Response cleanup

It would be nice to have a simple API to direct post-response cleanup efforts outside of the task. Consider the following example:

async def cleanup(request: Request, response: HTTPResponse):
    print("sleeping")
    await sleep(1)
    print("done")


@app.get("/")
async def handler(request: Request):
    response = await request.respond()
    await response.send("foobar")
    await response.eof()
    response.cleanup(cleanup)

In this example, we would immediately schedule a task using add_task API to allow the response to return as early as possible. But, it should also be smart enough to work even without eof() being called such that it would wait for the response to be sent and cleaned before proceeding to cleanup. Then you could even have handlers like this and guarantee that cleanup is run on a completed response.

async def cleanup(request: Request, response: HTTPResponse):
    print("sleeping")
    await sleep(1)
    print("done")


@app.get("/")
async def handler(request: Request):
    resp = json({"foo": "bar"})
    resp.cleanup(cleanup)
    return resp

[ahopkins]

You are correct. Scrap the shortcut and let’s fix this for real.

@app.get("/")
async def handler(request: Request):
    response = await request.respond()
    await response.send("foobar")
    await response.eof()

    # Client is free to close connection or start another request
    await do_something_here()

┌───────────────────┐    ┌────────────────┐     ┌───────────┐     ┌──────────┐
│ Connection closed ├───►│ Is in handler? ├──Y─►│ Eof sent? ├──Y─►│ Complete │
└───────────────────┘    └───────┬────────┘     └───┬───────┘     └──────────┘
                                 │                  │
                                 No                 N
                                 │                  │
                                 ▼                  │
                              ┌──────┐              │
                              │Cancel│◄─────────────┘
                              └──────┘

[Tronic]

I have no take on that. Only that sending the response inside handler was supposed to be first class API, and after-handler handling only a fallback that calls it (even if in practice most handlers would return a response, not send it).