Commit a8871194 authored by Joe Tsai's avatar Joe Tsai Committed by Joe Tsai

net/http: preserve original HTTP method when possible

In Go1.7, a 301, 302, or 303 redirect on a HEAD method, would still
cause the following redirects to still use a HEAD.
In CL/29852 this behavior was changed such that those codes always
caused a redirect with the GET method. Fix this such that both
GET and HEAD will preserve the method.

Fixes #18570

Change-Id: I4bfe69872a30799419e3fad9178f907fe439b449
Reviewed-on: https://go-review.googlesource.com/34981
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: default avatarEmmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: default avatarBrad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
parent ffedff7e
......@@ -413,19 +413,26 @@ func (c *Client) checkRedirect(req *Request, via []*Request) error {
// redirectBehavior describes what should happen when the
// client encounters a 3xx status code from the server
func redirectBehavior(reqMethod string, resp *Response, via []*Request) (redirectMethod string, shouldRedirect bool) {
func redirectBehavior(reqMethod string, resp *Response, ireq *Request) (redirectMethod string, shouldRedirect bool) {
switch resp.StatusCode {
case 301, 302, 303:
redirectMethod = "GET"
redirectMethod = reqMethod
shouldRedirect = true
// RFC 2616 allowed automatic redirection only with GET and
// HEAD requests. RFC 7231 lifts this restriction, but we still
// restrict other methods to GET to maintain compatibility.
// See Issue 18570.
if reqMethod != "GET" && reqMethod != "HEAD" {
redirectMethod = "GET"
}
case 307, 308:
redirectMethod = reqMethod
shouldRedirect = true
// Treat 307 and 308 specially, since they're new in
// Go 1.8, and they also require re-sending the request body.
loc := resp.Header.Get("Location")
if loc == "" {
if resp.Header.Get("Location") == "" {
// 308s have been observed in the wild being served
// without Location headers. Since Go 1.7 and earlier
// didn't follow these codes, just stop here instead
......@@ -434,7 +441,6 @@ func redirectBehavior(reqMethod string, resp *Response, via []*Request) (redirec
shouldRedirect = false
break
}
ireq := via[0]
if ireq.GetBody == nil && ireq.outgoingLength() != 0 {
// We had a request body, and 307/308 require
// re-sending it, but GetBody is not defined. So just
......@@ -443,7 +449,6 @@ func redirectBehavior(reqMethod string, resp *Response, via []*Request) (redirec
shouldRedirect = false
}
}
return redirectMethod, shouldRedirect
}
......@@ -474,7 +479,8 @@ func redirectBehavior(reqMethod string, resp *Response, via []*Request) (redirec
// If the server replies with a redirect, the Client first uses the
// CheckRedirect function to determine whether the redirect should be
// followed. If permitted, a 301, 302, or 303 redirect causes
// subsequent requests to use HTTP method "GET", with no body.
// subsequent requests to use HTTP method GET
// (or HEAD if the original request was HEAD), with no body.
// A 307 or 308 redirect preserves the original HTTP method and body,
// provided that the Request.GetBody function is defined.
// The NewRequest function automatically sets GetBody for common
......@@ -592,7 +598,7 @@ func (c *Client) Do(req *Request) (*Response, error) {
}
var shouldRedirect bool
redirectMethod, shouldRedirect = redirectBehavior(req.Method, resp, reqs)
redirectMethod, shouldRedirect = redirectBehavior(req.Method, resp, reqs[0])
if !shouldRedirect {
return resp, nil
}
......
......@@ -1665,9 +1665,9 @@ func TestClientRedirectTypes(t *testing.T) {
3: {method: "POST", serverStatus: 307, wantMethod: "POST"},
4: {method: "POST", serverStatus: 308, wantMethod: "POST"},
5: {method: "HEAD", serverStatus: 301, wantMethod: "GET"},
6: {method: "HEAD", serverStatus: 302, wantMethod: "GET"},
7: {method: "HEAD", serverStatus: 303, wantMethod: "GET"},
5: {method: "HEAD", serverStatus: 301, wantMethod: "HEAD"},
6: {method: "HEAD", serverStatus: 302, wantMethod: "HEAD"},
7: {method: "HEAD", serverStatus: 303, wantMethod: "HEAD"},
8: {method: "HEAD", serverStatus: 307, wantMethod: "HEAD"},
9: {method: "HEAD", serverStatus: 308, wantMethod: "HEAD"},
......
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