session

class Session(SessionRedirectMixin):
    """A Requests session.

    Provides cookie persistence, connection-pooling, and configuration.

    Basic Usage::

      >>> import requests
      >>> s = requests.Session()
      >>> s.get('https://httpbin.org/get')
      <Response [200]>

    Or as a context manager::

      >>> with requests.Session() as s:
      >>>     s.get('https://httpbin.org/get')
      <Response [200]>
    """

    __attrs__ = [
        'headers', 'cookies', 'auth', 'proxies', 'hooks', 'params', 'verify',
        'cert', 'prefetch', 'adapters', 'stream', 'trust_env',
        'max_redirects',
    ]

    def __init__(self):

        #: A case-insensitive dictionary of headers to be sent on each
        #: :class:`Request <Request>` sent from this
        #: :class:`Session <Session>`.
        self.headers = default_headers()

        #: Default Authentication tuple or object to attach to
        #: :class:`Request <Request>`.
        self.auth = None

        #: Dictionary mapping protocol or protocol and host to the URL of the proxy
        #: (e.g. {'http': 'foo.bar:3128', 'http://host.name': 'foo.bar:4012'}) to
        #: be used on each :class:`Request <Request>`.
        self.proxies = {}

        #: Event-handling hooks.
        self.hooks = default_hooks()

        #: Dictionary of querystring data to attach to each
        #: :class:`Request <Request>`. The dictionary values may be lists for
        #: representing multivalued query parameters.
        self.params = {}

        #: Stream response content default.
        self.stream = False

        #: SSL Verification default.
        self.verify = True

        #: SSL client certificate default, if String, path to ssl client
        #: cert file (.pem). If Tuple, ('cert', 'key') pair.
        self.cert = None

        #: Maximum number of redirects allowed. If the request exceeds this
        #: limit, a :class:`TooManyRedirects` exception is raised.
        #: This defaults to requests.models.DEFAULT_REDIRECT_LIMIT, which is
        #: 30.
        self.max_redirects = DEFAULT_REDIRECT_LIMIT

        #: Trust environment settings for proxy configuration, default
        #: authentication and similar.
        self.trust_env = True

        #: A CookieJar containing all currently outstanding cookies set on this
        #: session. By default it is a
        #: :class:`RequestsCookieJar <requests.cookies.RequestsCookieJar>`, but
        #: may be any other ``cookielib.CookieJar`` compatible object.
        self.cookies = cookiejar_from_dict({})

        # Default connection adapters.
        self.adapters = OrderedDict()
        self.mount('https://', HTTPAdapter())
        self.mount('http://', HTTPAdapter())

    def __enter__(self):
        return self

    def __exit__(self, *args):
        self.close()

    def prepare_request(self, request):
        """Constructs a :class:`PreparedRequest <PreparedRequest>` for
        transmission and returns it. The :class:`PreparedRequest` has settings
        merged from the :class:`Request <Request>` instance and those of the
        :class:`Session`.

        :param request: :class:`Request` instance to prepare with this
            session's settings.
        :rtype: requests.PreparedRequest
        """
        cookies = request.cookies or {}

        # Bootstrap CookieJar.
        if not isinstance(cookies, cookielib.CookieJar):
            cookies = cookiejar_from_dict(cookies)

        # Merge with session cookies
        merged_cookies = merge_cookies(
            merge_cookies(RequestsCookieJar(), self.cookies), cookies)

        # Set environment's basic authentication if not explicitly set.
        auth = request.auth
        if self.trust_env and not auth and not self.auth:
            auth = get_netrc_auth(request.url)

        p = PreparedRequest()
        p.prepare(
            method=request.method.upper(),
            url=request.url,
            files=request.files,
            data=request.data,
            json=request.json,
            headers=merge_setting(request.headers, self.headers, dict_class=CaseInsensitiveDict),
            params=merge_setting(request.params, self.params),
            auth=merge_setting(auth, self.auth),
            cookies=merged_cookies,
            hooks=merge_hooks(request.hooks, self.hooks),
        )
        return p

    def request(self, method, url,
            params=None, data=None, headers=None, cookies=None, files=None,
            auth=None, timeout=None, allow_redirects=True, proxies=None,
            hooks=None, stream=None, verify=None, cert=None, json=None):
        """Constructs a :class:`Request <Request>`, prepares it and sends it.
        Returns :class:`Response <Response>` object.

        :param method: method for the new :class:`Request` object.
        :param url: URL for the new :class:`Request` object.
        :param params: (optional) Dictionary or bytes to be sent in the query
            string for the :class:`Request`.
        :param data: (optional) Dictionary, list of tuples, bytes, or file-like
            object to send in the body of the :class:`Request`.
        :param json: (optional) json to send in the body of the
            :class:`Request`.
        :param headers: (optional) Dictionary of HTTP Headers to send with the
            :class:`Request`.
        :param cookies: (optional) Dict or CookieJar object to send with the
            :class:`Request`.
        :param files: (optional) Dictionary of ``'filename': file-like-objects``
            for multipart encoding upload.
        :param auth: (optional) Auth tuple or callable to enable
            Basic/Digest/Custom HTTP Auth.
        :param timeout: (optional) How long to wait for the server to send
            data before giving up, as a float, or a :ref:`(connect timeout,
            read timeout) <timeouts>` tuple.
        :type timeout: float or tuple
        :param allow_redirects: (optional) Set to True by default.
        :type allow_redirects: bool
        :param proxies: (optional) Dictionary mapping protocol or protocol and
            hostname to the URL of the proxy.
        :param stream: (optional) whether to immediately download the response
            content. Defaults to ``False``.
        :param verify: (optional) Either a boolean, in which case it controls whether we verify
            the server's TLS certificate, or a string, in which case it must be a path
            to a CA bundle to use. Defaults to ``True``.
        :param cert: (optional) if String, path to ssl client cert file (.pem).
            If Tuple, ('cert', 'key') pair.
        :rtype: requests.Response
        """
        # Create the Request.
        req = Request(
            method=method.upper(),
            url=url,
            headers=headers,
            files=files,
            data=data or {},
            json=json,
            params=params or {},
            auth=auth,
            cookies=cookies,
            hooks=hooks,
        )
        prep = self.prepare_request(req)

        proxies = proxies or {}

        settings = self.merge_environment_settings(
            prep.url, proxies, stream, verify, cert
        )

        # Send the request.
        send_kwargs = {
            'timeout': timeout,
            'allow_redirects': allow_redirects,
        }
        send_kwargs.update(settings)
        resp = self.send(prep, **send_kwargs)

        return resp

    def get(self, url, **kwargs):
        r"""Sends a GET request. Returns :class:`Response` object.

        :param url: URL for the new :class:`Request` object.
        :param \*\*kwargs: Optional arguments that ``request`` takes.
        :rtype: requests.Response
        """

        kwargs.setdefault('allow_redirects', True)
        return self.request('GET', url, **kwargs)