requests-oauth2client 1.0.0

An OAuth2.x Client based on requests.

requests_oauth2client is a Python OAuth 2.x client, able to obtain, refresh and revoke tokens from any OAuth2.x/OIDC compliant Authorization Server. It sits upon and extends the famous requests HTTP client module.

It can act as an OAuth 2.0 / 2.1 client, to automatically get and renew access tokens, based on the Client Credentials, Authorization Code, Refresh token, Token Exchange, Device Authorization, or CIBA grants.

It also supports OpenID Connect 1.0, PKCE, Client Assertions, Token Revocation, and Introspection, Resource Indicators, JWT-secured Authorization Requests, Pushed Authorization Requests, as well as using custom params to any endpoint, and other important features that are often overlooked in other client libraries.

And it also includes a wrapper around requests.Session that makes it super easy to use REST-style APIs, with or without OAuth 2.x.

Please note that despite the name, this library has no relationship with Google oauth2client library.

Documentation

Full module documentation is available at https://guillp.github.io/requests_oauth2client/

Installation

As easy as:

pip install requests_oauth2client

Usage

Import it like this:

from requests_oauth2client import *

Note that this automatically imports requests, so no need to import it yourself.

Calling APIs with Access Tokens

If you already managed to obtain an access token, you can simply use the BearerAuth Auth Handler for requests:

token = "an_access_token"
resp = requests.get("https://my.protected.api/endpoint", auth=BearerAuth(token))

This authentication handler will add a properly formatted Authorization header in the request, with your access token according to RFC6750.

Using an OAuth2Client

OAuth2Client offers several methods that implement the communication to the various endpoints that are standardised by OAuth 2.0 and its extensions. Those endpoints include the Token Endpoint, the Revocation, Introspection, UserInfo, BackChannel Authentication and Device Authorization Endpoints.

To initialize an OAuth2Client, you only need a Token Endpoint URI, and the credentials for your application, which are often a client_id and a client_secret:

oauth2client = OAuth2Client(
    token_endpoint="https://myas.local/token_endpoint",
    auth=("client_id", "client_secret"),
)

The Token Endpoint is the only Endpoint that is mandatory to obtain tokens. Credentials are used to authenticate the client everytime it sends a request to its Authorization Server. Usually, those are a static Client ID and Secret, which are the direct equivalent of a username and a password, but meant for an application instead of for a human user. The default authentication method used by OAuth2Client is Client Secret Post, but other standardised methods such as Client Secret Basic, Client Secret JWT or Private Key JWT are supported as well. See more about client authentication methods below.

Obtaining tokens

OAuth2Client has methods to send requests to the Token Endpoint using the different standardised (and/or custom) grants. Since the token endpoint and authentication method are already declared for the client at init time, the only required parameters are those that will be sent in the request to the Token Endpoint.

Those methods directly return a BearerToken if the request is successful, or raise an exception if it fails. BearerToken will manage the token expiration, will contain the eventual refresh token that matches the access token, and will keep track of other associated metadata as well. You can create such a BearerToken yourself if you need:

from requests_oauth2client import BearerToken

bearer_token = BearerToken(access_token="an_access_token", expires_in=60)
print(bearer_token)
# {'access_token': 'an_access_token',
#  'expires_in': 55,
#  'token_type': 'Bearer'}
print(bearer_token.expires_at)
# datetime.datetime(2021, 8, 20, 9, 56, 59, 498793)
assert not bearer_token.is_expired()

Note that the expires_in indicator here is not static. It keeps track of the token lifetime and is calculated as the time flies. The actual static expiration date is accessible with the expires_at property. You can check if a token is expired with bearer_token.is_expired().

You can use a BearerToken instance anywhere you can supply an access_token as string.

Using OAuth2Client as a requests Auth Handler

While using OAuth2Client directly is great for testing or debugging OAuth2.x flows, it is not a viable option for actual applications where tokens must be obtained, used during their lifetime then obtained again or refreshed once they are expired. requests_oauth2client contains several requests compatible Auth Handlers (as subclasses of requests.auth.AuthBase), that will take care of obtaining tokens when required, then will cache those tokens until they are expired, and will obtain new ones (or refresh them, when possible), once the initial token is expired. Those are best used with a requests.Session, or an ApiClient, which is a wrapper around Session with a few enhancements as described below.

Client Credentials grant

To send a request using the Client Credentials grant, use the aptly named .client_credentials() method, with the parameters to send in the token request as keyword parameters:

token = oauth2client.client_credentials(scope="myscope", resource="https://myapi.local")

Parameters such as scope, resource or audience that may be required by the AS can be passed as keyword parameters. Those will be included in the token request that is sent to the AS.

As Auth Handler

You can use the OAuth2ClientCredentialsAuth auth handler. It takes an OAuth2Client as parameter, and the additional kwargs to pass to the token endpoint:

import requests

auth = OAuth2ClientCredentialsAuth(
    oauth2client, scope="myscope", resource="https://myapi.local"
)

# use it like this:
requests.get("https://myapi.local/resource", auth=auth)

# or
session = requests.Session()
session.auth = auth

resp = session.get("https://myapi.local/resource")

Once again, extra parameters such as scope, resource or audience are allowed if required.

When you send your first request, OAuth2ClientCredentialsAuth will automatically retrieve an access token from the AS using the Client Credentials grant, then will include it in the request. Next requests will use the same token, as long as it is valid. A new token will be automatically retrieved once the previous one is expired.

Authorization Code Grant

Obtaining tokens with the Authorization code grant is made in 3 steps:

1. your application must open specific url called the Authentication Request in a browser.

2. your application must obtain and validate the Authorization Response, which is a redirection back to your application that contains an Authorization Code as parameter.

3. your application must then exchange this Authorization Code for an Access Token, with a request to the Token Endpoint.

OAuth2Client doesn't implement anything that is related to the Authorization Request or Response. It is only able to exchange the Authorization Code for a Token in step 3. But requests_oauth2client has other classes to help you with steps 1 and 2, as described below:

Generating Authorization Requests

You can generate valid authorization requests with the AuthorizationRequest class:

auth_request = AuthorizationRequest(
    authorization_endpoint,
    client_id,
    redirect_uri=redirect_uri,
    scope=scope,
    resource=resource,  # extra parameters can be included as well if required by your AS
)
print(auth_request)  # redirect the user to that URL to get a code

This request will look like this (with line breaks for display purposes only):

https://myas.local/authorize
?client_id=my_client_id
&redirect_uri=http%3A%2F%2Flocalhost%2Fcallback
&response_type=code
&state=kHWL4VwcbUbtPR4mtht6yMAGG_S-ZcBh5RxI_IGDmJc
&nonce=mSGOS1M3LYU9ncTvvutoqUR4n1EtmaC_sQ3db4dyMAc
&scope=openid+email+profile
&code_challenge=Dk11ttaDb_Hyq1dObMqQcTIlfYYRVblFMC9lFM3UWW8
&code_challenge_method=S256
&resource=https%3A%2F%2Fmy.resource.local%2Fapi

AuthorizationRequest supports PKCE and uses it by default. You can avoid it by passing code_challenge_method=None to AuthorizationRequest. You can obtain the generated code_verifier from auth_request.code_verifier.

Redirecting or otherwise sending the user to this url is your application responsibility, as well as obtaining the Authorization Response url.

Validating the Authorization Response

Once the user is successfully authenticated and authorized, the AS will respond with a redirection to your redirect_uri. That is the Authorization Response. It contains several parameters that must be retrieved by your client. The authorization code is one of those parameters, but you must also validate that the state matches your request. You can do this with:

response_uri = input(
    "Please enter the full url and/or params obtained on the redirect_uri: "
)
auth_response = auth_request.validate_callback(response_uri)

Exchanging code for tokens

To exchange a code for Access and/or ID tokens, use the OAuth2Client.authorization_code() method. If you have obtained an AuthorizationResponse as described above, you can simply do:

token = oauth2client.authorization_code(auth_response)

This will automatically include the code, redirect_uri and code_verifier parameters in the Token Request, as expected by the AS.

If you managed another way to obtain an Authorization Code, you can manually pass those parameters like this:

token = oauth2client.authorization_code(
    code=code,
    code_verifier=code_verifier,
    redirect_uri=redirect_uri,
    custom_param=custom_value,
)

As Auth Handler

The OAuth2AuthorizationCodeAuth handler takes an OAuth2Client and an authorization code as parameter, plus whatever additional keyword parameters are required by your Authorization Server:

api_client = ApiClient(
    "https://your.protected.api/endpoint",
    auth=OAuth2AuthorizationCodeAuth(
        client,
        code,
        code_verifier=auth_request.code_verifier,
        redirect_uri=redirect_uri,
    ),
)

resp = api_client.post(
    data={...}
)  # first call will exchange the code for an initial access/refresh tokens

OAuth2AuthorizationCodeAuth will take care of refreshing the token automatically once it is expired, using the refresh token, if available.

Device Authorization Grant

Helpers for the Device Authorization Grant are also included. To get device and user codes:

client = OAuth2Client(
    token_endpoint="https://myas.local/token",
    device_authorization_endpoint="https://myas.local/device",
    auth=(client_id, client_secret),
)

da_resp = client.authorize_device()

da_resp contains the Device Code, User Code, Verification URI and other info returned by the AS:

da_resp.device_code
da_resp.user_code
da_resp.verification_uri
da_resp.verification_uri_complete
da_resp.expires_at  # just like for BearerToken, expiration is tracked by requests_oauth2client
da_resp.interval

Send/show the Verification Uri and User Code to the user. He must use a browser to visit that url, authenticate and input the User Code. You can then request the Token endpoint to check if the user successfully authorized you using an OAuth2Client:

token = client.device_code(da_resp.device_code)

This will raise an exception, either AuthorizationPending, SlowDown, ExpiredToken, or AccessDenied if the user did not yet finish authorizing your device, if you should increase your pooling period, or if the device code is no longer valid, or the user finally denied your access, respectively. Other exceptions may be raised depending on the error code that the AS responds with. If the user did finish authorizing successfully, token will contain your access token.

To make pooling easier, you can use a DeviceAuthorizationPoolingJob like this:

pool_job = DeviceAuthorizationPoolingJob(
    client, device_auth_resp.device_code, interval=device_auth_resp.interval
)

resp = None
while resp is None:
    resp = pool_job()

assert isinstance(resp, BearerToken)

DeviceAuthorizationPoolingJob will automatically obey the pooling period. Everytime you call pool_job(), it will wait the appropriate number of seconds as indicated by the AS, and will apply slow_down requests.

As Auth Handler

Use OAuth2DeviceCodeAuth as auth handler to exchange a device code for an access token:

api_client = ApiClient(
    "https://your.protected.api/endpoint",
    auth=OAuth2DeviceCodeAuth(
        client,
        device_auth_resp.device_code,
        interval=device_auth_resp.interval,
        expires_in=device_auth_resp.expires_in,
    ),
)

resp = api_client.post(
    data={...}
)  # first call will hang until the user authorizes your app and the token endpoint returns a token.

Client-Initiated BackChannel Authentication (CIBA)

To initiate a BackChannel Authentication against the dedicated endpoint:

client = OAuth2Client(
    token_endpoint="https://myas.local/token",
    backchannel_authentication_endpoint="https://myas.local/backchannel_authorize",
    auth=(client_id, client_secret),
)

ba_resp = client.backchannel_authentication_request(
    scope="openid email profile",
    login_hint="[e-mail]",
)

ba_resp will contain the response attributes as returned by the AS, including an auth_req_id:

ba_resp.auth_req_id
ba_resp.expires_in  # decreases as times fly
ba_resp.expires_at  # a datetime to keep track of the expiration date, based on the "expires_in" returned by the AS
ba_resp.interval  # the pooling interval indicated by the AS
ba_resp.custom  # if the AS respond with additional attributes, they are also accessible

To pool the Token Endpoint until the end-user successfully authenticates:

pool_job = BackChannelAuthenticationPoolingJob(
    client=client,
    auth_req_id=ba_resp.auth_req_id,
    interval=bca_resp.interval,
)

resp = None
while resp is None:
    resp = pool_job()

assert isinstance(resp, BearerToken)

Hints by the AS to slow down pooling will automatically be obeyed.

Token Exchange

To send a token exchange request, use the OAuth2Client.token_exchange() method:

client = OAuth2Client(token_endpoint, auth=...)
token = client.token_exchange(
    subject_token="your_token_value",
    subject_token_type="urn:ietf:params:oauth:token-type:access_token",
)

As with the other grant-type specific methods, you may specify additional keyword parameters, that will be passed to the token endpoint, including any standardised attribute like actor_token or actor_token_type, or any custom parameter. There are short names for token types, that will be automatically translated to standardised types:

token = client.token_exchange(
    subject_token="your_token_value",
    subject_token_type="access_token",  # will be automatically replaced by "urn:ietf:params:oauth:token-type:access_token"
    actor_token="your_actor_token",
    actor_token_type="id_token",  # will be automatically replaced by "urn:ietf:params:oauth:token-type:id_token"
)

Or to make it even easier, types can be guessed based on the supplied subject or actor token:

token = client.token_exchange(
    subject_token=BearerToken(
        "your_token_value"
    ),  # subject_token_type will be "urn:ietf:params:oauth:token-type:access_token"
    actor_token=IdToken(
        "your_actor_token"
    ),  # actor_token_type will be "urn:ietf:params:oauth:token-type:id_token"
)

Supported Client Authentication Methods

requests_oauth2client supports several client authentication methods, as defined in multiple OAuth2.x standards. You select the appropriate method to use when initializing your OAuth2Client, with the auth parameter. Once initialized, a client will automatically use the configured authentication method every time it sends a requested to an endpoint that requires client authentication. You don't have anything else to do afterwards.

• client_secret_basic: client_id and client_secret are included in clear-text in the Authorization header. To use it, just pass a ClientSecretBasic(client_id, client_secret) as auth parameter:

  client = OAuth2Client(token_endpoint, auth=ClientSecretBasic(client_id, client_secret))
  

• client_secret_post: client_id and client_secret are included as part of the body form data. To use it, pass a ClientSecretPost(client_id, client_secret) as auth parameter. This also what is being used as default when you pass a tuple (client_id, client_secret) as auth:

  client = OAuth2Client(token_endpoint, auth=ClientSecretPost(client_id, client_secret))
  # or
  client = OAuth2Client(token_endpoint, auth=(client_id, client_secret))
  

• client_secret_jwt: client generates an ephemeral JWT assertion including information about itself (client_id), the AS (url of the endpoint), and expiration date. To use it, pass a ClientSecretJwt(client_id, client_secret) as auth parameter. Assertion generation is entirely automatic, you don't have anything to do:

  client = OAuth2Client(token_endpoint, auth=ClientSecretJwt(client_id, client_secret))
  

• private_key_jwt: client uses a JWT assertion like client_secret_jwt, but it is signed with an asymmetric key. To use it, you need a private signing key, in a dict that matches the JWK format. The matching public key must be registered for your client on AS side. Once you have that, using this auth method is simple with the PrivateKeyJwt(client_id, private_jwk) auth handler:

  private_jwk = {
      "kid": "mykid",
      "kty": "RSA",
      "e": "AQAB",
      "n": "...",
      "d": "...",
      "p": "...",
      "q": "...",
      "dp": "...",
      "dq": "...",
      "qi": "...",
  }
  
  client = OAuth2Client(
      "https://myas.local/token", auth=PrivateKeyJwt(client_id, private_jwk)
  )
  

  Note that you can also directly pass a (client_id, jwk) tuple, with the same effect:

  client = OAuth2Client(token_endpoint, auth=(client_id, private_jwk))
  

• none: client only includes its client_id in body form data, without any authentication credentials. Use PublicApp(client_id):

  client = OAuth2Client(token_endpoint, auth=PublicApp(client_id, client_secret))
  

Token Revocation

OAuth2Client can send revocation requests to a Revocation Endpoint. You need to provide a Revocation Endpoint URI when creating the OAuth2Client :

oauth2client = OAuth2Client(
    token_endpoint,
    revocation_endpoint=revocation_endpoint,
    auth=ClientSecretJwt("client_id", "client_secret"),
)

The OAuth2Client.revoke_token() method and its specialized aliases .revoke_access_token() and .revoke_refresh_token() are then available:

oauth2client.revoke_token("mytoken", token_type_hint="access_token")
oauth2client.revoke_access_token(
    "mytoken"
)  # will automatically add token_type_hint=access_token
oauth2client.revoke_refresh_token(
    "mytoken"
)  # will automatically add token_type_hint=refresh_token

Because Revocation Endpoints usually don't return meaningful responses, those methods return a boolean. This boolean indicates that a request was successfully sent and no error was returned. If the Authorization Server actually returns a standardised error, an exception will be raised instead.

Token Introspection

OAuth2Client can send requests to a Token Introspection Endpoint. You need to provide an Introspection Endpoint URI when creating the OAuth2Client:

oauth2client = OAuth2Client(
    token_endpoint,
    introspection_endpoint=introspection_endpoint,
    auth=ClientSecretJwt("client_id", "client_secret"),
)

The OAuth2Client.introspect_token() method is then available:

resp = oauth2client.introspect_token("mytoken", token_type_hint="access_token")

It returns whatever data is returned by the introspection endpoint (if it is a JSON, its content is returned decoded).

UserInfo Requests

OAuth2Client can send requests to an UserInfo Endpoint. You need to provide an UserInfo Endpoint URI when creating the OAuth2Client:

oauth2client = OAuth2Client(
    token_endpoint,
    userinfo_endpoint=userinfo_endpoint,
    auth=ClientSecretJwt("client_id", "client_secret"),
)

The OAuth2Client.userinfo()) method is then available:

resp = oauth2client.userinfo("mytoken")

It returns whatever data is returned by the userinfo endpoint (if it is a JSON, its content is returned decoded).

Initializing an OAuth2Client from a discovery document

You can initialize an OAuth2Client with the endpoint URIs mentioned in a standardised discovery document with the OAuth2Client.from_discovery_endpoint() class method:

oauth2client = OAuth2Client.from_discovery_endpoint(
    "https://myas.local/.well-known/openid-configuration"
)

This will fetch the document from the specified URI, then will decode it and initialize an OAuth2Client pointing to the appropriate endpoint URIs.

Specialized API Client

Using APIs usually involves multiple endpoints under the same root url, with a common authentication method. To make it easier, requests_oauth2client includes a requests.Session wrapper called ApiClient, which takes the root API url as parameter on initialization. You can then send requests to different endpoints by passing their relative path instead of the full url. ApiClient also accepts an auth parameter with an AuthHandler. You can pass any of the OAuth2 Auth Handler from this module, or any requests-compatible Authentication Handler. Which makes it very easy to call APIs that are protected with an OAuth2 Client Credentials Grant:

oauth2client = OAuth2Client("https://myas.local/token", (client_id, client_secret))
api = ApiClient(
    "https://myapi.local/root", auth=OAuth2ClientCredentialsAuth(oauth2client)
)

# will actually send a GET to https://myapi.local/root/resource/foo
resp = api.get("/resource/foo")

Note that ApiClient will never send requests "outside" its configured root url, unless you specifically give it a full url at request time. The leading / in /resource above is optional. A leading / will not "reset" the url path to root, which means that you can also write the relative path without the / and it will automatically be included:

api.get("resource/foo")  # will also send a GET to https://myapi.local/root/resource/foo

You may also pass the path as an iterable of strings (or string-able objects), in which case they will be joined with a / and appended to the url path:

# will send a GET to https://myapi.local/root/resource/foo
api.get(["resource", "foo"])
# will send a GET to https://myapi.local/root/users/1234/details
api.get(["users", 1234, "details"])

You can also use a syntax based on __getattr__ or __getitem__:

api.resource.get()  # will send a GET to https://myapi.local/root/resource
api["my-resource"].get()  # will send a GET to https://myapi.local/root/my-resource

Both __getattr__ and __getitem__ return a new ApiClient initialised on the new base_url. So you can easily call multiple sub-resources on the same API this way:

api = ApiClient("https://myapi.local")
users_api = api.users
user = users_api.get("userid")  # GET https://myapi.local/users/userid
other_user = users_api.get("other_userid")  # GET https://myapi.local/users/other_userid
resources_api = api.resources
resources = resources_api.get()  # GET https://myapi.local/resources

ApiClient will, by default, raise exceptions whenever a request returns an error status. You can disable that by passing raise_for_status=False when initializing your ApiClient:

api = ApiClient(
    "http://httpstat.us", raise_for_status=False
)  # raise_for_status defaults to True
resp = api.get("500")
assert resp is not None
# without raise_for_status=False, a requests.exceptions.HTTPError exception would be raised instead

You may override this at request time:

# raise_for_status at request-time overrides the value defined at init-time
resp = api.get("500", raise_for_status=True)

You can access the underlying requests.Session with the session attribute, and you can provide an already existing and configured Session instance at init time:

import requests

session = requests.Session()
session.proxies = {"https": "http://localhost:3128"}
api = ApiClient("https://myapi.local/resource", session=session)
assert api.session == session

Vendor-Specific clients

requests_oauth2client being flexible enough to handle most use cases, you should be able to use any AS by any vendor as long as it supports OAuth 2.0.

You can however create a subclass of OAuth2Client or ApiClient to make it easier to use with specific Authorization Servers or APIs. The sub-module requests_oauth2client.vendor_specific includes such classes for Auth0:

from requests_oauth2client.vendor_specific import Auth0Client

a0client = Auth0Client("mytenant.eu", (client_id, client_secret))
# this will automatically initialize the token endpoint to https://mytenant.eu.auth0.com/oauth/token
# and other endpoints accordingly
token = a0client.client_credentials(audience="audience")

# this is a wrapper around Auth0 Management API
a0mgmt = Auth0ManagementApiClient("mytenant.eu", (client_id, client_secret))
myusers = a0mgmt.get("users")