nginx 0.7.6 sends original POST body in proxied GET subrequests from SSI

[Igor Sysoev]

On Tue, Jul 08, 2008 at 04:22:45PM +0200, piespy wrote:

> Apologies if you get this twice, apparently the first time I sent it my
> confirmation hadn't been processed yet.
> 
> I have a PHP script (proxied via Apache) that accepts file uploads. These
> are then processed by an external batch processor, which may take a long
> time. To not keep the PHP script waiting for the batch process to complete,
> it writes a temporary file containing SSI include requests, and gives that
> file back to nginx via X-Accel-Redirect. This way nginx can wait for
> completion (when the first SSI include becomes ready), and then send the
> second SSI include to another PHP script that reports the batch process
> result to the browser.
> 
> However, when contacting the second PHP script, nginx resends the original
> POST body even though the subrequest correctly uses the GET method (since
> 0.6.26). I have verified this using tcpdump, the GET request has a
> Content-Length header equal to the original POST body length, and a
> Content-Type of e.g. "multipart/form-data;
> boundary=----------uwPZJQ9jJJ0O7Q94Bs8ae1", followed by the POST body.
> 
> Apparently this confuses PHP or Apache, so it closes the connection before
> nginx is ready, which causes nginx to consider the SSI include to have
> failed, with the following log message:
> 
> 2008/07/08 14:29:34 [error] 14064#0: *16 upstream prematurely closed
> connection while reading response header from upstream, client: [...]
> 
> The basic setup works fine when doing a POST without a file upload. But
> still, I think nginx should send neither Content-Length, Content-Type nor
> the POST body content in a GET subrequest (i.e., afaict, any of them).
> 
> 
> I've tried to fix it by clearing sr->request_body in line 1789 of
> ngx_http_core_module.c, but while that gets rid of the actual body content,
> the Content-Length and Content-Type headers are still there and I've been
> unable to remove these from the subrequest.
> 
> Any help is welcome, thanks.

   location /subrequest {
        proxy_pass_request_body  off;

-- 
Igor Sysoev
http://sysoev.ru/en/