ResponseWriter (Trailers) in Go
HTTP Trailers are a set of key/value pairs like headers that come after the HTTP response, instead of before.
package main
import (
"io"
"net/http"
)
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/sendstrailers", func(w http.ResponseWriter, req *http.Request) {
// Before any call to WriteHeader or Write, declare
// the trailers you will set during the HTTP
// response. These three headers are actually sent in
// the trailer.
w.Header().Set("Trailer", "AtEnd1, AtEnd2")
w.Header().Add("Trailer", "AtEnd3")
w.Header().Set("Content-Type", "text/plain; charset=utf-8") // normal header
w.WriteHeader(http.StatusOK)
w.Header().Set("AtEnd1", "value 1")
io.WriteString(w, "This HTTP response has both headers before this text and trailers at the end.\n")
w.Header().Set("AtEnd2", "value 2")
w.Header().Set("AtEnd3", "value 3") // These will appear as trailers.
})
}