helpers.py

# coding=UTF-8

"""Helper functions

Consists of functions to typically be used within templates, but also
available to Controllers. This module is available to templates as 'h'.
"""
import email.utils
import datetime
import logging
import re
import urllib
import pprint
import copy
import logging

from paste.deploy.converters import asbool
from webhelpers.html import escape, HTML, literal, url_escape
from webhelpers.html.tools import mail_to
from webhelpers.html.tags import *
from webhelpers.markdown import markdown
from webhelpers import paginate
from webhelpers.text import truncate
import webhelpers.date as date
from pylons import url as _pylons_default_url
from pylons.decorators.cache import beaker_cache
from pylons import config
from routes import redirect_to as _redirect_to
from routes import url_for as _routes_default_url_for
from alphabet_paginate import AlphaPage
import i18n
import ckan.exceptions
from pylons import request
from pylons import session
from pylons import c
from pylons.i18n import _, ungettext

import html_resources
from lib.maintain import deprecated
import ckan.model as model

get_available_locales = i18n.get_available_locales
get_locales_dict = i18n.get_locales_dict

log = logging.getLogger(__name__)

try:
    from collections import OrderedDict # from python 2.7
except ImportError:
    from sqlalchemy.util import OrderedDict

try:
    import json
except ImportError:
    import simplejson as json

_log = logging.getLogger(__name__)

def redirect_to(*args, **kw):
    '''A routes.redirect_to wrapper to retain the i18n settings'''
    kw['__ckan_no_root'] = True
    if are_there_flash_messages():
        kw['__no_cache__'] = True
    return _redirect_to(url_for(*args, **kw))

def url(*args, **kw):
    """Create url adding i18n information if selected
    wrapper for pylons.url"""
    locale = kw.pop('locale', None)
    my_url = _pylons_default_url(*args, **kw)
    return _add_i18n_to_url(my_url, locale=locale, **kw)

def url_for(*args, **kw):
    """Create url adding i18n information if selected
    wrapper for routes.url_for"""
    locale = kw.pop('locale', None)
    # remove __ckan_no_root and add after to not pollute url
    no_root = kw.pop('__ckan_no_root', False)
    # routes will get the wrong url for APIs if the ver is not provided
    if kw.get('controller') == 'api':
        ver = kw.get('ver')
        if not ver:
            raise Exception('api calls must specify the version! e.g. ver=1')
        # fix ver to include the slash
        kw['ver'] = '/%s' % ver
    my_url = _routes_default_url_for(*args, **kw)
    kw['__ckan_no_root'] = no_root
    return _add_i18n_to_url(my_url, locale=locale, **kw)

def url_for_static(*args, **kw):
    """Create url for static content that does not get translated
    eg css, js
    wrapper for routes.url_for"""
    my_url = _routes_default_url_for(*args, **kw)
    return my_url

def _add_i18n_to_url(url_to_amend, **kw):
    # If the locale keyword param is provided then the url is rewritten
    # using that locale .If return_to is provided this is used as the url
    # (as part of the language changing feature).
    # A locale of default will not add locale info to the url.


    default_locale = False
    locale = kw.pop('locale', None)
    no_root = kw.pop('__ckan_no_root', False)
    allowed_locales = ['default'] + i18n.get_locales()
    if locale and locale not in allowed_locales:
        locale = None
    if locale:
        if locale == 'default':
            default_locale = True
    else:
        try:
            locale = request.environ.get('CKAN_LANG')
            default_locale = request.environ.get('CKAN_LANG_IS_DEFAULT', True)
        except TypeError:
            default_locale = True
    try:
        root = request.environ.get('SCRIPT_NAME', '')
    except TypeError:
        root = ''
    if kw.get('qualified', False):
        # if qualified is given we want the full url ie http://...
        root = _routes_default_url_for('/', qualified=True)[:-1] + root
    # ckan.root_path is defined when we have none standard language
    # position in the url
    root_path = config.get('ckan.root_path', None)
    if root_path:
        # FIXME this can be written better once the merge
        # into the ecportal core is done - Toby
        # we have a special root specified so use that
        if default_locale:
            root = re.sub('/{{LANG}}', '', root_path)
        else:
            root = re.sub('{{LANG}}', locale, root_path)
        # make sure we don't have a trailing / on the root
        if root[-1] == '/':
            root = root[:-1]
        url = url_to_amend[len(re.sub('/{{LANG}}', '', root_path)):]
        url = '%s%s' % (root, url)
        root = re.sub('/{{LANG}}', '', root_path)
    else:
        if default_locale:
            url = url_to_amend
        else:
            # we need to strip the root from the url and the add it before
            # the language specification.
            url = url_to_amend[len(root):]
            url = '%s/%s%s' % (root, locale,  url)

    # stop the root being added twice in redirects
    if no_root:
        url = url_to_amend[len(root):]
        if not default_locale:
            url = '/%s%s' % (locale,  url)

    if url == '/packages':
        raise ckan.exceptions.CkanUrlException('There is a broken url being created %s' % kw)

    return url


def full_current_url():
    ''' Returns the fully qualified current url (eg http://...) useful
    for sharing etc '''
    return(url_for(request.environ['CKAN_CURRENT_URL'], qualified=True))

def lang():
    ''' Return the language code for the current locale eg `en` '''
    return request.environ.get('CKAN_LANG')

def lang_native_name(lang=None):
    ''' Return the langage name currently used in it's localised form
        either from parameter or current environ setting'''
    lang = lang or lang()
    locale = get_locales_dict().get(lang)
    if locale:
        return locale.display_name or locale.english_name
    return lang

class Message(object):
    """A message returned by ``Flash.pop_messages()``.

    Converting the message to a string returns the message text. Instances
    also have the following attributes:

    * ``message``: the message text.
    * ``category``: the category specified when the message was created.
    """

    def __init__(self, category, message, allow_html):
        self.category=category
        self.message=message
        self.allow_html=allow_html

    def __str__(self):
        return self.message

    __unicode__ = __str__

    def __html__(self):
        if self.allow_html:
            return self.message
        else:
            return escape(self.message)

class _Flash(object):

    # List of allowed categories.  If None, allow any category.
    categories = ["", "alert-info", "alert-error", "alert-success"]

    # Default category if none is specified.
    default_category = ""

    def __init__(self, session_key="flash", categories=None, default_category=None):
        self.session_key = session_key
        if categories is not None:
            self.categories = categories
        if default_category is not None:
            self.default_category = default_category
        if self.categories and self.default_category not in self.categories:
            raise ValueError("unrecognized default category %r" % (self.default_category,))

    def __call__(self, message, category=None, ignore_duplicate=False, allow_html=False):
        if not category:
            category = self.default_category
        elif self.categories and category not in self.categories:
            raise ValueError("unrecognized category %r" % (category,))
        # Don't store Message objects in the session, to avoid unpickling
        # errors in edge cases.
        new_message_tuple = (category, message, allow_html)
        messages = session.setdefault(self.session_key, [])
        # ``messages`` is a mutable list, so changes to the local variable are
        # reflected in the session.
        if ignore_duplicate:
            for i, m in enumerate(messages):
                if m[1] == message:
                    if m[0] != category:
                        messages[i] = new_message_tuple
                        session.save()
                    return    # Original message found, so exit early.
        messages.append(new_message_tuple)
        session.save()

    def pop_messages(self):
        messages = session.pop(self.session_key, [])
        # only save session if it has changed
        if messages:
            session.save()
        return [Message(*m) for m in messages]

    def are_there_messages(self):
        return bool(session.get(self.session_key))

flash = _Flash()
# this is here for backwards compatability
_flash = flash

def flash_notice(message, allow_html=False):
    ''' Show a flash message of type notice '''
    flash(message, category='alert-info', allow_html=allow_html)

def flash_error(message, allow_html=False):
    ''' Show a flash message of type error '''
    flash(message, category='alert-error', allow_html=allow_html)

def flash_success(message, allow_html=False):
    ''' Show a flash message of type success '''
    flash(message, category='alert-success', allow_html=allow_html)

def are_there_flash_messages():
    ''' Returns True if there are flash messages for the current user '''
    return flash.are_there_messages()



def nav_link(*args, **kwargs):
    # nav_link() used to need c passing as the first arg
    # this is deprecated as pointless
    # throws error if ckan.restrict_template_vars is True
    # When we move to strict helpers then this should be removed as a wrapper
    if len(args) > 2 or (len(args) > 1 and 'controller' in kwargs):
        if not asbool(config.get('ckan.restrict_template_vars', 'false')):
            return _nav_link(*args[1:], **kwargs)
        raise Exception('nav_link() calling has been changed. remove c in template %s or included one' % c.__template_name)
    return _nav_link(*args, **kwargs)

def _nav_link(text, controller, **kwargs):
    '''
    params
    class_: pass extra class(s) to add to the <a> tag
    icon: name of ckan icon to use within the link
    condition: if False then no link is returned
    '''
    highlight_actions = kwargs.pop("highlight_actions",
                                   kwargs["action"]).split()
    icon = kwargs.pop('icon', None)
    if icon:
        text = literal('<i class="ckan-icon ckan-icon-%s"></i> ' % icon) + text
    active =(' active' if
            c.controller == controller and c.action in highlight_actions
            else '')
    class_ = kwargs.pop('class_', '') + active
    if kwargs.pop('condition', True):
        link = link_to(
            text,
            url_for(controller=controller, **kwargs),
            class_=class_
        )
    else:
        link = ''
    return link

def nav_named_link(*args, **kwargs):
    # subnav_link() used to need c passing as the first arg
    # this is deprecated as pointless
    # throws error if ckan.restrict_template_vars is True
    # When we move to strict helpers then this should be removed as a wrapper
    if len(args) > 3 or (len(args) > 0 and 'text' in kwargs) or \
       (len(args) > 1 and 'name' in kwargs):
        if not asbool(config.get('ckan.restrict_template_vars', 'false')):
            return _nav_named_link(*args[1:], **kwargs)
        raise Exception('nav_named_link() calling has been changed. remove c in template %s or included one' % c.__template_name)
    return _nav_named_link(*args, **kwargs)

def _nav_named_link(text, name, **kwargs):
    return link_to(
        text,
        url_for(name, **kwargs),
#        class_=('active' if
#                c.action in highlight_actions
#                else '')
    )

def subnav_link(*args, **kwargs):
    # subnav_link() used to need c passing as the first arg
    # this is deprecated as pointless
    # throws error if ckan.restrict_template_vars is True
    # When we move to strict helpers then this should be removed as a wrapper
    if len(args) > 2 or (len(args) > 1 and 'action' in kwargs):
        if not asbool(config.get('ckan.restrict_template_vars', 'false')):
            return _subnav_link(*args[1:], **kwargs)
        raise Exception('subnav_link() calling has been changed. remove c in template %s or included one' % c.__template_name)
    return _subnav_link(*args, **kwargs)

def _subnav_link(text, action, **kwargs):
    return link_to(
        text,
        url_for(action=action, **kwargs),
        class_=('active' if c.action == action else '')
    )

def subnav_named_route(*args, **kwargs):
    # subnav_link() used to need c passing as the first arg
    # this is deprecated as pointless
    # throws error if ckan.restrict_template_vars is True
    # When we move to strict helpers then this should be removed as a wrapper
    if len(args) > 2 or (len(args) > 0 and 'text' in kwargs) or \
       (len(args) > 1 and 'routename' in kwargs):
        if not asbool(config.get('ckan.restrict_template_vars', 'false')):
            return _subnav_named_route(*args[1:], **kwargs)
        raise Exception('subnav_named_route() calling has been changed. remove c in template %s or included one' % c.__template_name)
    return _subnav_named_route(*args, **kwargs)

def _subnav_named_route(text, routename, **kwargs):
    """ Generate a subnav element based on a named route """
    return link_to(
        text,
        url_for(str(routename), **kwargs),
        class_=('active' if c.action == kwargs['action'] else '')
    )

def build_nav_main(*args):
    ''' build a set of menu items.

    args: tuples of (menu type, title) eg ('login', _('Login'))
    outputs <li><a href="...">title</a></li>
    '''
    output = ''
    for item in args:
        menu_item, title = item[:2]
        if len(item) == 3 and not check_access(item[2]):
            continue
        output += _make_menu_item(menu_item, title)
    return output


def _make_menu_item(menu_item, title):
    if menu_item not in _menu_items:
        log.error('menu item `%s` cannot be found' % menu_item)
        return literal('<li><a href="#">') + title + literal('</a></li>')
    item = _menu_items[menu_item]
    if 'name' in item:
        link = nav_named_link(title, **item)
    elif 'url' in item:
        return literal('<li><a href="%s">' % item.url) + title + literal('</a></li>')
    else:
        item = copy.copy(_menu_items[menu_item])
        controller = item.pop('controller')
        link = nav_link(title, controller, **item)
    return literal('<li>') + link + literal('</li>')


def default_group_type():
    return str( config.get('ckan.default.group_type', 'group') )


_menu_items = {
    'add dataset' : dict(controller='package', action='new'),
    'search' : dict(controller='package',
                    action='search',
                    highlight_actions = 'index search'),
    'default_group': dict(name='%s_index' % default_group_type()),
    'about' : dict(controller='home', action='about'),
    'login' : dict(controller='user', action='login'),
    'register' : dict(controller='user', action='register'),
}



def get_facet_items_dict(facet, limit=10, exclude_active=False):
    '''Return the list of unselected facet items for the given facet, sorted
    by count.

    Returns the list of unselected facet contraints or facet items (e.g. tag
    names like "russian" or "tolstoy") for the given search facet (e.g.
    "tags"), sorted by facet item count (i.e. the number of search results that
    match each facet item).

    Reads the complete list of facet items for the given facet from
    c.search_facets, and filters out the facet items that the user has already
    selected.

    Arguments:
    facet -- the name of the facet to filter.
    limit -- the max. number of facet items to return.
    exclude_active -- only return unselected facets.

    '''
    if not c.search_facets or \
       not c.search_facets.get(facet) or \
       not c.search_facets.get(facet).get('items'):
        return []
    facets = []
    for facet_item in c.search_facets.get(facet)['items']:
        if not len(facet_item['name'].strip()):
            continue
        if not (facet, facet_item['name']) in request.params.items():
            facets.append(dict(active=False, **facet_item))
        elif not exclude_active:
            facets.append(dict(active=True, **facet_item))
    facets = sorted(facets, key=lambda item: item['count'], reverse=True)
    if c.search_facets_limits:
        limit = c.search_facets_limits.get(facet)
    if limit:
        return facets[:limit]
    else:
        return facets

def unselected_facet_items(facet, limit=10):
    '''Return the list of unselected facet items for the given facet, sorted
    by count.

    Returns the list of unselected facet contraints or facet items (e.g. tag
    names like "russian" or "tolstoy") for the given search facet (e.g.
    "tags"), sorted by facet item count (i.e. the number of search results that
    match each facet item).

    Reads the complete list of facet items for the given facet from
    c.search_facets, and filters out the facet items that the user has already
    selected.

    Arguments:
    facet -- the name of the facet to filter.
    limit -- the max. number of facet items to return.

    '''
    # TODO if we agree to propossed change then we can just wrap
    # get_facet_items_dict()

    #return get_facet_items_dict(facet, limit=limit, exclude_active=True)
    if not c.search_facets or \
       not c.search_facets.get(facet) or \
       not c.search_facets.get(facet).get('items'):
        return []
    facets = []
    for facet_item in c.search_facets.get(facet)['items']:
        if not len(facet_item['name'].strip()):
            continue
        if not (facet, facet_item['name']) in request.params.items():
            facets.append(facet_item)
    facets = sorted(facets, key=lambda item: item['count'], reverse=True)
    if c.search_facets_limits:
        limit = c.search_facets_limits.get(facet)
    if limit:
        return facets[:limit]
    else:
        return facets

@deprecated()
def facet_items(*args, **kwargs):
    """
    DEPRECATED: Use the new facet data structure, and `unselected_facet_items()`
    """
    _log.warning('Deprecated function: ckan.lib.helpers:facet_items().  Will be removed in v1.8')
    # facet_items() used to need c passing as the first arg
    # this is deprecated as pointless
    # throws error if ckan.restrict_template_vars is True
    # When we move to strict helpers then this should be removed as a wrapper
    if len(args) > 2 or (len(args) > 0 and 'name' in kwargs) or (len(args) > 1 and 'limit' in kwargs):
        if not asbool(config.get('ckan.restrict_template_vars', 'false')):
            return _facet_items(*args[1:], **kwargs)
        raise Exception('facet_items() calling has been changed. remove c in template %s or included one' % c.__template_name)
    return _facet_items(*args, **kwargs)


def _facet_items(name, limit=10):
    if not c.facets or not c.facets.get(name):
        return []
    facets = []
    for k, v in c.facets.get(name).items():
        if not len(k.strip()):
            continue
        if not (name, k) in request.params.items():
            facets.append((k, v))
    return sorted(facets, key=lambda (k, v): v, reverse=True)[:limit]

def facet_title(name):
    # FIXME this looks like an i18n issue
    return config.get('search.facets.%s.title' % name, name.capitalize())

@deprecated('Please use check_access instead.')
def am_authorized(c, action, domain_object=None):
    ''' Deprecated. Please use check_access instead'''
    from ckan.authz import Authorizer
    if domain_object is None:
        domain_object = model.System()
    return Authorizer.am_authorized(c, action, domain_object)

def check_access(action, data_dict=None):
    from ckan.logic import check_access as check_access_logic,NotAuthorized

    context = {'model': model,
                'user': c.user or c.author}

    try:
        check_access_logic(action,context,data_dict)
        authorized = True
    except NotAuthorized:
        authorized = False

    return authorized

def linked_user(user, maxlength=0):
    if user in [model.PSEUDO_USER__LOGGED_IN, model.PSEUDO_USER__VISITOR]:
        return user
    if not isinstance(user, model.User):
        user_name = unicode(user)
        user = model.User.get(user_name)
        if not user:
            return user_name
    if user:
        _name = user.name if model.User.VALID_NAME.match(user.name) else user.id
        _icon = gravatar(user.email_hash, 20)
        displayname = user.display_name
        if maxlength and len(user.display_name) > maxlength:
            displayname = displayname[:maxlength] + '...'
        return _icon + link_to(displayname,
                       url_for(controller='user', action='read', id=_name))

def linked_authorization_group(authgroup, maxlength=0):
    if not isinstance(authgroup, model.AuthorizationGroup):
        authgroup_name = unicode(authgroup)
        authgroup = model.AuthorizationGroup.get(authgroup_name)
        if not authgroup:
            return authgroup_name
    if authgroup:
        displayname = authgroup.name or authgroup.id
        if maxlength and len(display_name) > maxlength:
            displayname = displayname[:maxlength] + '...'
        return link_to(displayname,
                       url_for(controller='authorization_group', action='read', id=displayname))

def group_name_to_title(name):
    group = model.Group.by_name(name)
    if group is not None:
        return group.display_name
    return name

def markdown_extract(text, extract_length=190):
    if (text is None) or (text.strip() == ''):
        return ''
    plain = re.sub(r'<.*?>', '', markdown(text))
    return unicode(truncate(plain, length=extract_length, indicator='...', whole_word=True))

def icon_url(name):
    return url_for_static('/images/icons/%s.png' % name)

def icon_html(url, alt=None, inline=True):
    classes = ''
    if inline: classes += 'inline-icon '
    return literal('<img src="%s" height="16px" width="16px" alt="%s" class="%s" /> ' % (url, alt, classes))

def icon(name, alt=None, inline=True):
    return icon_html(icon_url(name),alt,inline)

def resource_icon(res):
    if False:
        icon_name = 'page_white'
    # if (res.is_404?): icon_name = 'page_white_error'
    # also: 'page_white_gear'
    # also: 'page_white_link'
        return icon(icon_name)
    else:
        return icon(format_icon(res.get('format','')))

def format_icon(_format):
    _format = _format.lower()
    if ('json' in _format): return 'page_white_cup'
    if ('csv' in _format): return 'page_white_gear'
    if ('xls' in _format): return 'page_white_excel'
    if ('zip' in _format): return 'page_white_compressed'
    if ('api' in _format): return 'page_white_database'
    if ('plain text' in _format): return 'page_white_text'
    if ('xml' in _format): return 'page_white_code'
    return 'page_white'

def dict_list_reduce(list_, key, unique=True):
    ''' Take a list of dicts and create a new one containing just the
    values for the key with unique values if requested. '''
    new_list = []
    for item in list_:
        value = item.get(key)
        if not value or (unique and value in new_list):
            continue
        new_list.append(value)
    return new_list


def linked_gravatar(email_hash, size=100, default=None):
    return literal(
        '<a href="https://gravatar.com/" target="_blank"' +
        'title="%s">' % _('Update your avatar at gravatar.com') +
        '%s</a>' % gravatar(email_hash,size,default)
        )

_VALID_GRAVATAR_DEFAULTS = ['404', 'mm', 'identicon', 'monsterid', 'wavatar', 'retro']
def gravatar(email_hash, size=100, default=None):
    if default is None:
        default = config.get('ckan.gravatar_default', 'identicon')

    if not default in _VALID_GRAVATAR_DEFAULTS:
        # treat the default as a url
        default = urllib.quote(default, safe='')

    return literal('''<img src="http://gravatar.com/avatar/%s?s=%d&amp;d=%s"
        class="gravatar" />'''
        % (email_hash, size, default)
        )

def pager_url(page, partial=None, **kwargs):
    routes_dict = _pylons_default_url.environ['pylons.routes_dict']
    kwargs['controller'] = routes_dict['controller']
    kwargs['action'] = routes_dict['action']
    if routes_dict.get('id'):
        kwargs['id'] = routes_dict['id']
    kwargs['page'] = page
    return url(**kwargs)

class Page(paginate.Page):
    # Curry the pager method of the webhelpers.paginate.Page class, so we have
    # our custom layout set as default.
    def pager(self, *args, **kwargs):
        kwargs.update(
            format=u"<div class='pagination pagination-centered'><ul>$link_previous ~2~ $link_next</ul></div>",
            symbol_previous=u'«', symbol_next=u'»',
            curpage_attr={'class':'active'}, link_attr={}
        )
        return super(Page, self).pager(*args, **kwargs)

    # Put each page link into a <li> (for Bootstrap to style it)
    def _pagerlink(self, page, text, extra_attributes=None):
        anchor = super(Page, self)._pagerlink(page, text)
        extra_attributes = extra_attributes or {}
        return HTML.li(anchor, **extra_attributes)

    # Change 'current page' link from <span> to <li><a>
    # and '..' into '<li><a>..'
    # (for Bootstrap to style them properly)
    def _range(self, regexp_match):
        html = super(Page, self)._range(regexp_match)
        # Convert ..
        dotdot = '<span class="pager_dotdot">..</span>'
        dotdot_link = HTML.li(HTML.a('...', href='#'), class_='disabled')
        html = re.sub(dotdot, dotdot_link, html)

        # Convert current page
        text = '%s' % self.page
        current_page_span = str(HTML.span(c=text, **self.curpage_attr))
        current_page_link = self._pagerlink(self.page, text, extra_attributes=self.curpage_attr)
        return re.sub(current_page_span, current_page_link, html)

def render_datetime(datetime_, date_format=None, with_hours=False):
    '''Render a datetime object or timestamp string as a pretty string
    (Y-m-d H:m).
    If timestamp is badly formatted, then a blank string is returned.
    '''
    if not date_format:
        date_format = '%b %d, %Y'
        if with_hours:
            date_format += ', %H:%M'
    if isinstance(datetime_, datetime.datetime):
        return datetime_.strftime(date_format)
    elif isinstance(datetime_, basestring):
        try:
            datetime_ = date_str_to_datetime(datetime_)
        except TypeError:
            return ''
        except ValueError:
            return ''
        return datetime_.strftime(date_format)
    else:
        return ''

@deprecated()
def datetime_to_date_str(datetime_):
    '''DEPRECATED: Takes a datetime.datetime object and returns a string of it
    in ISO format.
    '''
    return datetime_.isoformat()

def date_str_to_datetime(date_str):
    '''Convert ISO-like formatted datestring to datetime object.

    This function converts ISO format date- and datetime-strings into
    datetime objects.  Times may be specified down to the microsecond.  UTC
    offset or timezone information may **not** be included in the string.

    Note - Although originally documented as parsing ISO date(-times), this
           function doesn't fully adhere to the format.  This function will
           throw a ValueError if the string contains UTC offset information.
           So in that sense, it is less liberal than ISO format.  On the
           other hand, it is more liberal of the accepted delimiters between
           the values in the string.  Also, it allows microsecond precision,
           despite that not being part of the ISO format.
    '''

    time_tuple = re.split('[^\d]+', date_str, maxsplit=5)

    # Extract seconds and microseconds
    if len(time_tuple) >= 6:
        m = re.match('(?P<seconds>\d{2})(\.(?P<microseconds>\d{6}))?$',
                     time_tuple[5])
        if not m:
            raise ValueError('Unable to parse %s as seconds.microseconds' %
                             time_tuple[5])
        seconds = int(m.groupdict().get('seconds'))
        microseconds = int(m.groupdict(0).get('microseconds'))
        time_tuple = time_tuple[:5] + [seconds, microseconds]

    return datetime.datetime(*map(int, time_tuple))

def parse_rfc_2822_date(date_str, assume_utc=True):
    """
    Parse a date string of the form specified in RFC 2822, and return a datetime.

    RFC 2822 is the date format used in HTTP headers.  It should contain timezone
    information, but that cannot be relied upon.

    If date_str doesn't contain timezone information, then the 'assume_utc' flag
    determines whether we assume this string is local (with respect to the
    server running this code), or UTC.  In practice, what this means is that if
    assume_utc is True, then the returned datetime is 'aware', with an associated
    tzinfo of offset zero.  Otherwise, the returned datetime is 'naive'.

    If timezone information is available in date_str, then the returned datetime
    is 'aware', ie - it has an associated tz_info object.

    Returns None if the string cannot be parsed as a valid datetime.
    """
    time_tuple = email.utils.parsedate_tz(date_str)

    # Not parsable
    if not time_tuple:
        return None

    # No timezone information available in the string
    if time_tuple[-1] is None and not assume_utc:
        return datetime.datetime.fromtimestamp(email.utils.mktime_tz(time_tuple))
    else:
        offset = 0 if time_tuple[-1] is None else time_tuple[-1]
        tz_info = _RFC2282TzInfo(offset)
    return datetime.datetime(*time_tuple[:6], microsecond=0, tzinfo=tz_info)

class _RFC2282TzInfo(datetime.tzinfo):
    """
    A datetime.tzinfo implementation used by parse_rfc_2822_date() function.

    In order to return timezone information, a concrete implementation of
    datetime.tzinfo is required.  This class represents tzinfo that knows
    about it's offset from UTC, has no knowledge of daylight savings time, and
    no knowledge of the timezone name.

    """

    def __init__(self, offset):
        """
        offset from UTC in seconds.
        """
        self.offset = datetime.timedelta(seconds=offset)

    def utcoffset(self, dt):
        return self.offset

    def dst(self, dt):
        """
        Dates parsed from an RFC 2822 string conflate timezone and dst, and so
        it's not possible to determine whether we're in DST or not, hence
        returning None.
        """
        return None

    def tzname(self, dt):
        return None


def time_ago_in_words_from_str(date_str, granularity='month'):
    if date_str:
        return date.time_ago_in_words(date_str_to_datetime(date_str), granularity=granularity)
    else:
        return _('Unknown')

def button_attr(enable, type='primary'):
    if enable:
        return 'class="btn %s"' % type
    return 'disabled class="btn disabled"'

def dataset_display_name(package_or_package_dict):
    if isinstance(package_or_package_dict, dict):
        return package_or_package_dict.get('title', '') or package_or_package_dict.get('name', '')
    else:
        return package_or_package_dict.title or package_or_package_dict.name

def dataset_link(package_or_package_dict):
    if isinstance(package_or_package_dict, dict):
        name = package_or_package_dict['name']
    else:
        name = package_or_package_dict.name
    text = dataset_display_name(package_or_package_dict)
    return link_to(
        text,
        url_for(controller='package', action='read', id=name)
        )

# TODO: (?) support resource objects as well
def resource_display_name(resource_dict):
    name = resource_dict.get('name', None)
    description = resource_dict.get('description', None)
    if name:
        return name
    elif description:
        description = description.split('.')[0]
        max_len = 60;
        if len(description)>max_len: description = description[:max_len]+'...'
        return description
    else:
        noname_string = _('no name')
        return '[%s] %s' % (noname_string, resource_dict['id'])

def resource_link(resource_dict, package_id):
    text = resource_display_name(resource_dict)
    url = url_for(controller='package',
        action='resource_read',
        id=package_id,
        resource_id=resource_dict['id'])
    return link_to(text, url)

def tag_link(tag):
    url = url_for(controller='tag', action='read', id=tag['name'])
    return link_to(tag['name'], url)

def group_link(group):
    url = url_for(controller='group', action='read', id=group['name'])
    return link_to(group['name'], url)

def dump_json(obj, **kw):
    return json.dumps(obj, **kw)

def auto_log_message(*args):
    # auto_log_message() used to need c passing as the first arg
    # this is deprecated as pointless
    # throws error if ckan.restrict_template_vars is True
    # When we move to strict helpers then this should be removed as a wrapper
    if len(args) and asbool(config.get('ckan.restrict_template_vars', 'false')):
        raise Exception('auto_log_message() calling has been changed. remove c in template %s or included one' % c.__template_name)
    return _auto_log_message()

def _auto_log_message():
    if (c.action=='new') :
        return _('Created new dataset.')
    elif (c.action=='editresources'):
        return _('Edited resources.')
    elif (c.action=='edit'):
        return _('Edited settings.')
    return ''

def activity_div(template, activity, actor, object=None, target=None):
    actor = '<span class="actor">%s</span>' % actor
    if object:
        object = '<span class="object">%s</span>' % object
    if target:
        target = '<span class="target">%s</span>' % target
    date = '<span class="date">%s</span>' % render_datetime(activity['timestamp'])
    template = template.format(actor=actor, date=date, object=object, target=target)
    template = '<div class="activity">%s %s</div>' % (template, date)
    return literal(template)

def snippet(template_name, **kw):
    ''' This function is used to load html snippets into pages. keywords
    can be used to pass parameters into the snippet rendering '''
    import ckan.lib.base as base
    return base.render_snippet(template_name, **kw)


def convert_to_dict(object_type, objs):
    ''' This is a helper function for converting lists of objects into
    lists of dicts. It is for backwards compatability only. '''

    def dictize_revision_list(revision, context):
        # conversionof revision lists
        def process_names(items):
            array = []
            for item in items:
                array.append(item.name)
            return array

        rev = {'id' : revision.id,
               'state' : revision.state,
               'timestamp' : revision.timestamp,
               'author' : revision.author,
               'packages' : process_names(revision.packages),
               'groups' : process_names(revision.groups),
               'message' : revision.message,}
        return rev
    import lib.dictization.model_dictize as md
    converters = {'package' : md.package_dictize,
                  'revisions' : dictize_revision_list}
    converter = converters[object_type]
    items = []
    context = {'model' : model}
    for obj in objs:
        item = converter(obj, context)
        items.append(item)
    return items


def include_resource(resource):
    r = getattr(html_resources, resource)
    r.need()

def debug_inspect(arg):
    ''' Output pprint.pformat view of supplied arg '''
    return literal('<pre>') + pprint.pformat(arg) + literal('</pre>')

def debug_full_info_as_list():
    ''' This dumps the template variables for debugging purposes only. '''
    out = []
    ignored_keys = ['c', 'app_globals', 'g', 'h', 'request', 'tmpl_context',
                    'actions', 'translator', 'session', 'N_', 'ungettext',
                    'config', 'response', '_']
    ignored_context_keys = ['__class__', '__context', '__delattr__', '__dict__',
                            '__doc__', '__format__', '__getattr__',
                            '__getattribute__', '__hash__', '__init__',
                            '__module__', '__new__', '__reduce__',
                            '__reduce_ex__', '__repr__', '__setattr__',
                            '__sizeof__', '__str__', '__subclasshook__',
                            '__template_name', '__template_path',
                            '__weakref__', 'action', 'environ', 'pylons',
                            'start_response']

    for key in c.__context.keys():
        if not key in ignored_keys:
            out.append((key, c.__context.get(key)))

    for key in dir(c.__context['tmpl_context']):
        if not key in ignored_context_keys:
            out.append((key, pprint.pformat(getattr(c, key))))

    return out

def debug_full_info():
    ''' This dumps the template variables for debugging purposes only. '''
    out  = []
    info = debug_full_info_as_list()

    for key, value in info:
        out.append('<b>%s<b> : <pre>%s</pre>' %
            (key, escape(value)))

    return literal('<br/>'.join(out))

def popular(type_, number, min=1, title=None):
    ''' display a popular icon. '''
    if type_ == 'views':
        title = ungettext('{number} view', '{number} views', number)
    elif type_ == 'recent views':
        title = ungettext('{number} recent view', '{number} recent views', number)
    elif not title:
        raise Exception('popular() did not recieve a valid type_ or title')
    return snippet('snippets/popular.html', title=title, number=number, min=min)

# these are the functions that will end up in `h` template helpers
# if config option restrict_template_vars is true
__allowed_functions__ = [
    # functions defined in ckan.lib.helpers
           'redirect_to',
           'url',
           'url_for',
           'url_for_static',
           'lang',
           'flash',
           'flash_error',
           'flash_notice',
           'flash_success',
           'nav_link',
           'nav_named_link',
           'subnav_link',
           'subnav_named_route',
           'default_group_type',
           'facet_items',
           'facet_title',
         #  am_authorized, # deprecated
           'check_access',
           'linked_user',
           'linked_authorization_group',
           'group_name_to_title',
           'markdown_extract',
           'icon',
           'icon_html',
           'icon_url',
           'resource_icon',
           'format_icon',
           'linked_gravatar',
           'gravatar',
           'pager_url',
           'render_datetime',
           'date_str_to_datetime',
           'datetime_to_date_str',
           'parse_rfc_2822_date',
           'time_ago_in_words_from_str',
           'button_attr',
           'dataset_display_name',
           'dataset_link',
           'resource_display_name',
           'resource_link',
           'tag_link',
           'group_link',
           'dump_json',
           'auto_log_message',
           'snippet',
           'convert_to_dict',
           'activity_div',
           'lang_native_name',
           'get_facet_items_dict',
           'unselected_facet_items',
           'include_resource',
           'build_nav_main',
           'debug_inspect',
           'dict_list_reduce',
           'full_current_url',
           'popular',
           'debug_full_info',
           'debug_full_info_as_list',
    # imported into ckan.lib.helpers
           'literal',
           'link_to',
           'get_available_locales',
           'get_locales_dict',
           'truncate',
           'file',
           'mail_to',
           'radio',
           'submit',
           'asbool',
]