Spring Cloud Netflix Zuul: Content-Encoding header always return to the client

Bug report 1. Client send request to Zuul, without Accept-Encoding header. We use PHP GuzzleHttp/6.3.3 lib; 2. Zuul will add Accept-Encoding: gzip header, and forward to the remote service; 3. remote service return compression response and Content-Encoding: gzip header. 4. Zuul will decompress response, then return to the client; but the response header also has the Content-Encoding header。 5. GuzzleHttp Client receive the response has Content-Encoding: gzip header. so it will decompress response body but the body is not compressed. then throw exception.

Detail info:

$: curl  -v -I http://127.0.0.1:7777/provider/env
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 7777 (#0)
> GET /provider/env HTTP/1.1
> Host: 127.0.0.1:7777
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 200
HTTP/1.1 200
... some other headers ....
< Content-Encoding: gzip
Content-Encoding: gzip
< Transfer-Encoding: chunked
Transfer-Encoding: chunked

request not accept gzip and response body not compressed, 
but return the Content-Encoding: gzip header.

GuzzleHttp Exception: cURL error 23: Error while processing content unencoding: invalid distance too far back (see http:\/\/curl.haxx.se\/libcurl\/c\/libcurl-errors.html)

Solution: https://github.com/spring-cloud/spring-cloud-netflix/blob/c24e7e05bfbacbfe26e1189fb326e5e3103f9cc9/spring-cloud-netflix-zuul/src/main/java/org/springframework/cloud/netflix/zuul/filters/ProxyRequestHelper.java#L232 add which case need add Content-Encoding header maybe can solve this problem.

// if request client not support gzip, don't add content-encoding header
 if (name.equalsIgnoreCase(HttpHeaders.CONTENT_ENCODING) && !isGzipRequested(context))) {
   return false;
}

Comment From: ryanjbaxter

Can you tell us what version of Spring Cloud you are using? What does the request look like that you are sending?

Comment From: billnote

Spring Cloud Version: Finchley.SR2

Request:

$: curl  -v -I http://127.0.0.1:7777/provider/env

It's sample request, does not contain any parameters and headers.

Comment From: amanzag

I believe this was introduced by #3062

Comment From: amanzag

I think I got to the bottom of it. With the fix introduced in #3062, the Content-Encoding header is always copied from the downstream response, and because of that, the SendResponseFilter can't decide if it should be included or not. It should probably be fixed by having 2 lists of ignored headers, one for requests and one for responses. Content-Encoding, for instance, should be ignored for responses but not for requests. Until this is fixed, here's a workaround that I found:

@Component
// This is a workaround for bug https://github.com/spring-cloud/spring-cloud-netflix/pull/3062
public class ContentTypeFixFilter extends ZuulFilter {

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() throws ZuulException {
        RequestContext.getCurrentContext().getZuulResponseHeaders().removeIf(h -> h.first().equals(HttpHeaders.CONTENT_ENCODING));
        return null;
    }

    @Override
    public String filterType() {
        return FilterConstants.ROUTE_TYPE;
    }

    @Override
    public int filterOrder() {
        return FilterConstants.RIBBON_ROUTING_FILTER_ORDER + 1;
    }
}

Comment From: Fantaztig

Was this issue ever resolved? I think we are experiencing it still in Hoxton.RELEASE.