def connect(self):
self.service = self.scope["service"]
scope = dict(self.scope)
scope["method"] = "get"
request = AsgiRequest(scope, b"")
request._request = request
request.user = self.scope["user"]
request.session = self.scope["session"]
if not self.scope["user"].is_authenticated:
self.authenticate(request)
if self.check_permissions(request):
raise AcceptConnection()
else:
raise DenyConnection()
def from_scope(cls, viewset_action, scope, view_kwargs, query_params):
"""
"This is the magic."
(reference: https://github.com/encode/django-rest-framework/blob/1e383f/rest_framework/viewsets.py#L47)
This method initializes a view properly so that calls to methods like get_queryset() and get_serializer_class(),
and permission checks have all the properties set, like self.kwargs and self.request, that they would expect.
The production of a Django HttpRequest object from a base websocket asgi scope, rather than an actual HTTP
request, is probably the largest "hack" in this project. By inspection of the ASGI spec, however,
the only difference between websocket and HTTP scopes is the existence of an HTTP method
(https://asgi.readthedocs.io/en/latest/specs/www.html).
This is because websocket connections are established over an HTTP connection, and so headers and everything
else are set just as they would be in a normal HTTP request. Therefore, the base of the request object for
every broadcast is the initial HTTP request. Subscriptions are retrieval operations, so the method is hard-coded
as GET.
"""
self = cls()
self.format_kwarg = None
self.action_map = dict()
self.args = []
self.kwargs = view_kwargs
base_request = AsgiRequest(
{
**scope, "method": "GET",
"query_string": urlencode(query_params)
},
BytesIO(),
)
# TODO: Run other middleware?
base_request.user = scope.get("user", None)
base_request.session = scope.get("session", None)
self.request = self.initialize_request(base_request)
self.action = viewset_action # TODO: custom subscription actions?
return self
async def handle(self, body):
from django_grip import GripMiddleware
from .eventrequest import EventRequest
from .eventstream import EventPermissionError
from .utils import sse_error_response
self.listener = None
request = AsgiRequest(self.scope, body)
gm = GripMiddleware()
gm.process_request(request)
if 'user' in self.scope:
request.user = self.scope['user']
try:
event_request = await self.parse_request(request)
response = None
except EventRequest.ResumeNotAllowedError as e:
response = HttpResponseBadRequest(
'Invalid request: %s.\n' % str(e))
except EventRequest.GripError as e:
if request.grip.proxied:
response = sse_error_response(
'internal-error',
'Invalid internal request.')
else:
response = sse_error_response(
'bad-request',
'Invalid request: %s.' % str(e))
except EventRequest.Error as e:
response = sse_error_response(
'bad-request',
'Invalid request: %s.' % str(e))
# for grip requests, prepare immediate response
if not response and request.grip.proxied:
try:
event_response = await self.get_events(event_request)
response = event_response.to_http_response(request)
except EventPermissionError as e:
response = sse_error_response(
'forbidden',
str(e),
{'channels': e.channels})
extra_headers = {}
extra_headers['Cache-Control'] = 'no-cache'
extra_headers['X-Accel-Buffering'] = 'no'
augment_cors_headers(extra_headers)
# if this was a grip request or we encountered an error, respond now
if response:
response = gm.process_response(request, response)
headers = []
for name, value in response.items():
if isinstance(name, six.text_type):
name = name.encode('utf-8')
if isinstance(value, six.text_type):
value = value.encode('utf-8')
headers.append((name, value))
for name, value in extra_headers.items():
if isinstance(name, six.text_type):
name = name.encode('utf-8')
if isinstance(value, six.text_type):
value = value.encode('utf-8')
headers.append((name, value))
await self.send_response(
response.status_code,
response.content,
headers=headers
)
return
# if we got here then the request was not a grip request, and there
# were no errors, so we can begin a local stream response
headers = [(six.b('Content-Type'), six.b('text/event-stream'))]
for name, value in extra_headers.items():
if isinstance(name, six.text_type):
name = name.encode('utf-8')
if isinstance(value, six.text_type):
value = value.encode('utf-8')
headers.append((name, value))
await self.send_headers(headers=headers)
self.listener = Listener()
self.is_streaming = True
asyncio.get_event_loop().create_task(self.stream(event_request))
async def handle(self, body):
from .eventrequest import EventRequest
from .eventstream import EventPermissionError
from .utils import sse_encode_event, sse_error_response, make_id
self.listener = None
request = AsgiRequest(self.scope, body)
# TODO use GripMiddleware
request.grip_proxied = False
for name, value in self.scope['headers']:
if name == b'grip-sig':
request.grip_proxied = True
break
if 'user' in self.scope:
request.user = self.scope['user']
try:
event_request = await self.parse_request(request)
response = None
except EventRequest.ResumeNotAllowedError as e:
response = HttpResponseBadRequest(
'Invalid request: %s.\n' % str(e))
except EventRequest.GripError as e:
if request.grip_proxied:
response = sse_error_response(
'internal-error',
'Invalid internal request.')
else:
response = sse_error_response(
'bad-request',
'Invalid request: %s.' % str(e))
except EventRequest.Error as e:
response = sse_error_response(
'bad-request',
'Invalid request: %s.' % str(e))
user = None
if hasattr(request, 'user') and request.user.is_authenticated:
user = request.user
# for grip requests, prepare immediate response
if not response and request.grip_proxied:
try:
event_response = await self.get_events(event_request, user)
response = event_response.to_http_response(request)
except EventPermissionError as e:
response = sse_error_response(
'forbidden',
str(e),
{'channels': e.channels})
extra_headers = {}
extra_headers['Cache-Control'] = 'no-cache'
cors_origin = ''
if hasattr(settings, 'EVENTSTREAM_ALLOW_ORIGIN'):
cors_origin = settings.EVENTSTREAM_ALLOW_ORIGIN
if cors_origin:
extra_headers['Access-Control-Allow-Origin'] = cors_origin
# if this was a grip request or we encountered an error, respond now
if response:
headers = []
for name, value in response.items():
headers.append((name, value))
for name, value in extra_headers.items():
headers.append((name, value))
await self.send_response(
response.status_code,
response.content,
headers=headers
)
return
# if we got here then the request was not a grip request, and there
# were no errors, so we can begin a local stream response
headers = [('Content-Type', 'text/event-stream')]
for name, value in extra_headers.items():
headers.append((name, value))
await self.send_headers(headers=headers)
body = b':' + (b' ' * 2048) + b'\n\n'
body += b'event: stream-open\ndata:\n\n'
await self.send_body(body, more_body=True)
self.listener = Listener()
self.is_streaming = True
asyncio.get_event_loop().create_task(self.stream(event_request, user))