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authorErik Johnston <erik@matrix.org>2020-07-03 19:02:19 +0100
committerGitHub <noreply@github.com>2020-07-03 19:02:19 +0100
commit5cdca53aa07f921029cb8027693095d150c37e32 (patch)
treed272c8d95776493ab7d4020a555293a510b2104e /synapse/http/server.py
parentFix inconsistent handling of upper and lower cases of email addresses. (#7021) (diff)
downloadsynapse-5cdca53aa07f921029cb8027693095d150c37e32.tar.xz
Merge different Resource implementation classes (#7732)
Diffstat (limited to 'synapse/http/server.py')
-rw-r--r--synapse/http/server.py365
1 files changed, 190 insertions, 175 deletions
diff --git a/synapse/http/server.py b/synapse/http/server.py
index d192de7923..2b35f86066 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -14,6 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import abc
 import collections
 import html
 import logging
@@ -21,7 +22,7 @@ import types
 import urllib
 from http import HTTPStatus
 from io import BytesIO
-from typing import Awaitable, Callable, TypeVar, Union
+from typing import Any, Callable, Dict, Tuple, Union
 
 import jinja2
 from canonicaljson import encode_canonical_json, encode_pretty_printed_json, json
@@ -62,99 +63,43 @@ HTML_ERROR_TEMPLATE = """<!DOCTYPE html>
 """
 
 
-def wrap_json_request_handler(h):
-    """Wraps a request handler method with exception handling.
-
-    Also does the wrapping with request.processing as per wrap_async_request_handler.
-
-    The handler method must have a signature of "handle_foo(self, request)",
-    where "request" must be a SynapseRequest.
-
-    The handler must return a deferred or a coroutine. If the deferred succeeds
-    we assume that a response has been sent. If the deferred fails with a SynapseError we use
-    it to send a JSON response with the appropriate HTTP reponse code. If the
-    deferred fails with any other type of error we send a 500 reponse.
+def return_json_error(f: failure.Failure, request: SynapseRequest) -> None:
+    """Sends a JSON error response to clients.
     """
 
-    async def wrapped_request_handler(self, request):
-        try:
-            await h(self, request)
-        except SynapseError as e:
-            code = e.code
-            logger.info("%s SynapseError: %s - %s", request, code, e.msg)
-
-            # Only respond with an error response if we haven't already started
-            # writing, otherwise lets just kill the connection
-            if request.startedWriting:
-                if request.transport:
-                    try:
-                        request.transport.abortConnection()
-                    except Exception:
-                        # abortConnection throws if the connection is already closed
-                        pass
-            else:
-                respond_with_json(
-                    request,
-                    code,
-                    e.error_dict(),
-                    send_cors=True,
-                    pretty_print=_request_user_agent_is_curl(request),
-                )
-
-        except Exception:
-            # failure.Failure() fishes the original Failure out
-            # of our stack, and thus gives us a sensible stack
-            # trace.
-            f = failure.Failure()
-            logger.error(
-                "Failed handle request via %r: %r",
-                request.request_metrics.name,
-                request,
-                exc_info=(f.type, f.value, f.getTracebackObject()),
-            )
-            # Only respond with an error response if we haven't already started
-            # writing, otherwise lets just kill the connection
-            if request.startedWriting:
-                if request.transport:
-                    try:
-                        request.transport.abortConnection()
-                    except Exception:
-                        # abortConnection throws if the connection is already closed
-                        pass
-            else:
-                respond_with_json(
-                    request,
-                    500,
-                    {"error": "Internal server error", "errcode": Codes.UNKNOWN},
-                    send_cors=True,
-                    pretty_print=_request_user_agent_is_curl(request),
-                )
-
-    return wrap_async_request_handler(wrapped_request_handler)
-
-
-TV = TypeVar("TV")
-
-
-def wrap_html_request_handler(
-    h: Callable[[TV, SynapseRequest], Awaitable]
-) -> Callable[[TV, SynapseRequest], Awaitable[None]]:
-    """Wraps a request handler method with exception handling.
+    if f.check(SynapseError):
+        error_code = f.value.code
+        error_dict = f.value.error_dict()
 
-    Also does the wrapping with request.processing as per wrap_async_request_handler.
-
-    The handler method must have a signature of "handle_foo(self, request)",
-    where "request" must be a SynapseRequest.
-    """
+        logger.info("%s SynapseError: %s - %s", request, error_code, f.value.msg)
+    else:
+        error_code = 500
+        error_dict = {"error": "Internal server error", "errcode": Codes.UNKNOWN}
 
-    async def wrapped_request_handler(self, request):
-        try:
-            await h(self, request)
-        except Exception:
-            f = failure.Failure()
-            return_html_error(f, request, HTML_ERROR_TEMPLATE)
+        logger.error(
+            "Failed handle request via %r: %r",
+            request.request_metrics.name,
+            request,
+            exc_info=(f.type, f.value, f.getTracebackObject()),
+        )
 
-    return wrap_async_request_handler(wrapped_request_handler)
+    # Only respond with an error response if we haven't already started writing,
+    # otherwise lets just kill the connection
+    if request.startedWriting:
+        if request.transport:
+            try:
+                request.transport.abortConnection()
+            except Exception:
+                # abortConnection throws if the connection is already closed
+                pass
+    else:
+        respond_with_json(
+            request,
+            error_code,
+            error_dict,
+            send_cors=True,
+            pretty_print=_request_user_agent_is_curl(request),
+        )
 
 
 def return_html_error(
@@ -249,7 +194,113 @@ class HttpServer(object):
         pass
 
 
-class JsonResource(HttpServer, resource.Resource):
+class _AsyncResource(resource.Resource, metaclass=abc.ABCMeta):
+    """Base class for resources that have async handlers.
+
+    Sub classes can either implement `_async_render_<METHOD>` to handle
+    requests by method, or override `_async_render` to handle all requests.
+
+    Args:
+        extract_context: Whether to attempt to extract the opentracing
+            context from the request the servlet is handling.
+    """
+
+    def __init__(self, extract_context=False):
+        super().__init__()
+
+        self._extract_context = extract_context
+
+    def render(self, request):
+        """ This gets called by twisted every time someone sends us a request.
+        """
+        defer.ensureDeferred(self._async_render_wrapper(request))
+        return NOT_DONE_YET
+
+    @wrap_async_request_handler
+    async def _async_render_wrapper(self, request):
+        """This is a wrapper that delegates to `_async_render` and handles
+        exceptions, return values, metrics, etc.
+        """
+        try:
+            request.request_metrics.name = self.__class__.__name__
+
+            with trace_servlet(request, self._extract_context):
+                callback_return = await self._async_render(request)
+
+                if callback_return is not None:
+                    code, response = callback_return
+                    self._send_response(request, code, response)
+        except Exception:
+            # failure.Failure() fishes the original Failure out
+            # of our stack, and thus gives us a sensible stack
+            # trace.
+            f = failure.Failure()
+            self._send_error_response(f, request)
+
+    async def _async_render(self, request):
+        """Delegates to `_async_render_<METHOD>` methods, or returns a 400 if
+        no appropriate method exists. Can be overriden in sub classes for
+        different routing.
+        """
+
+        method_handler = getattr(
+            self, "_async_render_%s" % (request.method.decode("ascii"),), None
+        )
+        if method_handler:
+            raw_callback_return = method_handler(request)
+
+            # Is it synchronous? We'll allow this for now.
+            if isinstance(raw_callback_return, (defer.Deferred, types.CoroutineType)):
+                callback_return = await raw_callback_return
+            else:
+                callback_return = raw_callback_return
+
+            return callback_return
+
+        _unrecognised_request_handler(request)
+
+    @abc.abstractmethod
+    def _send_response(
+        self, request: SynapseRequest, code: int, response_object: Any,
+    ) -> None:
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def _send_error_response(
+        self, f: failure.Failure, request: SynapseRequest,
+    ) -> None:
+        raise NotImplementedError()
+
+
+class DirectServeJsonResource(_AsyncResource):
+    """A resource that will call `self._async_on_<METHOD>` on new requests,
+    formatting responses and errors as JSON.
+    """
+
+    def _send_response(
+        self, request, code, response_object,
+    ):
+        """Implements _AsyncResource._send_response
+        """
+        # TODO: Only enable CORS for the requests that need it.
+        respond_with_json(
+            request,
+            code,
+            response_object,
+            send_cors=True,
+            pretty_print=_request_user_agent_is_curl(request),
+            canonical_json=self.canonical_json,
+        )
+
+    def _send_error_response(
+        self, f: failure.Failure, request: SynapseRequest,
+    ) -> None:
+        """Implements _AsyncResource._send_error_response
+        """
+        return_json_error(f, request)
+
+
+class JsonResource(DirectServeJsonResource):
     """ This implements the HttpServer interface and provides JSON support for
     Resources.
 
@@ -269,17 +320,15 @@ class JsonResource(HttpServer, resource.Resource):
         "_PathEntry", ["pattern", "callback", "servlet_classname"]
     )
 
-    def __init__(self, hs, canonical_json=True):
-        resource.Resource.__init__(self)
+    def __init__(self, hs, canonical_json=True, extract_context=False):
+        super().__init__(extract_context)
 
         self.canonical_json = canonical_json
         self.clock = hs.get_clock()
         self.path_regexs = {}
         self.hs = hs
 
-    def register_paths(
-        self, method, path_patterns, callback, servlet_classname, trace=True
-    ):
+    def register_paths(self, method, path_patterns, callback, servlet_classname):
         """
         Registers a request handler against a regular expression. Later request URLs are
         checked against these regular expressions in order to identify an appropriate
@@ -295,37 +344,42 @@ class JsonResource(HttpServer, resource.Resource):
 
             servlet_classname (str): The name of the handler to be used in prometheus
                 and opentracing logs.
-
-            trace (bool): Whether we should start a span to trace the servlet.
         """
         method = method.encode("utf-8")  # method is bytes on py3
 
-        if trace:
-            # We don't extract the context from the servlet because we can't
-            # trust the sender
-            callback = trace_servlet(servlet_classname)(callback)
-
         for path_pattern in path_patterns:
             logger.debug("Registering for %s %s", method, path_pattern.pattern)
             self.path_regexs.setdefault(method, []).append(
                 self._PathEntry(path_pattern, callback, servlet_classname)
             )
 
-    def render(self, request):
-        """ This gets called by twisted every time someone sends us a request.
+    def _get_handler_for_request(
+        self, request: SynapseRequest
+    ) -> Tuple[Callable, str, Dict[str, str]]:
+        """Finds a callback method to handle the given request.
+
+        Returns:
+            A tuple of the callback to use, the name of the servlet, and the
+            key word arguments to pass to the callback
         """
-        defer.ensureDeferred(self._async_render(request))
-        return NOT_DONE_YET
+        request_path = request.path.decode("ascii")
+
+        # Loop through all the registered callbacks to check if the method
+        # and path regex match
+        for path_entry in self.path_regexs.get(request.method, []):
+            m = path_entry.pattern.match(request_path)
+            if m:
+                # We found a match!
+                return path_entry.callback, path_entry.servlet_classname, m.groupdict()
+
+        # Huh. No one wanted to handle that? Fiiiiiine. Send 400.
+        return _unrecognised_request_handler, "unrecognised_request_handler", {}
 
-    @wrap_json_request_handler
     async def _async_render(self, request):
-        """ This gets called from render() every time someone sends us a request.
-            This checks if anyone has registered a callback for that method and
-            path.
-        """
         callback, servlet_classname, group_dict = self._get_handler_for_request(request)
 
-        # Make sure we have a name for this handler in prometheus.
+        # Make sure we have an appopriate name for this handler in prometheus
+        # (rather than the default of JsonResource).
         request.request_metrics.name = servlet_classname
 
         # Now trigger the callback. If it returns a response, we send it
@@ -338,81 +392,42 @@ class JsonResource(HttpServer, resource.Resource):
             }
         )
 
-        callback_return = callback(request, **kwargs)
+        raw_callback_return = callback(request, **kwargs)
 
         # Is it synchronous? We'll allow this for now.
-        if isinstance(callback_return, (defer.Deferred, types.CoroutineType)):
-            callback_return = await callback_return
+        if isinstance(raw_callback_return, (defer.Deferred, types.CoroutineType)):
+            callback_return = await raw_callback_return
+        else:
+            callback_return = raw_callback_return
 
-        if callback_return is not None:
-            code, response = callback_return
-            self._send_response(request, code, response)
+        return callback_return
 
-    def _get_handler_for_request(self, request):
-        """Finds a callback method to handle the given request
 
-        Args:
-            request (twisted.web.http.Request):
+class DirectServeHtmlResource(_AsyncResource):
+    """A resource that will call `self._async_on_<METHOD>` on new requests,
+    formatting responses and errors as HTML.
+    """
 
-        Returns:
-            Tuple[Callable, str, dict[unicode, unicode]]: callback method, the
-                label to use for that method in prometheus metrics, and the
-                dict mapping keys to path components as specified in the
-                handler's path match regexp.
-
-                The callback will normally be a method registered via
-                register_paths, so will return (possibly via Deferred) either
-                None, or a tuple of (http code, response body).
-        """
-        request_path = request.path.decode("ascii")
-
-        # Loop through all the registered callbacks to check if the method
-        # and path regex match
-        for path_entry in self.path_regexs.get(request.method, []):
-            m = path_entry.pattern.match(request_path)
-            if m:
-                # We found a match!
-                return path_entry.callback, path_entry.servlet_classname, m.groupdict()
-
-        # Huh. No one wanted to handle that? Fiiiiiine. Send 400.
-        return _unrecognised_request_handler, "unrecognised_request_handler", {}
+    # The error template to use for this resource
+    ERROR_TEMPLATE = HTML_ERROR_TEMPLATE
 
     def _send_response(
-        self, request, code, response_json_object, response_code_message=None
+        self, request: SynapseRequest, code: int, response_object: Any,
     ):
-        # TODO: Only enable CORS for the requests that need it.
-        respond_with_json(
-            request,
-            code,
-            response_json_object,
-            send_cors=True,
-            response_code_message=response_code_message,
-            pretty_print=_request_user_agent_is_curl(request),
-            canonical_json=self.canonical_json,
-        )
-
-
-class DirectServeResource(resource.Resource):
-    def render(self, request):
+        """Implements _AsyncResource._send_response
         """
-        Render the request, using an asynchronous render handler if it exists.
-        """
-        async_render_callback_name = "_async_render_" + request.method.decode("ascii")
-
-        # Try and get the async renderer
-        callback = getattr(self, async_render_callback_name, None)
+        # We expect to get bytes for us to write
+        assert isinstance(response_object, bytes)
+        html_bytes = response_object
 
-        # No async renderer for this request method.
-        if not callback:
-            return super().render(request)
+        respond_with_html_bytes(request, 200, html_bytes)
 
-        resp = trace_servlet(self.__class__.__name__)(callback)(request)
-
-        # If it's a coroutine, turn it into a Deferred
-        if isinstance(resp, types.CoroutineType):
-            defer.ensureDeferred(resp)
-
-        return NOT_DONE_YET
+    def _send_error_response(
+        self, f: failure.Failure, request: SynapseRequest,
+    ) -> None:
+        """Implements _AsyncResource._send_error_response
+        """
+        return_html_error(f, request, self.ERROR_TEMPLATE)
 
 
 class StaticResource(File):