Answer by SolidSnake for okhttp 3: how to decompress gzip/deflate response manually using Java/Android

After 6 hours of digging I found the correct solution and as usual it was easier than I thought, so I was basically trying to decompress a page that's not gzipped for that reason it was failing. Now once I hit the second page (which is compressed) I get a gzipped response where the code above should handle it. Also if anyone wants the solution I used a modified interceptor just like the one in this answer so you don't need to use a custom function to handle the decompression.

I modified the unzip method to make the okhttp interceptor work with compressed and uncompressed responses:

    OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder().addInterceptor(new UnzippingInterceptor());
    OkHttpClient client = clientBuilder.build();

And the Interceptor is like dis:

private class UnzippingInterceptor implements Interceptor {
    @Override
    public Response intercept(Chain chain) throws IOException {
        Response response = chain.proceed(chain.request());
        return unzip(response);


    // copied from okhttp3.internal.http.HttpEngine (because is private)
    private Response unzip(final Response response) throws IOException
    {
        if (response.body() == null)
        {
            return response;
        }

        //check if we have gzip response
        String contentEncoding = response.headers().get("Content-Encoding");

        //this is used to decompress gzipped responses
        if (contentEncoding != null && contentEncoding.equals("gzip"))
        {
            Long contentLength = response.body().contentLength();
            GzipSource responseBody = new GzipSource(response.body().source());
            Headers strippedHeaders = response.headers().newBuilder().build();
            return response.newBuilder().headers(strippedHeaders)
                    .body(new RealResponseBody(response.body().contentType().toString(), contentLength, Okio.buffer(responseBody)))
                    .build();
        }
        else
        {
            return response;
        }
    }
}
}