Nginx X-Accel-Redirect stripping Content-Encoding header

[Danack]

I have Nginx setup to allow requests to be served with the X-Accel-Redirect
header. This works fine for images, but I'm trying to get it to work for
Javascript files that are already gzip'ed on the disk.

It appears Nginx is stripping off the 'Content-Encoding: gzip' header. This
makes the browser not unzip the content when it receives it, which obviously
makes it not work.

Is it possible to make Nginx preserve the Content-Encoding header to allow
pre-gzipped content through X-Accel-Redirect? Or is there another way to
allow this work?

The headers seen are:

With Accel = doesn't work

Accept-Ranges:bytes
Cache-Control:max-age=1209600, s-maxage=120960
Connection:keep-alive
Content-Length:125499
Content-Type:application/javascript
Date:Fri, 28 Jun 2013 09:52:33 GMT
ETag:"51c8efa3-1ea3b"
Expires:Fri, 12 Jul 2013 09:52:33 GMT
Last-Modified:Tue, 25 Jun 2013 01:17:23 GMT
Server:nginx/1.4.1


No accel = works

Cache-Control:max-age=1209600, s-maxage=120960
Connection:keep-alive
Content-Encoding:gzip
Content-Length:125499
Content-Type:application/javascript
Date:Fri, 28 Jun 2013 09:53:04 GMT
Expires:Fri, 12 Jul 2013 09:53:04 GMT
HTTP1/0 200 Ok:
Pragma:cache
Server:nginx/1.4.1
X-Powered-By:PHP/5.4.9


In case it's relevant, the code that is serving the content is:

[code]
public static function  proxyFile($fileNameToServe, $mimeType, $alreadyGzip
= false){
        $seconds_to_cache = 3600 * 24 * 7 * 2; 

        

        if ($alreadyGzip) {
            header('Content-Encoding: gzip');
            $filesize = filesize($fileNameToServe);
            header('Content-Length: '.$filesize);
        }

        if(defined('X-ACCEL-REDIRECT') == true &&
constant('X-ACCEL-REDIRECT') == true){
            $filenameToProxy = str_replace(PATH_TO_ROOT."var/cache",
'/protected_files', $fileNameToServe );
            sendProxyHeaders($mimeType, $seconds_to_cache);
            header("X-Accel-Redirect: ".$filenameToProxy);
            exit(0);
        }
        else{
            sendProxyHeaders($mimeType, $seconds_to_cache);
            $fileHandle = fopen($fileNameToServe, 'r');

            if($fileHandle == false){
                throw new \Exception("Failed to open file [$fileNameToServe]
for serving.");
            }

            while (!feof($fileHandle)) {
                $contents = fread($fileHandle, 8192);
                echo $contents;
            }

            fclose($fileHandle);
        }

        exit(0);
    }

    function	sendProxyHeaders($mimeType, $seconds_to_cache,
$secondsForCDNToCache = false){
    	$currentTimeStamp = gmdate("D, d M Y H:i:s", time()) . " GMT";
    	$timeStamp = gmdate("D, d M Y H:i:s", time() + $seconds_to_cache) . "
GMT";
    
    	if($secondsForCDNToCache === false){
    		$secondsForCDNToCache = intval($seconds_to_cache / 10);
    	}
    
    	header("HTTP1/0 200 Ok");
    	header("Content-Type: $mimeType");
    	header("Date: $currentTimeStamp");
    	header("Expires: $timeStamp");
    	header("Pragma: cache");

    	//max-age = browser max age
    	//s-maxage = intermediate (cache e.g. CDN)
    	header("Cache-Control: max-age=$seconds_to_cache,
s-maxage=$secondsForCDNToCache");
    }

[/code]

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,240406,240406#msg-240406