requests/models.py

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

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

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

import collections
import datetime

from io import BytesIO, UnsupportedOperation
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.fields import RequestField
from .packages.urllib3.filepost import encode_multipart_formdata
from .packages.urllib3.util import parse_url
from .packages.urllib3.exceptions import (
    DecodeError, ReadTimeoutError, ProtocolError, LocationParseError)
from .exceptions import (
    HTTPError, MissingSchema, InvalidURL, ChunkedEncodingError,
    ContentDecodingError, ConnectionError, StreamConsumedError)
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, to_native_string)
from .compat import (
    cookielib, urlunparse, urlsplit, urlencode, str, bytes, StringIO,
    is_py2, chardet, json, builtin_str, basestring)
from .status_codes import codes

#: The set of HTTP status codes that indicate an automatically
#: processable redirect.
REDIRECT_STATI = (
    codes.moved,              # 301
    codes.found,              # 302
    codes.other,              # 303
    codes.temporary_redirect, # 307
    codes.permanent_redirect, # 308
)
DEFAULT_REDIRECT_LIMIT = 30
CONTENT_CHUNK_SIZE = 10 * 1024
ITER_CHUNK_SIZE = 512

json_dumps = json.dumps


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 arbitrary
        if parameters are supplied as a dict.

        """
        if (not files):
            raise ValueError("Files must be provided.")
        elif isinstance(data, basestring):
            raise ValueError("Data must not be a string.")

        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:
                    # Don't call str() on bytestrings: in Py3 it all goes wrong.
                    if not isinstance(v, bytes):
                        v = str(v)

                    new_fields.append(
                        (field.decode('utf-8') if isinstance(field, bytes) else field,
                         v.encode('utf-8') if isinstance(v, str) else v))

        for (k, v) in files:
            # support for explicit filename
            ft = None
            fh = None
            if isinstance(v, (tuple, list)):
                if len(v) == 2:
                    fn, fp = v
                elif len(v) == 3:
                    fn, fp, ft = v
                else:
                    fn, fp, ft, fh = v
            else:
                fn = guess_filename(v) or k
                fp = v
            if isinstance(fp, str):
                fp = StringIO(fp)
            if isinstance(fp, bytes):
                fp = BytesIO(fp)

            rf = RequestField(name=k, data=fp.read(),
                              filename=fn, headers=fh)
            rf.make_multipart(content_type=ft)
            new_fields.append(rf)

        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 event not in self.hooks:
            raise ValueError('Unsupported event specified, with event name "%s"' % (event))

        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 to the request. If a dictionary is provided, form-encoding will take place.
    :param json: json for the body to attach to the request (if data is not specified).
    :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=None,
        params=None,
        auth=None,
        cookies=None,
        hooks=None,
        json=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.json = json
        self.params = params
        self.auth = auth
        self.cookies = cookies

    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,
            url=self.url,
            headers=self.headers,
            files=self.files,
            data=self.data,
            json=self.json,
            params=self.params,
            auth=self.auth,
            cookies=self.cookies,
            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
        # The `CookieJar` used to create the Cookie header will be stored here
        # after prepare_cookies is called
        self._cookies = None
        #: request body to send to the server.
        self.body = None
        #: dictionary of callback hooks, for internal usage.
        self.hooks = default_hooks()

    def prepare(self, method=None, url=None, headers=None, files=None,
                data=None, params=None, auth=None, cookies=None, hooks=None,
                json=None):
        """Prepares the entire request with the given parameters."""

        self.prepare_method(method)
        self.prepare_url(url, params)
        self.prepare_headers(headers)
        self.prepare_cookies(cookies)
        self.prepare_body(data, files, json)
        self.prepare_auth(auth, 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
        self.prepare_hooks(hooks)

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

    def copy(self):
        p = PreparedRequest()
        p.method = self.method
        p.url = self.url
        p.headers = self.headers.copy() if self.headers is not None else None
        p._cookies = self._cookies.copy() if self._cookies is not None else None
        p.body = self.body
        p.hooks = self.hooks
        return p

    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.
        #: We're unable to blindy call unicode/str functions
        #: as this will include the bytestring indicator (b'')
        #: on python 3.x.
        #: https://github.com/kennethreitz/requests/pull/2238
        if isinstance(url, bytes):
            url = url.decode('utf8')
        else:
            url = unicode(url) if is_py2 else str(url)

        # Don't do any URL preparation for non-HTTP schemes like `mailto`,
        # `data` etc to work around exceptions from `url_parse`, which
        # handles RFC 3986 only.
        if ':' in url and not url.lower().startswith('http'):
            self.url = url
            return

        # Support for unicode domain names and paths.
        try:
            scheme, auth, host, port, path, query, fragment = parse_url(url)
        except LocationParseError as e:
            raise InvalidURL(*e.args)

        if not scheme:
            raise MissingSchema("Invalid URL {0!r}: No schema supplied. "
                                "Perhaps you meant http://{0}?".format(url))

        if not host:
            raise InvalidURL("Invalid URL %r: No host supplied" % url)

        # Only want to apply IDNA to the hostname
        try:
            host = host.encode('idna').decode('utf-8')
        except UnicodeError:
            raise InvalidURL('URL has an invalid label.')

        # Carefully reconstruct the network location
        netloc = auth or ''
        if netloc:
            netloc += '@'
        netloc += host
        if port:
            netloc += ':' + str(port)

        # 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(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, None, query, fragment]))
        self.url = url

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

        if headers:
            self.headers = CaseInsensitiveDict((to_native_string(name), value) for name, value in headers.items())
        else:
            self.headers = CaseInsensitiveDict()

    def prepare_body(self, data, files, json=None):
        """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

        if json is not None:
            content_type = 'application/json'
            body = json_dumps(json)

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

        try:
            length = super_len(data)
        except (TypeError, AttributeError, UnsupportedOperation):
            length = None

        if is_stream:
            body = data

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

            if length is not None:
                self.headers['Content-Length'] = builtin_str(length)
            else:
                self.headers['Transfer-Encoding'] = 'chunked'
        else:
            # Multi-part file uploads.
            if files:
                (body, content_type) = self._encode_files(files, data)
            else:
                if data and json is None:
                    body = self._encode_params(data)
                    if isinstance(data, basestring) 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 ('content-type' not 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'] = builtin_str(body.tell())
            body.seek(0, 0)
        elif body is not None:
            l = super_len(body)
            if l:
                self.headers['Content-Length'] = builtin_str(l)
        elif (self.method not in ('GET', 'HEAD')) and (self.headers.get('Content-Length') is None):
            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):
            self._cookies = cookies
        else:
            self._cookies = cookiejar_from_dict(cookies)

        cookie_header = get_cookie_header(self._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.
    """

    __attrs__ = [
        '_content',
        'status_code',
        'headers',
        'url',
        'history',
        'encoding',
        'reason',
        'cookies',
        'elapsed',
        'request',
    ]

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

        self._content = False
        self._content_consumed = False

        #: Integer Code of responded HTTP Status, e.g. 404 or 200.
        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).
        #: Use of ``raw`` requires that ``stream=True`` be set 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 = []

        #: Textual reason of responded HTTP Status, e.g. "Not Found" or "OK".
        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)

        #: The :class:`PreparedRequest <PreparedRequest>` object to which this
        #: is a response.
        self.request = None

    def __getstate__(self):
        # Consume everything; accessing the content attribute makes
        # sure the content has been fully read.
        if not self._content_consumed:
            self.content

        return dict(
            (attr, getattr(self, attr, None))
            for attr in self.__attrs__
        )

    def __setstate__(self, state):
        for name, value in state.items():
            setattr(self, name, value)

        # pickled objects do not have .raw
        setattr(self, '_content_consumed', True)
        setattr(self, 'raw', None)

    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 HTTPError:
            return False
        return True

    @property
    def is_redirect(self):
        """True if this Response is a well-formed HTTP redirect that could have
        been processed automatically (by :meth:`Session.resolve_redirects`).
        """
        return ('location' in self.headers and self.status_code in REDIRECT_STATI)

    @property
    def is_permanent_redirect(self):
        """True if this Response one of the permanant versions of redirect"""
        return ('location' in self.headers and self.status_code in (codes.moved_permanently, codes.permanent_redirect))

    @property
    def apparent_encoding(self):
        """The apparent encoding, provided by the chardet library"""
        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 decode_unicode is True, content will be decoded using the best
        available encoding based on the response.
        """
        def generate():
            try:
                # Special case for urllib3.
                try:
                    for chunk in self.raw.stream(chunk_size, decode_content=True):
                        yield chunk
                except ProtocolError as e:
                    raise ChunkedEncodingError(e)
                except DecodeError as e:
                    raise ContentDecodingError(e)
                except ReadTimeoutError as e:
                    raise ConnectionError(e)
            except AttributeError:
                # Standard file-like object.
                while True:
                    chunk = self.raw.read(chunk_size)
                    if not chunk:
                        break
                    yield chunk

            self._content_consumed = True

        if self._content_consumed and isinstance(self._content, bool):
            raise StreamConsumedError()
        # simulate reading small chunks of the content
        reused_chunks = iter_slices(self._content, chunk_size)

        stream_chunks = generate()

        chunks = reused_chunks if self._content_consumed else stream_chunks

        if decode_unicode:
            chunks = stream_decode_response_unicode(chunks, self)

        return chunks

    def iter_lines(self, chunk_size=ITER_CHUNK_SIZE, decode_unicode=None, delimiter=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

            if delimiter:
                lines = chunk.split(delimiter)
            else:
                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, encoding will be guessed using
        ``chardet``.

        The encoding of the response content is determined based solely on HTTP
        headers, following RFC 2616 to the letter. If you can take advantage of
        non-HTTP knowledge to make a better guess at the encoding, you should
        set ``r.encoding`` appropriately before accessing this property.
        """

        # 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:
                try:
                    return json.loads(self.content.decode(encoding), **kwargs)
                except UnicodeDecodeError:
                    # Wrong UTF codec detected; usually because it's not UTF-8
                    # but some other 8-bit codec.  This is an RFC violation,
                    # and the server didn't bother to tell us what codec *was*
                    # used.
                    pass
        return json.loads(self.text, **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):
        """Releases the connection back to the pool. Once this method has been
        called the underlying ``raw`` object must not be accessed again.

        *Note: Should not normally need to be called explicitly.*
        """
        return self.raw.release_conn()