net/http: add example for setting trailers in an Handler
Change-Id: I6a8bb853a538c80d95589321d3226784bc017eef
Reviewed-on: https://go-review.googlesource.com/12327
Reviewed-by: Andrew Gerrand <adg@golang.org>
diff --git a/src/net/http/example_test.go b/src/net/http/example_test.go
index 88b97d9..1774795 100644
--- a/src/net/http/example_test.go
+++ b/src/net/http/example_test.go
@@ -6,6 +6,7 @@
import (
"fmt"
+ "io"
"io/ioutil"
"log"
"net/http"
@@ -86,3 +87,25 @@
fmt.Fprintf(w, "Welcome to the home page!")
})
}
+
+// HTTP Trailers are a set of key/value pairs like headers that come
+// after the HTTP response, instead of before.
+func ExampleResponseWriter_trailers() {
+ 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.
+ })
+}
diff --git a/src/net/http/server.go b/src/net/http/server.go
index fda26ba..aad55d0 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -60,7 +60,7 @@
// WriteHeader. Changing the header after a call to
// WriteHeader (or Write) has no effect unless the modified
// headers were declared as trailers by setting the
- // "Trailer" header before the call to WriteHeader.
+ // "Trailer" header before the call to WriteHeader (see example).
// To suppress implicit response headers, set their value to nil.
Header() Header
