testing: handle preflight requests rucio#5843

lib/rucio/web/rest/flaskapi/v1/common.py

@@ -25,19 +25,56 @@
 from flask.views import MethodView
 from werkzeug.datastructures import Headers
 from werkzeug.exceptions import HTTPException
+from werkzeug.wrappers import Request, Response
 
 from rucio.api.authentication import validate_auth_token
 from rucio.common.exception import RucioException, CannotAuthenticate, UnsupportedRequestedContentType
 from rucio.common.schema import get_schema_value
 from rucio.common.utils import generate_uuid, render_json
 from rucio.core.vo import map_vo
+from rucio.common import config
+from configparser import NoOptionError, NoSectionError
+
 
 if TYPE_CHECKING:
     from typing import Optional, Union, Dict, Sequence, Tuple, Callable, Any, List
 
     HeadersType = Union[Headers, Dict[str, str], Sequence[Tuple[str, str]]]
 
 
+class CORSMiddleware(object):
+    """
+    WebUI 2.0 makes preflight requests to the API, which are not handled by the API.
+    This middleware intercepts the preflight OPTIONS requests and returns a 200 OK response.
+    """
+
+    def __init__(self, app):
+        self.app = app
+
+    def __call__(self, environ, start_response):
+        try:
+            webui_urls = config.config_get_list('webui', 'urls')
+        except (NoOptionError, NoSectionError, RuntimeError) as error:
+            logging.exception('Could not get webui urls from config file')
+            return str(error), 500
+
+        request = Request(environ)
+
+        if request.environ.get('REQUEST_METHOD') == 'OPTIONS':
+            if request.origin in webui_urls:
+                response = Response(status=200)
+                response.headers['Access-Control-Allow-Origin'] = request.origin
+                response.headers['Access-Control-Allow-Methods'] = 'GET, POST, PUT, DELETE, OPTIONS'
+                response.headers['Access-Control-Allow-Headers'] = '*'
+                response.headers['Access-Control-Allow-Credentials'] = 'true'
+                return response(environ, start_response)
+            response = Response(status=403)
+            return response(environ, start_response)
+
+        # bypass this middleware for non-OPTIONS requests
+        return self.app(environ, start_response)
+
+
 class ErrorHandlingMethodView(MethodView):
     """
     Special MethodView that handles generic RucioExceptions and more generic

lib/rucio/web/rest/flaskapi/v1/main.py

@@ -17,7 +17,7 @@
 import importlib
 
 from flask import Flask
-
+from rucio.web.rest.flaskapi.v1.common import CORSMiddleware
 from rucio.common.config import config_get
 from rucio.common.exception import ConfigurationError
 from rucio.common.logging import setup_logging
@@ -72,6 +72,7 @@ def apply_endpoints(app, modules):
     endpoints = DEFAULT_ENDPOINTS
 
 application = Flask(__name__)
+application.wsgi_app = CORSMiddleware(application.wsgi_app)
 apply_endpoints(application, endpoints)
 setup_logging(application)