net/http: setting Content-Type header to []string{""} in http handler causes two Content-Type headers to be emitted #13495

odeke-em · 2015-12-05T03:26:08Z

This issue is a followup of #5953 which was noticed during a port of tests to http2 in CL https://go-review.googlesource.com/#/c/17462/ or in code

diff --git a/src/net/http/sniff_test.go b/src/net/http/sniff_test.go
index 293a7f5..a372210 100644
--- a/src/net/http/sniff_test.go
+++ b/src/net/http/sniff_test.go
@@ -88,15 +88,18 @@ func testServerContentType(t *testing.T, h2 bool) {

 // Issue 5953: shouldn't sniff if the handler set a Content-Type header,
 // even if it's the empty string.
-func TestServerIssue5953(t *testing.T) {
+func TestServerIssue5953_h1(t *testing.T) { testServerIssue5953(t, false) }
+func TestServerIssue5953_h2(t *testing.T) { testServerIssue5953(t, true) }
+
+func testServerIssue5953(t *testing.T, h2 bool) {
    defer afterTest(t)
-   ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+   cst := newClientServerTest(t, h2, HandlerFunc(func(w ResponseWriter, r *Request) {
        w.Header()["Content-Type"] = []string{""}
        fmt.Fprintf(w, "<html><head></head><body>hi</body></html>")
    }))
-   defer ts.Close()
+   defer cst.close()

-   resp, err := Get(ts.URL)
+   resp, err := cst.c.Get(cst.ts.URL)
    if err != nil {
        t.Fatal(err)
    }

$ go test --cover
--- FAIL: TestServerIssue5953_h2 (0.00s)
    sniff_test.go:110: Content-Type = ["" "text/html; charset=utf-8"]; want [""]
FAIL
coverage: 77.4% of statements
exit status 1
FAIL    net/http    22.409s

gopherbot · 2015-12-09T00:00:18Z

CL https://golang.org/cl/17591 mentions this issue.

gopherbot · 2015-12-09T00:00:34Z

CL https://golang.org/cl/17590 mentions this issue.


        http2: fix two cases of Server behavior not matching HTTP/1

* don't send automatic Content-Length from Server on HEAD requests if response size is 0 (it's possible the handler didn't write because they looked at the method) * don't send Content-Type if handler explicitly set it to nothing. Matches the behavior of HTTP/1. Updates golang/go#13532 Updates golang/go#13495 Change-Id: If6e0898095cf88cb14efb6bbe82c88dbc2077e6b Reviewed-on: https://go-review.googlesource.com/17590 Reviewed-by: Blake Mizerany <blake.mizerany@gmail.com>

mikioh changed the title ~~net/http2: setting Content-Type header to []string{""} in http handler causes two Content-Type headers to be emitted~~ net/http: setting Content-Type header to []string{""} in http handler causes two Content-Type headers to be emitted Dec 8, 2015

bradfitz closed this in 3d3d6eb Dec 9, 2015

golang locked and limited conversation to collaborators Dec 14, 2016

gopherbot added the FrozenDueToAge label Dec 14, 2016

golang / go

net/http: setting Content-Type header to []string{""} in http handler causes two Content-Type headers to be emitted #13495

net/http: setting Content-Type header to []string{""} in http handler causes two Content-Type headers to be emitted #13495

odeke-em commented Dec 5, 2015

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gopherbot commented Dec 9, 2015

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net/http: setting Content-Type header to []string{""} in http handler causes two Content-Type headers to be emitted #13495

net/http: setting Content-Type header to []string{""} in http handler causes two Content-Type headers to be emitted #13495

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