Fast CGI module "multipart/mixed" problem (it only accepts 1 "Content-Type" header)

[Maxim Dounin]

Hello!

On Wed, Jan 15, 2014 at 11:56:30AM -0500, ariesone wrote:

> It seems, when my FCGI server responds to NGINX with "Status: 200
> OK\r\nContent-Type:
> multipart/mixed;boundary=whatever\r\n\r\nboundary=whatever\r\nContent-Type:
> image/jpeg\r\n\r\n<BINARY DATA>"
> 
> The FASTCGI module is taking the 2nd "Content-Type" only and uses it in the
> initial response with the 200.
> 
> The client gets confused when it sees the boundaries and data later.
> If I remove the subsequent "Content-Type:" headers, the initial one with the
> boundary indicator is sent; however, the client now does not know how to
> interpret the <BINARY DATA>.

The second Content-Type header is expected to be in response body 
from nginx point of view (i.e., after double CRLF which marks end 
of headers), and nginx shouldn't try to interpret it anyhow.

While string you provided looks correct at a first glance, it may 
be incorrect depending on language and OS used (e.g., in Perl on 
Windows it will likely produce wrong results due to "\n" expanded 
to CRLF).  Symptoms suggest this is likely the cause and you 
should focus on what your app actually returns.

-- 
Maxim Dounin
http://nginx.org/