text: # -*- coding: utf-8 -*-
  """
  oauthlib.oauth2.rfc6749
  ~~~~~~~~~~~~~~~~~~~~~~~
  
  This module is an implementation of various logic needed
  for consuming OAuth 2.0 RFC6749.
  """
  from __future__ import absolute_import, unicode_literals
  
  import time
  import warnings
  
  from oauthlib.common import generate_token
  from oauthlib.oauth2.rfc6749 import tokens
  from oauthlib.oauth2.rfc6749.errors import (InsecureTransportError,
                                              TokenExpiredError)
  from oauthlib.oauth2.rfc6749.parameters import (parse_token_response,
                                                  prepare_token_request,
                                                  prepare_token_revocation_request)
  from oauthlib.oauth2.rfc6749.utils import is_secure_transport
  
  AUTH_HEADER = 'auth_header'
  URI_QUERY = 'query'
  BODY = 'body'
  
  FORM_ENC_HEADERS = {
      'Content-Type': 'application/x-www-form-urlencoded'
  }
  
  class Client(object):
  
      """Base OAuth2 client responsible for access token management.
  
      This class also acts as a generic interface providing methods common to all
      client types such as ``prepare_authorization_request`` and
      ``prepare_token_revocation_request``. The ``prepare_x_request`` methods are
      the recommended way of interacting with clients (as opposed to the abstract
      prepare uri/body/etc methods). They are recommended over the older set
      because they are easier to use (more consistent) and add a few additional
      security checks, such as HTTPS and state checking.
  
      Some of these methods require further implementation only provided by the
      specific purpose clients such as
      :py:class:`oauthlib.oauth2.MobileApplicationClient` and thus you should always
      seek to use the client class matching the OAuth workflow you need. For
      Python, this is usually :py:class:`oauthlib.oauth2.WebApplicationClient`.
  
      """
  
      def __init__(self, client_id,
                   default_token_placement=AUTH_HEADER,
                   token_type='Bearer',
                   access_token=None,
                   refresh_token=None,
                   mac_key=None,
                   mac_algorithm=None,
                   token=None,
                   scope=None,
                   state=None,
                   redirect_url=None,
                   state_generator=generate_token,
                   **kwargs):
          """Initialize a client with commonly used attributes.
  
          :param client_id: Client identifier given by the OAuth provider upon
          registration.
  
          :param default_token_placement: Tokens can be supplied in the Authorization
          header (default), the URL query component (``query``) or the request
          body (``body``).
  
          :param token_type: OAuth 2 token type. Defaults to Bearer. Change this
          if you specify the ``access_token`` parameter and know it is of a
          different token type, such as a MAC, JWT or SAML token. Can
          also be supplied as ``token_type`` inside the ``token`` dict parameter.
  
          :param access_token: An access token (string) used to authenticate
          requests to protected resources. Can also be supplied inside the
          ``token`` dict parameter.
  
          :param refresh_token: A refresh token (string) used to refresh expired
          tokens. Can also be supplied inside the ``token`` dict parameter.
  
          :param mac_key: Encryption key used with MAC tokens.
  
          :param mac_algorithm:  Hashing algorithm for MAC tokens.
  
          :param token: A dict of token attributes such as ``access_token``,
          ``token_type`` and ``expires_at``.
  
          :param scope: A list of default scopes to request authorization for.
  
          :param state: A CSRF protection string used during authorization.
  
          :param redirect_url: The redirection endpoint on the client side to which
          the user returns after authorization.
  
          :param state_generator: A no argument state generation callable. Defaults
          to :py:meth:`oauthlib.common.generate_token`.
          """
  
          self.client_id = client_id
          self.default_token_placement = default_token_placement
          self.token_type = token_type
          self.access_token = access_token
          self.refresh_token = refresh_token
          self.mac_key = mac_key
          self.mac_algorithm = mac_algorithm
          self.token = token or {}
          self.scope = scope
          self.state_generator = state_generator
          self.state = state
          self.redirect_url = redirect_url
          self.code = None
          self.expires_in = None
          self._expires_at = None
          self.populate_token_attributes(self.token)
  
      @property
      def token_types(self):
          """Supported token types and their respective methods
  
          Additional tokens can be supported by extending this dictionary.
  
          The Bearer token spec is stable and safe to use.
  
          The MAC token spec is not yet stable and support for MAC tokens
          is experimental and currently matching version 00 of the spec.
          """
          return {
              'Bearer': self._add_bearer_token,
              'MAC': self._add_mac_token
          }
  
      def prepare_request_uri(self, *args, **kwargs):
          """Abstract method used to create request URIs."""
          raise NotImplementedError("Must be implemented by inheriting classes.")
  
      def prepare_request_body(self, *args, **kwargs):
          """Abstract method used to create request bodies."""
          raise NotImplementedError("Must be implemented by inheriting classes.")
  
      def parse_request_uri_response(self, *args, **kwargs):
          """Abstract method used to parse redirection responses."""
          raise NotImplementedError("Must be implemented by inheriting classes.")
  
      def add_token(self, uri, http_method='GET', body=None, headers=None,
                    token_placement=None, **kwargs):
          """Add token to the request uri, body or authorization header.
  
          The access token type provides the client with the information
          required to successfully utilize the access token to make a protected
          resource request (along with type-specific attributes).  The client
          MUST NOT use an access token if it does not understand the token
          type.
  
          For example, the "bearer" token type defined in
          [`I-D.ietf-oauth-v2-bearer`_] is utilized by simply including the access
          token string in the request:
  
          .. code-block:: http
  
              GET /resource/1 HTTP/1.1
              Host: example.com
              Authorization: Bearer mF_9.B5f-4.1JqM
  
          while the "mac" token type defined in [`I-D.ietf-oauth-v2-http-mac`_] is
          utilized by issuing a MAC key together with the access token which is
          used to sign certain components of the HTTP requests:
  
          .. code-block:: http
  
              GET /resource/1 HTTP/1.1
              Host: example.com
              Authorization: MAC id="h480djs93hd8",
                                  nonce="274312:dj83hs9s",
                                  mac="kDZvddkndxvhGRXZhvuDjEWhGeE="
  
          .. _`I-D.ietf-oauth-v2-bearer`: https://tools.ietf.org/html/rfc6749#section-12.2
          .. _`I-D.ietf-oauth-v2-http-mac`: https://tools.ietf.org/html/rfc6749#section-12.2
          """
          if not is_secure_transport(uri):
              raise InsecureTransportError()
  
          token_placement = token_placement or self.default_token_placement
  
          case_insensitive_token_types = dict(
              (k.lower(), v) for k, v in self.token_types.items())
          if not self.token_type.lower() in case_insensitive_token_types:
              raise ValueError("Unsupported token type: %s" % self.token_type)
  
          if not (self.access_token or self.token.get('access_token')):
              raise ValueError("Missing access token.")
  
          if self._expires_at and self._expires_at < time.time():
              raise TokenExpiredError()
  
          return case_insensitive_token_types[self.token_type.lower()](uri, http_method, body,
                                                                       headers, token_placement, **kwargs)
  
      def prepare_authorization_request(self, authorization_url, state=None,
              redirect_url=None, scope=None, **kwargs):
          """Prepare the authorization request.
  
          This is the first step in many OAuth flows in which the user is
          redirected to a certain authorization URL. This method adds
          required parameters to the authorization URL.
  
          :param authorization_url: Provider authorization endpoint URL.
  
          :param state: CSRF protection string. Will be automatically created if
          not provided. The generated state is available via the ``state``
          attribute. Clients should verify that the state is unchanged and
          present in the authorization response. This verification is done
          automatically if using the ``authorization_response`` parameter
          with ``prepare_token_request``.
  
          :param redirect_url: Redirect URL to which the user will be returned
          after authorization. Must be provided unless previously setup with
          the provider. If provided then it must also be provided in the
          token request.
  
          :param kwargs: Additional parameters to included in the request.
  
          :returns: The prepared request tuple with (url, headers, body).
          """
          if not is_secure_transport(authorization_url):
              raise InsecureTransportError()
  
          self.state = state or self.state_generator()
          self.redirect_url = redirect_url or self.redirect_url
          self.scope = scope or self.scope
          auth_url = self.prepare_request_uri(
                  authorization_url, redirect_uri=self.redirect_url,
                  scope=self.scope, state=self.state, **kwargs)
          return auth_url, FORM_ENC_HEADERS, ''
  
      def prepare_token_request(self, token_url, authorization_response=None,
              redirect_url=None, state=None, body='', **kwargs):
          """Prepare a token creation request.
  
          Note that these requests usually require client authentication, either
          by including client_id or a set of provider specific authentication
          credentials.
  
          :param token_url: Provider token creation endpoint URL.
  
          :param authorization_response: The full redirection URL string, i.e.
          the location to which the user was redirected after successfull
          authorization. Used to mine credentials needed to obtain a token
          in this step, such as authorization code.
  
          :param redirect_url: The redirect_url supplied with the authorization
          request (if there was one).
  
          :param body: Request body (URL encoded string).
  
          :param kwargs: Additional parameters to included in the request.
  
          :returns: The prepared request tuple with (url, headers, body).
          """
          if not is_secure_transport(token_url):
              raise InsecureTransportError()
  
          state = state or self.state
          if authorization_response:
              self.parse_request_uri_response(
                      authorization_response, state=state)
          self.redirect_url = redirect_url or self.redirect_url
          body = self.prepare_request_body(body=body,
                  redirect_uri=self.redirect_url, **kwargs)
  
          return token_url, FORM_ENC_HEADERS, body
  
      def prepare_refresh_token_request(self, token_url, refresh_token=None,
              body='', scope=None, **kwargs):
          """Prepare an access token refresh request.
  
          Expired access tokens can be replaced by new access tokens without
          going through the OAuth dance if the client obtained a refresh token.
          This refresh token and authentication credentials can be used to
          obtain a new access token, and possibly a new refresh token.
  
          :param token_url: Provider token refresh endpoint URL.
  
          :param refresh_token: Refresh token string.
  
          :param body: Request body (URL encoded string).
  
          :param scope: List of scopes to request. Must be equal to
          or a subset of the scopes granted when obtaining the refresh
          token.
  
          :param kwargs: Additional parameters to included in the request.
  
          :returns: The prepared request tuple with (url, headers, body).
          """
          if not is_secure_transport(token_url):
              raise InsecureTransportError()
  
          self.scope = scope or self.scope
          body = self.prepare_refresh_body(body=body,
                  refresh_token=refresh_token, scope=self.scope, **kwargs)
          return token_url, FORM_ENC_HEADERS, body
  
      def prepare_token_revocation_request(self, revocation_url, token,
              token_type_hint="access_token", body='', callback=None, **kwargs):
          """Prepare a token revocation request.
  
          :param revocation_url: Provider token revocation endpoint URL.
  
          :param token: The access or refresh token to be revoked (string).
  
          :param token_type_hint: ``"access_token"`` (default) or
          ``"refresh_token"``. This is optional and if you wish to not pass it you
          must provide ``token_type_hint=None``.
  
          :param callback: A jsonp callback such as ``package.callback`` to be invoked
          upon receiving the response. Not that it should not include a () suffix.
  
          :param kwargs: Additional parameters to included in the request.
  
          :returns: The prepared request tuple with (url, headers, body).
  
          Note that JSONP request may use GET requests as the parameters will
          be added to the request URL query as opposed to the request body.
  
          An example of a revocation request
  
          .. code-block: http
  
              POST /revoke HTTP/1.1
              Host: server.example.com
              Content-Type: application/x-www-form-urlencoded
              Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
  
              token=45ghiukldjahdnhzdauz&token_type_hint=refresh_token
  
          An example of a jsonp revocation request
  
          .. code-block: http
  
              GET /revoke?token=agabcdefddddafdd&callback=package.myCallback HTTP/1.1
              Host: server.example.com
              Content-Type: application/x-www-form-urlencoded
              Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
  
          and an error response
  
          .. code-block: http
  
          package.myCallback({"error":"unsupported_token_type"});
  
          Note that these requests usually require client credentials, client_id in
          the case for public clients and provider specific authentication
          credentials for confidential clients.
          """
          if not is_secure_transport(revocation_url):
              raise InsecureTransportError()
  
          return prepare_token_revocation_request(revocation_url, token,
                  token_type_hint=token_type_hint, body=body, callback=callback,
                  **kwargs)
  
      def parse_request_body_response(self, body, scope=None, **kwargs):
          """Parse the JSON response body.
  
          If the access token request is valid and authorized, the
          authorization server issues an access token as described in
          `Section 5.1`_.  A refresh token SHOULD NOT be included.  If the request
          failed client authentication or is invalid, the authorization server
          returns an error response as described in `Section 5.2`_.
  
          :param body: The response body from the token request.
          :param scope: Scopes originally requested.
          :return: Dictionary of token parameters.
          :raises: Warning if scope has changed. OAuth2Error if response is invalid.
  
          These response are json encoded and could easily be parsed without
          the assistance of OAuthLib. However, there are a few subtle issues
          to be aware of regarding the response which are helpfully addressed
          through the raising of various errors.
  
          A successful response should always contain
  
          **access_token**
                  The access token issued by the authorization server. Often
                  a random string.
  
          **token_type**
              The type of the token issued as described in `Section 7.1`_.
              Commonly ``Bearer``.
  
          While it is not mandated it is recommended that the provider include
  
          **expires_in**
              The lifetime in seconds of the access token.  For
              example, the value "3600" denotes that the access token will
              expire in one hour from the time the response was generated.
              If omitted, the authorization server SHOULD provide the
              expiration time via other means or document the default value.
  
          **scope**
              Providers may supply this in all responses but are required to only
              if it has changed since the authorization request.
  
          .. _`Section 5.1`: https://tools.ietf.org/html/rfc6749#section-5.1
          .. _`Section 5.2`: https://tools.ietf.org/html/rfc6749#section-5.2
          .. _`Section 7.1`: https://tools.ietf.org/html/rfc6749#section-7.1
          """
          self.token = parse_token_response(body, scope=scope)
          self.populate_token_attributes(self.token)
          return self.token
  
      def prepare_refresh_body(self, body='', refresh_token=None, scope=None, **kwargs):
          """Prepare an access token request, using a refresh token.
  
          If the authorization server issued a refresh token to the client, the
          client makes a refresh request to the token endpoint by adding the
          following parameters using the "application/x-www-form-urlencoded"
          format in the HTTP request entity-body:
  
          grant_type
                  REQUIRED.  Value MUST be set to "refresh_token".
          refresh_token
                  REQUIRED.  The refresh token issued to the client.
          scope
                  OPTIONAL.  The scope of the access request as described by
                  Section 3.3.  The requested scope MUST NOT include any scope
                  not originally granted by the resource owner, and if omitted is
                  treated as equal to the scope originally granted by the
                  resource owner.
          """
          refresh_token = refresh_token or self.refresh_token
          return prepare_token_request('refresh_token', body=body, scope=scope,
                                       refresh_token=refresh_token, **kwargs)
  
      def _add_bearer_token(self, uri, http_method='GET', body=None,
                            headers=None, token_placement=None):
          """Add a bearer token to the request uri, body or authorization header."""
          if token_placement == AUTH_HEADER:
              headers = tokens.prepare_bearer_headers(self.access_token, headers)
  
          elif token_placement == URI_QUERY:
              uri = tokens.prepare_bearer_uri(self.access_token, uri)
  
          elif token_placement == BODY:
              body = tokens.prepare_bearer_body(self.access_token, body)
  
          else:
              raise ValueError("Invalid token placement.")
          return uri, headers, body
  
      def _add_mac_token(self, uri, http_method='GET', body=None,
                         headers=None, token_placement=AUTH_HEADER, ext=None, **kwargs):
          """Add a MAC token to the request authorization header.
  
          Warning: MAC token support is experimental as the spec is not yet stable.
          """
          headers = tokens.prepare_mac_header(self.access_token, uri,
                                              self.mac_key, http_method, headers=headers, body=body, ext=ext,
                                              hash_algorithm=self.mac_algorithm, **kwargs)
          return uri, headers, body
  
      def _populate_attributes(self, response):
          warnings.warn("Please switch to the public method "
                        "populate_token_attributes.", DeprecationWarning)
          return self.populate_token_attributes(response)
  
      def populate_code_attributes(self, response):
          """Add attributes from an auth code response to self."""
  
          if 'code' in response:
              self.code = response.get('code')
  
      def populate_token_attributes(self, response):
          """Add attributes from a token exchange response to self."""
  
          if 'access_token' in response:
              self.access_token = response.get('access_token')
  
          if 'refresh_token' in response:
              self.refresh_token = response.get('refresh_token')
  
          if 'token_type' in response:
              self.token_type = response.get('token_type')
  
          if 'expires_in' in response:
              self.expires_in = response.get('expires_in')
              self._expires_at = time.time() + int(self.expires_in)
  
          if 'expires_at' in response:
              self._expires_at = int(response.get('expires_at'))
  
          if 'mac_key' in response:
              self.mac_key = response.get('mac_key')
  
          if 'mac_algorithm' in response:
              self.mac_algorithm = response.get('mac_algorithm')
  