Thank you -- that makes sense. I was initially thrown off by the fact that the connection remains open for netcat to get the full HTTP response.
For posterity, another way to get the desired behaviour is to invoke netcat as follows, noting that it won't exit by itself anymore: > cat ~/tmp/payload - | nc localhost 8080 On Monday, January 15, 2018 at 12:49:05 PM UTC-5, Axel Wagner wrote: > > I assume netcat closes the connection once it gets an EOF from stdin. Thus > the server notices the client disconnecting and cancels the context, as > advertised. > Try running nc without piping the input in and typing it out on the > console. > > On Mon, Jan 15, 2018 at 5:07 PM, <jesse....@gmail.com <javascript:>> > wrote: > >> According to https://golang.org/pkg/net/http/#Request.Context: >> >> For incoming server requests, the context is canceled when the client's >>> connection closes, the request is canceled (with HTTP/2), or when the >>> ServeHTTP method returns. >> >> >> My expectation, then, is for the following code to block: >> >> package main >> >> import ( >> "fmt" >> "io/ioutil" >> "net/http" >> ) >> >> func main() { >> s := &http.Server{ >> Addr: ":8080", >> Handler: http.HandlerFunc(func(w http.ResponseWriter, r * >> http.Request) { >> ioutil.ReadAll(r.Body) >> >> <-r.Context().Done() >> >> w.Write([]byte(fmt.Sprintf( >> "request context done: %+v\n", >> r.Context().Err(), >> ))) >> }), >> } >> s.ListenAndServe() >> } >> >> >> >> Instead, it always returns immediately, reporting that the context was >> canceled: >> >> > printf "POST / HTTP/1.1\r\nHost: localhost\r\nContent-Length: >> 4\r\n\r\nbody" | nc localhost 8080 >> HTTP/1.1 200 OK >> Date: Mon, 15 Jan 2018 16:01:46 GMT >> Content-Length: 39 >> Content-Type: text/plain; charset=utf-8 >> >> >> request context done: context canceled >> >> >> Curiously, if I don't ioutil.ReadAll(r.Body), the request blocks as >> expected. >> >> Am I missing something? My hope was to be able to use the default context >> to detect client disconnection. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golang-nuts...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
