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package iris
import (
type gzipResponseWriter struct {
gzipWriter *gzip.Writer
var gzpool = sync.Pool{New: func() interface{} { return &gzipResponseWriter{} }}
func acquireGzipResponseWriter(underline ResponseWriter) *gzipResponseWriter {
w := gzpool.Get().(*gzipResponseWriter)
w.ResponseWriter = underline
w.gzipWriter = fs.AcquireGzipWriter(w.ResponseWriter)
return w
func releaseGzipResponseWriter(w *gzipResponseWriter) {
// Write compresses and writes that data to the underline response writer
func (w *gzipResponseWriter) Write(contents []byte) (int, error) {
return w.gzipWriter.Write(contents)
var rpool = sync.Pool{New: func() interface{} { return &responseWriter{statusCode: StatusOK} }}
func acquireResponseWriter(underline http.ResponseWriter) *responseWriter {
w := rpool.Get().(*responseWriter)
w.ResponseWriter = underline
return w
func releaseResponseWriter(w *responseWriter) {
w.statusCodeSent = false
w.beforeFlush = nil
w.statusCode = StatusOK
// ResponseWriter interface is used by the context to serve an HTTP handler to
// construct an HTTP response.
// A ResponseWriter may not be used after the Handler.ServeHTTP method
// has returned.
type ResponseWriter interface {
// NOTE: Users: Uncomment the below code if you are already using Go from master branch.
// HTTP/2 Go 1.8 Push feature,
// as described in the source code(master):
// .
// I have already tested the feature on my machine, but
// in order to avoid breaking the users' workspace:
// Uncomment these when 1.8 released (I guess in the middle of February)
// TODO:
// http.Pusher
Writef(format string, a ...interface{}) (n int, err error)
WriteString(s string) (n int, err error)
SetContentType(cType string)
ContentType() string
StatusCode() int
SetBeforeFlush(cb func())
clone() ResponseWriter
// responseWriter is the basic response writer,
// it writes directly to the underline http.ResponseWriter
type responseWriter struct {
statusCode int // the saved status code which will be used from the cache service
statusCodeSent bool // reply header has been (logically) written
// yes only one callback, we need simplicity here because on EmitError the beforeFlush events should NOT be cleared
// but the response is cleared.
// Sometimes is useful to keep the event,
// so we keep one func only and let the user decide when he/she wants to override it with an empty func before the EmitError (context's behavior)
beforeFlush func()
var _ ResponseWriter = &responseWriter{}
// StatusCode returns the status code header value
func (w *responseWriter) StatusCode() int {
return w.statusCode
// Writef formats according to a format specifier and writes to the response.
// Returns the number of bytes written and any write error encountered
func (w *responseWriter) Writef(format string, a ...interface{}) (n int, err error) {
return fmt.Fprintf(w.ResponseWriter, format, a...)
// WriteString writes a simple string to the response.
// Returns the number of bytes written and any write error encountered
func (w *responseWriter) WriteString(s string) (n int, err error) {
return w.Write([]byte(s))
// Write writes to the client
// If WriteHeader has not yet been called, Write calls
// WriteHeader(http.StatusOK) before writing the data. If the Header
// does not contain a Content-Type line, Write adds a Content-Type set
// to the result of passing the initial 512 bytes of written data to
// DetectContentType.
// Depending on the HTTP protocol version and the client, calling
// Write or WriteHeader may prevent future reads on the
// Request.Body. For HTTP/1.x requests, handlers should read any
// needed request body data before writing the response. Once the
// headers have been flushed (due to either an explicit Flusher.Flush
// call or writing enough data to trigger a flush), the request body
// may be unavailable. For HTTP/2 requests, the Go HTTP server permits
// handlers to continue to read the request body while concurrently
// writing the response. However, such behavior may not be supported
// by all HTTP/2 clients. Handlers should read before writing if
// possible to maximize compatibility.
func (w *responseWriter) Write(contents []byte) (int, error) {
return w.ResponseWriter.Write(contents)
// prin to write na benei to write header
// meta to write den ginete edw
// prepei omws kai mono me WriteHeader kai xwris Write na pigenei to status code
// prepei na exw function flushStatusCode kai na elenxei an exei dw9ei status code na to kanei write aliws 200
// WriteHeader sends an HTTP response header with status code.
// If WriteHeader is not called explicitly, the first call to Write
// will trigger an implicit WriteHeader(http.StatusOK).
// Thus explicit calls to WriteHeader are mainly used to
// send error codes.
func (w *responseWriter) WriteHeader(statusCode int) {
w.statusCode = statusCode
// SetBeforeFlush registers the unique callback which called exactly before the response is flushed to the client
func (w *responseWriter) SetBeforeFlush(cb func()) {
w.beforeFlush = cb
func (w *responseWriter) flushResponse() {
if w.beforeFlush != nil {
func (w *responseWriter) tryWriteHeader() {
if !w.statusCodeSent { // by write
w.statusCodeSent = true
// ContentType returns the content type, if not setted returns empty string
func (w *responseWriter) ContentType() string {
return w.ResponseWriter.Header().Get(contentType)
// SetContentType sets the content type header
func (w *responseWriter) SetContentType(cType string) {
w.ResponseWriter.Header().Set(contentType, cType)
// Hijack lets the caller take over the connection.
// After a call to Hijack(), the HTTP server library
// will not do anything else with the connection.
// It becomes the caller's responsibility to manage
// and close the connection.
// The returned net.Conn may have read or write deadlines
// already set, depending on the configuration of the
// Server. It is the caller's responsibility to set
// or clear those deadlines as needed.
func (w *responseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
if h, isHijacker := w.ResponseWriter.(http.Hijacker); isHijacker {
w.statusCodeSent = true
return h.Hijack()
return nil, nil, errors.New("Hijack is not supported by this ResponseWriter.")
// Flush sends any buffered data to the client.
func (w *responseWriter) Flush() {
// The Flusher interface is implemented by ResponseWriters that allow
// an HTTP handler to flush buffered data to the client.
// The default HTTP/1.x and HTTP/2 ResponseWriter implementations
// support Flusher, but ResponseWriter wrappers may not. Handlers
// should always test for this ability at runtime.
// Note that even for ResponseWriters that support Flush,
// if the client is connected through an HTTP proxy,
// the buffered data may not reach the client until the response
// completes.
if fl, isFlusher := w.ResponseWriter.(http.Flusher); isFlusher {
// NOTE: Users: Uncomment the below code if you are already using Go from master branch.
// HTTP/2 Go 1.8 Push feature,
// as described in the source code(master):
// .
// I have already tested the feature on my machine, but
// in order to avoid breaking the users' workspace:
// Uncomment these when 1.8 released (I guess in the middle of February)
// TODO:
// // Push initiates an HTTP/2 server push. This constructs a synthetic
// // request using the given target and options, serializes that request
// // into a PUSH_PROMISE frame, then dispatches that request using the
// // server's request handler. If opts is nil, default options are used.
// //
// // The target must either be an absolute path (like "/path") or an absolute
// // URL that contains a valid host and the same scheme as the parent request.
// // If the target is a path, it will inherit the scheme and host of the
// // parent request.
// //
// // The HTTP/2 spec disallows recursive pushes and cross-authority pushes.
// // Push may or may not detect these invalid pushes; however, invalid
// // pushes will be detected and canceled by conforming clients.
// //
// // Handlers that wish to push URL X should call Push before sending any
// // data that may trigger a request for URL X. This avoids a race where the
// // client issues requests for X before receiving the PUSH_PROMISE for X.
// //
// // Push returns ErrNotSupported if the client has disabled push or if push
// // is not supported on the underlying connection.
// func (w *responseWriter) Push(target string, opts *http.PushOptions) error {
// if pusher, isPusher := w.ResponseWriter.(http.Pusher); isPusher {
// return pusher.Push(target, opts)
// }
// return errors.New("HTTP/2 Push feature is not supported, yet.")
// }
// CloseNotify returns a channel that receives at most a
// single value (true) when the client connection has gone
// away.
// CloseNotify may wait to notify until Request.Body has been
// fully read.
// After the Handler has returned, there is no guarantee
// that the channel receives a value.
// If the protocol is HTTP/1.1 and CloseNotify is called while
// processing an idempotent request (such a GET) while
// HTTP/1.1 pipelining is in use, the arrival of a subsequent
// pipelined request may cause a value to be sent on the
// returned channel. In practice HTTP/1.1 pipelining is not
// enabled in browsers and not seen often in the wild. If this
// is a problem, use HTTP/2 or only use CloseNotify on methods
// such as POST.
func (w *responseWriter) CloseNotify() <-chan bool {
if notifier, supportsCloseNotify := w.ResponseWriter.(http.CloseNotifier); supportsCloseNotify {
return notifier.CloseNotify()
ch := make(chan bool, 1)
return ch
// clone returns a clone of this response writer
// it copies the header, status code, headers and the beforeFlush finally returns a new ResponseRecorder
func (w *responseWriter) clone() ResponseWriter {
wc := &responseWriter{}
wc.ResponseWriter = w.ResponseWriter
wc.statusCode = w.statusCode
wc.beforeFlush = w.beforeFlush
wc.statusCodeSent = w.statusCodeSent
return wc
// writeTo writes a response writer (temp: status code, headers and body) to another response writer
func (w *responseWriter) writeTo(to ResponseWriter) {
// set the status code, failure status code are first class
if w.statusCode >= 400 {
// append the headers
if w.Header() != nil {
for k, values := range w.Header() {
for _, v := range values {
if to.Header().Get(v) == "" {
to.Header().Add(k, v)
// the body is not copied, this writer doesn't supports recording
func (w *responseWriter) releaseMe() {