297 lines
11 KiB
Python
297 lines
11 KiB
Python
import os
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import sys
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import asyncio
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from engineio.static_files import get_static_file
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class ASGIApp:
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"""ASGI application middleware for Engine.IO.
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This middleware dispatches traffic to an Engine.IO application. It can
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also serve a list of static files to the client, or forward unrelated
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HTTP traffic to another ASGI application.
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:param engineio_server: The Engine.IO server. Must be an instance of the
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``engineio.AsyncServer`` class.
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:param static_files: A dictionary with static file mapping rules. See the
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documentation for details on this argument.
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:param other_asgi_app: A separate ASGI app that receives all other traffic.
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:param engineio_path: The endpoint where the Engine.IO application should
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be installed. The default value is appropriate for
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most cases. With a value of ``None``, all incoming
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traffic is directed to the Engine.IO server, with the
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assumption that routing, if necessary, is handled by
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a different layer. When this option is set to
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``None``, ``static_files`` and ``other_asgi_app`` are
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ignored.
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:param on_startup: function to be called on application startup; can be
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coroutine
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:param on_shutdown: function to be called on application shutdown; can be
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coroutine
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Example usage::
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import engineio
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import uvicorn
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eio = engineio.AsyncServer()
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app = engineio.ASGIApp(eio, static_files={
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'/': {'content_type': 'text/html', 'filename': 'index.html'},
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'/index.html': {'content_type': 'text/html',
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'filename': 'index.html'},
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})
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uvicorn.run(app, '127.0.0.1', 5000)
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"""
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def __init__(self, engineio_server, other_asgi_app=None,
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static_files=None, engineio_path='engine.io',
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on_startup=None, on_shutdown=None):
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self.engineio_server = engineio_server
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self.other_asgi_app = other_asgi_app
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self.engineio_path = engineio_path
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if self.engineio_path is not None:
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if not self.engineio_path.startswith('/'):
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self.engineio_path = '/' + self.engineio_path
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if not self.engineio_path.endswith('/'):
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self.engineio_path += '/'
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self.static_files = static_files or {}
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self.on_startup = on_startup
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self.on_shutdown = on_shutdown
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async def __call__(self, scope, receive, send):
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if scope['type'] == 'lifespan':
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await self.lifespan(scope, receive, send)
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elif scope['type'] in ['http', 'websocket'] and (
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self.engineio_path is None
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or self._ensure_trailing_slash(scope['path']).startswith(
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self.engineio_path)):
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await self.engineio_server.handle_request(scope, receive, send)
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else:
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static_file = get_static_file(scope['path'], self.static_files) \
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if scope['type'] == 'http' and self.static_files else None
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if static_file and os.path.exists(static_file['filename']):
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await self.serve_static_file(static_file, receive, send)
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elif self.other_asgi_app is not None:
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await self.other_asgi_app(scope, receive, send)
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else:
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await self.not_found(receive, send)
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async def serve_static_file(self, static_file, receive,
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send): # pragma: no cover
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event = await receive()
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if event['type'] == 'http.request':
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with open(static_file['filename'], 'rb') as f:
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payload = f.read()
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await send({'type': 'http.response.start',
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'status': 200,
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'headers': [(b'Content-Type', static_file[
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'content_type'].encode('utf-8'))]})
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await send({'type': 'http.response.body',
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'body': payload})
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async def lifespan(self, scope, receive, send):
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if self.other_asgi_app is not None and self.on_startup is None and \
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self.on_shutdown is None:
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# let the other ASGI app handle lifespan events
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await self.other_asgi_app(scope, receive, send)
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return
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while True:
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event = await receive()
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if event['type'] == 'lifespan.startup':
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if self.on_startup:
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try:
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await self.on_startup() \
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if asyncio.iscoroutinefunction(self.on_startup) \
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else self.on_startup()
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except:
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await send({'type': 'lifespan.startup.failed'})
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return
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await send({'type': 'lifespan.startup.complete'})
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elif event['type'] == 'lifespan.shutdown':
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if self.on_shutdown:
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try:
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await self.on_shutdown() \
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if asyncio.iscoroutinefunction(self.on_shutdown) \
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else self.on_shutdown()
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except:
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await send({'type': 'lifespan.shutdown.failed'})
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return
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await send({'type': 'lifespan.shutdown.complete'})
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return
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async def not_found(self, receive, send):
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"""Return a 404 Not Found error to the client."""
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await send({'type': 'http.response.start',
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'status': 404,
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'headers': [(b'Content-Type', b'text/plain')]})
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await send({'type': 'http.response.body',
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'body': b'Not Found'})
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def _ensure_trailing_slash(self, path):
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if not path.endswith('/'):
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path += '/'
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return path
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async def translate_request(scope, receive, send):
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class AwaitablePayload: # pragma: no cover
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def __init__(self, payload):
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self.payload = payload or b''
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async def read(self, length=None):
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if length is None:
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r = self.payload
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self.payload = b''
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else:
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r = self.payload[:length]
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self.payload = self.payload[length:]
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return r
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event = await receive()
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payload = b''
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if event['type'] == 'http.request':
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payload += event.get('body') or b''
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while event.get('more_body'):
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event = await receive()
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if event['type'] == 'http.request':
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payload += event.get('body') or b''
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elif event['type'] == 'websocket.connect':
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pass
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else:
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return {}
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raw_uri = scope['path']
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query_string = ''
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if 'query_string' in scope and scope['query_string']:
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try:
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query_string = scope['query_string'].decode('utf-8')
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except UnicodeDecodeError:
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pass
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else:
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raw_uri += '?' + query_string
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environ = {
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'wsgi.input': AwaitablePayload(payload),
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'wsgi.errors': sys.stderr,
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'wsgi.version': (1, 0),
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'wsgi.async': True,
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'wsgi.multithread': False,
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'wsgi.multiprocess': False,
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'wsgi.run_once': False,
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'SERVER_SOFTWARE': 'asgi',
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'REQUEST_METHOD': scope.get('method', 'GET'),
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'PATH_INFO': scope['path'],
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'QUERY_STRING': query_string,
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'RAW_URI': raw_uri,
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'SCRIPT_NAME': '',
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'SERVER_PROTOCOL': 'HTTP/1.1',
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'REMOTE_ADDR': '127.0.0.1',
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'REMOTE_PORT': '0',
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'SERVER_NAME': 'asgi',
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'SERVER_PORT': '0',
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'asgi.receive': receive,
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'asgi.send': send,
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'asgi.scope': scope,
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}
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for hdr_name, hdr_value in scope['headers']:
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try:
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hdr_name = hdr_name.upper().decode('utf-8')
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hdr_value = hdr_value.decode('utf-8')
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except UnicodeDecodeError:
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# skip header if it cannot be decoded
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continue
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if hdr_name == 'CONTENT-TYPE':
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environ['CONTENT_TYPE'] = hdr_value
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continue
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elif hdr_name == 'CONTENT-LENGTH':
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environ['CONTENT_LENGTH'] = hdr_value
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continue
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key = 'HTTP_%s' % hdr_name.replace('-', '_')
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if key in environ:
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hdr_value = f'{environ[key]},{hdr_value}'
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environ[key] = hdr_value
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environ['wsgi.url_scheme'] = environ.get('HTTP_X_FORWARDED_PROTO', 'http')
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return environ
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async def make_response(status, headers, payload, environ):
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headers = [(h[0].encode('utf-8'), h[1].encode('utf-8')) for h in headers]
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if environ['asgi.scope']['type'] == 'websocket':
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if status.startswith('200 '):
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await environ['asgi.send']({'type': 'websocket.accept',
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'headers': headers})
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else:
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if payload:
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reason = payload.decode('utf-8') \
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if isinstance(payload, bytes) else str(payload)
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await environ['asgi.send']({'type': 'websocket.close',
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'reason': reason})
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else:
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await environ['asgi.send']({'type': 'websocket.close'})
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return
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await environ['asgi.send']({'type': 'http.response.start',
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'status': int(status.split(' ')[0]),
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'headers': headers})
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await environ['asgi.send']({'type': 'http.response.body',
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'body': payload})
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class WebSocket: # pragma: no cover
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"""
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This wrapper class provides an asgi WebSocket interface that is
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somewhat compatible with eventlet's implementation.
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"""
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def __init__(self, handler, server):
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self.handler = handler
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self.asgi_receive = None
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self.asgi_send = None
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async def __call__(self, environ):
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self.asgi_receive = environ['asgi.receive']
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self.asgi_send = environ['asgi.send']
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await self.asgi_send({'type': 'websocket.accept'})
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await self.handler(self)
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return '' # send nothing as response
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async def close(self):
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try:
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await self.asgi_send({'type': 'websocket.close'})
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except Exception:
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# if the socket is already close we don't care
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pass
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async def send(self, message):
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msg_bytes = None
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msg_text = None
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if isinstance(message, bytes):
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msg_bytes = message
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else:
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msg_text = message
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await self.asgi_send({'type': 'websocket.send',
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'bytes': msg_bytes,
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'text': msg_text})
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async def wait(self):
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event = await self.asgi_receive()
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if event['type'] != 'websocket.receive':
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raise OSError()
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if event.get('bytes', None) is not None:
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return event['bytes']
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elif event.get('text', None) is not None:
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return event['text']
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else: # pragma: no cover
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raise OSError()
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_async = {
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'asyncio': True,
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'translate_request': translate_request,
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'make_response': make_response,
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'websocket': WebSocket,
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}
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