RFC6749: The OAuth 2.0 Authorization Framework

This section contains the generic implementation of RFC6749. You should read Introduce OAuth 2.0 at first. Here are some tips:

  1. Have a better understanding of OAuth 2.0

  2. How to use OAuth 2 Session for Requests

  3. How to implement Flask OAuth Client

  4. How to implement Flask OAuth 2.0 Server

  5. How to implement Django OAuth Client

  6. How to implement Django OAuth 2.0 Server

API References

Here are the API references for developers. For framework level interfaces, check:

Servers

class authlib.oauth2.rfc6749.AuthorizationServer(scopes_supported=None)

Authorization server that handles Authorization Endpoint and Token Endpoint.

Parameters

scopes_supported – A list of supported scopes by this authorization server.

authenticate_client(request, methods, endpoint='token')

Authenticate client via HTTP request information with the given methods, such as client_secret_basic, client_secret_post.

create_authorization_response(request=None, grant_user=None)

Validate authorization request and create authorization response.

Parameters
  • request – HTTP request instance.

  • grant_user – if granted, it is resource owner. If denied, it is None.

Returns

Response

create_endpoint_response(name, request=None)

Validate endpoint request and create endpoint response.

Parameters
  • name – Endpoint name

  • request – HTTP request instance.

Returns

Response

create_json_request(request)

This method MUST be implemented in framework integrations. It is used to create an HttpRequest instance.

Parameters

request – the “request” instance in framework

Returns

HttpRequest instance

create_oauth2_request(request)

This method MUST be implemented in framework integrations. It is used to create an OAuth2Request instance.

Parameters

request – the “request” instance in framework

Returns

OAuth2Request instance

create_token_response(request=None)

Validate token request and create token response.

Parameters

request – HTTP request instance

generate_token(grant_type, client, user=None, scope=None, expires_in=None, include_refresh_token=True)

Generate the token dict.

Parameters
  • grant_type – current requested grant_type.

  • client – the client that making the request.

  • user – current authorized user.

  • expires_in – if provided, use this value as expires_in.

  • scope – current requested scope.

  • include_refresh_token – should refresh_token be included.

Returns

Token dict

get_authorization_grant(request)

Find the authorization grant for current request.

Parameters

request – OAuth2Request instance.

Returns

grant instance

Validate current HTTP request for authorization page. This page is designed for resource owner to grant or deny the authorization.

get_error_uri(request, error)

Return a URI for the given error, framework may implement this method.

get_token_grant(request)

Find the token grant for current request.

Parameters

request – OAuth2Request instance.

Returns

grant instance

handle_response(status, body, headers)

Return HTTP response. Framework MUST implement this function.

query_client(client_id)

Query OAuth client by client_id. The client model class MUST implement the methods described by ClientMixin.

register_client_auth_method(method, func)

Add more client auth method. The default methods are:

  • none: The client is a public client and does not have a client secret

  • client_secret_post: The client uses the HTTP POST parameters

  • client_secret_basic: The client uses HTTP Basic

Parameters
  • method – Name of the Auth method

  • func – Function to authenticate the client

The auth method accept two parameters: query_client and request, an example for this method:

def authenticate_client_via_custom(query_client, request):
    client_id = request.headers['X-Client-Id']
    client = query_client(client_id)
    do_some_validation(client)
    return client

authorization_server.register_client_auth_method(
    'custom', authenticate_client_via_custom)
register_endpoint(endpoint_cls)

Add extra endpoint to authorization server. e.g. RevocationEndpoint:

authorization_server.register_endpoint(RevocationEndpoint)
Parameters

endpoint_cls – A endpoint class

register_grant(grant_cls, extensions=None)

Register a grant class into the endpoint registry. Developers can implement the grants in authlib.oauth2.rfc6749.grants and register with this method:

class AuthorizationCodeGrant(grants.AuthorizationCodeGrant):
    def authenticate_user(self, credential):
        # ...

authorization_server.register_grant(AuthorizationCodeGrant)
Parameters
  • grant_cls – a grant class.

  • extensions – extensions for the grant class.

register_token_generator(grant_type, func)

Register a function as token generator for the given grant_type. Developers MUST register a default token generator with a special grant_type=none:

def generate_bearer_token(grant_type, client, user=None, scope=None,
                          expires_in=None, include_refresh_token=True):
    token = {'token_type': 'Bearer', 'access_token': ...}
    if include_refresh_token:
        token['refresh_token'] = ...
    ...
    return token

authorization_server.register_token_generator('none', generate_bearer_token)

If you register a generator for a certain grant type, that generator will only works for the given grant type:

authorization_server.register_token_generator('client_credentials', generate_bearer_token)
Parameters
  • grant_type – string name of the grant type

  • func – a function to generate token

save_token(token, request)

Define function to save the generated token into database.

send_signal(name, *args, **kwargs)

Framework integration can re-implement this method to support signal system.

validate_requested_scope(scope, state=None)

Validate if requested scope is supported by Authorization Server. Developers CAN re-write this method to meet your needs.

class authlib.oauth2.rfc6749.ResourceProtector
get_token_validator(token_type)

Get token validator from registry for the given token type.

parse_request_authorization(request)

Parse the token and token validator from request Authorization header. Here is an example of Authorization header:

Authorization: Bearer a-token-string

This method will parse this header, if it can find the validator for Bearer, it will return the validator and a-token-string.

Returns

validator, token_string

Raise

MissingAuthorizationError

Raise

UnsupportedTokenTypeError

register_token_validator(validator: authlib.oauth2.rfc6749.resource_protector.TokenValidator)

Register a token validator for a given Authorization type. Authlib has a built-in BearerTokenValidator per rfc6750.

validate_request(scopes, request)

Validate the request and return a token.

Client Model

class authlib.oauth2.rfc6749.ClientMixin

Implementation of OAuth 2 Client described in Section 2 with some methods to help validation. A client has at least these information:

  • client_id: A string represents client identifier.

  • client_secret: A string represents client password.

  • token_endpoint_auth_method: A way to authenticate client at token

    endpoint.

check_client_secret(client_secret)

Check client_secret matching with the client. For instance, in the client table, the column is called client_secret:

def check_client_secret(self, client_secret):
    return self.client_secret == client_secret
Parameters

client_secret – A string of client secret

Returns

bool

check_endpoint_auth_method(method, endpoint)

Check if client support the given method for the given endpoint. There is a token_endpoint_auth_method defined via RFC7591. Developers MAY re-implement this method with:

def check_endpoint_auth_method(self, method, endpoint):
    if endpoint == 'token':
        # if client table has ``token_endpoint_auth_method``
        return self.token_endpoint_auth_method == method
    return True

Method values defined by this specification are:

  • “none”: The client is a public client as defined in OAuth 2.0,

    and does not have a client secret.

  • “client_secret_post”: The client uses the HTTP POST parameters

    as defined in OAuth 2.0

  • “client_secret_basic”: The client uses HTTP Basic as defined in

    OAuth 2.0

check_grant_type(grant_type)

Validate if the client can handle the given grant_type. There are four grant types defined by RFC6749:

  • authorization_code

  • implicit

  • client_credentials

  • password

For instance, there is a allowed_grant_types column in your client:

def check_grant_type(self, grant_type):
    return grant_type in self.grant_types
Parameters

grant_type – the requested grant_type string.

Returns

bool

check_redirect_uri(redirect_uri)

Validate redirect_uri parameter in Authorization Endpoints. For instance, in the client table, there is an allowed_redirect_uris column:

def check_redirect_uri(self, redirect_uri):
    return redirect_uri in self.allowed_redirect_uris
Parameters

redirect_uri – A URL string for redirecting.

Returns

bool

check_response_type(response_type)

Validate if the client can handle the given response_type. There are two response types defined by RFC6749: code and token. For instance, there is a allowed_response_types column in your client:

def check_response_type(self, response_type):
    return response_type in self.response_types
Parameters

response_type – the requested response_type string.

Returns

bool

get_allowed_scope(scope)

A method to return a list of requested scopes which are supported by this client. For instance, there is a scope column:

def get_allowed_scope(self, scope):
    if not scope:
        return ''
    allowed = set(scope_to_list(self.scope))
    return list_to_scope([s for s in scope.split() if s in allowed])
Parameters

scope – the requested scope.

Returns

string of scope

get_client_id()

A method to return client_id of the client. For instance, the value in database is saved in a column called client_id:

def get_client_id(self):
    return self.client_id
Returns

string

get_default_redirect_uri()

A method to get client default redirect_uri. For instance, the database table for client has a column called default_redirect_uri:

def get_default_redirect_uri(self):
    return self.default_redirect_uri
Returns

A URL string

Token Model

class authlib.oauth2.rfc6749.AuthorizationCodeMixin
get_redirect_uri()

A method to get authorization code’s redirect_uri. For instance, the database table for authorization code has a column called redirect_uri:

def get_redirect_uri(self):
    return self.redirect_uri
Returns

A URL string

get_scope()

A method to get scope of the authorization code. For instance, the column is called scope:

def get_scope(self):
    return self.scope
Returns

scope string

class authlib.oauth2.rfc6749.TokenMixin
check_client(client)

A method to check if this token is issued to the given client. For instance, client_id is saved on token table:

def check_client(self, client):
    return self.client_id == client.client_id
Returns

bool

get_expires_in()

A method to get the expires_in value of the token. e.g. the column is called expires_in:

def get_expires_in(self):
    return self.expires_in
Returns

timestamp int

get_scope()

A method to get scope of the authorization code. For instance, the column is called scope:

def get_scope(self):
    return self.scope
Returns

scope string

is_expired()

A method to define if this token is expired. For instance, there is a column expired_at in the table:

def is_expired(self):
    return self.expired_at < now
Returns

boolean

is_revoked()

A method to define if this token is revoked. For instance, there is a boolean column revoked in the table:

def is_revoked(self):
    return self.revoked
Returns

boolean

Errors

class authlib.oauth2.rfc6749.OAuth2Error(description=None, uri=None, status_code=None, state=None, redirect_uri=None, redirect_fragment=False, error=None)
get_body()

Get a list of body.

class authlib.oauth2.rfc6749.InsecureTransportError(description=None, uri=None, status_code=None, state=None, redirect_uri=None, redirect_fragment=False, error=None)
classmethod check(uri)

Check and raise InsecureTransportError with the given URI.

class authlib.oauth2.rfc6749.InvalidRequestError(description=None, uri=None, status_code=None, state=None, redirect_uri=None, redirect_fragment=False, error=None)

The request is missing a required parameter, includes an unsupported parameter value (other than grant type), repeats a parameter, includes multiple credentials, utilizes more than one mechanism for authenticating the client, or is otherwise malformed.

https://tools.ietf.org/html/rfc6749#section-5.2

class authlib.oauth2.rfc6749.InvalidClientError(description=None, uri=None, status_code=None, state=None, redirect_uri=None, redirect_fragment=False, error=None)

Client authentication failed (e.g., unknown client, no client authentication included, or unsupported authentication method). The authorization server MAY return an HTTP 401 (Unauthorized) status code to indicate which HTTP authentication schemes are supported. If the client attempted to authenticate via the “Authorization” request header field, the authorization server MUST respond with an HTTP 401 (Unauthorized) status code and include the “WWW-Authenticate” response header field matching the authentication scheme used by the client.

https://tools.ietf.org/html/rfc6749#section-5.2

class authlib.oauth2.rfc6749.InvalidGrantError(description=None, uri=None, status_code=None, state=None, redirect_uri=None, redirect_fragment=False, error=None)

The provided authorization grant (e.g., authorization code, resource owner credentials) or refresh token is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client.

https://tools.ietf.org/html/rfc6749#section-5.2

class authlib.oauth2.rfc6749.UnauthorizedClientError(description=None, uri=None, status_code=None, state=None, redirect_uri=None, redirect_fragment=False, error=None)

The authenticated client is not authorized to use this authorization grant type.

https://tools.ietf.org/html/rfc6749#section-5.2

class authlib.oauth2.rfc6749.UnsupportedGrantTypeError(grant_type)

The authorization grant type is not supported by the authorization server.

https://tools.ietf.org/html/rfc6749#section-5.2

class authlib.oauth2.rfc6749.InvalidScopeError(description=None, uri=None, status_code=None, state=None, redirect_uri=None, redirect_fragment=False, error=None)

The requested scope is invalid, unknown, malformed, or exceeds the scope granted by the resource owner.

https://tools.ietf.org/html/rfc6749#section-5.2

class authlib.oauth2.rfc6749.AccessDeniedError(description=None, uri=None, status_code=None, state=None, redirect_uri=None, redirect_fragment=False, error=None)

The resource owner or authorization server denied the request.

Used in authorization endpoint for “code” and “implicit”. Defined in Section 4.1.2.1.

Grant Types

class authlib.oauth2.rfc6749.grants.AuthorizationCodeGrant(request, server)

The authorization code grant type is used to obtain both access tokens and refresh tokens and is optimized for confidential clients. Since this is a redirection-based flow, the client must be capable of interacting with the resource owner’s user-agent (typically a web browser) and capable of receiving incoming requests (via redirection) from the authorization server:

+----------+
| Resource |
|   Owner  |
|          |
+----------+
     ^
     |
    (B)
+----|-----+          Client Identifier      +---------------+
|         -+----(A)-- & Redirection URI ---->|               |
|  User-   |                                 | Authorization |
|  Agent  -+----(B)-- User authenticates --->|     Server    |
|          |                                 |               |
|         -+----(C)-- Authorization Code ---<|               |
+-|----|---+                                 +---------------+
  |    |                                         ^      v
 (A)  (C)                                        |      |
  |    |                                         |      |
  ^    v                                         |      |
+---------+                                      |      |
|         |>---(D)-- Authorization Code ---------'      |
|  Client |          & Redirection URI                  |
|         |                                             |
|         |<---(E)----- Access Token -------------------'
+---------+       (w/ Optional Refresh Token)
TOKEN_ENDPOINT_AUTH_METHODS = ['client_secret_basic', 'client_secret_post']

Allowed client auth methods for token endpoint

AUTHORIZATION_CODE_LENGTH = 48

Generated “code” length

validate_authorization_request()

The client constructs the request URI by adding the following parameters to the query component of the authorization endpoint URI using the “application/x-www-form-urlencoded” format. Per Section 4.1.1.

response_type

REQUIRED. Value MUST be set to “code”.

client_id

REQUIRED. The client identifier as described in Section 2.2.

redirect_uri

OPTIONAL. As described in Section 3.1.2.

scope

OPTIONAL. The scope of the access request as described by Section 3.3.

state

RECOMMENDED. An opaque value used by the client to maintain state between the request and callback. The authorization server includes this value when redirecting the user-agent back to the client. The parameter SHOULD be used for preventing cross-site request forgery as described in Section 10.12.

The client directs the resource owner to the constructed URI using an HTTP redirection response, or by other means available to it via the user-agent.

For example, the client directs the user-agent to make the following HTTP request using TLS (with extra line breaks for display purposes only):

GET /authorize?response_type=code&client_id=s6BhdRkqt3&state=xyz
&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
Host: server.example.com

The authorization server validates the request to ensure that all required parameters are present and valid. If the request is valid, the authorization server authenticates the resource owner and obtains an authorization decision (by asking the resource owner or by establishing approval via other means).

create_authorization_response(redirect_uri, grant_user)

If the resource owner grants the access request, the authorization server issues an authorization code and delivers it to the client by adding the following parameters to the query component of the redirection URI using the “application/x-www-form-urlencoded” format. Per Section 4.1.2.

code

REQUIRED. The authorization code generated by the authorization server. The authorization code MUST expire shortly after it is issued to mitigate the risk of leaks. A maximum authorization code lifetime of 10 minutes is RECOMMENDED. The client MUST NOT use the authorization code more than once. If an authorization code is used more than once, the authorization server MUST deny the request and SHOULD revoke (when possible) all tokens previously issued based on that authorization code. The authorization code is bound to the client identifier and redirection URI.

state

REQUIRED if the “state” parameter was present in the client authorization request. The exact value received from the client.

For example, the authorization server redirects the user-agent by sending the following HTTP response.

HTTP/1.1 302 Found
Location: https://client.example.com/cb?code=SplxlOBeZQQYbYS6WxSbIA
       &state=xyz
Parameters
  • redirect_uri – Redirect to the given URI for the authorization

  • grant_user – if resource owner granted the request, pass this resource owner, otherwise pass None.

Returns

(status_code, body, headers)

validate_token_request()

The client makes a request to the token endpoint by sending the following parameters using the “application/x-www-form-urlencoded” format per Section 4.1.3:

grant_type

REQUIRED. Value MUST be set to “authorization_code”.

code

REQUIRED. The authorization code received from the authorization server.

redirect_uri

REQUIRED, if the “redirect_uri” parameter was included in the authorization request as described in Section 4.1.1, and their values MUST be identical.

client_id

REQUIRED, if the client is not authenticating with the authorization server as described in Section 3.2.1.

If the client type is confidential or the client was issued client credentials (or assigned other authentication requirements), the client MUST authenticate with the authorization server as described in Section 3.2.1.

For example, the client makes the following HTTP request using TLS:

POST /token HTTP/1.1
Host: server.example.com
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
Content-Type: application/x-www-form-urlencoded

grant_type=authorization_code&code=SplxlOBeZQQYbYS6WxSbIA
&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
create_token_response()

If the access token request is valid and authorized, the authorization server issues an access token and optional refresh token as described in Section 5.1. If the request client authentication failed or is invalid, the authorization server returns an error response as described in Section 5.2. Per Section 4.1.4.

An example successful response:

HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store
Pragma: no-cache

{
    "access_token":"2YotnFZFEjr1zCsicMWpAA",
    "token_type":"example",
    "expires_in":3600,
    "refresh_token":"tGzv3JOkF0XG5Qx2TlKWIA",
    "example_parameter":"example_value"
}
Returns

(status_code, body, headers)

generate_authorization_code()

“The method to generate “code” value for authorization code data. Developers may rewrite this method, or customize the code length with:

class MyAuthorizationCodeGrant(AuthorizationCodeGrant):
    AUTHORIZATION_CODE_LENGTH = 32  # default is 48
save_authorization_code(code, request)

Save authorization_code for later use. Developers MUST implement it in subclass. Here is an example:

def save_authorization_code(self, code, request):
    client = request.client
    item = AuthorizationCode(
        code=code,
        client_id=client.client_id,
        redirect_uri=request.redirect_uri,
        scope=request.scope,
        user_id=request.user.id,
    )
    item.save()
query_authorization_code(code, client)

Get authorization_code from previously savings. Developers MUST implement it in subclass:

def query_authorization_code(self, code, client):
    return Authorization.get(code=code, client_id=client.client_id)
Parameters
  • code – a string represent the code.

  • client – client related to this code.

Returns

authorization_code object

delete_authorization_code(authorization_code)

Delete authorization code from database or cache. Developers MUST implement it in subclass, e.g.:

def delete_authorization_code(self, authorization_code):
    authorization_code.delete()
Parameters

authorization_code – the instance of authorization_code

authenticate_user(authorization_code)

Authenticate the user related to this authorization_code. Developers MUST implement this method in subclass, e.g.:

def authenticate_user(self, authorization_code):
    return User.query.get(authorization_code.user_id)
Parameters

authorization_code – AuthorizationCode object

Returns

user

class authlib.oauth2.rfc6749.grants.ImplicitGrant(request, server)

The implicit grant type is used to obtain access tokens (it does not support the issuance of refresh tokens) and is optimized for public clients known to operate a particular redirection URI. These clients are typically implemented in a browser using a scripting language such as JavaScript.

Since this is a redirection-based flow, the client must be capable of interacting with the resource owner’s user-agent (typically a web browser) and capable of receiving incoming requests (via redirection) from the authorization server.

Unlike the authorization code grant type, in which the client makes separate requests for authorization and for an access token, the client receives the access token as the result of the authorization request.

The implicit grant type does not include client authentication, and relies on the presence of the resource owner and the registration of the redirection URI. Because the access token is encoded into the redirection URI, it may be exposed to the resource owner and other applications residing on the same device:

+----------+
| Resource |
|  Owner   |
|          |
+----------+
     ^
     |
    (B)
+----|-----+          Client Identifier     +---------------+
|         -+----(A)-- & Redirection URI --->|               |
|  User-   |                                | Authorization |
|  Agent  -|----(B)-- User authenticates -->|     Server    |
|          |                                |               |
|          |<---(C)--- Redirection URI ----<|               |
|          |          with Access Token     +---------------+
|          |            in Fragment
|          |                                +---------------+
|          |----(D)--- Redirection URI ---->|   Web-Hosted  |
|          |          without Fragment      |     Client    |
|          |                                |    Resource   |
|     (F)  |<---(E)------- Script ---------<|               |
|          |                                +---------------+
+-|--------+
  |    |
 (A)  (G) Access Token
  |    |
  ^    v
+---------+
|         |
|  Client |
|         |
+---------+
AUTHORIZATION_ENDPOINT = True

authorization_code grant type has authorization endpoint

TOKEN_ENDPOINT_AUTH_METHODS = ['none']

Allowed client auth methods for token endpoint

validate_authorization_request()

The client constructs the request URI by adding the following parameters to the query component of the authorization endpoint URI using the “application/x-www-form-urlencoded” format. Per Section 4.2.1.

response_type

REQUIRED. Value MUST be set to “token”.

client_id

REQUIRED. The client identifier as described in Section 2.2.

redirect_uri

OPTIONAL. As described in Section 3.1.2.

scope

OPTIONAL. The scope of the access request as described by Section 3.3.

state

RECOMMENDED. An opaque value used by the client to maintain state between the request and callback. The authorization server includes this value when redirecting the user-agent back to the client. The parameter SHOULD be used for preventing cross-site request forgery as described in Section 10.12.

The client directs the resource owner to the constructed URI using an HTTP redirection response, or by other means available to it via the user-agent.

For example, the client directs the user-agent to make the following HTTP request using TLS:

GET /authorize?response_type=token&client_id=s6BhdRkqt3&state=xyz
&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
Host: server.example.com
create_authorization_response(redirect_uri, grant_user)

If the resource owner grants the access request, the authorization server issues an access token and delivers it to the client by adding the following parameters to the fragment component of the redirection URI using the “application/x-www-form-urlencoded” format. Per Section 4.2.2.

access_token

REQUIRED. The access token issued by the authorization server.

token_type

REQUIRED. The type of the token issued as described in Section 7.1. Value is case insensitive.

expires_in

RECOMMENDED. 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

OPTIONAL, if identical to the scope requested by the client; otherwise, REQUIRED. The scope of the access token as described by Section 3.3.

state

REQUIRED if the “state” parameter was present in the client authorization request. The exact value received from the client.

The authorization server MUST NOT issue a refresh token.

For example, the authorization server redirects the user-agent by sending the following HTTP response:

HTTP/1.1 302 Found
Location: http://example.com/cb#access_token=2YotnFZFEjr1zCsicMWpAA
       &state=xyz&token_type=example&expires_in=3600

Developers should note that some user-agents do not support the inclusion of a fragment component in the HTTP “Location” response header field. Such clients will require using other methods for redirecting the client than a 3xx redirection response – for example, returning an HTML page that includes a ‘continue’ button with an action linked to the redirection URI.

Parameters
  • redirect_uri – Redirect to the given URI for the authorization

  • grant_user – if resource owner granted the request, pass this resource owner, otherwise pass None.

Returns

(status_code, body, headers)

class authlib.oauth2.rfc6749.grants.ResourceOwnerPasswordCredentialsGrant(request, server)

The resource owner password credentials grant type is suitable in cases where the resource owner has a trust relationship with the client, such as the device operating system or a highly privileged

application. The authorization server should take special care when enabling this grant type and only allow it when other flows are not viable.

This grant type is suitable for clients capable of obtaining the resource owner’s credentials (username and password, typically using an interactive form). It is also used to migrate existing clients using direct authentication schemes such as HTTP Basic or Digest authentication to OAuth by converting the stored credentials to an access token:

+----------+
| Resource |
|  Owner   |
|          |
+----------+
    v
    |    Resource Owner
   (A) Password Credentials
    |
    v
+---------+                                  +---------------+
|         |>--(B)---- Resource Owner ------->|               |
|         |         Password Credentials     | Authorization |
| Client  |                                  |     Server    |
|         |<--(C)---- Access Token ---------<|               |
|         |    (w/ Optional Refresh Token)   |               |
+---------+                                  +---------------+
validate_token_request()

The client makes a request to the token endpoint by adding the following parameters using the “application/x-www-form-urlencoded” format per Appendix B with a character encoding of UTF-8 in the HTTP request entity-body:

grant_type

REQUIRED. Value MUST be set to “password”.

username

REQUIRED. The resource owner username.

password

REQUIRED. The resource owner password.

scope

OPTIONAL. The scope of the access request as described by Section 3.3.

If the client type is confidential or the client was issued client credentials (or assigned other authentication requirements), the client MUST authenticate with the authorization server as described in Section 3.2.1.

For example, the client makes the following HTTP request using transport-layer security (with extra line breaks for display purposes only):

POST /token HTTP/1.1
Host: server.example.com
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
Content-Type: application/x-www-form-urlencoded

grant_type=password&username=johndoe&password=A3ddj3w
create_token_response()

If the access token request is valid and authorized, the authorization server issues an access token and optional refresh token as described in Section 5.1. If the request failed client authentication or is invalid, the authorization server returns an error response as described in Section 5.2.

An example successful response:

HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store
Pragma: no-cache

{
    "access_token":"2YotnFZFEjr1zCsicMWpAA",
    "token_type":"example",
    "expires_in":3600,
    "refresh_token":"tGzv3JOkF0XG5Qx2TlKWIA",
    "example_parameter":"example_value"
}
Returns

(status_code, body, headers)

authenticate_user(username, password)

validate the resource owner password credentials using its existing password validation algorithm:

def authenticate_user(self, username, password):
    user = get_user_by_username(username)
    if user.check_password(password):
       return user
class authlib.oauth2.rfc6749.grants.ClientCredentialsGrant(request, server)

The client can request an access token using only its client credentials (or other supported means of authentication) when the client is requesting access to the protected resources under its control, or those of another resource owner that have been previously arranged with the authorization server.

The client credentials grant type MUST only be used by confidential clients:

+---------+                                  +---------------+
|         |                                  |               |
|         |>--(A)- Client Authentication --->| Authorization |
| Client  |                                  |     Server    |
|         |<--(B)---- Access Token ---------<|               |
|         |                                  |               |
+---------+                                  +---------------+

https://tools.ietf.org/html/rfc6749#section-4.4

validate_token_request()

The client makes a request to the token endpoint by adding the following parameters using the “application/x-www-form-urlencoded” format per Appendix B with a character encoding of UTF-8 in the HTTP request entity-body:

grant_type

REQUIRED. Value MUST be set to “client_credentials”.

scope

OPTIONAL. The scope of the access request as described by Section 3.3.

The client MUST authenticate with the authorization server as described in Section 3.2.1.

For example, the client makes the following HTTP request using transport-layer security (with extra line breaks for display purposes only):

POST /token HTTP/1.1
Host: server.example.com
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
Content-Type: application/x-www-form-urlencoded

grant_type=client_credentials

The authorization server MUST authenticate the client.

create_token_response()

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.

An example successful response:

HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store
Pragma: no-cache

{
    "access_token":"2YotnFZFEjr1zCsicMWpAA",
    "token_type":"example",
    "expires_in":3600,
    "example_parameter":"example_value"
}
Returns

(status_code, body, headers)

class authlib.oauth2.rfc6749.grants.RefreshTokenGrant(request, server)

A special grant endpoint for refresh_token grant_type. Refreshing an Access Token per Section 6.

INCLUDE_NEW_REFRESH_TOKEN = False

The authorization server MAY issue a new refresh token

validate_token_request()

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 per Appendix B with a character encoding of UTF-8 in the HTTP request entity-body, per Section 6:

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.

For example, the client makes the following HTTP request using transport-layer security (with extra line breaks for display purposes only):

POST /token HTTP/1.1
Host: server.example.com
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
Content-Type: application/x-www-form-urlencoded

grant_type=refresh_token&refresh_token=tGzv3JOkF0XG5Qx2TlKWIA
create_token_response()

If valid and authorized, the authorization server issues an access token as described in Section 5.1. If the request failed verification or is invalid, the authorization server returns an error response as described in Section 5.2.

authenticate_refresh_token(refresh_token)

Get token information with refresh_token string. Developers MUST implement this method in subclass:

def authenticate_refresh_token(self, refresh_token):
    token = Token.get(refresh_token=refresh_token)
    if token and not token.refresh_token_revoked:
        return token
Parameters

refresh_token – The refresh token issued to the client

Returns

token

authenticate_user(credential)

Authenticate the user related to this credential. Developers MUST implement this method in subclass:

def authenticate_user(self, credential):
    return User.query.get(credential.user_id)
Parameters

credential – Token object

Returns

user

revoke_old_credential(credential)

The authorization server MAY revoke the old refresh token after issuing a new refresh token to the client. Developers MUST implement this method in subclass:

def revoke_old_credential(self, credential):
    credential.revoked = True
    credential.save()
Parameters

credential – Token object