def register_paths(
self, method, path_patterns, callback, servlet_classname, trace=True
):
"""
Registers a request handler against a regular expression. Later request URLs are
checked against these regular expressions in order to identify an appropriate
handler for that request.
Args:
method (str): GET, POST etc
path_patterns (Iterable[str]): A list of regular expressions to which
the request URLs are compared.
callback (function): The handler for the request. Usually a Servlet
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 register(self, http_server):
"""Called by the server to register this as a handler to the
appropriate path.
"""
url_args = list(self.PATH_ARGS)
handler = self._handle_request
method = self.METHOD
if self.CACHE:
handler = self._cached_handler
url_args.append("txn_id")
args = "/".join("(?P<%s>[^/]+)" % (arg, ) for arg in url_args)
pattern = re.compile("^/_synapse/replication/%s/%s$" %
(self.NAME, args))
handler = trace_servlet(self.__class__.__name__,
extract_context=True)(handler)
# We don't let register paths trace this servlet using the default tracing
# options because we wish to extract the context explicitly.
http_server.register_paths(method, [pattern],
handler,
self.__class__.__name__,
trace=False)
def register(self, http_server):
""" Register this servlet with the given HTTP server. """
if hasattr(self, "PATTERNS"):
patterns = self.PATTERNS
for method in ("GET", "PUT", "POST", "OPTIONS", "DELETE"):
if hasattr(self, "on_%s" % (method, )):
servlet_classname = self.__class__.__name__
method_handler = getattr(self, "on_%s" % (method, ))
http_server.register_paths(
method,
patterns,
trace_servlet(servlet_classname, method_handler),
servlet_classname,
)
else:
raise NotImplementedError("RestServlet must register something.")
async def _async_render_wrapper(self, request: SynapseRequest) -> None:
"""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)
def render(self, request):
"""
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)
# No async renderer for this request method.
if not callback:
return super().render(request)
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
