Use flask session store instead of DIYing

roc_fnb/util/env_file.py

@@ -0,0 +1,29 @@
+from os import environ
+
+
+def env_file(key, default_file=KeyError, default=KeyError, default_fn=KeyError):
+    """
+    Return a value from an environment variable or file specified by one.
+
+    Checks first for the value specified by key with "_FILE" appended. If that
+    is found, read from the file there. Otherwise return the value of the
+    environment variable, the contents of the specified default file, the default
+    value, or raises KeyError.
+    """
+    if fp := environ.get(f'{key}_FILE'):
+        with open(fp) as file:
+            return file.read()
+    if var := environ.get(key):
+        return var
+    if default_file is not KeyError:
+        try:
+            with open(default_file) as file:
+                return file.read()
+        except FileNotFoundError:
+            ... # fallthrough
+    if default is not KeyError:
+        return default
+    if default_fn is not KeyError:
+        return default_fn()
+    raise KeyError(f'no environment variable found ${key} nor {key}_FILE and default was not specified')   
+    

roc_fnb/website/models/test_user.py

@@ -26,31 +26,6 @@ def test_user_and_check_password(user):
     assert user.check_password('monkey')
 
 
-def test_jwt(user):
-    user._id = (_id := ObjectId(randbytes(12)))
-    token = user.jwt
-    header, payload, sig = (base64_decode(part.replace('.', ''))
-                            for part in token.split('.'))
-    header = json.loads(header)
-    payload = json.loads(payload)
-    assert header['alg'] == 'RS256'
-    assert header['typ'] == 'JWT'
-    assert set(header.keys()) == {'alg', 'typ'}
-    # Note that JWT contents are visible to the user: this can be useful but
-    # must be done with caution
-    assert payload['email'] == user.email
-    assert payload['name'] == user.name
-    assert ObjectId(base64_decode(payload['_id'])) == user._id == _id
-    assert set(payload.keys()) == {'email', 'name', '_id', 'admin', 'moderator'}
-
-    result = user.verify_jwt(token)
-    assert result.email == user.email
-    assert result.name == user.name
-    assert result._id == user._id == _id
-    assert not result.admin
-    assert not result.moderator
-
-
 def test_store_and_retreive(user: User, database: Database):
     try:
         database.store_user(user)
@@ -73,13 +48,3 @@ def test_store_and_retreive_by_id(user: User, database: Database):
     finally:
         if id := user._id:
             database.delete_user(id)
-
-def test_store_and_retreive_by_jwt(user: User, database: Database):
-    try:
-        token = database.store_user(user).jwt
-        assert user._id is not None
-        retreived = database.get_user_from_token(token)
-        assert retreived == user
-    finally:
-        if id := user._id:
-            database.delete_user(id)

roc_fnb/website/models/user.py

@@ -2,7 +2,7 @@ from base64 import b64decode, b64encode
 from dataclasses import dataclass
 import json
 from random import randbytes
-from typing import Optional, Any
+from typing import Optional, Any, Self
 
 from bson.objectid import ObjectId
 import scrypt
@@ -24,6 +24,12 @@ class JwtUser:
     moderator: bool
     admin: bool
 
+    @classmethod
+    def from_json(cls, data: dict) -> Self:
+        _id = ObjectId(base64_decode(data.pop('_id')))
+        return cls(_id=_id, **data)
+
+
 @dataclass
 class User:
     _id: Optional[ObjectId]
@@ -63,6 +69,11 @@ class User:
 
     @property
     def public_fields(self):
+        """
+        Session data is visible to client scripts.
+        
+        This is a feature, not a bug; client scripts may need to gather login info.
+        """
         return {
             '_id': base64_encode(self._id.binary),
             "email": self.email,
@@ -73,18 +84,3 @@ class User:
 
     def check_password(self, password: str) -> bool:
         return self.password_hash == scrypt.hash(password, self.salt)
-    
-    @property
-    def jwt(self) -> str:
-        return jwt.encode(self.public_fields, PRIVATE_KEY, algorithm='RS256')
-    
-    @staticmethod
-    def verify_jwt(token: str) -> JwtUser:
-        verified = jwt.decode(token, PUBLIC_KEY, verify=True, algorithms=['RS256'])
-        return JwtUser(
-            _id=ObjectId(base64_decode(verified['_id'])),
-            name=verified['name'],
-            email=verified['email'],
-            moderator=verified['moderator'],
-            admin=verified['admin'],
-        )

roc_fnb/website/server.py

@@ -1,11 +1,15 @@
+from functools import wraps
+import json
 from pathlib import Path
+from random import randbytes
 from sys import stderr
 
 from flask import (Flask, redirect, url_for, request, send_file, make_response,
-                   abort, render_template, g)
+                   abort, render_template, session, g)
 
+from roc_fnb.util.env_file import env_file
 from roc_fnb.website.database import Database
-from roc_fnb.website.models.user import User
+from roc_fnb.website.models.user import JwtUser
 
 db = Database.from_env()
 
@@ -16,13 +20,31 @@ app = Flask(
     static_folder=Path(__file__).absolute().parent / 'static',
 )
 
+app.secret_key = env_file('FLASK_SECRET', default_file='./flask.secret', default_fn=lambda: randbytes(12))
 
 @app.before_request
 def decode_user():
-    if token := request.cookies.get('auth-token'):
-        g.user = User.verify_jwt(token)
+    if user := session.get('user'):
+        g.user = JwtUser.from_json(data=json.loads(user))
 
 
+def require_user(admin = False, moderator = False):
+    """
+    A decorator for any routes which require authentication.
+    
+    https://stackoverflow.com/a/51820573
+    """
+    def _require_user(handler):
+        @wraps(handler)
+        def __require_user():
+            if getattr(g, 'user', None) is None \
+                or (admin and not user.admin) \
+                or (moderator and not user.moderator):
+                abort(401)
+            return handler()
+        return __require_user
+    return _require_user
+
 @app.route('/ig')
 def ig_redir():
     return redirect('https://instagram.com/RocFNB')
@@ -44,16 +66,16 @@ def submit_login():
     user = db.get_user_by_name(form['name'])
     if not user.check_password(form['password']):
         abort(401)  # unauthorized
-    response = make_response(redirect('/me'))
-    response.set_cookie('auth-token', user.jwt)
-    return response
+    session['user'] = json.dumps(user.public_fields)
+    return redirect('/me')
 
 @app.get('/login')
 def render_login_page():
+    if getattr(g, 'user', None):
+        return redirect('/me')
     return render_template('login.html')
 
 @app.get('/me')
+@require_user()
 def get_profile():
-    if g.user is not None:
     return render_template('profile.html', user=g.user)
-    abort(401)