net/http: On redirect original request headers are not kept

[stephane....@gmail.com]

Hi again,

  I'm quite stressing the net/http package ;)

  I have discovered that if I set a custom HTTP header to a request, and hit a 301/302/etc. redirect, those headers are not kept. Example code:

package main

import (

"log"

"net/http"

)

func main() {

client := &http.Client{}

req, err := http.NewRequest("GET", "http://combo.cc/redirect", nil)

if err != nil {

log.Fatalln(err)

}

req.Header.Set("User-Agent", "MSIE 5.15 (MacintoshOS 9)")

log.Println("User-Agent before redirect:", req.UserAgent())

resp, err := client.Do(req)

if err != nil {

log.Fatalln(err)

}

defer resp.Body.Close()

log.Println("User-Agent after redirect:", resp.Request.UserAgent())

}

  Output:

2012/03/31 14:43:02 User-Agent before redirect: MSIE 5.15 (MacintoshOS 9)

2012/03/31 14:43:02 User-Agent after redirect: 

  This is what I'm getting on my nginx access.log:

    

93.56.194.199 - - [31/Mar/2012:14:36:59 +0200] "GET /redirect HTTP/1.1" 301 185 "-" "MSIE 5.15 (MacintoshOS 9)"

93.56.194.199 - - [31/Mar/2012:14:36:59 +0200] "GET / HTTP/1.1" 200 798 "http://combo.cc/redirect" "Go http package"

  As you can see the first request had my custom header, the second one did not.

  In http://golang.org/src/pkg/net/http/client.go, line 204, upon redirect a new set of headers is being constructed, and only "Referer" is set, instread of copying the headers from the original request.

  If this looks like a bug to you, I'll open a report.

Stephane

[Brad Fitzpatrick]

You can mutate the subsequent redirect requests with your Client's CheckRedirect function.

[Jamie Hall]

For reference, this is occurring in net/http/client.go, lines 255 - 279, when a new request is created and just its URL and Method copied.

To maintain the original header values (which is really quite useful, and I can't think of any drawbacks), simply store a reference to the original headers

after line 255 and change line 261 to:

req.Header = oldheader

[Dave Cheney]

Jamie, is there an issue logged for this ? The thread of discussion is
over a year old now.

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[Jamie Hall]

Sorry, I didn't spot the date until after I'd posted. Yes, the following issue relates to this for future reference:

Issue 4800

On Saturday, 31 March 2012 13:44:13 UTC+1, stephane....@gmail.com wrote:

[xingyu...@gmail.com]

find 

old row : req.Header = make(Header)

new row : req.Header = ireq.Header

在 2012年3月31日星期六UTC+8下午8时44分13秒，stephane....@gmail.com写道：