António P. P. Almeida Wrote:
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> XSendfile in Nginx is called X-Accel-Redirect.
>
> The way X-Accel-Redirect works is that your app/backend sends a
> "special" header with the location of the file that is to be served by
> Nginx. Usually the application case is for speeding up the delivery of
> protected/private files. Let's say you have a ecommerce site that
> sells digital downloads. Then these files will be protected and for
> speeding up the delivery your application sends an X-Accel-Redirect
> header with the location of the file. Then the file is delivered by
> Nginx as a regular static file.
>
> Example: I request to download:
>
> http://myshop.com/downloads/big_hit.flac
>
> The file is stocked at /path/to/the/flac_files/big_hit.flac
>
> your ecommerce sends an header:
>
> X-Accel-Redirect: /path/to/the/flac_files/big_hit.flac
>
> when Nginx sees this he knows that now the file is to be served
> directly from the file system as a regular static file. Note that the
> real location is hidden from the client.
>
> Note that the real location must be protected from direct access by
> the client always, be it from your app, be it from your server, for
> example using the internal keyword:
>
> http://nginx.org/en/docs/http/ngx_http_core_module.html#internal
>
> In a nutshell that's how it works.

I ended up using nginx as a reverse proxy, although this is what I wanted to avoid in the first place (bandwidth reasons).
Main traffic passes through nginx which forwards it to apache by proxy_pass, and apache sends back the X-Accel-Redirect and nginx responds with the file (protected with internal; ).