Source code for oauth2.grant

"""
Grants are the heart of OAuth 2.0. Each Grant defines one way for a client to
retrieve an authorization. They are defined in
`Section 4 <http://tools.ietf.org/html/rfc6749#section-4>`_ of the OAuth 2.0
spec.

OAuth 2.0 comes in two flavours of how an access token is issued:
two-legged and three-legged auth. To avoid confusion they are explained in
short here.

Three-legged OAuth
------------------
The "three" symbolizes the parties that are involved:

* The client that wants to access a resource on behalf of the user.
* The user who grants access to her resources.
* The server that issues the access token if the user allows it.

Two-legged OAuth
----------------
The two-legged OAuth process differs from the three-legged process by one
missing participant. The user cannot allow or deny access.

So there are two remaining parties:

* The client that wants to access a resource.
* The server that issues the access.
"""
import time

from oauth2.compatibility import json, quote, urlencode
from oauth2.datatype import AccessToken, AuthorizationCode
from oauth2.error import (AccessTokenNotFound, AuthCodeNotFound,
                          InvalidSiteAdapter, OAuthInvalidError,
                          RedirectUriUnknown, UserIdentifierMissingError,
                          UserNotAuthenticated)
from oauth2.tokengenerator import StatelessTokenGenerator
from oauth2.web import (AuthorizationCodeGrantSiteAdapter,
                        ImplicitGrantSiteAdapter,
                        ResourceOwnerGrantSiteAdapter, Response)


def encode_scopes(scopes, use_quote=False):
    """
    Creates a string out of a list of scopes.

    :param scopes: A list of scopes
    :param use_quote: Boolean flag indicating whether the string should be quoted

    :return: Scopes as a string
    """
    scopes_as_string = Scope.separator.join(scopes)
    return quote(scopes_as_string) if use_quote else scopes_as_string


def json_error_response(error, response, status_code=400):
    """
    Formats an error as a response containing a JSON body.
    """
    msg = {"error": error.error, "error_description": error.explanation}

    response.status_code = status_code
    response.add_header("Content-Type", "application/json")
    response.body = json.dumps(msg)

    return response


def json_success_response(data, response):
    """
    Formats the response of a successful token request as JSON.

    Also adds default headers and status code.
    """
    response.body = json.dumps(data)
    response.status_code = 200

    response.add_header("Content-Type", "application/json")
    response.add_header("Cache-Control", "no-store")
    response.add_header("Pragma", "no-cache")


class ResponseTypeGrant(object):
    def error_response(self, response):
        pass


[docs]class Scope(object): """ Handling of the "scope" parameter in a request. If ``available`` and ``default`` are both ``None``, the "scope" parameter is ignored (the default). :param available: A list of strings each defining one supported scope. :param default: Value to fall back to in case no scope is present in a request. """ separator = " " def __init__(self, available=None, default=None): self.scopes = [] self.send_back = False self.available_scopes = available if isinstance(available, list) else [] self.default = default def compare(self, previous_scopes): """ Compares the scopes read from request with previously issued scopes. :param previous_scopes: A list of scopes. :return: ``True`` """ for scope in self.scopes: if scope not in previous_scopes: raise OAuthInvalidError(error="invalid_scope", explanation="Invalid scope parameter in request") return True
[docs] def parse(self, request, source): """ Parses scope value in given request. Expects the value of the "scope" parameter in request to be a string where each requested scope is separated by a white space:: # One scope requested "profile_read" # Multiple scopes "profile_read profile_write" :param request: An instance of :class:`oauth2.web.Request`. :param source: Where to read the scope from. Pass "body" in case of a application/x-www-form-urlencoded body and "query" in case the scope is supplied as a query parameter in the URL of a request. """ if source == "body": req_scope = request.post_param("scope") elif source == "query": req_scope = request.get_param("scope") else: raise ValueError("Unknown scope source '%s'" % source) if req_scope is None: if self.default is not None: self.scopes = [self.default] self.send_back = True return elif len(self.available_scopes) != 0: raise OAuthInvalidError(error="invalid_scope", explanation="Missing scope parameter in request") else: return req_scopes = req_scope.split(self.separator) self.scopes = [scope for scope in req_scopes if scope in self.available_scopes] if len(self.scopes) == 0 and self.default is not None: self.scopes = [self.default] self.send_back = True
[docs]class ScopeGrant(object): """ Handling of scopes in the OAuth 2.0 flow. Inherited by all grants that need to support scopes. :param default_scope: The scope identifier that is returned by default. (optional) :param scopes: A list of strings identifying the scopes that the grant supports. :param scope_class: The class that does the actual handling in a request. Default: :class:`oauth2.grant.Scope`. """ def __init__(self, default_scope=None, scopes=None, scope_class=Scope, **kwargs): self.default_scope = default_scope self.scopes = scopes self.scope_class = scope_class super(ScopeGrant, self).__init__(**kwargs) def _create_scope_handler(self): return self.scope_class(available=self.scopes, default=self.default_scope)
class GrantHandler(object): """ Base class every oauth2 handler can extend. """ def process(self, request, response, environ): """ Handles the logic of how a user gets an access token. This includes steps like calling the implementation of a `SiteAdapter` if the user is authorized or generating a new access token. This method uses data read in `read_validate_params`. """ raise NotImplementedError def read_validate_params(self, request): """ Reads and validates the incoming data. """ raise NotImplementedError def handle_error(self, error, response): """ Takes all the actions necessary to return an error response in the format defined for a specific grant handler. """ raise NotImplementedError
[docs]class GrantHandlerFactory(object): """ Base class every handler factory can extend. This class defines the basic interface of each Grant. """ def __call__(self, request, server): raise NotImplementedError
class AuthRequestMixin(object): """ Generalization of reading and validating an incoming request used by `oauth2.grant.AuthorizationCodeAuthHandler` and `oauth2.grant.ImplicitGrantHandler`. """ def __init__(self, client_authenticator, scope_handler, token_generator, **kwargs): self.client = None self.state = None self.client_authenticator = client_authenticator self.scope_handler = scope_handler self.token_generator = token_generator super(AuthRequestMixin, self).__init__(**kwargs) def read_validate_params(self, request): """ Reads and validates data in an incoming request as required by the Authorization Request of the Authorization Code Grant and the Implicit Grant. """ self.client = self.client_authenticator.by_identifier(request) response_type = request.get_param("response_type") if self.client.response_type_supported(response_type) is False: raise OAuthInvalidError(error="unauthorized_client") self.state = request.get_param("state") self.scope_handler.parse(request, "query") return True class AuthorizeMixin(object): """ Used by all grants that involve user interaction. """ def __init__(self, site_adapter, **kwargs): self.site_adapter = site_adapter super(AuthorizeMixin, self).__init__(**kwargs) def authorize(self, request, response, environ, scopes): """ Controls all steps to authorize a request by a user. :param request: The incoming :class:`oauth2.web.Request` :param response: The :class:`oauth2.web.Response` that will be returned eventually :param environ: The environment variables of this request :param scopes: The scopes requested by an application :return: A tuple containing (`dict`, user_id) or the response. """ if self.site_adapter.user_has_denied_access(request) is True: raise OAuthInvalidError(error="access_denied", explanation="Authorization denied by user") try: result = self.site_adapter.authenticate(request, environ, scopes, self.client) return self.sanitize_return_value(result) except UserNotAuthenticated: return self.site_adapter.render_auth_page(request, response, environ, scopes, self.client) @staticmethod def sanitize_return_value(value): if isinstance(value, tuple) and len(value) is 2: return value return value, None class AccessTokenMixin(object): """ Used by grants that handle refresh token and unique token. """ def __init__(self, access_token_store, token_generator, unique_token=False, **kwargs): self.access_token_store = access_token_store self.token_generator = token_generator # Stateless token can't have unique_token by definition if isinstance(token_generator, StatelessTokenGenerator): unique_token = False self.unique_token = unique_token super(AccessTokenMixin, self).__init__(**kwargs) def create_token(self, client_id, data, grant_type, scopes, user_id): if self.unique_token: if user_id is None: raise UserIdentifierMissingError try: access_token = self.access_token_store.fetch_existing_token_of_user(client_id, grant_type, user_id) if (access_token.scopes == scopes and access_token.is_expired() is False): token_data = {"access_token": access_token.token, "token_type": "Bearer"} if access_token.refresh_token is not None: token_data["refresh_token"] = access_token.refresh_token token_data["expires_in"] = access_token.expires_in return token_data except AccessTokenNotFound: pass token_data = self.token_generator.create_access_token_data(data, scopes, grant_type, user_id, client_id) access_token = AccessToken(client_id=client_id, data=data, grant_type=grant_type, token=token_data["access_token"], scopes=scopes, user_id=user_id) if "refresh_token" in token_data: expires_at = int(time.time()) + token_data["expires_in"] access_token.expires_at = expires_at access_token.refresh_token = token_data["refresh_token"] refresh_expires_in = self.token_generator.refresh_expires_in refresh_expires_at = int(time.time()) + refresh_expires_in if refresh_expires_in else refresh_expires_in access_token.refresh_expires_at = refresh_expires_at self.access_token_store.save_token(access_token) return token_data
[docs]class SiteAdapterMixin(object): """ Mixed in by Grant classes that require a site adapter. A concrete class must set the class attribute ``site_adapter_class`` that contains a reference to the site adapter class that this class expects. """ site_adapter_class = None def __init__(self, site_adapter, **kwargs): if isinstance(site_adapter, self.site_adapter_class) is False: raise InvalidSiteAdapter( "Site adapter must inherit from class '{0}'".format(self.site_adapter_class.__name__) ) self.site_adapter = site_adapter super(SiteAdapterMixin, self).__init__(**kwargs)
class AuthorizationCodeAuthHandler(AuthorizeMixin, AuthRequestMixin, GrantHandler): """ Implementation of the first step of the Authorization Code Grant (three-legged). """ token_expiration = 600 def __init__(self, auth_token_store, **kwargs): self.auth_code_store = auth_token_store super(AuthorizationCodeAuthHandler, self).__init__(**kwargs) def process(self, request, response, environ): """ Generates a new authorization token. A form to authorize the access of the application can be displayed with the help of `oauth2.web.SiteAdapter`. """ data = self.authorize(request, response, environ, self.scope_handler.scopes) if isinstance(data, Response): return data code = self.token_generator.generate() expires = int(time.time()) + self.token_expiration auth_code = AuthorizationCode(client_id=self.client.identifier, code=code, expires_at=expires, redirect_uri=self.client.redirect_uri, scopes=self.scope_handler.scopes, data=data[0], user_id=data[1]) self.auth_code_store.save_code(auth_code) response.add_header("Location", self._generate_location(code)) response.body = "" response.status_code = 302 return response def handle_error(self, error, response): """ Redirects the client in case an error in the auth process occurred. """ query_params = {"error": error.error} query = urlencode(query_params) location = "%s?%s" % (self.client.redirect_uri, query) response.status_code = 302 response.body = "" response.add_header("Location", location) return response def _generate_location(self, code): query = "code=" + code if self.state is not None: query += "&state=" + quote(self.state) return "%s?%s" % (self.client.redirect_uri, query) class AuthorizationCodeTokenHandler(AccessTokenMixin, GrantHandler): """ Implementation of the second step of the Authorization Code Grant (three-legged). """ def __init__(self, auth_token_store, client_authenticator, **kwargs): self.client = None self.code = None self.data = {} self.redirect_uri = None self.scopes = [] self.user_id = None self.auth_code_store = auth_token_store self.client_authenticator = client_authenticator super(AuthorizationCodeTokenHandler, self).__init__(**kwargs) def read_validate_params(self, request): """ Reads and validates the data from the incoming request. A valid request is issued via POST consists of the following form-encoded body: client_id - Identifier of the requesting client (required) client_secret - Secret phrase generated by the auth system (required) code - Authorization code acquired in the Authorization Request (required) redirect_uri - URI that the OAuth2 server should redirect to (optional) """ self._read_params(request) self._validate_code() return True def process(self, request, response, environ): """ Generates a new access token and returns it. Returns the access token and the type of the token as JSON. Calls `oauth2.store.AccessTokenStore` to persist the token. """ token_data = self.create_token( client_id=self.client.identifier, data=self.data, grant_type=AuthorizationCodeGrant.grant_type, scopes=self.scopes, user_id=self.user_id) self.auth_code_store.delete_code(self.code) if self.scopes: token_data["scope"] = encode_scopes(self.scopes) json_success_response(data=token_data, response=response) return response def handle_error(self, error, response): return json_error_response(error, response) def _read_params(self, request): self.client = self.client_authenticator.by_identifier_secret(request) self.code = request.post_param("code") self.redirect_uri = request.post_param("redirect_uri") if self.code is None or self.redirect_uri is None: raise OAuthInvalidError(error="invalid_request", explanation="Missing required parameter in request") try: self.client.redirect_uri = self.redirect_uri except RedirectUriUnknown: raise OAuthInvalidError(error="invalid_request", explanation="Invalid redirect_uri parameter") def _validate_code(self): try: stored_code = self.auth_code_store.fetch_by_code(self.code) except AuthCodeNotFound: raise OAuthInvalidError(error="invalid_request", explanation="Invalid authorization code parameter") if stored_code.code != self.code: raise OAuthInvalidError(error="invalid_grant", explanation="Invalid code parameter in request") if stored_code.redirect_uri != self.redirect_uri: raise OAuthInvalidError(error="invalid_request", explanation="Invalid redirect_uri parameter") if stored_code.is_expired(): raise OAuthInvalidError(error="invalid_grant", explanation="Authorization code has expired") self.data = stored_code.data self.scopes = stored_code.scopes self.user_id = stored_code.user_id
[docs]class AuthorizationCodeGrant(GrantHandlerFactory, ScopeGrant, SiteAdapterMixin): """ Implementation of the Authorization Code Grant auth flow. This is a three-legged OAuth process. Register an instance of this class with :class:`oauth2.AuthorizationController` like this:: auth_controller = AuthorizationController() auth_controller.add_grant_type(AuthorizationCodeGrant()) """ grant_type = "authorization_code" site_adapter_class = AuthorizationCodeGrantSiteAdapter def __init__(self, unique_token=False, expires_in=0, **kwargs): self.unique_token = unique_token self.expires_in = expires_in super(AuthorizationCodeGrant, self).__init__(**kwargs) def __call__(self, request, server): """ :param request: Incoming request :type request: oauth2.web.Request :param server: The OAuth2 provider instance """ if (request.method == "POST" and request.post_param("grant_type") == "authorization_code" and request.path == server.token_path): return AuthorizationCodeTokenHandler( access_token_store=server.access_token_store, auth_token_store=server.auth_code_store, client_authenticator=server.client_authenticator, token_generator=server.token_generator, unique_token=self.unique_token) if (request.method == "GET" and request.get_param("response_type") == "code" and request.path == server.authorize_path): scope_handler = self._create_scope_handler() return AuthorizationCodeAuthHandler( auth_token_store=server.auth_code_store, client_authenticator=server.client_authenticator, scope_handler=scope_handler, site_adapter=self.site_adapter, token_generator=server.token_generator) return None
[docs]class ImplicitGrant(GrantHandlerFactory, ScopeGrant, SiteAdapterMixin): """ Implementation of the Implicit Grant auth flow. This is a three-legged OAuth process. Register an instance of this class with :class:`oauth2.AuthorizationController` like this:: auth_controller = AuthorizationController() auth_controller.add_grant_type(ImplicitGrant()) """ grant_type = "implicit" site_adapter_class = ImplicitGrantSiteAdapter def __call__(self, request, server): response_type = request.get_param("response_type") if (response_type == "token" and request.path == server.authorize_path): return ImplicitGrantHandler( access_token_store=server.access_token_store, client_authenticator=server.client_authenticator, scope_handler=self._create_scope_handler(), site_adapter=self.site_adapter, token_generator=server.token_generator) return None
class ImplicitGrantHandler(AuthorizeMixin, AuthRequestMixin, GrantHandler): def __init__(self, access_token_store, **kwargs): self.access_token_store = access_token_store super(ImplicitGrantHandler, self).__init__(**kwargs) def process(self, request, response, environ): data = self.authorize(request, response, environ, self.scope_handler.scopes) if isinstance(data, Response): return data token = self.token_generator.generate() access_token = AccessToken(client_id=self.client.identifier, grant_type=ImplicitGrant.grant_type, token=token, data=data[0], scopes=self.scope_handler.scopes) self.access_token_store.save_token(access_token) return self._redirect_access_token(response, token) def handle_error(self, error, response): redirect_location = "%s#error=%s" % (self.client.redirect_uri, error.error) response.add_header("Location", redirect_location) response.body = "" response.status_code = 302 return response def _redirect_access_token(self, response, token): uri_with_fragment = "{0}#access_token={1}&token_type=bearer".format(self.client.redirect_uri, token) if self.state is not None: uri_with_fragment += "&state=" + quote(self.state) if self.scope_handler.send_back is True: scopes_as_string = encode_scopes(self.scope_handler.scopes, use_quote=True) uri_with_fragment += "&scope=" + scopes_as_string response.status_code = 302 response.add_header("Location", uri_with_fragment) response.content = "" return response
[docs]class ResourceOwnerGrant(GrantHandlerFactory, ScopeGrant, SiteAdapterMixin): """ Implementation of the Resource Owner Password Credentials Grant auth flow. In this Grant a user provides a user name and a password. An access token is issued if the auth server was able to verify the user by her credentials. Register an instance of this class with :class:`oauth2.AuthorizationController` like this:: auth_controller = AuthorizationController() auth_controller.add_grant_type(ResourceOwnerGrant()) """ grant_type = "password" site_adapter_class = ResourceOwnerGrantSiteAdapter def __init__(self, unique_token=False, expires_in=0, **kwargs): self.unique_token = unique_token self.expires_in = expires_in super(ResourceOwnerGrant, self).__init__(**kwargs) def __call__(self, request, server): """ Checks if the incoming request can be handled by the ResourceOwnerGrantHandler and returns an instance of it. """ if request.post_param("grant_type") != self.grant_type: return None return ResourceOwnerGrantHandler( access_token_store=server.access_token_store, client_authenticator=server.client_authenticator, scope_handler=self._create_scope_handler(), site_adapter=self.site_adapter, token_generator=server.token_generator, unique_token=self.unique_token)
class ResourceOwnerGrantHandler(GrantHandler, AccessTokenMixin): """ Class for handling Resource Owner authorization requests. See http://tools.ietf.org/html/rfc6749#section-4.3 """ OWNER_NOT_AUTHENTICATED = "Unable to authenticate resource owner" def __init__(self, client_authenticator, scope_handler, site_adapter, **kwargs): """ :param client_authenticator: Client authenticator :type client_authenticator: oauth2.client_authenticator.ClientAuthenticator :param scope_handler: Scope handler :type scope_handler: oauth2.grant.Scope :param site_adapter: Site adapter :type site_adapter: oauth2.web.SiteAdapter """ self.client_authenticator = client_authenticator self.scope_handler = scope_handler self.site_adapter = site_adapter self.client = None self.password = None self.username = None super(ResourceOwnerGrantHandler, self).__init__(**kwargs) def process(self, request, response, environ): """ Takes the incoming request, asks the concrete SiteAdapter to validate it and issues a new access token that is returned to the client on successful validation. """ try: data = self.site_adapter.authenticate(request, environ, self.scope_handler.scopes, self.client) data = AuthorizeMixin.sanitize_return_value(data) except UserNotAuthenticated: raise OAuthInvalidError(error="invalid_client", explanation=self.OWNER_NOT_AUTHENTICATED) if isinstance(data, Response): return data token_data = self.create_token( client_id=self.client.identifier, data=data[0], grant_type=ResourceOwnerGrant.grant_type, scopes=self.scope_handler.scopes, user_id=data[1]) if self.scope_handler.send_back: token_data["scope"] = encode_scopes(self.scope_handler.scopes) json_success_response(data=token_data, response=response) return response def read_validate_params(self, request): """ Checks if all incoming parameters meet the expected values. """ self.client = self.client_authenticator.by_identifier_secret(request) self.password = request.post_param("password") self.username = request.post_param("username") self.scope_handler.parse(request=request, source="body") return True def handle_error(self, error, response): status_code = 400 if error.explanation == self.OWNER_NOT_AUTHENTICATED: status_code = 401 return json_error_response(error, response, status_code=status_code)
[docs]class RefreshToken(GrantHandlerFactory, ScopeGrant): """ Handles requests for refresh tokens as defined in http://tools.ietf.org/html/rfc6749#section-6. Adding a Refresh Token to the :class:`oauth2.AuthorizationController` like this:: auth_controller = AuthorizationController() auth_controller.add_grant_type(ResourceOwnerGrant(tokens_expire=600)) auth_controller.add_grant_type(RefreshToken(tokens_expire=1200)) will cause :class:`oauth2.grant.AuthorizationCodeGrant` and :class:`oauth2.grant.ResourceOwnerGrant` to include a refresh token and expiration in the response. If tokens_expire == 0, the tokens will never expire. """ grant_type = "refresh_token" def __init__(self, expires_in, reissue_refresh_tokens=False, **kwargs): self.refresh_expires_in = expires_in self.reissue_refresh_tokens = reissue_refresh_tokens if expires_in else True super(RefreshToken, self).__init__(**kwargs) def __call__(self, request, server): """ Determines if the current request requests a refresh token. :return: An instance of :class:`RefreshTokenHandler`. """ if request.path != server.token_path: return None if request.post_param("grant_type") != "refresh_token": return None return RefreshTokenHandler( access_token_store=server.access_token_store, client_authenticator=server.client_authenticator, scope_handler=self._create_scope_handler(), token_generator=server.token_generator, reissue_refresh_tokens=self.reissue_refresh_tokens )
class RefreshTokenHandler(GrantHandler): """ Validates an incoming request and issues a new access token. """ def __init__(self, access_token_store, client_authenticator, scope_handler, token_generator, reissue_refresh_tokens=False): self.access_token_store = access_token_store self.client_authenticator = client_authenticator self.scope_handler = scope_handler self.token_generator = token_generator self.client = None self.data = {} self.refresh_grant_type = None self.refresh_token = None self.user_id = None self.reissue_refresh_tokens = reissue_refresh_tokens def process(self, request, response, environ): """ Create a new access token. :param request: The incoming :class:`oauth2.web.Request`. :param response: The :class:`oauth2.web.Response` that will be returned to the client. :param environ: A ``dict`` containing data of the environment. :return: :class:`oauth2.web.Response` """ token_data = self.token_generator.create_access_token_data(self.data, self.scope_handler.scopes, self.refresh_grant_type, self.user_id, self.client.identifier) expires_at = int(time.time()) + token_data["expires_in"] access_token = AccessToken(client_id=self.client.identifier, token=token_data["access_token"], grant_type=self.refresh_grant_type, data=self.data, expires_at=expires_at, scopes=self.scope_handler.scopes, user_id=self.user_id) if self.reissue_refresh_tokens: self.access_token_store.delete_refresh_token(self.refresh_token) access_token.refresh_token = token_data["refresh_token"] refresh_expires_in = self.token_generator.refresh_expires_in refresh_expires_at = int(time.time()) + refresh_expires_in access_token.refresh_expires_at = refresh_expires_at else: del token_data["refresh_token"] self.access_token_store.save_token(access_token) json_success_response(data=token_data, response=response) return response def read_validate_params(self, request): """ Validate the incoming request. :param request: The incoming :class:`oauth2.web.Request`. :return: Returns ``True`` if data is valid. :raises: :class:`oauth2.error.OAuthInvalidError` """ self.refresh_token = request.post_param("refresh_token") if self.refresh_token is None: raise OAuthInvalidError(error="invalid_request", explanation="Missing refresh_token in request body") self.client = self.client_authenticator.by_identifier_secret(request) try: access_token = self.access_token_store.fetch_by_refresh_token(self.refresh_token) except AccessTokenNotFound: raise OAuthInvalidError(error="invalid_request", explanation="Invalid refresh token") refresh_token_expires_at = access_token.refresh_expires_at self.refresh_grant_type = access_token.grant_type if refresh_token_expires_at != 0 and refresh_token_expires_at < int(time.time()): raise OAuthInvalidError(error="invalid_request", explanation="Invalid refresh token") self.data = access_token.data self.user_id = access_token.user_id self.scope_handler.parse(request, "body") self.scope_handler.compare(access_token.scopes) return True def handle_error(self, error, response): return json_error_response(error, response) class ClientCredentialsGrant(GrantHandlerFactory, ScopeGrant): grant_type = "client_credentials" def __call__(self, request, server): if request.path != server.token_path: return None if request.post_param("grant_type") == self.grant_type: return ClientCredentialsHandler( access_token_store=server.access_token_store, client_authenticator=server.client_authenticator, scope_handler=self._create_scope_handler(), token_generator=server.token_generator) return None class ClientCredentialsHandler(GrantHandler): def __init__(self, access_token_store, client_authenticator, scope_handler, token_generator): self.access_token_store = access_token_store self.client_authenticator = client_authenticator self.scope_handler = scope_handler self.token_generator = token_generator self.client = None def process(self, request, response, environ): body = {"token_type": "Bearer"} token = self.token_generator.generate() expires_in = self.token_generator.expires_in.get(ClientCredentialsGrant.grant_type, None) expires_at = expires_in if expires_in is None else int(time.time()) + expires_in access_token = AccessToken( client_id=self.client.identifier, grant_type=ClientCredentialsGrant.grant_type, token=token, expires_at=expires_at, scopes=self.scope_handler.scopes) self.access_token_store.save_token(access_token) body["access_token"] = token if expires_in is not None: body["expires_in"] = expires_in if self.scope_handler.send_back: body["scope"] = encode_scopes(self.scope_handler.scopes) json_success_response(data=body, response=response) return response def read_validate_params(self, request): self.client = self.client_authenticator.by_identifier_secret(request) self.scope_handler.parse(request=request, source="body") def handle_error(self, error, response): return json_error_response(error, response)