Method ServeHTTP

modules/caddyhttp/encode/encode.go:162–199

(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler)

}

func (enc *Encode) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
	if isEncodeAllowed(r.Header) {
		for _, encName := range AcceptedEncodings(r, enc.Prefer) {
			if _, ok := enc.writerPools[encName]; !ok {
				continue // encoding not offered
			}
			w = enc.openResponseWriter(encName, w, r.Method == http.MethodConnect)
			defer w.(*responseWriter).Close()

			// to comply with RFC 9110 section 8.8.3(.3), we modify the Etag when encoding
			// by appending a hyphen and the encoder name; the problem is, the client will
			// send back that Etag in an If-None-Match header, but upstream handlers that set
			// the Etag in the first place don't know that we appended to their Etag! so here
			// we have to strip our addition so the upstream handlers can still honor client
			// caches without knowing about our changes...
			if etag := r.Header.Get("If-None-Match"); etag != "" && !strings.HasPrefix(etag, "W/") {
				ourSuffix := "-" + encName + `"`
				if before, ok := strings.CutSuffix(etag, ourSuffix); ok {
					etag = before + `"`
					r.Header.Set("If-None-Match", etag)
				}
			}

			break
		}
	}

	err := next.ServeHTTP(w, r)
	// If there was an error, disable encoding completely
	// This prevents corruption when handle_errors processes the response
	if err != nil {
		if ew, ok := w.(*responseWriter); ok {
			ew.disabled = true
		}
	}

	return err
}

func (enc *Encode) addEncoding(e Encoding) error {
	ae := e.AcceptEncoding()