Method WriteHeader

modules/caddyhttp/encode/encode.go:259–283

WriteHeader stores the status to write when the time comes to actually write the header.

(status int)

// WriteHeader stores the status to write when the time comes
// to actually write the header.
func (rw *responseWriter) WriteHeader(status int) {
	rw.statusCode = status

	// See #5849 and RFC 9110 section 15.4.5 (https://www.rfc-editor.org/rfc/rfc9110.html#section-15.4.5) - 304
	// Not Modified must have certain headers set as if it was a 200 response, and according to the issue
	// we would miss the Vary header in this case when compression was also enabled; note that we set this
	// header in the responseWriter.init() method but that is only called if we are writing a response body
	if status == http.StatusNotModified && !hasVaryValue(rw.Header(), "Accept-Encoding") {
		rw.Header().Add("Vary", "Accept-Encoding")
	}

	// write status immediately if status is 2xx and the request is CONNECT
	// since it means the response is successful.
	// see: https://github.com/caddyserver/caddy/issues/6733#issuecomment-2525058845
	if rw.isConnect && 200 <= status && status <= 299 {
		rw.ResponseWriter.WriteHeader(status)
		rw.wroteHeader = true
	}

	// write status immediately when status code is informational
	// see: https://caddy.community/t/disappear-103-early-hints-response-with-encode-enable-caddy-v2-7-6/23081/5
	if 100 <= status && status <= 199 {
		rw.ResponseWriter.WriteHeader(status)
	}
}

// Match determines, if encoding should be done based on the ResponseMatcher.
func (enc *Encode) Match(rw *responseWriter) bool {