Disable setting Accept-Encoding: gzip unless explicitly set

pkg/proxy/proxy.go

@@ -61,7 +61,25 @@ func NewProxy(cfg Config) (*Proxy, error) {
 		p.logger = log.NewNopLogger()
 	}
 
+	transport := &http.Transport{
+		// Values taken from `http.DefaultTransport`.
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+		}).DialContext,
+		ForceAttemptHTTP2:     true,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+
+		// Non-default transport values.
+		DisableCompression: true,
+	}
+
 	p.handler = &httputil.ReverseProxy{
+		Transport:      transport,
 		Director:       p.modifyRequest,
 		ModifyResponse: p.modifyResponse,
 		ErrorHandler:   p.errorHandler,