Started with the login function and it works more or less :-)

backend/src/app.py

@@ -1,13 +1,51 @@
-import time 
-from flask import Flask
+import os
+import time
+import flask
 import flask_sqlalchemy
 import flask_praetorian
 import flask_cors
 
-import os
+db = flask_sqlalchemy.SQLAlchemy()
+guard = flask_praetorian.Praetorian()
+cors = flask_cors.CORS()
 
-app = Flask(__name__)
 
+# A generic user model that might be used by an app powered by flask-praetorian
+class User(db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    username = db.Column(db.Text, unique=True)
+    password = db.Column(db.Text)
+    roles = db.Column(db.Text)
+    is_active = db.Column(db.Boolean, default=True, server_default='true')
+
+    @property
+    def rolenames(self):
+        try:
+            return self.roles.split(',')
+        except Exception:
+            return []
+
+    @classmethod
+    def lookup(cls, username):
+        return cls.query.filter_by(username=username).one_or_none()
+
+    @classmethod
+    def identify(cls, id):
+        return cls.query.get(id)
+
+    @property
+    def identity(self):
+        return self.id
+
+    def is_valid(self):
+        return self.is_active
+
+
+# Initialize flask app for the example
+app = flask.Flask(__name__)
+app.config['SECRET_KEY'] = 'top secret'
+app.config['JWT_ACCESS_LIFESPAN'] = {'hours': 24}
+app.config['JWT_REFRESH_LIFESPAN'] = {'days': 30}
 # Read environment variables
 if "DEBUG" in os.environ and os.environ["DEBUG"] == 'yes':
     debug = True
@@ -22,26 +60,93 @@ if "PORT" in os.environ:
 else:
     port = 5000
 
+# Initialize the flask-praetorian instance for the app
+guard.init_app(app, User)
 
-db = flask_sqlalchemy.SQLAlchemy()
-guard = flask_praetorian.Praetorian()
-cors = flask_cors.CORS()
+# Initialize a local database for the example
+app.config['SQLALCHEMY_DATABASE_URI'] = f"sqlite:///{os.path.join(os.getcwd(), 'database.db')}"
+db.init_app(app)
 
-class User(db.Model):
-    id = db.Column(db.Integer, primary_key=True)
-    username = db.Column(db.Text, unique=True)
-    password = db.Column(db.Text)
+# Initializes CORS so that the api_tool can talk to the example app
+cors.init_app(app)
+
+# Add users for the example
+with app.app_context():
+    db.create_all()
+    if db.session.query(User).filter_by(username='Yasoob').count() < 1:
+        db.session.add(User(
+          username='Yasoob',
+          password=guard.hash_password('strongpassword'),
+          roles='admin'
+            ))
+    db.session.commit()
 
 
-
-@app.route('/')
+# Set up some routes for the example
+@app.route('/api/')
 def home():
-    return "Hello World"
+    return {"Hello": "World"}, 200
 
+  
+@app.route('/api/login', methods=['POST'])
+def login():
+    """
+    Logs a user in by parsing a POST request containing user credentials and
+    issuing a JWT token.
+    .. example::
+       $ curl http://localhost:5000/api/login -X POST \
+         -d '{"username":"Yasoob","password":"strongpassword"}'
+    """
+    req = flask.request.get_json(force=True)
+    username = req.get('username', None)
+    password = req.get('password', None)
+    user = guard.authenticate(username, password)
+    ret = {'access_token': guard.encode_jwt_token(user)}
+    return ret, 200
+
+  
+@app.route('/api/refresh', methods=['POST'])
+def refresh():
+    """
+    Refreshes an existing JWT by creating a new one that is a copy of the old
+    except that it has a refrehsed access expiration.
+    .. example::
+       $ curl http://localhost:5000/api/refresh -X GET \
+         -H "Authorization: Bearer <your_token>"
+    """
+    print("refresh request")
+    old_token = request.get_data()
+    new_token = guard.refresh_jwt_token(old_token)
+    ret = {'access_token': new_token}
+    return ret, 200
+  
+  
+@app.route('/api/protected')
+@flask_praetorian.auth_required
+def protected():
+    """
+    A protected endpoint. The auth_required decorator will require a header
+    containing a valid JWT
+    .. example::
+       $ curl http://localhost:5000/api/protected -X GET \
+         -H "Authorization: Bearer <your_token>"
+    """
+    return {'message': f'protected endpoint (allowed user {flask_praetorian.current_user().username})'}
+    
 @app.route('/time')
 def get_current_time():
     return {'time': time.time()}
 
 
+# Run the example
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port=5000)
+import time 
+from flask import Flask
+import flask_sqlalchemy
+import flask_praetorian
+import flask_cors
+
+
 if __name__ == '__main__':
     app.run(debug=debug, host=host, port=port)