text: import logging
  from functools import wraps
  from typing import Iterable, Optional, Tuple
  
  import trio
  
  from tokamak.web import methods, router
  from tokamak.web.request import Request
  
  logger = logging.getLogger("tokamak")
  
  
  class Tokamak:
      """
      When using the Tokamak App instance, you should define handlers
      that take a `tokamak.web.request.Request` instance, which uses
      in-memory-channels to send back a Response and to schedule background
      work.
      """
  
      def __init__(
          self,
          router: Optional[router.AsgiRouter] = None,
          background_task_limit: int = 10,
      ):
          self.router = router
          # The channel limit, not total limit; will apply back-pressure
          self.background_task_limit = background_task_limit
  
      async def lifespan(self, scope, receive, send):
          while True:
              message = await receive()
              if message["type"] == "lifespan.startup":
                  logger.warn("========·°·°~> Starting tokamak °°···°°🚀···°° ")
                  await send({"type": "lifespan.startup.complete"})
              elif message["type"] == "lifespan.shutdown":
                  logger.warn("~°°···°°°~ Shutting down tokamak ~°°···🚉···°°°~ ")
                  await send({"type": "lifespan.shutdown.complete"})
                  return
  
      async def http(self, scope, receive, send):
          path: str = scope.get("path", "")
          route, context = self.router.get_route(path)
  
          bg_send_chan, bg_recv_chan = trio.open_memory_channel(
              self.background_task_limit
          )
          # http allows one response: what about streaming?
          resp_send_chan, resp_recv_chan = trio.open_memory_channel(1)
  
          request = Request(context, scope, receive, resp_send_chan, bg_send_chan)
  
          await route(request, method=scope.get(methods.SCOPE_METHOD_KEY))
  
          async with resp_recv_chan:
              async for response in resp_recv_chan:
                  await send(
                      {
                          "type": "http.response.start",
                          "status": response.status_code,
                          "headers": response.raw_headers,
                      }
                  )
                  if response.streaming:
                      async for chunk in response.streaming_body:
                          await send(
                              {
                                  "type": "http.response.body",
                                  "body": chunk,
                                  "more_body": True,
                              }
                          )
                      await send(
                          {"type": "http.response.body", "body": b"", "more_body": False}
                      )
                  else:
                      await send({"type": "http.response.body", "body": response.body})
  
          async with bg_recv_chan:
              async for background_task in bg_recv_chan:
                  await background_task()
  
          return None
  
      async def ws(self, scope, receive, send):
          path: str = scope.get("path", "")
          headers: Iterable[Tuple[bytes, bytes]] = scope.get("headers", [])
          qparams: Optional[bytes] = scope.get("query_string")
          http_version: Optional[str] = scope.get("http_version")
          method: Optional[str] = scope.get("method")
  
          bg_send_chan, bg_recv_chan = trio.open_memory_channel(
              self.background_task_limit
          )
          resp_send_chan, resp_recv_chan = trio.open_memory_channel(1)
  
      async def __call__(self, scope, receive, send):
          if scope["type"] == "lifespan":
              return await self.lifespan(scope, receive, send)
          elif scope["type"] == "http":
              return await self.http(scope, receive, send)
          elif scope["type"] == "websocket":
              return await self.ws(scope, receive, send)
  