Golang : How to return HTTP status code?

Was helping out a friend today on her work and one of the problems that she encountered during coding was on returning HTTP status code. Golang has a builtin constants of HTTP status codes ( http://golang.org/pkg/net/http/#pkg-constants ) that developer can use to return the status back to the client.

Here is an example usage :

 package main

 import (
  "net/http"
 )

 func returnCode200(w http.ResponseWriter, r *http.Request) {
  // see http://golang.org/pkg/net/http/#pkg-constants
  w.WriteHeader(http.StatusOK)
  w.Write([]byte("☄ HTTP status code returned!"))
 }

 func returnCode500(w http.ResponseWriter, r *http.Request) {
  // see http://golang.org/pkg/net/http/#pkg-constants
  w.WriteHeader(http.StatusInternalServerError)
  w.Write([]byte("☄ HTTP status code returned!"))
 }

 func main() {
  mux := http.NewServeMux()
  mux.HandleFunc("/", returnCode200)
  mux.HandleFunc("/fivehundred", returnCode500)

  http.ListenAndServe(":8080", mux)
 }

Sample tests with curl :

curl -I socketloop.com:8080

HTTP/1.1 200 OK

Date: Tue, 12 May 2015 07:11:40 GMT

Content-Length: 26

Content-Type: text/plain; charset=utf-8

curl -I socketloop.com:8080/fivehundred

HTTP/1.1 500 Internal Server Error

Date: Tue, 12 May 2015 07:13:06 GMT

Content-Length: 26

Content-Type: text/plain; charset=utf-8

References :

 StatusContinue = 100
 StatusSwitchingProtocols = 101

 StatusOK = 200
 StatusCreated = 201
 StatusAccepted = 202
 StatusNonAuthoritativeInfo = 203
 StatusNoContent = 204
 StatusResetContent = 205
 StatusPartialContent = 206

 StatusMultipleChoices = 300
 StatusMovedPermanently  = 301
 StatusFound = 302
 StatusSeeOther = 303
 StatusNotModified = 304
 StatusUseProxy = 305
 StatusTemporaryRedirect = 307

 StatusBadRequest = 400
 StatusUnauthorized = 401
 StatusPaymentRequired = 402
 StatusForbidden = 403
 StatusNotFound = 404
 StatusMethodNotAllowed = 405
 StatusNotAcceptable = 406
 StatusProxyAuthRequired = 407
 StatusRequestTimeout = 408
 StatusConflict = 409
 StatusGone = 410
 StatusLengthRequired = 411
 StatusPreconditionFailed = 412
 StatusRequestEntityTooLarge = 413
 StatusRequestURITooLong = 414
 StatusUnsupportedMediaType = 415
 StatusRequestedRangeNotSatisfiable = 416
 StatusExpectationFailed = 417
 StatusTeapot = 418

 StatusInternalServerError = 500
 StatusNotImplemented = 501
 StatusBadGateway = 502
 StatusServiceUnavailable = 503
 StatusGatewayTimeout = 504
 StatusHTTPVersionNotSupported = 505

http://golang.org/pkg/net/http/#pkg-constants