http_gun/cancellation

Cancels in-flight requests from another part of the program.

with_token runs a callback with a Token; attach it to a client view with http_gun.with_cancellation, which replaces existing tokens, or http_gun.with_additional_cancellation, which preserves them. cancel stops every request made through such a view that has not finished, before its headers or while its body is read, and the token stays cancelled. Returning from the callback, an exception and the creator’s exit also cancel.

use token <- cancellation.with_token
let client = client |> http_gun.with_cancellation(token)
spawn_watchdog(fn() { cancellation.cancel(token) })
http_gun.send(client, req)

Cancellation is local: it says nothing about whether the server processed the request, and the failure’s evidence says whether it may have been sent.

pub type Token =
  @internal Token

pub fn cancel(token: Token) -> Nil

pub fn is_cancelled(token: Token) -> Bool

pub fn with_token(run: fn(Token) -> value) -> value