models.py

# -*- coding: utf-8 -*-

"""
requests.models
~~~~~~~~~~~~~~~

This module contains the primary objects that power Requests.
"""

import collections
import logging
import datetime

from io import BytesIO
from .hooks import default_hooks
from .structures import CaseInsensitiveDict

from .auth import HTTPBasicAuth
from .cookies import cookiejar_from_dict, get_cookie_header
from .packages.urllib3.filepost import encode_multipart_formdata
from .exceptions import HTTPError, RequestException, MissingSchema, InvalidURL
from .utils import (
    guess_filename, get_auth_from_url, requote_uri,
    stream_decode_response_unicode, to_key_val_list, parse_header_links,
    iter_slices, guess_json_utf, super_len)
from .compat import (
    cookielib, urlparse, urlunparse, urlsplit, urlencode, str, bytes, StringIO,
    is_py2, chardet, json, builtin_str, basestring)

CONTENT_CHUNK_SIZE = 10 * 1024
ITER_CHUNK_SIZE = 512

log = logging.getLogger(__name__)


class RequestEncodingMixin(object):
    @property
    def path_url(self):
        """Build the path URL to use."""

        url = []

        p = urlsplit(self.url)

        path = p.path
        if not path:
            path = '/'

        url.append(path)

        query = p.query
        if query:
            url.append('?')
            url.append(query)

        return ''.join(url)

    @staticmethod
    def _encode_params(data):
        """Encode parameters in a piece of data.

        Will successfully encode parameters when passed as a dict or a list of
        2-tuples. Order is retained if data is a list of 2-tuples but arbitrary
        if parameters are supplied as a dict.
        """

        if isinstance(data, (str, bytes)):
            return data
        elif hasattr(data, 'read'):
            return data
        elif hasattr(data, '__iter__'):
            result = []
            for k, vs in to_key_val_list(data):
                if isinstance(vs, basestring) or not hasattr(vs, '__iter__'):
                    vs = [vs]
                for v in vs:
                    if v is not None:
                        result.append(
                            (k.encode('utf-8') if isinstance(k, str) else k,
                             v.encode('utf-8') if isinstance(v, str) else v))
            return urlencode(result, doseq=True)
        else:
            return data

    @staticmethod
    def _encode_files(files, data):
        """Build the body for a multipart/form-data request.

        Will successfully encode files when passed as a dict or a list of
        2-tuples. Order is retained if data is a list of 2-tuples but abritrary
        if parameters are supplied as a dict.

        """
        if (not files) or isinstance(data, str):
            return None

        new_fields = []
        fields = to_key_val_list(data or {})
        files = to_key_val_list(files or {})

        for field, val in fields:
            if isinstance(val, basestring) or not hasattr(val, '__iter__'):
                val = [val]
            for v in val:
                if v is not None:
                    new_fields.append(
                        (field.encode('utf-8') if isinstance(field, str) else field,
                         v.encode('utf-8') if isinstance(v, str) else v))

        for (k, v) in files:
            # support for explicit filename
            ft = None
            if isinstance(v, (tuple, list)):
                if len(v) == 2:
                    fn, fp = v
                else:
                    fn, fp, ft = v
            else:
                fn = guess_filename(v) or k
                fp = v
            if isinstance(fp, str):
                fp = StringIO(fp)
            if isinstance(fp, bytes):
                fp = BytesIO(fp)

            if ft:
                new_v = (fn, fp.read(), ft)
            else:
                new_v = (fn, fp.read())
            new_fields.append((k, new_v))

        body, content_type = encode_multipart_formdata(new_fields)

        return body, content_type


class RequestHooksMixin(object):
    def register_hook(self, event, hook):
        """Properly register a hook."""

        if isinstance(hook, collections.Callable):
            self.hooks[event].append(hook)
        elif hasattr(hook, '__iter__'):
            self.hooks[event].extend(h for h in hook if isinstance(h, collections.Callable))

    def deregister_hook(self, event, hook):
        """Deregister a previously registered hook.
        Returns True if the hook existed, False if not.
        """

        try:
            self.hooks[event].remove(hook)
            return True
        except ValueError:
            return False


class Request(RequestHooksMixin):
    """A user-created :class:`Request <Request>` object.

    Used to prepare a :class:`PreparedRequest <PreparedRequest>`, which is sent to the server.

    :param method: HTTP method to use.
    :param url: URL to send.
    :param headers: dictionary of headers to send.
    :param files: dictionary of {filename: fileobject} files to multipart upload.
    :param data: the body to attach the request. If a dictionary is provided, form-encoding will take place.
    :param params: dictionary of URL parameters to append to the URL.
    :param auth: Auth handler or (user, pass) tuple.
    :param cookies: dictionary or CookieJar of cookies to attach to this request.
    :param hooks: dictionary of callback hooks, for internal usage.

    Usage::

      >>> import requests
      >>> req = requests.Request('GET', 'http://httpbin.org/get')
      >>> req.prepare()
      <PreparedRequest [GET]>

    """
    def __init__(self,
        method=None,
        url=None,
        headers=None,
        files=None,
        data=dict(),
        params=dict(),
        auth=None,
        cookies=None,
        hooks=None):

        # Default empty dicts for dict params.
        data = [] if data is None else data
        files = [] if files is None else files
        headers = {} if headers is None else headers
        params = {} if params is None else params
        hooks = {} if hooks is None else hooks

        self.hooks = default_hooks()
        for (k, v) in list(hooks.items()):
            self.register_hook(event=k, hook=v)

        self.method = method
        self.url = url
        self.headers = headers
        self.files = files
        self.data = data
        self.params = params
        self.auth = auth
        self.cookies = cookies
        self.hooks = hooks

    def __repr__(self):
        return '<Request [%s]>' % (self.method)

    def prepare(self):
        """Constructs a :class:`PreparedRequest <PreparedRequest>` for transmission and returns it."""
        p = PreparedRequest()

        p.prepare_method(self.method)
        p.prepare_url(self.url, self.params)
        p.prepare_headers(self.headers)
        p.prepare_cookies(self.cookies)
        p.prepare_body(self.data, self.files)
        p.prepare_auth(self.auth, self.url)
        # Note that prepare_auth must be last to enable authentication schemes
        # such as OAuth to work on a fully prepared request.

        # This MUST go after prepare_auth. Authenticators could add a hook
        p.prepare_hooks(self.hooks)

        return p


class PreparedRequest(RequestEncodingMixin, RequestHooksMixin):
    """The fully mutable :class:`PreparedRequest <PreparedRequest>` object,
    containing the exact bytes that will be sent to the server.

    Generated from either a :class:`Request <Request>` object or manually.

    Usage::

      >>> import requests
      >>> req = requests.Request('GET', 'http://httpbin.org/get')
      >>> r = req.prepare()
      <PreparedRequest [GET]>

      >>> s = requests.Session()
      >>> s.send(r)
      <Response [200]>

    """

    def __init__(self):
        #: HTTP verb to send to the server.
        self.method = None
        #: HTTP URL to send the request to.
        self.url = None
        #: dictionary of HTTP headers.
        self.headers = None
        #: request body to send to the server.
        self.body = None
        #: dictionary of callback hooks, for internal usage.
        self.hooks = default_hooks()

    def __repr__(self):
        return '<PreparedRequest [%s]>' % (self.method)

    def prepare_method(self, method):
        """Prepares the given HTTP method."""
        self.method = method
        if self.method is not None:
            self.method = self.method.upper()

    def prepare_url(self, url, params):
        """Prepares the given HTTP URL."""
        #: Accept objects that have string representations.
        try:
            url = unicode(url)
        except NameError:
            # We're on Python 3.
            url = str(url)
        except UnicodeDecodeError:
            pass

        # Support for unicode domain names and paths.
        scheme, netloc, path, _params, query, fragment = urlparse(url)

        if not scheme:
            raise MissingSchema("Invalid URL %r: No schema supplied" % url)

        if not netloc:
            raise InvalidURL("Invalid URL %t: No netloc supplied" % url)

        try:
            netloc = netloc.encode('idna').decode('utf-8')
        except UnicodeError:
            raise InvalidURL('URL has an invalid label.')

        # Bare domains aren't valid URLs.
        if not path:
            path = '/'

        if is_py2:
            if isinstance(scheme, str):
                scheme = scheme.encode('utf-8')
            if isinstance(netloc, str):
                netloc = netloc.encode('utf-8')
            if isinstance(path, str):
                path = path.encode('utf-8')
            if isinstance(_params, str):
                _params = _params.encode('utf-8')
            if isinstance(query, str):
                query = query.encode('utf-8')
            if isinstance(fragment, str):
                fragment = fragment.encode('utf-8')

        enc_params = self._encode_params(params)
        if enc_params:
            if query:
                query = '%s&%s' % (query, enc_params)
            else:
                query = enc_params

        url = requote_uri(urlunparse([scheme, netloc, path, _params, query, fragment]))
        self.url = url

    def prepare_headers(self, headers):
        """Prepares the given HTTP headers."""

        if headers:
            headers = dict((name.encode('ascii'), value) for name, value in headers.items())
            self.headers = CaseInsensitiveDict(headers)
        else:
            self.headers = CaseInsensitiveDict()

    def prepare_body(self, data, files):
        """Prepares the given HTTP body data."""

        # Check if file, fo, generator, iterator.
        # If not, run through normal process.

        # Nottin' on you.
        body = None
        content_type = None
        length = None
        is_stream = False

        is_stream = all([
            hasattr(data, '__iter__'),
            not isinstance(data, basestring),
            not isinstance(data, list),
            not isinstance(data, dict)
        ])

        try:
            length = super_len(data)
        except (TypeError, AttributeError):
            length = False

        if is_stream:
            body = data

            if files:
                raise NotImplementedError('Streamed bodies and files are mutually exclusive.')

            if length:
                self.headers['Content-Length'] = str(length)
            else:
                self.headers['Transfer-Encoding'] = 'chunked'
        # Check if file, fo, generator, iterator.
        # If not, run through normal process.

        else:
            # Multi-part file uploads.
            if files:
                (body, content_type) = self._encode_files(files, data)
            else:
                if data:
                    body = self._encode_params(data)
                    if isinstance(data, str) or isinstance(data, builtin_str) or hasattr(data, 'read'):
                        content_type = None
                    else:
                        content_type = 'application/x-www-form-urlencoded'

            self.prepare_content_length(body)

            # Add content-type if it wasn't explicitly provided.
            if (content_type) and (not 'content-type' in self.headers):
                self.headers['Content-Type'] = content_type

        self.body = body

    def prepare_content_length(self, body):
        if hasattr(body, 'seek') and hasattr(body, 'tell'):
            body.seek(0, 2)
            self.headers['Content-Length'] = str(body.tell())
            body.seek(0, 0)
        elif body is not None:
            l = super_len(body)
            if l:
                self.headers['Content-Length'] = str(l)
        elif self.method not in ('GET', 'HEAD'):
            self.headers['Content-Length'] = '0'

    def prepare_auth(self, auth, url=''):
        """Prepares the given HTTP auth data."""

        # If no Auth is explicitly provided, extract it from the URL first.
        if auth is None:
            url_auth = get_auth_from_url(self.url)
            auth = url_auth if any(url_auth) else None

        if auth:
            if isinstance(auth, tuple) and len(auth) == 2:
                # special-case basic HTTP auth
                auth = HTTPBasicAuth(*auth)

            # Allow auth to make its changes.
            r = auth(self)

            # Update self to reflect the auth changes.
            self.__dict__.update(r.__dict__)

            # Recompute Content-Length
            self.prepare_content_length(self.body)

    def prepare_cookies(self, cookies):
        """Prepares the given HTTP cookie data."""

        if isinstance(cookies, cookielib.CookieJar):
            cookies = cookies
        else:
            cookies = cookiejar_from_dict(cookies)

        if 'cookie' not in self.headers:
            cookie_header = get_cookie_header(cookies, self)
            if cookie_header is not None:
                self.headers['Cookie'] = cookie_header

    def prepare_hooks(self, hooks):
        """Prepares the given hooks."""
        for event in hooks:
            self.register_hook(event, hooks[event])


class Response(object):
    """The :class:`Response <Response>` object, which contains a
    server's response to an HTTP request.
    """

    def __init__(self):
        super(Response, self).__init__()

        self._content = False
        self._content_consumed = False

        #: Integer Code of responded HTTP Status.
        self.status_code = None

        #: Case-insensitive Dictionary of Response Headers.
        #: For example, ``headers['content-encoding']`` will return the
        #: value of a ``'Content-Encoding'`` response header.
        self.headers = CaseInsensitiveDict()

        #: File-like object representation of response (for advanced usage).
        #: Requires that ``stream=True` on the request.
        # This requirement does not apply for use internally to Requests.
        self.raw = None

        #: Final URL location of Response.
        self.url = None

        #: Encoding to decode with when accessing r.text.
        self.encoding = None

        #: A list of :class:`Response <Response>` objects from
        #: the history of the Request. Any redirect responses will end
        #: up here. The list is sorted from the oldest to the most recent request.
        self.history = []

        self.reason = None

        #: A CookieJar of Cookies the server sent back.
        self.cookies = cookiejar_from_dict({})

        #: The amount of time elapsed between sending the request
        #: and the arrival of the response (as a timedelta)
        self.elapsed = datetime.timedelta(0)

    def __repr__(self):
        return '<Response [%s]>' % (self.status_code)

    def __bool__(self):
        """Returns true if :attr:`status_code` is 'OK'."""
        return self.ok

    def __nonzero__(self):
        """Returns true if :attr:`status_code` is 'OK'."""
        return self.ok

    def __iter__(self):
        """Allows you to use a response as an iterator."""
        return self.iter_content(128)

    @property
    def ok(self):
        try:
            self.raise_for_status()
        except RequestException:
            return False
        return True

    @property
    def apparent_encoding(self):
        """The apparent encoding, provided by the lovely Charade library
        (Thanks, Ian!)."""
        return chardet.detect(self.content)['encoding']

    def iter_content(self, chunk_size=1, decode_unicode=False):
        """Iterates over the response data.  When stream=True is set on the
        request, this avoids reading the content at once into memory for
        large responses.  The chunk size is the number of bytes it should
        read into memory.  This is not necessarily the length of each item
        returned as decoding can take place.
        """
        if self._content_consumed:
            # simulate reading small chunks of the content
            return iter_slices(self._content, chunk_size)

        def generate():
            while 1:
                chunk = self.raw.read(chunk_size, decode_content=True)
                if not chunk:
                    break
                yield chunk
            self._content_consumed = True

        gen = generate()

        if decode_unicode:
            gen = stream_decode_response_unicode(gen, self)

        return gen

    def iter_lines(self, chunk_size=ITER_CHUNK_SIZE, decode_unicode=None):
        """Iterates over the response data, one line at a time.  When
        stream=True is set on the request, this avoids reading the
        content at once into memory for large responses.
        """

        pending = None

        for chunk in self.iter_content(chunk_size=chunk_size,
                                       decode_unicode=decode_unicode):

            if pending is not None:
                chunk = pending + chunk
            lines = chunk.splitlines()

            if lines and lines[-1] and chunk and lines[-1][-1] == chunk[-1]:
                pending = lines.pop()
            else:
                pending = None

            for line in lines:
                yield line

        if pending is not None:
            yield pending

    @property
    def content(self):
        """Content of the response, in bytes."""

        if self._content is False:
            # Read the contents.
            try:
                if self._content_consumed:
                    raise RuntimeError(
                        'The content for this response was already consumed')

                if self.status_code == 0:
                    self._content = None
                else:
                    self._content = bytes().join(self.iter_content(CONTENT_CHUNK_SIZE)) or bytes()

            except AttributeError:
                self._content = None

        self._content_consumed = True
        # don't need to release the connection; that's been handled by urllib3
        # since we exhausted the data.
        return self._content

    @property
    def text(self):
        """Content of the response, in unicode.

        if Response.encoding is None and chardet module is available, encoding
        will be guessed.
        """

        # Try charset from content-type
        content = None
        encoding = self.encoding

        if not self.content:
            return str('')

        # Fallback to auto-detected encoding.
        if self.encoding is None:
            encoding = self.apparent_encoding

        # Decode unicode from given encoding.
        try:
            content = str(self.content, encoding, errors='replace')
        except (LookupError, TypeError):
            # A LookupError is raised if the encoding was not found which could
            # indicate a misspelling or similar mistake.
            #
            # A TypeError can be raised if encoding is None
            #
            # So we try blindly encoding.
            content = str(self.content, errors='replace')

        return content

    def json(self, **kwargs):
        """Returns the json-encoded content of a response, if any.

        :param \*\*kwargs: Optional arguments that ``json.loads`` takes.
        """

        if not self.encoding and len(self.content) > 3:
            # No encoding set. JSON RFC 4627 section 3 states we should expect
            # UTF-8, -16 or -32. Detect which one to use; If the detection or
            # decoding fails, fall back to `self.text` (using chardet to make
            # a best guess).
            encoding = guess_json_utf(self.content)
            if encoding is not None:
                return json.loads(self.content.decode(encoding), **kwargs)
        return json.loads(self.text or self.content, **kwargs)

    @property
    def links(self):
        """Returns the parsed header links of the response, if any."""

        header = self.headers.get('link')

        # l = MultiDict()
        l = {}

        if header:
            links = parse_header_links(header)

            for link in links:
                key = link.get('rel') or link.get('url')
                l[key] = link

        return l

    def raise_for_status(self):
        """Raises stored :class:`HTTPError`, if one occurred."""

        http_error_msg = ''

        if 400 <= self.status_code < 500:
            http_error_msg = '%s Client Error: %s' % (self.status_code, self.reason)

        elif 500 <= self.status_code < 600:
            http_error_msg = '%s Server Error: %s' % (self.status_code, self.reason)

        if http_error_msg:
            raise HTTPError(http_error_msg, response=self)

    def close(self):
        return self.raw.release_conn()