import logging import sys import urllib from threading import Lock from typing import Any, Callable, Dict, List, Optional import tornado.web from django import http from django.conf import settings from django.core import exceptions, signals from django.urls import resolvers from django.core.exceptions import MiddlewareNotUsed from django.core.handlers import base from django.core.handlers.exception import convert_exception_to_response from django.core.handlers.wsgi import WSGIRequest, get_script_name from django.urls import set_script_prefix, set_urlconf from django.http import HttpRequest, HttpResponse from django.utils.module_loading import import_string from tornado.wsgi import WSGIContainer from zerver.decorator import RespondAsynchronously from zerver.lib.response import json_response from zerver.lib.types import ViewFuncT from zerver.middleware import async_request_restart, async_request_stop from zerver.tornado.descriptors import get_descriptor_by_handler_id current_handler_id = 0 handlers = {} # type: Dict[int, 'AsyncDjangoHandler'] def get_handler_by_id(handler_id: int) -> 'AsyncDjangoHandler': return handlers[handler_id] def allocate_handler_id(handler: 'AsyncDjangoHandler') -> int: global current_handler_id handlers[current_handler_id] = handler handler.handler_id = current_handler_id current_handler_id += 1 return handler.handler_id def clear_handler_by_id(handler_id: int) -> None: del handlers[handler_id] def handler_stats_string() -> str: return "%s handlers, latest ID %s" % (len(handlers), current_handler_id) def finish_handler(handler_id: int, event_queue_id: str, contents: List[Dict[str, Any]], apply_markdown: bool) -> None: err_msg = "Got error finishing handler for queue %s" % (event_queue_id,) try: # We call async_request_restart here in case we are # being finished without any events (because another # get_events request has supplanted this request) handler = get_handler_by_id(handler_id) request = handler._request async_request_restart(request) if len(contents) != 1: request._log_data['extra'] = "[%s/1]" % (event_queue_id,) else: request._log_data['extra'] = "[%s/1/%s]" % (event_queue_id, contents[0]["type"]) handler.zulip_finish(dict(result='success', msg='', events=contents, queue_id=event_queue_id), request, apply_markdown=apply_markdown) except IOError as e: if str(e) != 'Stream is closed': logging.exception(err_msg) except AssertionError as e: if str(e) != 'Request closed': logging.exception(err_msg) except Exception: logging.exception(err_msg) # Modified version of the base Tornado handler for Django # We mark this for nocoverage, since we only change 1 line of actual code. class AsyncDjangoHandlerBase(tornado.web.RequestHandler, base.BaseHandler): # nocoverage initLock = Lock() def __init__(self, *args: Any, **kwargs: Any) -> None: super().__init__(*args, **kwargs) # Set up middleware if needed. We couldn't do this earlier, because # settings weren't available. self._request_middleware = None # type: Optional[List[Callable[[HttpRequest], HttpResponse]]] self.initLock.acquire() # Check that middleware is still uninitialised. if self._request_middleware is None: self.load_middleware() self.initLock.release() self._auto_finish = False # Handler IDs are allocated here, and the handler ID map must # be cleared when the handler finishes its response allocate_handler_id(self) def __repr__(self) -> str: descriptor = get_descriptor_by_handler_id(self.handler_id) return "AsyncDjangoHandler<%s, %s>" % (self.handler_id, descriptor) def load_middleware(self) -> None: """ Populate middleware lists from settings.MIDDLEWARE. This is copied from Django. This uses settings.MIDDLEWARE setting with the old business logic. The middleware architecture is not compatible with our asynchronous handlers. The problem occurs when we return None from our handler. The Django middlewares throw exception because they can't handler None, so we can either upgrade the Django middlewares or just override this method to use the new setting with the old logic. The added advantage is that due to this our event system code doesn't change. """ self._request_middleware = [] # type: Optional[List[Callable[[HttpRequest], HttpResponse]]] self._view_middleware = [] # type: List[Callable[[HttpRequest, ViewFuncT, List[str], Dict[str, Any]], Optional[HttpResponse]]] self._template_response_middleware = [] # type: List[Callable[[HttpRequest, HttpResponse], HttpResponse]] self._response_middleware = [] # type: List[Callable[[HttpRequest, HttpResponse], HttpResponse]] self._exception_middleware = [] # type: List[Callable[[HttpRequest, Exception], Optional[HttpResponse]]] handler = convert_exception_to_response(self._legacy_get_response) for middleware_path in settings.MIDDLEWARE: mw_class = import_string(middleware_path) try: mw_instance = mw_class() except MiddlewareNotUsed as exc: if settings.DEBUG: if str(exc): base.logger.debug('MiddlewareNotUsed(%r): %s', middleware_path, exc) else: base.logger.debug('MiddlewareNotUsed: %r', middleware_path) continue if hasattr(mw_instance, 'process_request'): self._request_middleware.append(mw_instance.process_request) if hasattr(mw_instance, 'process_view'): self._view_middleware.append(mw_instance.process_view) if hasattr(mw_instance, 'process_template_response'): self._template_response_middleware.insert(0, mw_instance.process_template_response) if hasattr(mw_instance, 'process_response'): self._response_middleware.insert(0, mw_instance.process_response) if hasattr(mw_instance, 'process_exception'): self._exception_middleware.insert(0, mw_instance.process_exception) # We only assign to this when initialization is complete as it is used # as a flag for initialization being complete. self._middleware_chain = handler def get(self, *args: Any, **kwargs: Any) -> None: environ = WSGIContainer.environ(self.request) environ['PATH_INFO'] = urllib.parse.unquote(environ['PATH_INFO']) request = WSGIRequest(environ) request._tornado_handler = self set_script_prefix(get_script_name(environ)) signals.request_started.send(sender=self.__class__) try: response = self.get_response(request) if not response: return finally: signals.request_finished.send(sender=self.__class__) self.set_status(response.status_code) for h in response.items(): self.set_header(h[0], h[1]) if not hasattr(self, "_new_cookies"): self._new_cookies = [] # type: List[http.cookie.SimpleCookie] self._new_cookies.append(response.cookies) self.write(response.content) self.finish() def head(self, *args: Any, **kwargs: Any) -> None: self.get(*args, **kwargs) def post(self, *args: Any, **kwargs: Any) -> None: self.get(*args, **kwargs) def delete(self, *args: Any, **kwargs: Any) -> None: self.get(*args, **kwargs) def on_connection_close(self) -> None: client_descriptor = get_descriptor_by_handler_id(self.handler_id) if client_descriptor is not None: client_descriptor.disconnect_handler(client_closed=True) # Based on django.core.handlers.base: get_response def get_response(self, request: HttpRequest) -> HttpResponse: "Returns an HttpResponse object for the given HttpRequest" try: try: # Setup default url resolver for this thread. urlconf = settings.ROOT_URLCONF set_urlconf(urlconf) resolver = resolvers.RegexURLResolver(r'^/', urlconf) response = None # Apply request middleware for middleware_method in self._request_middleware: response = middleware_method(request) if response: break if hasattr(request, "urlconf"): # Reset url resolver with a custom urlconf. urlconf = request.urlconf set_urlconf(urlconf) resolver = resolvers.RegexURLResolver(r'^/', urlconf) ### ADDED BY ZULIP request._resolver = resolver ### END ADDED BY ZULIP callback, callback_args, callback_kwargs = resolver.resolve( request.path_info) # Apply view middleware if response is None: for view_middleware_method in self._view_middleware: response = view_middleware_method(request, callback, callback_args, callback_kwargs) if response: break ### THIS BLOCK MODIFIED BY ZULIP if response is None: try: response = callback(request, *callback_args, **callback_kwargs) if response is RespondAsynchronously: async_request_stop(request) return None clear_handler_by_id(self.handler_id) except Exception as e: clear_handler_by_id(self.handler_id) # If the view raised an exception, run it through exception # middleware, and if the exception middleware returns a # response, use that. Otherwise, reraise the exception. for exception_middleware_method in self._exception_middleware: response = exception_middleware_method(request, e) if response: break if response is None: raise if response is None: try: view_name = callback.__name__ except AttributeError: view_name = callback.__class__.__name__ + '.__call__' raise ValueError("The view %s.%s returned None." % (callback.__module__, view_name)) # If the response supports deferred rendering, apply template # response middleware and the render the response if hasattr(response, 'render') and callable(response.render): for template_middleware_method in self._template_response_middleware: response = template_middleware_method(request, response) response = response.render() except http.Http404 as e: if settings.DEBUG: from django.views import debug response = debug.technical_404_response(request, e) else: try: callback, param_dict = resolver.resolve404() response = callback(request, **param_dict) except Exception: try: response = self.handle_uncaught_exception(request, resolver, sys.exc_info()) finally: signals.got_request_exception.send(sender=self.__class__, request=request) except exceptions.PermissionDenied: logging.warning( 'Forbidden (Permission denied): %s', request.path, extra={ 'status_code': 403, 'request': request }) try: callback, param_dict = resolver.resolve403() response = callback(request, **param_dict) except Exception: try: response = self.handle_uncaught_exception(request, resolver, sys.exc_info()) finally: signals.got_request_exception.send( sender=self.__class__, request=request) except SystemExit: # See https://code.djangoproject.com/ticket/4701 raise except Exception: exc_info = sys.exc_info() signals.got_request_exception.send(sender=self.__class__, request=request) return self.handle_uncaught_exception(request, resolver, exc_info) finally: # Reset urlconf on the way out for isolation set_urlconf(None) ### ZULIP CHANGE: The remainder of this function was moved ### into its own function, just below, so we can call it from ### finish(). response = self.apply_response_middleware(request, response, resolver) return response ### Copied from get_response (above in this file) def apply_response_middleware(self, request: HttpRequest, response: HttpResponse, resolver: resolvers.RegexURLResolver) -> HttpResponse: try: # Apply response middleware, regardless of the response for middleware_method in self._response_middleware: response = middleware_method(request, response) if hasattr(self, 'apply_response_fixes'): response = self.apply_response_fixes(request, response) except Exception: # Any exception should be gathered and handled signals.got_request_exception.send(sender=self.__class__, request=request) response = self.handle_uncaught_exception(request, resolver, sys.exc_info()) return response class AsyncDjangoHandler(AsyncDjangoHandlerBase): def zulip_finish(self, response: Dict[str, Any], request: HttpRequest, apply_markdown: bool) -> None: # Make sure that Markdown rendering really happened, if requested. # This is a security issue because it's where we escape HTML. # c.f. ticket #64 # # apply_markdown=True is the fail-safe default. if response['result'] == 'success' and 'messages' in response and apply_markdown: for msg in response['messages']: if msg['content_type'] != 'text/html': self.set_status(500) self.finish('Internal error: bad message format') if response['result'] == 'error': self.set_status(400) # Call the Django response middleware on our object so that # e.g. our own logging code can run; but don't actually use # the headers from that since sending those to Tornado seems # tricky; instead just send the (already json-rendered) # content on to Tornado django_response = json_response(res_type=response['result'], data=response, status=self.get_status()) django_response = self.apply_response_middleware(request, django_response, request._resolver) # Pass through the content-type from Django, as json content should be # served as application/json self.set_header("Content-Type", django_response['Content-Type']) self.finish(django_response.content)