Basic Usage

In its simplest form, there is not much to using flask_jwt_extended. You use create_access_token() to make new access JWTs, the jwt_required() decorator to protect endpoints, and get_jwt_identity() function to get the identity of a JWT in a protected endpoint.

from flask import Flask, jsonify, request
from flask_jwt_extended import (
    JWTManager, jwt_required, create_access_token,
    get_jwt_identity
)

app = Flask(__name__)

# Setup the Flask-JWT-Extended extension
app.config['JWT_SECRET_KEY'] = 'super-secret'  # Change this!
jwt = JWTManager(app)


# Provide a method to create access tokens. The create_access_token()
# function is used to actually generate the token, and you can return
# it to the caller however you choose.
@app.route('/login', methods=['POST'])
def login():
    if not request.is_json:
        return jsonify({"msg": "Missing JSON in request"}), 400

    username = request.json.get('username', None)
    password = request.json.get('password', None)
    if not username:
        return jsonify({"msg": "Missing username parameter"}), 400
    if not password:
        return jsonify({"msg": "Missing password parameter"}), 400

    if username != 'test' or password != 'test':
        return jsonify({"msg": "Bad username or password"}), 401

    # Identity can be any data that is json serializable
    access_token = create_access_token(identity=username)
    return jsonify(access_token=access_token), 200


# Protect a view with jwt_required, which requires a valid access token
# in the request to access.
@app.route('/protected', methods=['GET'])
@jwt_required
def protected():
    # Access the identity of the current user with get_jwt_identity
    current_user = get_jwt_identity()
    return jsonify(logged_in_as=current_user), 200


if __name__ == '__main__':
    app.run()

To access a jwt_required protected view, all we have to do is send in the JWT with the request. By default, this is done with an authorization header that looks like:

Authorization: Bearer <access_token>

We can see this in action using CURL:

$ curl http://localhost:5000/protected
{
  "msg": "Missing Authorization Header"
}

$ curl -H "Content-Type: application/json" -X POST \
  -d '{"username":"test","password":"test"}' http://localhost:5000/login
{
  "access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmcmVzaCI6dHJ1ZSwianRpIjoiZjhmNDlmMjUtNTQ4OS00NmRjLTkyOWUtZTU2Y2QxOGZhNzRlIiwidXNlcl9jbGFpbXMiOnt9LCJuYmYiOjE0NzQ0NzQ3OTEsImlhdCI6MTQ3NDQ3NDc5MSwiaWRlbnRpdHkiOiJ0ZXN0IiwiZXhwIjoxNDc0NDc1NjkxLCJ0eXBlIjoiYWNjZXNzIn0.vCy0Sec61i9prcGIRRCbG8e9NV6_wFH2ICFgUGCLKpc"
}

$ export ACCESS="eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmcmVzaCI6dHJ1ZSwianRpIjoiZjhmNDlmMjUtNTQ4OS00NmRjLTkyOWUtZTU2Y2QxOGZhNzRlIiwidXNlcl9jbGFpbXMiOnt9LCJuYmYiOjE0NzQ0NzQ3OTEsImlhdCI6MTQ3NDQ3NDc5MSwiaWRlbnRpdHkiOiJ0ZXN0IiwiZXhwIjoxNDc0NDc1NjkxLCJ0eXBlIjoiYWNjZXNzIn0.vCy0Sec61i9prcGIRRCbG8e9NV6_wFH2ICFgUGCLKpc"

$ curl -H "Authorization: Bearer $ACCESS" http://localhost:5000/protected
{
  "logged_in_as": "test"
}

NOTE: Remember to change the secret key of your application, and ensure that no one is able to view it. The JSON Web Tokens are signed with the secret key, so if someone gets that, they can create arbitrary tokens, and in essence log in as any user.