWeeklyChartList", True)
        
        seq = []
        for node in doc.getElementsByTagName("chart"):
            seq.append( (node.getAttribute("from"), node.getAttribute("to")) )
        
        return seq
    
    def get_weekly_artist_charts(self, from_date = None, to_date = None):
        """Returns the weekly artist charts for the week starting from the from_date value to the to_date value."""
        
        params = self._get_params()
        if from_date and to_date:
            params["from"] = from_date
            params["to"] = to_date
        
        doc = self._request("user.getWeeklyArtistChart", True, params)
        
        seq = []
        for node in doc.getElementsByTagName("artist"):
            item = Artist(_extract(node, "name"), self.network)
            weight = _number(_extract(node, "playcount"))
            seq.append(TopItem(item, weight))
        
        return seq

    def get_weekly_album_charts(self, from_date = None, to_date = None):
        """Returns the weekly album charts for the week starting from the from_date value to the to_date value."""
        
        params = self._get_params()
        if from_date and to_date:
            params["from"] = from_date
            params["to"] = to_date
        
        doc = self._request("user.getWeeklyAlbumChart", True, params)
        
        seq = []
        for node in doc.getElementsByTagName("album"):
            item = Album(_extract(node, "artist"), _extract(node, "name"), self.network)
            weight = _number(_extract(node, "playcount"))
            seq.append(TopItem(item, weight))
        
        return seq

    def get_weekly_track_charts(self, from_date = None, to_date = None):
        """Returns the weekly track charts for the week starting from the from_date value to the to_date value."""
        
        params = self._get_params()
        if from_date and to_date:
            params["from"] = from_date
            params["to"] = to_date
        
        doc = self._request("user.getWeeklyTrackChart", True, params)
        
        seq = []
        for node in doc.getElementsByTagName("track"):
            item = Track(_extract(node, "artist"), _extract(node, "name"), self.network)
            weight = _number(_extract(node, "playcount"))
            seq.append(TopItem(item, weight))
        
        return seq
    
    def compare_with_user(self, user, shared_artists_limit = None):
        """Compare this user with another Last.fm user.
        Returns a sequence (tasteometer_score, (shared_artist1, shared_artist2, ...))
        user: A User object or a username string/unicode object.
        """
        
        if isinstance(user, User):
            user = user.get_name()
        
        params = self._get_params()
        if shared_artists_limit:
            params['limit'] = shared_artists_limit
        params['type1'] = 'user'
        params['type2'] = 'user'
        params['value1'] = self.get_name()
        params['value2'] = user
        
        doc = self._request('tasteometer.compare', False, params)
        
        score = _extract(doc, 'score')
        
        artists = doc.getElementsByTagName('artists')[0]
        shared_artists_names = _extract_all(artists, 'name')
        
        shared_artists_seq = []
        
        for name in shared_artists_names:
            shared_artists_seq.append(Artist(name, self.network))
        
        return (score, shared_artists_seq)
    
    def get_image(self):
        """Returns the user's avatar."""
            
        doc = self._request("user.getInfo", True)
        
        return _extract(doc, "image")
    
    def get_url(self, domain_name = DOMAIN_ENGLISH):
        """Returns the url of the user page on the network. 
        * domain_name: The network's language domain. Possible values:
          o DOMAIN_ENGLISH
          o DOMAIN_GERMAN
          o DOMAIN_SPANISH
          o DOMAIN_FRENCH
          o DOMAIN_ITALIAN
          o DOMAIN_POLISH
          o DOMAIN_PORTUGUESE
          o DOMAIN_SWEDISH
          o DOMAIN_TURKISH
          o DOMAIN_RUSSIAN
          o DOMAIN_JAPANESE
          o DOMAIN_CHINESE 
        """
        
        name = _url_safe(self.get_name())
        
        return self.network._get_url(domain_name, "user") %{'name': name}

    def get_library(self):
        """Returns the associated Library object. """
        
        return Library(self, self.network)

    def get_shouts(self, limit=50):
        """
            Returns a sequqence of Shout objects
        """
        
        shouts = []
        for node in _collect_nodes(limit, self, "user.getShouts", False):
            shouts.append(Shout(
                                _extract(node, "body"),
                                User(_extract(node, "author"), self.network),
                                _extract(node, "date")
                                )
                            )
        return shouts
    
    def shout(self, message):
        """
            Post a shout
        """
        
        params = self._get_params()
        params["message"] = message
        
        self._request("user.Shout", False, params)

class AuthenticatedUser(User):
    def __init__(self, network):
        User.__init__(self, "", network);
    
    def _get_params(self):
        return {"user": self.get_name()}
        
    def get_name(self):
        """Returns the name of the authenticated user."""
        
        doc = self._request("user.getInfo", True, {"user": ""})    # hack
        
        self.name = _extract(doc, "name")
        return self.name
        
    def get_recommended_events(self, limit=50):
        """
        Returns a sequence of Event objects
        if limit==None it will return all
        """
        
        seq = []
        for node in _collect_nodes(limit, self, "user.getRecommendedEvents", False):
            seq.append(Event(_extract(node, "id"), self.network))
        
        return seq
        
    def get_recommended_artists(self, limit=50):
        """
        Returns a sequence of Event objects
        if limit==None it will return all
        """
        
        seq = []
        for node in _collect_nodes(limit, self, "user.getRecommendedArtists", False):
            seq.append(Artist(_extract(node, "name"), self.network))
        
        return seq
    
class _Search(_BaseObject):
    """An abstract class. Use one of its derivatives."""
    
    def __init__(self, ws_prefix, search_terms, network):
        _BaseObject.__init__(self, network)
        
        self._ws_prefix = ws_prefix
        self.search_terms = search_terms
        
        self._last_page_index = 0
    
    def _get_params(self):
        params = {}
        
        for key in self.search_terms.keys():
            params[key] = self.search_terms[key]
        
        return params
    
    def get_total_result_count(self):
        """Returns the total count of all the results."""
        
        doc = self._request(self._ws_prefix + ".search", True)
        
        return _extract(doc, "opensearch:totalResults")
    
    def _retreive_page(self, page_index):
        """Returns the node of matches to be processed"""
        
        params = self._get_params()
        params["page"] = str(page_index)
        doc = self._request(self._ws_prefix + ".search", True, params)
        
        return doc.getElementsByTagName(self._ws_prefix + "matches")[0]
    
    def _retrieve_next_page(self):
        self._last_page_index += 1
        return self._retreive_page(self._last_page_index)

class AlbumSearch(_Search):
    """Search for an album by name."""
    
    def __init__(self, album_name, network):
        
        _Search.__init__(self, "album", {"album": album_name}, network)
    
    def get_next_page(self):
        """Returns the next page of results as a sequence of Album objects."""
        
        master_node = self._retrieve_next_page()
        
        seq = []
        for node in master_node.getElementsByTagName("album"):
            seq.append(Album(_extract(node, "artist"), _extract(node, "name"), self.network))
        
        return seq

class ArtistSearch(_Search):
    """Search for an artist by artist name."""
    
    def __init__(self, artist_name, network):
        _Search.__init__(self, "artist", {"artist": artist_name}, network)

    def get_next_page(self):
        """Returns the next page of results as a sequence of Artist objects."""
        
        master_node = self._retrieve_next_page()
        
        seq = []
        for node in master_node.getElementsByTagName("artist"):
            artist = Artist(_extract(node, "name"), self.network)
            artist.listener_count = _number(_extract(node, "listeners"))
            seq.append(artist)
        
        return seq

class TagSearch(_Search):
    """Search for a tag by tag name."""
    
    def __init__(self, tag_name, network):
        
        _Search.__init__(self, "tag", {"tag": tag_name}, network)
        
    def get_next_page(self):
        """Returns the next page of results as a sequence of Tag objects."""
        
        master_node = self._retrieve_next_page()
        
        seq = []
        for node in master_node.getElementsByTagName("tag"):
            tag = Tag(_extract(node, "name"), self.network)
            tag.tag_count = _number(_extract(node, "count"))
            seq.append(tag)
        
        return seq

class TrackSearch(_Search):
    """Search for a track by track title. If you don't wanna narrow the results down
    by specifying the artist name, set it to empty string."""
    
    def __init__(self, artist_name, track_title, network):
        
        _Search.__init__(self, "track", {"track": track_title, "artist": artist_name}, network)

    def get_next_page(self):
        """Returns the next page of results as a sequence of Track objects."""
        
        master_node = self._retrieve_next_page()
        
        seq = []
        for node in master_node.getElementsByTagName("track"):
            track = Track(_extract(node, "artist"), _extract(node, "name"), self.network)
            track.listener_count = _number(_extract(node, "listeners"))
            seq.append(track)
        
        return seq

class VenueSearch(_Search):
    """Search for a venue by its name. If you don't wanna narrow the results down
    by specifying a country, set it to empty string."""
    
    def __init__(self, venue_name, country_name, network):
        
        _Search.__init__(self, "venue", {"venue": venue_name, "country": country_name}, network)

    def get_next_page(self):
        """Returns the next page of results as a sequence of Track objects."""
        
        master_node = self._retrieve_next_page()
        
        seq = []
        for node in master_node.getElementsByTagName("venue"):
            seq.append(Venue(_extract(node, "id"), self.network))
        
        return seq

class Venue(_BaseObject):
    """A venue where events are held."""
    
    # TODO: waiting for a venue.getInfo web service to use.
    
    id = None
    
    def __init__(self, id, network):
        _BaseObject.__init__(self, network)
        
        self.id = _number(id)
    
    def __repr__(self):
        return "pylast.Venue(%s, %s)" %(repr(self.id), repr(self.network))
    
    @_string_output
    def __str__(self):
        return "Venue #" + str(self.id)
    
    def __eq__(self, other):
        return self.get_id() == other.get_id()
    
    def _get_params(self):
        return {"venue": self.get_id()}
        
    def get_id(self):
        """Returns the id of the venue."""
        
        return self.id
    
    def get_upcoming_events(self):
        """Returns the upcoming events in this venue."""
        
        doc = self._request("venue.getEvents", True)
        
        seq = []
        for node in doc.getElementsByTagName("event"):
            seq.append(Event(_extract(node, "id"), self.network))
        
        return seq
    
    def get_past_events(self):
        """Returns the past events held in this venue."""
        
        doc = self._request("venue.getEvents", True)
        
        seq = []
        for node in doc.getElementsByTagName("event"):
            seq.append(Event(_extract(node, "id"), self.network))
        
        return seq

def md5(text):
    """Returns the md5 hash of a string."""
    
    h = hashlib.md5()
    h.update(_unicode(text).encode("utf-8"))
    
    return h.hexdigest()

def _unicode(text):
    if sys.version_info[0] == 3:
        if type(text) in (bytes, bytearray):
            return str(text, "utf-8")
        elif type(text) == str:
            return text
        else:
            return str(text)
        
    elif sys.version_info[0] ==2:
        if type(text) in (str,):
            return unicode(text, "utf-8")
        elif type(text) == unicode:
            return text
        else:
            return unicode(text)

def _string(text):
    """For Python2 routines that can only process str type."""
    
    if sys.version_info[0] == 3:
        if type(text) != str:
            return str(text)
        else:
            return text
    
    elif sys.version_info[0] == 2:
        if type(text) == str:
            return text
        
        if type(text) == int:
            return str(text)
        
        return text.encode("utf-8")

def _collect_nodes(limit, sender, method_name, cacheable, params=None):
    """
        Returns a sequqnce of dom.Node objects about as close to
        limit as possible
    """
    
    if not params:
        params = sender._get_params()
    
    nodes = []
    page = 1
    end_of_pages = False
    
    while not end_of_pages and (not limit or (limit and len(nodes) < limit)):
        params["page"] = str(page)
        doc = sender._request(method_name, cacheable, params)
        
        main = doc.documentElement.childNodes[1]
        
        if main.hasAttribute("totalPages"):
            total_pages = _number(main.getAttribute("totalPages"))
        elif main.hasAttribute("totalpages"):
            total_pages = _number(main.getAttribute("totalpages"))
        else:
            raise Exception("No total pages attribute")
        
        for node in main.childNodes:
            if not node.nodeType == xml.dom.Node.TEXT_NODE and len(nodes) < limit:
                nodes.append(node)
        
        if page >= total_pages:
            end_of_pages = True
        
        page += 1
    
    return nodes
    
def _extract(node, name, index = 0):
    """Extracts a value from the xml string"""
    
    nodes = node.getElementsByTagName(name)
    
    if len(nodes):
        if nodes[index].firstChild:
            return _unescape_htmlentity(nodes[index].firstChild.data.strip())
    else:
        return None

def _extract_all(node, name, limit_count = None):
    """Extracts all the values from the xml string. returning a list."""
    
    seq = []
    
    for i in range(0, len(node.getElementsByTagName(name))):
        if len(seq) == limit_count:
            break
        
        seq.append(_extract(node, name, i))
    
    return seq

def _url_safe(text):
    """Does all kinds of tricks on a text to make it safe to use in a url."""
    
    return url_quote_plus(url_quote_plus(_string(text))).lower()

def _number(string):
    """
        Extracts an int from a string. Returns a 0 if None or an empty string was passed
    """
    
    if not string:
        return 0
    elif string == "":
        return 0
    else:
        try:
            return int(string)
        except ValueError:
            return float(string)

def _unescape_htmlentity(string):
    
    #string = _unicode(string)  
    
    mapping = htmlentitydefs.name2codepoint
    for key in mapping:
        string = string.replace("&%s;" %key, unichr(mapping[key]))
    
    return string
    
def extract_items(topitems_or_libraryitems):
    """Extracts a sequence of items from a sequence of TopItem or LibraryItem objects."""
    
    seq = []
    for i in topitems_or_libraryitems:
        seq.append(i.item)
    
    return seq

class ScrobblingError(Exception):
    def __init__(self, message):
        Exception.__init__(self)
        self.message = message
    
    @_string_output
    def __str__(self):
        return self.message

class BannedClientError(ScrobblingError):
    def __init__(self):
        ScrobblingError.__init__(self, "This version of the client has been banned")

class BadAuthenticationError(ScrobblingError):
    def __init__(self):
        ScrobblingError.__init__(self, "Bad authentication token")

class BadTimeError(ScrobblingError):
    def __init__(self):
        ScrobblingError.__init__(self, "Time provided is not close enough to current time")

class BadSessionError(ScrobblingError):
    def __init__(self):
        ScrobblingError.__init__(self, "Bad session id, consider re-handshaking")

class _ScrobblerRequest(object):
    
    def __init__(self, url, params, network, type="POST"):
        
        for key in params:
                params[key] = str(params[key])
        
        self.params = params
        self.type = type
        (self.hostname, self.subdir) = url_split_host(url[len("http:"):])
        self.network = network
    
    def execute(self):
        """Returns a string response of this request."""
        
        connection = HTTPConnection(self.hostname)

        data = []
        for name in self.params.keys():
            value = url_quote_plus(self.params[name])
            data.append('='.join((name, value)))
        data = "&".join(data)
        
        headers = {
            "Content-type": "application/x-www-form-urlencoded",
            "Accept-Charset": "utf-8",
            "User-Agent": "pylast" + "/" + __version__,
            "HOST": self.hostname
            }
        
        if self.type == "GET":
            connection.request("GET", self.subdir + "?" + data, headers = headers)
        else:
            connection.request("POST", self.subdir, data, headers)
        response = _unicode(connection.getresponse().read())
        
        self._check_response_for_errors(response)
        
        return response
        
    def _check_response_for_errors(self, response):
        """When passed a string response it checks for erros, raising
        any exceptions as necessary."""
        
        lines = response.split("\n")
        status_line = lines[0]
        
        if status_line == "OK":
            return
        elif status_line == "BANNED":
            raise BannedClientError()
        elif status_line == "BADAUTH":
            raise BadAuthenticationError()
        elif status_line == "BADTIME":
            raise BadTimeError()
        elif status_line == "BADSESSION":
            raise BadSessionError()
        elif status_line.startswith("FAILED "):
            reason = status_line[status_line.find("FAILED ")+len("FAILED "):]
            raise ScrobblingError(reason)
    
class Scrobbler(object):
    """A class for scrobbling tracks to Last.fm"""
    
    session_id = None
    nowplaying_url = None
    submissions_url = None
    
    def __init__(self, network, client_id, client_version):
        self.client_id = client_id
        self.client_version = client_version
        self.username = network.username
        self.password = network.password_hash
        self.network = network
    
    def _do_handshake(self):
        """Handshakes with the server"""
        
        timestamp = str(int(time.time()))
        
        if self.password and self.username:
            token = md5(self.password + timestamp)
        elif self.network.api_key and self.network.api_secret and self.network.session_key:
            if not self.username:
                self.username = self.network.get_authenticated_user().get_name()
            token = md5(self.network.api_secret + timestamp)
        
        params = {"hs": "true", "p": "1.2.1", "c": self.client_id,
            "v": self.client_version, "u": self.username, "t": timestamp,
            "a": token}
        
        if self.network.session_key and self.network.api_key:
            params["sk"] = self.network.session_key
            params["api_key"] = self.network.api_key
        
        server = self.network.submission_server
        response = _ScrobblerRequest(server, params, self.network, "GET").execute().split("\n")
        
        self.session_id = response[1]
        self.nowplaying_url = response[2]
        self.submissions_url = response[3]
    
    def _get_session_id(self, new = False):
        """Returns a handshake. If new is true, then it will be requested from the server
        even if one was cached."""
        
        if not self.session_id or new:
            self._do_handshake()
        
        return self.session_id
    
    def report_now_playing(self, artist, title, album = "", duration = "", track_number = "", mbid = ""):
        
        _deprecation_warning("DeprecationWarning: Use Netowrk.update_now_playing(...) instead")
        
        params = {"s": self._get_session_id(), "a": artist, "t": title,
            "b": album, "l": duration, "n": track_number, "m": mbid}
        
        try:
            _ScrobblerRequest(self.nowplaying_url, params, self.network).execute()
        except BadSessionError:
            self._do_handshake()
            self.report_now_playing(artist, title, album, duration, track_number, mbid)
    
    def scrobble(self, artist, title, time_started, source, mode, duration, album="", track_number="", mbid=""):
        """Scrobble a track. parameters:
            artist: Artist name.
            title: Track title.
            time_started: UTC timestamp of when the track started playing.
            source: The source of the track
                SCROBBLE_SOURCE_USER: Chosen by the user (the most common value, unless you have a reason for choosing otherwise, use this).
                SCROBBLE_SOURCE_NON_PERSONALIZED_BROADCAST: Non-personalised broadcast (e.g. Shoutcast, BBC Radio 1).
                SCROBBLE_SOURCE_PERSONALIZED_BROADCAST: Personalised recommendation except Last.fm (e.g. Pandora, Launchcast).
                SCROBBLE_SOURCE_LASTFM: ast.fm (any mode). In this case, the 5-digit recommendation_key value must be set.
                SCROBBLE_SOURCE_UNKNOWN: Source unknown.
            mode: The submission mode
                SCROBBLE_MODE_PLAYED: The track was played.
                SCROBBLE_MODE_LOVED: The user manually loved the track (implies a listen)
                SCROBBLE_MODE_SKIPPED: The track was skipped (Only if source was Last.fm)
                SCROBBLE_MODE_BANNED: The track was banned (Only if source was Last.fm)
            duration: Track duration in seconds.
            album: The album name.
            track_number: The track number on the album.
            mbid: MusicBrainz ID.
        """
        
        _deprecation_warning("DeprecationWarning: Use Network.scrobble(...) instead")
        
        params = {"s": self._get_session_id(), "a[0]": _string(artist), "t[0]": _string(title),
            "i[0]": str(time_started), "o[0]": source, "r[0]": mode, "l[0]": str(duration),
            "b[0]": _string(album), "n[0]": track_number, "m[0]": mbid}
        
        _ScrobblerRequest(self.submissions_url, params, self.network).execute()
    
    def scrobble_many(self, tracks):
        """
            Scrobble several tracks at once.
            
            tracks: A sequence of a sequence of parameters for each trach. The order of parameters
                is the same as if passed to the scrobble() method.
        """
        
        _deprecation_warning("DeprecationWarning: Use Network.scrobble_many(...) instead")
        
        remainder = []
        
        if len(tracks) > 50:
            remainder = tracks[50:]
            tracks = tracks[:50]
        
        params = {"s": self._get_session_id()}
        
        i = 0
        for t in tracks:
            _pad_list(t, 9, "")
            params["a[%s]" % str(i)] = _string(t[0])
            params["t[%s]" % str(i)] = _string(t[1])
            params["i[%s]" % str(i)] = str(t[2])
            params["o[%s]" % str(i)] = t[3]
            params["r[%s]" % str(i)] = t[4]
            params["l[%s]" % str(i)] = str(t[5])
            params["b[%s]" % str(i)] = _string(t[6])
            params["n[%s]" % str(i)] = t[7]
            params["m[%s]" % str(i)] = t[8]
            
            i += 1
        
        _ScrobblerRequest(self.submissions_url, params, self.network).execute()
        
        if remainder:
            self.scrobble_many(remainder)