Proxy stripping Content-Length, Transfer-Encoding

[Graham Leggett <mi...@sharp.fm>]

Hi all,

In httpd v2.0 mod_proxy, both the Content-Length and Transfer-Encoding 
headers are stripped from the backend server response before passing it 
to the frontend:

  /* We need to copy the output headers and treat them as input
   * headers as well.  BUT, we need to do this before we remove
   * TE and C-L, so that they are preserved accordingly for
   * ap_http_filter to know where to end.
   */
  rp->headers_in = apr_table_copy(r->pool, r->headers_out);

  /* In order for ap_set_keepalive to work properly, we can NOT
   * have any length information stored in the output headers.
   */
  apr_table_unset(r->headers_out,"Transfer-Encoding");
  apr_table_unset(r->headers_out,"Content-Length");

After much discussion, the removal of the Content-Length was taken out 
in httpd-2.1. Can anyone confirm this didn't break anything? If it 
didn't I want to remove this in httpd v2.0 also.

What concerns me too is the removal of the transfer encoding - I assume 
this is because it is a hop-by-hop header - my question is why are we 
not removing all hop-by-hop headers, like we do for the initial request 
from the browser?

  /* We need to copy the output headers and treat them as input
   * headers as well.  BUT, we need to do this before we remove
   * TE, so that they are preserved accordingly for
   * ap_http_filter to know where to end.
   */
  rp->headers_in = apr_table_copy(r->pool, r->headers_out);

  apr_table_unset(r->headers_out,"Transfer-Encoding");

Regards,
Graham
-- 
-----------------------------------------
minfrin@sharp.fm		"There's a moon
					over Bourbon Street
						tonight..."

Re: Proxy stripping Content-Length, Transfer-Encoding

[Brian Pane <br...@cnet.com>]

On Wed, 2003-01-08 at 23:25, Graham Leggett wrote:
> Hi all,
> 
> In httpd v2.0 mod_proxy, both the Content-Length and Transfer-Encoding 
> headers are stripped from the backend server response before passing it 
> to the frontend:
> 
>   /* We need to copy the output headers and treat them as input
>    * headers as well.  BUT, we need to do this before we remove
>    * TE and C-L, so that they are preserved accordingly for
>    * ap_http_filter to know where to end.
>    */
>   rp->headers_in = apr_table_copy(r->pool, r->headers_out);
> 
>   /* In order for ap_set_keepalive to work properly, we can NOT
>    * have any length information stored in the output headers.
>    */
>   apr_table_unset(r->headers_out,"Transfer-Encoding");
>   apr_table_unset(r->headers_out,"Content-Length");
> 
> After much discussion, the removal of the Content-Length was taken out 
> in httpd-2.1. Can anyone confirm this didn't break anything? If it 
> didn't I want to remove this in httpd v2.0 also.

I haven't heard reports of anything breaking in 2.1
due to the change.  I'll add an entry in the 2.0 STATUS
file to track votes on back-porting the change.

> What concerns me too is the removal of the transfer encoding - I assume 
> this is because it is a hop-by-hop header - my question is why are we 
> not removing all hop-by-hop headers, like we do for the initial request 
> from the browser?

I think we should be removing all hop-by-hop headers here.

Brian