前言
flask_jwt_extended 最基本的使用只需要掌握三个函数：
- create_access_token() 用来创建 Token 令牌
- get_jwt_identity() 用来根据令牌取得之前的 identity 信息
- jwt_required() 这是一个装饰器，用来保护 flask 节点
简单示例
以下是官方文档给的简单示例https://flask-jwt-extended.readthedocs.io/en/latest/basic_usage/
from flask import Flask
from flask import jsonify
from flask import request
from flask_jwt_extended import create_access_token
from flask_jwt_extended import get_jwt_identity
from flask_jwt_extended import jwt_required
from flask_jwt_extended import JWTManager
app = Flask(__name__)
# Setup the Flask-JWT-Extended extension
app.config["JWT_SECRET_KEY"] = "super-secret" # Change this!
jwt = JWTManager(app)
# Create a route to authenticate your users and return JWTs. The
# create_access_token() function is used to actually generate the JWT.
@app.route("/login", methods=["POST"])
def login():
username = request.json.get("username", None)
password = request.json.get("password", None)
if username != "test" or password != "test":
return jsonify({"msg": "Bad username or password"}), 401
access_token = create_access_token(identity=username)
return jsonify(access_token=access_token)
# Protect a route with jwt_required, which will kick out requests
# without a valid JWT present.
@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()
需要token验证的接口，在请求头部加如下格式token
Authorization: Bearer <access_token>
user_lookup_loader() 使用
在大多数 Web 应用程序中，重要的是能够访问正在访问受保护路由的用户。我们提供了几个回调函数，可以在使用 JWT 时实现无缝连接。
第一个是user_identity_loader()，它将User用于创建 JWT 的任何对象转换为 JSON 可序列化格式。
另一方面，当请求中存在 JWT 时，您可以使用它user_lookup_loader() 来自动加载您的对象。User加载的用户在您的受保护路由中可用current_user。
以下是官方文档给的示例
from hmac import compare_digest
from flask import Flask
from flask import jsonify
from flask import request
from flask_sqlalchemy import SQLAlchemy
from flask_jwt_extended import create_access_token
from flask_jwt_extended import current_user
from flask_jwt_extended import jwt_required
from flask_jwt_extended import JWTManager
app = Flask(__name__)
app.config["JWT_SECRET_KEY"] = "super-secret" # Change this!
app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite://"
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
jwt = JWTManager(app)
db = SQLAlchemy(app)
class User(db.Model):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.Text, nullable=False, unique=True)
full_name = db.Column(db.Text, nullable=False)
# NOTE: In a real application make sure to properly hash and salt passwords
def check_password(self, password):
return compare_digest(password, "password")
# Register a callback function that takes whatever object is passed in as the
# identity when creating JWTs and converts it to a JSON serializable format.
@jwt.user_identity_loader
def user_identity_lookup(user):
return user.id
# Register a callback function that loads a user from your database whenever
# a protected route is accessed. This should return any python object on a
# successful lookup, or None if the lookup failed for any reason (for example
# if the user has been deleted from the database).
@jwt.user_lookup_loader
def user_lookup_callback(_jwt_header, jwt_data):
identity = jwt_data["sub"]
return User.query.filter_by(id=identity).one_or_none()
@app.route("/login", methods=["POST"])
def login():
username = request.json.get("username", None)
password = request.json.get("password", None)
user = User.query.filter_by(username=username).one_or_none()
if not user or not user.check_password(password):
return jsonify("Wrong username or password"), 401
# Notice that we are passing in the actual sqlalchemy user object here
access_token = create_access_token(identity=user)
return jsonify(access_token=access_token)
@app.route("/who_am_i", methods=["GET"])
@jwt_required()
def protected():
# We can now access our sqlalchemy User object via `current_user`.
return jsonify(
id=current_user.id,
full_name=current_user.full_name,
username=current_user.username,
)
if __name__ == "__main__":
db.create_all()
db.session.add(User(full_name="Bruce Wayne", username="batman"))
db.session.add(User(full_name="Ann Takamaki", username="panther"))
db.session.add(User(full_name="Jester Lavore", username="little_sapphire"))
db.session.commit()
app.run()
详细讲解
前面简单示例中使用get_jwt_identity()方法获取identity 信息，也就是username。在上面示例中使用current_user 也可以获取到当前用户对象
current_user 必须要在@jwt_required()装饰器中使用。
from flask_jwt_extended import (
create_access_token, create_refresh_token, jwt_required, get_jwt_identity, current_user
)
class UserInfo(Resource):
@jwt_required()
def get(self):
"""根据token 解析用户username"""
print(f"xxxxxxxxxxxxxx: {current_user}")
return {
"msg": 'success'
}
如果直接使用会出现报错RuntimeError: You must provide a @jwt.user_lookup_loader callback to use this method
提示我们需先使用@jwt.user_lookup_loader 提供callback 回调函数
@jwt.user_identity_loader
def user_identity_lookup(user):
"""注册一个回调函数，该函数在创建JWT时将传入的任何对象作为标识，
并将其转换为JSON可序列化格式。"""
return user.id
@jwt.user_lookup_loader
def user_lookup_callback(_jwt_header, jwt_data):
"""注册一个回调函数，每当访问受保护的路由时，该函数将从数据库中加载用户。
如果查找成功，则应返回任何python对象，如果查找因任何原因失败
（例如，如果用户已从数据库中删除），则应返回None
"""
identity = jwt_data["sub"]
return Users.query.filter_by(id=identity).one_or_none()
之前生成token是根据username 传一个字符串得到token，现在可以改成传user对象了
access_token = create_access_token(identity=user)
完整代码示例
class Login(Resource):
def post(self):
args = reqparse.RequestParser() \
.add_argument('username', type=str, location='json', required=True, help="用户名不能为空") \
.add_argument("password", type=str, location='json', required=True, help="密码不能为空") \
.parse_args()
print(f"args: {args}")
user = Users.query.filter_by(username=args.get('username')).first()
if not user:
return {"code": 222, "msg": f"用户名或密码不正确"}
else:
if not user.is_active:
return {"code": 333, "msg": f"{user.username} not active"}
else:
# 验证密码
if user.verify_password(args.get('password')):
access_token = create_access_token(identity=user)
return jsonify({
"code": "0",
"message": "success",
"data": {
"access_token": access_token,
"userid": user.id
}
})
else:
return {"code": 222, "msg": f"用户名或密码不正确"}
# 注册
api.add_resource(Login, '/api/v1/login')
完成上面代码后current_user 返回的就是一个user对象了
class UserInfo(Resource):
@jwt_required()
def get(self):
"""根据token 解析用户username"""
print(f"xxxxxxxxxxxxxx: {current_user}")
return {
"msg": 'success',
"data": {
"id": current_user.id,
"username": current_user.username
}
}
# 注册
api.add_resource(UserInfo, '/api/v1/userinfo')
接口测试
GET http://127.0.0.1:5000/api/v1/userinfo HTTP/1.1
User-Agent: Fiddler
Host: 127.0.0.1:5000
Content-Type: application/json
Content-Length: 0
Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJmcmVzaCI6ZmFsc2UsImlhdCI6MTY2MTk5NTAyNiwianRpIjoiNzA4MWMyOTYtZDZlOC00YThmLWIwOGMtZjg0YzhiNzIyM2JhIiwidHlwZSI6ImFjY2VzcyIsInN1YiI6NSwibmJmIjoxNjYxOTk1MDI2LCJleHAiOjE2NjE5OTg2MjZ9.GHqjOjfC1RCoNe0fCq-mxIP0_mE4ojiUMwd1RzSY8C8
HTTP/1.1 200 OK
Server: Werkzeug/2.2.2 Python/3.8.5
Date: Thu, 01 Sep 2022 01:30:31 GMT
Content-Type: application/json
Content-Length: 91
Connection: close
{
"msg": "success",
"data": {
"id": 5,
"username": "test5"
}
}