def build(
self, req: Union[Request, ASGIRequest], resp: Union[_Response, _ASGIResponse]
):
self.build_content(req, resp)
resp.content_type = self.content_type
if isinstance(self.status, int):
self.status = code_to_http_status(self.status)
resp.status = self.status
resp.set_headers(self.headers)
for name, params in self._stacked.items():
method = getattr(resp, name)
for args, kwds in params:
method(*args, **kwds)
def __call__(self, env, start_response): # noqa: C901
"""WSGI `app` method.
Makes instances of App callable from a WSGI server. May be used to
host an App or called directly in order to simulate requests when
testing the App.
(See also: PEP 3333)
Args:
env (dict): A WSGI environment dictionary
start_response (callable): A WSGI helper function for setting
status and headers on a response.
"""
req = self._request_type(env, options=self.req_options)
resp = self._response_type(options=self.resp_options)
resource = None
responder = None
params = {}
dependent_mw_resp_stack = []
mw_req_stack, mw_rsrc_stack, mw_resp_stack = self._middleware
req_succeeded = False
try:
# NOTE(ealogar): The execution of request middleware
# should be before routing. This will allow request mw
# to modify the path.
# NOTE: if flag set to use independent middleware, execute
# request middleware independently. Otherwise, only queue
# response middleware after request middleware succeeds.
if self._independent_middleware:
for process_request in mw_req_stack:
process_request(req, resp)
if resp.complete:
break
else:
for process_request, process_response in mw_req_stack:
if process_request and not resp.complete:
process_request(req, resp)
if process_response:
dependent_mw_resp_stack.insert(0, process_response)
if not resp.complete:
# NOTE(warsaw): Moved this to inside the try except
# because it is possible when using object-based
# traversal for _get_responder() to fail. An example is
# a case where an object does not have the requested
# next-hop child resource. In that case, the object
# being asked to dispatch to its child will raise an
# HTTP exception signalling the problem, e.g. a 404.
responder, params, resource, req.uri_template = self._get_responder(
req)
except Exception as ex:
if not self._handle_exception(req, resp, ex, params):
raise
else:
try:
# NOTE(kgriffs): If the request did not match any
# route, a default responder is returned and the
# resource is None. In that case, we skip the
# resource middleware methods. Resource will also be
# None when a middleware method already set
# resp.complete to True.
if resource:
# Call process_resource middleware methods.
for process_resource in mw_rsrc_stack:
process_resource(req, resp, resource, params)
if resp.complete:
break
if not resp.complete:
responder(req, resp, **params)
req_succeeded = True
except Exception as ex:
if not self._handle_exception(req, resp, ex, params):
raise
# Call process_response middleware methods.
for process_response in mw_resp_stack or dependent_mw_resp_stack:
try:
process_response(req, resp, resource, req_succeeded)
except Exception as ex:
if not self._handle_exception(req, resp, ex, params):
raise
req_succeeded = False
body = []
length = 0
try:
body, length = self._get_body(resp, env.get('wsgi.file_wrapper'))
except Exception as ex:
if not self._handle_exception(req, resp, ex, params):
raise
req_succeeded = False
resp_status = code_to_http_status(resp.status)
default_media_type = self.resp_options.default_media_type
if req.method == 'HEAD' or resp_status in _BODILESS_STATUS_CODES:
body = []
# PERF(vytas): move check for the less common and much faster path
# of resp_status being in {204, 304} here; NB: this builds on the
# assumption _TYPELESS_STATUS_CODES <= _BODILESS_STATUS_CODES.
# NOTE(kgriffs): Based on wsgiref.validate's interpretation of
# RFC 2616, as commented in that module's source code. The
# presence of the Content-Length header is not similarly
# enforced.
if resp_status in _TYPELESS_STATUS_CODES:
default_media_type = None
elif (length is not None and req.method == 'HEAD'
and resp_status not in _BODILESS_STATUS_CODES
and 'content-length' not in resp._headers):
# NOTE(kgriffs): We really should be returning a Content-Length
# in this case according to my reading of the RFCs. By
# optionally using len(data) we let a resource simulate HEAD
# by turning around and calling it's own on_get().
resp._headers['content-length'] = str(length)
else:
# PERF(kgriffs): Böse mußt sein. Operate directly on resp._headers
# to reduce overhead since this is a hot/critical code path.
# NOTE(kgriffs): We always set content-length to match the
# body bytes length, even if content-length is already set. The
# reason being that web servers and LBs behave unpredictably
# when the header doesn't match the body (sometimes choosing to
# drop the HTTP connection prematurely, for example).
if length is not None:
resp._headers['content-length'] = str(length)
headers = resp._wsgi_headers(default_media_type)
# Return the response per the WSGI spec.
start_response(resp_status, headers)
return body
