Simple JWT

A JSON Web Token authentication plugin for the Django REST Framework.

Simple JWT provides a JSON Web Token authentication backend for the Django REST Framework. It aims to provide an out-of-the-box solution for JWT authentication which avoids some of the common pitfalls of the JWT specification. Assuming users of the library don't extensively and invasively subclass everything, Simple JWT's behavior shouldn't be surprising. Settings variable defaults should be safe.

Requirements

Python (3.6, 3.7)
Django (2.0, 2.1, 2.2)
Django REST Framework (3.8, 3.9, 3.10)

These are the officially supported python and package versions. Other versions will probably work. You're free to modify the tox config and see what is possible.

Installation

Simple JWT can be installed with pip:

pip install djangorestframework_simplejwt

Then, your django project must be configured to use the library. In settings.py, add rest_framework_simplejwt.authentication.JWTAuthentication to the list of authentication classes:

REST_FRAMEWORK = {
    ...
    'DEFAULT_AUTHENTICATION_CLASSES': (
        ...
        'rest_framework_simplejwt.authentication.JWTAuthentication',
    )
    ...
}

Also, in your root urls.py file (or any other url config), include routes for Simple JWT's TokenObtainPairView and TokenRefreshView views:

from rest_framework_simplejwt.views import (
    TokenObtainPairView,
    TokenRefreshView,
)

urlpatterns = [
    ...
    url(r'^api/token/$', TokenObtainPairView.as_view(), name='token_obtain_pair'),
    url(r'^api/token/refresh/$', TokenRefreshView.as_view(), name='token_refresh'),
    ...
]

You can also include a route for Simple JWT's TokenVerifyView if you wish to allow API users to verify HMAC-signed tokens without having access to your signing key:

urlpatterns = [
    ...
    url(r'^api/token/verify/$', TokenVerifyView.as_view(), name='token_verify'),
    ...
]

Usage

To verify that Simple JWT is working, you can use curl to issue a couple of test requests:

curl \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{"username": "davidattenborough", "password": "boatymcboatface"}' \
  http://localhost:8000/api/token/

...
{
  "access":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX3BrIjoxLCJ0b2tlbl90eXBlIjoiYWNjZXNzIiwiY29sZF9zdHVmZiI6IuKYgyIsImV4cCI6MTIzNDU2LCJqdGkiOiJmZDJmOWQ1ZTFhN2M0MmU4OTQ5MzVlMzYyYmNhOGJjYSJ9.NHlztMGER7UADHZJlxNG0WSi22a2KaYSfd1S-AuT7lU",
  "refresh":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX3BrIjoxLCJ0b2tlbl90eXBlIjoicmVmcmVzaCIsImNvbGRfc3R1ZmYiOiLimIMiLCJleHAiOjIzNDU2NywianRpIjoiZGUxMmY0ZTY3MDY4NDI3ODg5ZjE1YWMyNzcwZGEwNTEifQ.aEoAYkSJjoWH1boshQAaTkf8G3yn0kapko6HFRt7Rh4"
}

You can use the returned access token to prove authentication for a protected view:

curl \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX3BrIjoxLCJ0b2tlbl90eXBlIjoiYWNjZXNzIiwiY29sZF9zdHVmZiI6IuKYgyIsImV4cCI6MTIzNDU2LCJqdGkiOiJmZDJmOWQ1ZTFhN2M0MmU4OTQ5MzVlMzYyYmNhOGJjYSJ9.NHlztMGER7UADHZJlxNG0WSi22a2KaYSfd1S-AuT7lU" \
  http://localhost:8000/api/some-protected-view/

When this short-lived access token expires, you can use the longer-lived refresh token to obtain another access token:

curl \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{"refresh":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX3BrIjoxLCJ0b2tlbl90eXBlIjoicmVmcmVzaCIsImNvbGRfc3R1ZmYiOiLimIMiLCJleHAiOjIzNDU2NywianRpIjoiZGUxMmY0ZTY3MDY4NDI3ODg5ZjE1YWMyNzcwZGEwNTEifQ.aEoAYkSJjoWH1boshQAaTkf8G3yn0kapko6HFRt7Rh4"}' \
  http://localhost:8000/api/token/refresh/

...
{"access":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX3BrIjoxLCJ0b2tlbl90eXBlIjoiYWNjZXNzIiwiY29sZF9zdHVmZiI6IuKYgyIsImV4cCI6MTIzNTY3LCJqdGkiOiJjNzE4ZTVkNjgzZWQ0NTQyYTU0NWJkM2VmMGI0ZGQ0ZSJ9.ekxRxgb9OKmHkfy-zs1Ro_xs1eMLXiR17dIDBVxeT-w"}

Settings

Some of Simple JWT's behavior can be customized through settings variables in settings.py:

# Django project settings.py

from datetime import timedelta

...

SIMPLE_JWT = {
    'ACCESS_TOKEN_LIFETIME': timedelta(minutes=5),
    'REFRESH_TOKEN_LIFETIME': timedelta(days=1),
    'ROTATE_REFRESH_TOKENS': False,
    'BLACKLIST_AFTER_ROTATION': True,

    'ALGORITHM': 'HS256',
    'SIGNING_KEY': settings.SECRET_KEY,
    'VERIFYING_KEY': None,

    'AUTH_HEADER_TYPES': ('Bearer',),
    'USER_ID_FIELD': 'id',
    'USER_ID_CLAIM': 'user_id',

    'AUTH_TOKEN_CLASSES': ('rest_framework_simplejwt.tokens.AccessToken',),
    'TOKEN_TYPE_CLAIM': 'token_type',

    'JTI_CLAIM': 'jti',

    'SLIDING_TOKEN_REFRESH_EXP_CLAIM': 'refresh_exp',
    'SLIDING_TOKEN_LIFETIME': timedelta(minutes=5),
    'SLIDING_TOKEN_REFRESH_LIFETIME': timedelta(days=1),
}

Above, the default values for these settings are shown.

ACCESS_TOKEN_LIFETIME: A datetime.timedelta object which specifies how long access tokens are valid. This timedelta value is added to the current UTC time during token generation to obtain the token's default "exp" claim value.
REFRESH_TOKEN_LIFETIME: A datetime.timedelta object which specifies how long refresh tokens are valid. This timedelta value is added to the current UTC time during token generation to obtain the token's default "exp" claim value.
ROTATE_REFRESH_TOKENS: When set to True, if a refresh token is submitted to the TokenRefreshView, a new refresh token will be returned along with the new access token. This new refresh token will be supplied via a "refresh" key in the JSON response. New refresh tokens will have a renewed expiration time which is determined by adding the timedelta in the REFRESH_TOKEN_LIFETIME setting to the current time when the request is made. If the blacklist app is in use and the BLACKLIST_AFTER_ROTATION setting is set to True, refresh tokens submitted to the refresh view will be added to the blacklist.
BLACKLIST_AFTER_ROTATION: When set to True, causes refresh tokens submitted to the TokenRefreshView to be added to the blacklist if the blacklist app is in use and the ROTATE_REFRESH_TOKENS setting is set to True.
ALGORITHM: The algorithm from the PyJWT library which will be used to perform signing/verification operations on tokens. To use symmetric HMAC signing and verification, the following algorithms may be used: 'HS256', 'HS384', 'HS512'. When an HMAC algorithm is chosen, the SIGNING_KEY setting will be used as both the signing key and the verifying key. In that case, the VERIFYING_KEY setting will be ignored. To use asymmetric RSA signing and verification, the following algorithms may be used: 'RS256', 'RS384', 'RS512'. When an RSA algorithm is chosen, the SIGNING_KEY setting must be set to a string which contains an RSA private key. Likewise, the VERIFYING_KEY setting must be set to a string which contains an RSA public key.
SIGNING_KEY: The signing key which is used to sign the content of generated tokens. For HMAC signing, this should be a random string with at least as many bits of data as is required by the signing protocol. For RSA signing, this should be a string which contains an RSA private key which is 2048 bits or longer. Since Simple JWT defaults to using 256-bit HMAC signing, the SIGNING_KEY setting defaults to the value of the SECRET_KEY setting for your django project. Although this is the most reasonable default that Simple JWT can provide, it is recommended that developers change this setting to a value which is independent from the django project secret key. This will make changing the signing key used for tokens easier in the event that it is compromised.
VERIFYING_KEY: The verifying key which is used to verify the content of generated tokens. If an HMAC algorithm has been specified by the ALGORITHM setting, the VERIFYING_KEY setting will be ignored and the value of the SIGNING_KEY setting will be used. If an RSA algorithm has been specified by the ALGORITHM setting, the VERIFYING_KEY setting must be set to a string which contains an RSA public key.
AUTH_HEADER_TYPES: The authorization header type(s) that will be accepted for views that require authentication. For example, a value of 'Bearer' means that views requiring authentication would look for a header with the following format: Authorization: Bearer <token>. This setting may also contain a list or tuple of possible header types (e.g. ('Bearer', 'JWT')). If a list or tuple is used in this way, and authentication fails, the first item in the collection will be used to build the "WWW-Authenticate" header in the response.
USER_ID_FIELD: The database field from the user model that will be included in generated tokens to identify users. It is recommended that the value of this setting specifies a field which does not normally change once its initial value is chosen. For example, specifying a "username" or "email" field would be a poor choice since an account's username or email might change depending on how account management in a given service is designed. This could allow a new account to be created with an old username while an existing token is still valid which uses that username as a user identifier.
USER_ID_CLAIM: The claim in generated tokens which will be used to store user identifiers. For example, a setting value of 'user_id' would mean generated tokens include a "user_id" claim that contains the user's identifier.
AUTH_TOKEN_CLASSES: A list of dot paths to classes which specify the types of token that are allowed to prove authentication. More about this in the "Token types" section below.
TOKEN_TYPE_CLAIM: The claim name that is used to store a token's type. More about this in the "Token types" section below.
JTI_CLAIM: The claim name that is used to store a token's unique identifier. This identifier is used to identify revoked tokens in the blacklist app. It may be necessary in some cases to use another claim besides the default "jti" claim to store such a value.
SLIDING_TOKEN_LIFETIME: A datetime.timedelta object which specifies how long sliding tokens are valid to prove authentication. This timedelta value is added to the current UTC time during token generation to obtain the token's default "exp" claim value. More about this in the "Sliding tokens" section below.
SLIDING_TOKEN_REFRESH_LIFETIME: A datetime.timedelta object which specifies how long sliding tokens are valid to be refreshed. This timedelta value is added to the current UTC time during token generation to obtain the token's default "exp" claim value. More about this in the "Sliding tokens" section below.
SLIDING_TOKEN_REFRESH_EXP_CLAIM: The claim name that is used to store the exipration time of a sliding token's refresh period. More about this in the "Sliding tokens" section below.

Customizing token claims

If you wish to customize the claims contained in web tokens which are generated by the TokenObtainPairView and TokenObtainSlidingView views, create a subclass for the desired view as well as a subclass for its corresponding serializer. Here's an example of how to customize the claims in tokens generated by the TokenObtainPairView:

from rest_framework_simplejwt.serializers import TokenObtainPairSerializer
from rest_framework_simplejwt.views import TokenObtainPairView

class MyTokenObtainPairSerializer(TokenObtainPairSerializer):
    @classmethod
    def get_token(cls, user):
        token = super().get_token(user)

        # Add custom claims
        token['name'] = user.name
        # ...

        return token

class MyTokenObtainPairView(TokenObtainPairView):
    serializer_class = MyTokenObtainPairSerializer

Note that the example above will cause the customized claims to be present in both refresh and access tokens which are generated by the view. This follows from the fact that the get_token method above produces the refresh token for the view, which is in turn used to generate the view's access token.

As with the standard token views, you'll also need to include a url route to your subclassed view.

Creating tokens manually

Sometimes, you may wish to manually create a token for a user. This could be done as follows:

from rest_framework_simplejwt.tokens import RefreshToken

def get_tokens_for_user(user):
    refresh = RefreshToken.for_user(user)

    return {
        'refresh': str(refresh),
        'access': str(refresh.access_token),
    }

The above function get_tokens_for_user will return the serialized representations of new refresh and access tokens for the given user. In general, a token for any subclass of rest_framework_simplejwt.tokens.Token can be created in this way.

Token types

Simple JWT provides two different token types which can be used to prove authentication. In a token's payload, its type can be identified by the value of its token type claim, which is "token_type" by default. This may have a value of "access", "sliding", or "refresh" however refresh tokens are not considered valid for authentication at this time. The claim name used to store the type can be customized by changing the TOKEN_TYPE_CLAIM setting.

By default, Simple JWT expects an "access" token to prove authentication. The allowed auth token types are determined by the value of the AUTH_TOKEN_CLASSES setting. This setting contains a list of dot paths to token classes. It includes the 'rest_framework_simplejwt.tokens.AccessToken' dot path by default but may also include the 'rest_framework_simplejwt.tokens.SlidingToken' dot path. Either or both of those dot paths may be present in the list of auth token classes. If they are both present, then both of those token types may be used to prove authentication.

Sliding tokens

Sliding tokens offer a more convenient experience to users of tokens with the trade-offs of being less secure and, in the case that the blacklist app is being used, less performant. A sliding token is one which contains both an expiration claim and a refresh expiration claim. As long as the timestamp in a sliding token's expiration claim has not passed, it can be used to prove authentication. Additionally, as long as the timestamp in its refresh expiration claim has not passed, it may also be submitted to a refresh view to get another copy of itself with a renewed expiration claim.

If you want to use sliding tokens, change the AUTH_TOKEN_CLASSES setting to ('rest_framework_simplejwt.tokens.SlidingToken',). (Alternatively, the AUTH_TOKEN_CLASSES setting may include dot paths to both the AccessToken and SlidingToken token classes in the rest_framework_simplejwt.tokens module if you want to allow both token types to be used for authentication.)

Also, include urls for the sliding token specific TokenObtainSlidingView and TokenRefreshSlidingView views along side or in place of urls for the access token specific TokenObtainPairView and TokenRefreshView views:

from rest_framework_simplejwt.views import (
    TokenObtainSlidingView,
    TokenRefreshSlidingView,
)

urlpatterns = [
    ...
    url(r'^api/token/$', TokenObtainSlidingView.as_view(), name='token_obtain'),
    url(r'^api/token/refresh/$', TokenRefreshSlidingView.as_view(), name='token_refresh'),
    ...
]

Be aware that, if you are using the blacklist app, Simple JWT will validate all sliding tokens against the blacklist for each authenticated request. This will reduce the performance of authenticated API views.

Blacklist app

Simple JWT includes an app that provides token blacklist functionality. To use this app, include it in your list of installed apps in settings.py:

# Django project settings.py

...

INSTALLED_APPS = (
    ...
    'rest_framework_simplejwt.token_blacklist',
    ...
}

Also, make sure to run python manage.py migrate to run the app's migrations.

If the blacklist app is detected in INSTALLED_APPS, Simple JWT will add any generated refresh or sliding tokens to a list of outstanding tokens. It will also check that any refresh or sliding token does not appear in a blacklist of tokens before it considers it as valid.

The Simple JWT blacklist app implements its outstanding and blacklisted token lists using two models: OutstandingToken and BlacklistedToken. Model admins are defined for both of these models. To add a token to the blacklist, find its corresponding OutstandingToken record in the admin and use the admin again to create a BlacklistedToken record that points to the OutstandingToken record.

Alternatively, you can blacklist a token by creating a BlacklistMixin subclass instance and calling the instance's blacklist method:

from rest_framework_simplejwt.tokens import RefreshToken

token = RefreshToken(base64_encoded_token_string)
token.blacklist()

This will create unique outstanding token and blacklist records for the token's "jti" claim or whichever claim is specified by the JTI_CLAIM setting.

The blacklist app also provides a management command, flushexpiredtokens, which will delete any tokens from the outstanding list and blacklist that have expired. You should set up a cron job on your server or hosting platform which runs this command daily.

Experimental features

JWTTokenUserAuthentication backend

The JWTTokenUserAuthentication backend's authenticate method does not perform a database lookup to obtain a user instance. Instead, it returns a rest_framework_simplejwt.models.TokenUser instance which acts as a stateless user object backed only by a validated token instead of a record in a database. This can facilitate developing single sign-on functionality between separately hosted Django apps which all share the same token secret key. To use this feature, add the rest_framework_simplejwt.authentication.JWTTokenUserAuthentication backend (instead of the default JWTAuthentication backend) to the Django REST Framework's DEFAULT_AUTHENTICATION_CLASSES config setting:

REST_FRAMEWORK = {
    ...
    'DEFAULT_AUTHENTICATION_CLASSES': (
        ...
        'rest_framework_simplejwt.authentication.JWTTokenUserAuthentication',
    )
    ...
}

Development and Running the Tests

To do development work for Simple JWT, make your own fork on Github, clone it locally, make and activate a virtualenv for it, then from within the project directory:

pip install --upgrade pip setuptools
pip install -e .[dev]

To run the tests:

pytest

To run the tests in all supported environments with tox, first install pyenv. Next, install the relevant Python minor versions and create a .python-version file in the project directory:

pyenv install 3.7.x
pyenv install 3.6.x
pyenv install 3.5.x
cat > .python-version <<EOF
3.7.x
3.6.x
3.5.x
EOF

Above, the x in each case should be replaced with the latest corresponding patch version. The .python-version file will tell pyenv and tox that you're testing against multiple versions of Python. Next, run tox:

tox

Acknowledgements

This project borrows code from the Django REST Framework as well as concepts from the implementation of another JSON web token library for the Django REST Framework, django-rest-framework-jwt. The licenses from both of those projects have been included in this repository in the "licenses" directory.

iMerica/django-rest-framework-simplejwt