Compatibility changes for upcoming flask version 2.3 (#493)

* Switched from _request_ctx_stack.top to flask.g

* Handle JSONEncoder changes

Author: jrast

flask_jwt_extended/config.py

@@ -1,6 +1,7 @@
 from datetime import datetime
 from datetime import timedelta
 from datetime import timezone
+from json import JSONEncoder
 from typing import Iterable
 from typing import List
 from typing import Optional
@@ -9,9 +10,9 @@
 from typing import Union
 
 from flask import current_app
-from flask.json import JSONEncoder
 from jwt.algorithms import requires_cryptography
 
+from flask_jwt_extended.internal_utils import get_json_encoder
 from flask_jwt_extended.typing import ExpiresDelta
 
 
@@ -284,7 +285,7 @@ def error_msg_key(self) -> str:
 
     @property
     def json_encoder(self) -> Type[JSONEncoder]:
-        return current_app.json_encoder
+        return get_json_encoder(current_app)
 
     @property
     def decode_audience(self) -> Union[str, Iterable[str]]:

flask_jwt_extended/internal_utils.py

@@ -1,12 +1,25 @@
+import json
 from typing import Any
+from typing import Type
 from typing import TYPE_CHECKING
 
 from flask import current_app
+from flask import Flask
 
 from flask_jwt_extended.exceptions import RevokedTokenError
 from flask_jwt_extended.exceptions import UserClaimsVerificationError
 from flask_jwt_extended.exceptions import WrongTokenError
 
+try:
+    from flask.json.provider import DefaultJSONProvider
+
+    HAS_JSON_PROVIDER = True
+except ModuleNotFoundError:  # pragma: no cover
+    # The flask.json.provider module was added in Flask 2.2.
+    # Further details are handled in get_json_encoder.
+    HAS_JSON_PROVIDER = False
+
+
 if TYPE_CHECKING:  # pragma: no cover
     from flask_jwt_extended import JWTManager
 
@@ -51,3 +64,35 @@ def custom_verification_for_token(jwt_header: dict, jwt_data: dict) -> None:
     if not jwt_manager._token_verification_callback(jwt_header, jwt_data):
         error_msg = "User claims verification failed"
         raise UserClaimsVerificationError(error_msg, jwt_header, jwt_data)
+
+
+class JSONEncoder(json.JSONEncoder):
+    """A JSON encoder which uses the app.json_provider_class for the default"""
+
+    def default(self, o: Any) -> Any:
+        # If the registered JSON provider does not implement a default classmethod
+        # use the method defined by the DefaultJSONProvider
+        default = getattr(
+            current_app.json_provider_class, "default", DefaultJSONProvider.default
+        )
+        return default(o)
+
+
+def get_json_encoder(app: Flask) -> Type[json.JSONEncoder]:
+    """Get the JSON Encoder for the provided flask app
+
+    Starting with flask version 2.2 the flask application provides a
+    interface to register a custom JSON Encoder/Decoder under the json_provider_class.
+    As this interface is not compatible with the standard JSONEncoder, the `default`
+    method of the class is wrapped.
+
+    Lookup Order:
+      - app.json_encoder - For Flask < 2.2
+      - app.json_provider_class.default
+      - flask.json.provider.DefaultJSONProvider.default
+
+    """
+    if not HAS_JSON_PROVIDER:  # pragma: no cover
+        return app.json_encoder
+
+    return JSONEncoder

flask_jwt_extended/tokens.py

@@ -3,14 +3,14 @@
 from datetime import timedelta
 from datetime import timezone
 from hmac import compare_digest
+from json import JSONEncoder
 from typing import Any
 from typing import Iterable
 from typing import List
 from typing import Type
 from typing import Union
 
 import jwt
-from flask.json import JSONEncoder
 
 from flask_jwt_extended.exceptions import CSRFError
 from flask_jwt_extended.exceptions import JWTDecodeError

flask_jwt_extended/utils.py

@@ -3,7 +3,7 @@
 from typing import Optional
 
 import jwt
-from flask import _request_ctx_stack
+from flask import g
 from flask import Response
 from werkzeug.local import LocalProxy
 
@@ -23,7 +23,7 @@ def get_jwt() -> dict:
     :return:
         The payload (claims) of the JWT in the current request
     """
-    decoded_jwt = getattr(_request_ctx_stack.top, "jwt", None)
+    decoded_jwt = g.get("_jwt_extended_jwt", None)
     if decoded_jwt is None:
         raise RuntimeError(
             "You must call `@jwt_required()` or `verify_jwt_in_request()` "
@@ -41,7 +41,7 @@ def get_jwt_header() -> dict:
     :return:
         The headers of the JWT in the current request
     """
-    decoded_header = getattr(_request_ctx_stack.top, "jwt_header", None)
+    decoded_header = g.get("_jwt_extended_jwt_header", None)
     if decoded_header is None:
         raise RuntimeError(
             "You must call `@jwt_required()` or `verify_jwt_in_request()` "
@@ -73,7 +73,7 @@ def get_jwt_request_location() -> Optional[str]:
         The location of the JWT in the current request; e.g., "cookies",
         "query-string", "headers", or "json"
     """
-    return getattr(_request_ctx_stack.top, "jwt_location", None)
+    return g.get("_jwt_extended_jwt_location", None)
 
 
 def get_current_user() -> Any:
@@ -91,7 +91,7 @@ def get_current_user() -> Any:
         The current user object for the JWT in the current request
     """
     get_jwt()  # Raise an error if not in a decorated context
-    jwt_user_dict = getattr(_request_ctx_stack.top, "jwt_user", None)
+    jwt_user_dict = g.get("_jwt_extended_jwt_user", None)
     if jwt_user_dict is None:
         raise RuntimeError(
             "You must provide a `@jwt.user_lookup_loader` callback to use "

flask_jwt_extended/view_decorators.py

@@ -8,8 +8,8 @@
 from typing import Tuple
 from typing import Union
 
-from flask import _request_ctx_stack
 from flask import current_app
+from flask import g
 from flask import request
 from werkzeug.exceptions import BadRequest
 
@@ -85,10 +85,6 @@ def verify_jwt_in_request(
     if request.method in config.exempt_methods:
         return None
 
-    # Should be impossible to hit, this makes mypy checks happy
-    if not _request_ctx_stack.top:  # pragma: no cover
-        raise RuntimeError("No _request_ctx_stack.top present, aborting")
-
     try:
         jwt_data, jwt_header, jwt_location = _decode_jwt_from_request(
             locations, fresh, refresh=refresh, verify_type=verify_type
@@ -97,18 +93,18 @@ def verify_jwt_in_request(
     except NoAuthorizationError:
         if not optional:
             raise
-        _request_ctx_stack.top.jwt = {}
-        _request_ctx_stack.top.jwt_header = {}
-        _request_ctx_stack.top.jwt_user = {"loaded_user": None}
-        _request_ctx_stack.top.jwt_location = None
+        g._jwt_extended_jwt = {}
+        g._jwt_extended_jwt_header = {}
+        g._jwt_extended_jwt_user = {"loaded_user": None}
+        g._jwt_extended_jwt_location = None
         return None
 
     # Save these at the very end so that they are only saved in the requet
     # context if the token is valid and all callbacks succeed
-    _request_ctx_stack.top.jwt_user = _load_user(jwt_header, jwt_data)
-    _request_ctx_stack.top.jwt_header = jwt_header
-    _request_ctx_stack.top.jwt = jwt_data
-    _request_ctx_stack.top.jwt_location = jwt_location
+    g._jwt_extended_jwt_user = _load_user(jwt_header, jwt_data)
+    g._jwt_extended_jwt_header = jwt_header
+    g._jwt_extended_jwt = jwt_data
+    g._jwt_extended_jwt_location = jwt_location
 
     return jwt_header, jwt_data
 

tests/test_config.py

@@ -1,12 +1,18 @@
+import json
+from datetime import date
 from datetime import timedelta
 
 import pytest
 from dateutil.relativedelta import relativedelta
+from flask import __version__ as flask_version
 from flask import Flask
-from flask.json import JSONEncoder
 
 from flask_jwt_extended import JWTManager
 from flask_jwt_extended.config import config
+from flask_jwt_extended.internal_utils import JSONEncoder
+
+
+flask_version_tuple = tuple(map(int, flask_version.split(".")))
 
 
 @pytest.fixture(scope="function")
@@ -65,8 +71,6 @@ def test_default_configs(app):
 
         assert config.identity_claim_key == "sub"
 
-        assert config.json_encoder is app.json_encoder
-
         assert config.error_msg_key == "msg"
 
 
@@ -112,11 +116,6 @@ def test_override_configs(app, delta_func):
 
     app.config["JWT_ERROR_MESSAGE_KEY"] = "message"
 
-    class CustomJSONEncoder(JSONEncoder):
-        pass
-
-    app.json_encoder = CustomJSONEncoder
-
     with app.test_request_context():
         assert config.token_location == ["cookies", "query_string", "json"]
         assert config.jwt_in_query_string is True
@@ -162,11 +161,29 @@ class CustomJSONEncoder(JSONEncoder):
 
         assert config.identity_claim_key == "foo"
 
-        assert config.json_encoder is CustomJSONEncoder
-
         assert config.error_msg_key == "message"
 
 
+@pytest.mark.skipif(
+    flask_version_tuple >= (2, 2, 0), reason="Only applies to Flask <= 2.2.0"
+)
+def test_config_json_encoder_flask21(app):
+    with app.test_request_context():
+        assert config.json_encoder == app.json_encoder
+        dump = json.dumps({"d": date(2022, 8, 12)}, cls=config.json_encoder)
+        assert dump == '{"d": "Fri, 12 Aug 2022 00:00:00 GMT"}'
+
+
+@pytest.mark.skipif(
+    flask_version_tuple < (2, 2, 0), reason="Only applies to Flask > 2.2.0"
+)
+def test_config_json_encoder_flask(app):
+    with app.test_request_context():
+        assert config.json_encoder == JSONEncoder
+        dump = json.dumps({"d": date(2022, 8, 12)}, cls=config.json_encoder)
+        assert dump == '{"d": "Fri, 12 Aug 2022 00:00:00 GMT"}'
+
+
 def test_tokens_never_expire(app):
     app.config["JWT_ACCESS_TOKEN_EXPIRES"] = False
     app.config["JWT_REFRESH_TOKEN_EXPIRES"] = False

tox.ini

@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = py37,py38,py39,py310,pypy3.9,mypy,coverage,style,docs
+envlist = py{37,38,39,310}-{flask21,flask},pypy3.9,mypy,coverage,style,docs
 
 [testenv]
 commands =
@@ -13,6 +13,8 @@ deps =
   pytest
   cryptography
   python-dateutil
+  flask21: Flask>=2.1,<2.2
+  flask: Flask>=2.2
 
 [testenv:mypy]
 commands =