@@ -20,7 +20,7 @@ that accepts POSTs.
 and <a href="/flask-app-immutabledict-examples.html">ImmutableDict</a>
 are several other callables with code examples from the same `flask.app` package.
 
-These topics are also useful while reading the `BadRequest` examples:
+These subjects go along with the `BadRequest` code examples:
 
 * [web development](/web-development.html) and [web design](/web-design.html)
 * [Flask](/flask.html) and [web framework](/web-frameworks.html) concepts
@@ -166,6 +166,7 @@ import hashlib
 import logging
 import os
 import warnings
+from urllib.parse import urlparse
 from functools import wraps
 
 from flask import Blueprint, current_app, g, request, session
@@ -175,7 +176,7 @@ from werkzeug.security import safe_str_cmp
 from wtforms import ValidationError
 from wtforms.csrf.core import CSRF
 
-from ._compat import FlaskWTFDeprecationWarning, string_types, urlparse
+from ._compat import FlaskWTFDeprecationWarning
 
 __all__ = ('generate_csrf', 'validate_csrf', 'CSRFProtect')
 logger = logging.getLogger(__name__)
@@ -222,7 +223,7 @@ class CsrfProtect(CSRFProtect):
             '"flask_wtf.CsrfProtect" has been renamed to "CSRFProtect" '
             'and will be removed in 1.0.'
         ), stacklevel=2)
-        super(CsrfProtect, self).__init__(app=app)
+        super().__init__(app=app)
 
 
 ~~class CSRFError(BadRequest):
 
@@ -1084,7 +1084,8 @@ from util import base64_to_pil
 ~~app = Flask(__name__)
 
 
-from keras.applications.mobilenet_v2 import MobileNetV2
+
+from tensorflow.keras.applications.mobilenet_v2 import MobileNetV2
 model = MobileNetV2(weights='imagenet')
 
 print('Model loaded. Check http://127.0.0.1:5000/')
@@ -1107,7 +1108,6 @@ def model_predict(img, model):
 
 
 
-
 ## ... source file continues with no further Flask examples...
 
 ```
 
@@ -22,7 +22,7 @@ Flask web applications.
 and <a href="/flask-app-immutabledict-examples.html">ImmutableDict</a>
 are several other callables with code examples from the same `flask.app` package.
 
-You should read up on these subjects along with these `Headers` examples:
+These topics are also useful while reading the `Headers` examples:
 
 * [web development](/web-development.html) and [web design](/web-design.html)
 * [Flask](/flask.html) and [web framework](/web-frameworks.html) concepts
@@ -60,21 +60,27 @@ from CTFd.cache import cache, clear_standings
 from CTFd.config import TestingConfig
 from CTFd.models import (
     Awards,
+    ChallengeComments,
     ChallengeFiles,
     Challenges,
+    Comments,
     Fails,
+    Fields,
     Files,
     Flags,
     Hints,
     Notifications,
+    PageComments,
     PageFiles,
     Pages,
     Solves,
     Tags,
+    TeamComments,
     Teams,
     Tokens,
     Tracking,
     Unlocks,
+    UserComments,
     Users,
 )
 
@@ -149,6 +155,7 @@ import operator
 import re
 import six
 import sys
+import warnings
 
 from collections import OrderedDict
 from functools import wraps, partial
 
@@ -77,8 +77,8 @@ DEFAULTS = {
     'CUSTOMIZATION_DEBUG': False,
     'CUSTOMIZATION_DIR': None,
     'CUSTOM_COUNTRIES': {},
+    'CUSTOM_LANGUAGES': {},
     'DB_LOG': False,
-    'DEBUG': False,
 
 
 ## ... source file abbreviated to get to ImmutableDict examples ...
 
@@ -38,7 +38,7 @@ from flask import redirect, render_template, request, session, url_for
 from itsdangerous.exc import BadSignature, BadTimeSignature, SignatureExpired
 
 from CTFd.cache import clear_team_session, clear_user_session
-from CTFd.models import Teams, Users, db
+from CTFd.models import Teams, UserFieldEntries, UserFields, Users, db
 from CTFd.utils import config, email, get_app_config, get_config
 from CTFd.utils import user as current_user
 from CTFd.utils import validators
@@ -551,7 +551,7 @@ from werkzeug.urls import url_quote_plus
 
 from flask_debugtoolbar.compat import iteritems
 from flask_debugtoolbar.toolbar import DebugToolbar
-from flask_debugtoolbar.utils import decode_text
+from flask_debugtoolbar.utils import decode_text, gzip_compress, gzip_decompress
 
 try:
     from importlib.metadata import version
@@ -666,6 +666,7 @@ import hashlib
 import logging
 import os
 import warnings
+from urllib.parse import urlparse
 from functools import wraps
 
 ~~from flask import Blueprint, current_app, g, request, session
@@ -675,7 +676,7 @@ from werkzeug.security import safe_str_cmp
 from wtforms import ValidationError
 from wtforms.csrf.core import CSRF
 
-from ._compat import FlaskWTFDeprecationWarning, string_types, urlparse
+from ._compat import FlaskWTFDeprecationWarning
 
 __all__ = ('generate_csrf', 'validate_csrf', 'CSRFProtect')
 logger = logging.getLogger(__name__)
@@ -714,7 +715,7 @@ def generate_csrf(secret_key=None, token_key=None):
             if not request.referrer:
                 self._error_response('The referrer header is missing.')
 
-            good_referrer = 'https://{0}/'.format(request.host)
+            good_referrer = f'https://{request.host}/'
 
             if not same_origin(request.referrer, good_referrer):
                 self._error_response('The referrer does not match the host.')
@@ -727,7 +728,7 @@ def generate_csrf(secret_key=None, token_key=None):
             self._exempt_blueprints.add(view.name)
             return view
 
-        if isinstance(view, string_types):
+        if isinstance(view, str):
             view_location = view
         else:
             view_location = '.'.join((view.__module__, view.__name__))
 
@@ -218,6 +218,7 @@ def us_signin_send_code():
 
 
 @auth_required(
+    lambda: config_value("API_ENABLED_METHODS"),
     within=lambda: config_value("FRESHNESS"),
     grace=lambda: config_value("FRESHNESS_GRACE_PERIOD"),
 )
@@ -233,7 +234,6 @@ def us_setup():
         form = form_class(meta=suppress_form_csrf())
 
 
-
 ## ... source file abbreviated to get to after_this_request examples ...
 
 
 
@@ -158,6 +158,7 @@ from flask_pluginengine import current_plugin
 from speaklater import is_lazy_string, make_lazy_string
 from werkzeug.utils import cached_property
 
+from indico.core.config import config
 from indico.util.caching import memoize_request
 
 
 
@@ -179,7 +179,128 @@ def _get_item(model, view_arg, name):
 ```
 
 
-## Example 3 from indico
+## Example 3 from Flask-SocketIO
+[Flask-SocketIO](https://github.com/miguelgrinberg/Flask-SocketIO)
+([PyPI package information](https://pypi.org/project/Flask-SocketIO/),
+[official tutorial](https://blog.miguelgrinberg.com/post/easy-websockets-with-flask-and-gevent)
+and
+[project documentation](https://flask-socketio.readthedocs.io/en/latest/))
+is a code library by [Miguel Grinberg](https://blog.miguelgrinberg.com/index)
+that provides Socket.IO integration for [Flask](/flask.html) applications.
+This extension makes it easier to add bi-directional communications on the
+web via the [WebSockets](/websockets.html) protocol.
+
+The Flask-SocketIO project is open source under the
+[MIT license](https://github.com/miguelgrinberg/Flask-SocketIO/blob/master/LICENSE).
+
+[**Flask-SocketIO / flask_socketio / __init__.py**](https://github.com/miguelgrinberg/Flask-SocketIO/blob/master/./flask_socketio/__init__.py)
+
+```python
+# __init__.py
+from functools import wraps
+import os
+import sys
+
+gevent_socketio_found = True
+try:
+    from socketio import socketio_manage
+except ImportError:
+    gevent_socketio_found = False
+if gevent_socketio_found:
+    print('The gevent-socketio package is incompatible with this version of '
+          'the Flask-SocketIO extension. Please uninstall it, and then '
+          'install the latest version of python-socketio in its place.')
+    sys.exit(1)
+
+import flask
+~~from flask import _request_ctx_stack, has_request_context, json as flask_json
+from flask.sessions import SessionMixin
+import socketio
+from socketio.exceptions import ConnectionRefusedError
+from werkzeug.debug import DebuggedApplication
+from werkzeug.serving import run_with_reloader
+
+from .namespace import Namespace
+from .test_client import SocketIOTestClient
+
+__version__ = '4.3.2dev'
+
+
+class _SocketIOMiddleware(socketio.WSGIApp):
+    def __init__(self, socketio_app, flask_app, socketio_path='socket.io'):
+        self.flask_app = flask_app
+        super(_SocketIOMiddleware, self).__init__(socketio_app,
+                                                  flask_app.wsgi_app,
+                                                  socketio_path=socketio_path)
+
+    def __call__(self, environ, start_response):
+        environ = environ.copy()
+        environ['flask.app'] = self.flask_app
+        return super(_SocketIOMiddleware, self).__call__(environ,
+                                                         start_response)
+
+
+## ... source file abbreviated to get to has_request_context examples ...
+
+
+        self.default_exception_handler = exception_handler
+        return exception_handler
+
+    def on_event(self, message, handler, namespace=None):
+        self.on(message, namespace=namespace)(handler)
+
+    def on_namespace(self, namespace_handler):
+        if not isinstance(namespace_handler, Namespace):
+            raise ValueError('Not a namespace instance.')
+        namespace_handler._set_socketio(self)
+        if self.server:
+            self.server.register_namespace(namespace_handler)
+        else:
+            self.namespace_handlers.append(namespace_handler)
+
+    def emit(self, event, *args, **kwargs):
+        namespace = kwargs.pop('namespace', '/')
+        room = kwargs.pop('room', None)
+        include_self = kwargs.pop('include_self', True)
+        skip_sid = kwargs.pop('skip_sid', None)
+        if not include_self and not skip_sid:
+            skip_sid = flask.request.sid
+        callback = kwargs.pop('callback', None)
+        if callback:
+            sid = None
+~~            if has_request_context():
+                sid = getattr(flask.request, 'sid', None)
+            original_callback = callback
+
+            def _callback_wrapper(*args):
+                return self._handle_event(original_callback, None, namespace,
+                                          sid, *args)
+
+            if sid:
+                callback = _callback_wrapper
+        self.server.emit(event, *args, namespace=namespace, room=room,
+                         skip_sid=skip_sid, callback=callback, **kwargs)
+
+    def send(self, data, json=False, namespace=None, room=None,
+             callback=None, include_self=True, skip_sid=None, **kwargs):
+        skip_sid = flask.request.sid if not include_self else skip_sid
+        if json:
+            self.emit('json', data, namespace=namespace, room=room,
+                      skip_sid=skip_sid, callback=callback, **kwargs)
+        else:
+            self.emit('message', data, namespace=namespace, room=room,
+                      skip_sid=skip_sid, callback=callback, **kwargs)
+
+    def close_room(self, room, namespace=None):
+        self.server.close_room(room, namespace)
+
+
+## ... source file continues with no further has_request_context examples...
+
+```
+
+
+## Example 4 from indico
 [indico](https://github.com/indico/indico)
 ([project website](https://getindico.io/),
 [documentation](https://docs.getindico.io/en/stable/installation/)
@@ -231,6 +352,12 @@ class AddRequestIDFilter(object):
         return True
 
 
+class AddUserIDFilter(object):
+    def filter(self, record):
+~~        record.user_id = unicode(session.user.id) if has_request_context() and session and session.user else '-'
+        return True
+
+
 class RequestInfoFormatter(logging.Formatter):
     def format(self, record):
         rv = super(RequestInfoFormatter, self).format(record)
Original file line number	Diff line number	Diff line change
`@@ -218,6 +218,7 @@ def us_signin_send_code():`
`218`	`218`
`219`	`219`
`220`	`220`	`@auth_required(`
	`221`	`+ lambda: config_value("API_ENABLED_METHODS"),`
`221`	`222`	`within=lambda: config_value("FRESHNESS"),`
`222`	`223`	`grace=lambda: config_value("FRESHNESS_GRACE_PERIOD"),`
`223`	`224`	`)`
`@@ -233,7 +234,6 @@ def us_setup():`
`233`	`234`	`form = form_class(meta=suppress_form_csrf())`
`234`	`235`
`235`	`236`
`236`		`-`
`237`	`237`	`## ... source file abbreviated to get to after_this_request examples ...`
`238`	`238`
`239`	`239`