// ServeHTTP implements the HTTP Handler interface of the http package.
func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Get the URL path.
path := r.URL.Path
// Call this in an inline function to handle errors.
statusCode, err := func() (int, error) {
// Check the origin.
if !s.checkOriginFunc(r) {
return http.StatusForbidden, fmt.Errorf("origin not allowed")
}
// Set the required HTTP headers for cross origin requests if enabled.
if s.enableCORS {
// Parse the origin url.
origin := r.Header["Origin"]
if len(origin) == 0 || len(origin[0]) == 0 {
return 400, fmt.Errorf("failed to set header: Access-Control-Allow-Origin: HTTP request origin header is empty")
}
w.Header().Set("Access-Control-Allow-Origin", origin[0]) // Set allowed origin.
w.Header().Set("Access-Control-Allow-Methods", "POST,GET") // Only allow POST and GET requests.
}
// Strip the base URL.
if len(path) < s.httpURLStripLength {
return http.StatusBadRequest, fmt.Errorf("invalid request")
}
path = path[s.httpURLStripLength:]
// Route the HTTP request in a very simple way by comparing the strings.
if path == httpURLWebSocketSuffix {
// Handle the websocket request.
s.webSocketServer.HandleRequest(w, r)
} else if path == httpURLAjaxSocketSuffix {
// Handle the ajax request.
s.ajaxSocketServer.HandleRequest(w, r)
} else {
return http.StatusBadRequest, fmt.Errorf("invalid request")
}
return http.StatusAccepted, nil
}()
// Handle the error.
if err != nil {
// Set the HTTP status code.
w.WriteHeader(statusCode)
// Get the remote address and user agent.
remoteAddr, _ := utils.RemoteAddress(r)
userAgent := r.Header.Get("User-Agent")
// Log the invalid request.
log.L.WithFields(logrus.Fields{
"remoteAddress": remoteAddr,
"userAgent": userAgent,
"url": r.URL.Path,
}).Warningf("handle HTTP request: %v", err)
}
}
func handleWebSocket(rw http.ResponseWriter, req *http.Request) {
// Get the remote address and user agent.
remoteAddr, requestRemoteAddrMethodUsed := utils.RemoteAddress(req)
userAgent := req.Header.Get("User-Agent")
// This has to be a GET request.
if req.Method != "GET" {
log.L.WithFields(logrus.Fields{
"remoteAddress": remoteAddr,
"userAgent": userAgent,
"method": req.Method,
}).Warning("client accessed websocket handler with an invalid request method")
http.Error(rw, "Method not allowed", 405)
return
}
// Upgrade to a websocket.
ws, err := upgrader.Upgrade(rw, req, nil)
if err != nil {
log.L.WithFields(logrus.Fields{
"remoteAddress": remoteAddr,
"userAgent": userAgent,
}).Warningf("failed to upgrade to websocket layer: %v", err)
http.Error(rw, "Bad Request", 400)
return
}
// Create a new websocket value.
w := newWebSocket(ws)
// Set the user agent.
w.userAgent = userAgent
// Set the remote address get function.
if requestRemoteAddrMethodUsed {
// Obtain the remote address from the websocket directly.
w.remoteAddrFunc = func() string {
return utils.RemovePortFromRemoteAddr(w.ws.RemoteAddr().String())
}
} else {
// Obtain the remote address from the current string.
// It was obtained using the request Headers. So don't use the
// websocket RemoteAddr() method, because it does not return
// the clients IP address.
w.remoteAddrFunc = func() string {
return remoteAddr
}
}
// Start the handlers in new goroutines.
go w.writeLoop()
go w.readLoop()
// Trigger the event that a new socket connection was made.
triggerOnNewSocketConnection(w)
}
// ServeHTTP implements the HTTP Handler interface of the http package.
func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Get the URL path.
path := r.URL.Path
// Call this in an inline function to handle errors.
err := func() error {
// Strip the base URL.
if len(path) < s.httpURLStripLength {
return fmt.Errorf("invalid request")
}
path = path[s.httpURLStripLength:]
// Route the HTTP request in a very simple way by comparing the strings.
if path == httpURLWebSocketSuffix {
// Handle the websocket request.
s.webSocketServer.HandleRequest(w, r)
} else if path == httpURLAjaxSocketSuffix {
// Handle the ajax request.
s.ajaxSocketServer.HandleRequest(w, r)
} else {
return fmt.Errorf("invalid request")
}
return nil
}()
// Handle the error.
if err != nil {
// Get the remote address and user agent.
remoteAddr, _ := utils.RemoteAddress(r)
userAgent := r.Header.Get("User-Agent")
// Log the invalid request.
log.L.WithFields(logrus.Fields{
"remoteAddress": remoteAddr,
"userAgent": userAgent,
"url": r.URL.Path,
}).Warningf("handle HTTP request: %v", err)
http.Error(w, "Bad Request", 400)
}
}
func (s *Server) HandleRequest(w http.ResponseWriter, req *http.Request) {
// Get the remote address and user agent.
remoteAddr, _ := utils.RemoteAddress(req)
userAgent := req.Header.Get("User-Agent")
// Get the request body data.
body, err := ioutil.ReadAll(req.Body)
if err != nil {
log.L.WithFields(logrus.Fields{
"remoteAddress": remoteAddr,
"userAgent": userAgent,
}).Warningf("failed to read ajax request body: %v", err)
http.Error(w, "Internal Server Error", 500)
return
}
// Check for bad requests.
if req.Method != "POST" {
log.L.WithFields(logrus.Fields{
"remoteAddress": remoteAddr,
"userAgent": userAgent,
}).Warningf("client accessed the ajax interface with an invalid http method: %s", req.Method)
http.Error(w, "Bad Request", 400)
return
}
// Get the request body as string.
data := string(body)
// Get the head of the body data delimited by an delimiter.
var head string
i := strings.Index(data, ajaxSocketDataDelimiter)
if i < 0 {
// There is no delimiter. The complete data is the head.
head = data
data = ""
} else {
// Extract the head.
head = data[:i]
data = data[i+1:]
}
// Validate the head length.
if len(head) < ajaxSocketDataKeyLength {
log.L.WithFields(logrus.Fields{
"remoteAddress": remoteAddr,
"userAgent": userAgent,
}).Warningf("ajax: head data is too short: '%s'", head)
http.Error(w, "Bad Request", 400)
return
}
// The head is split into key and value.
key := head[:ajaxSocketDataKeyLength]
value := head[ajaxSocketDataKeyLength:]
// Handle the specific request.
switch key {
case ajaxSocketDataKeyInit:
s.initAjaxRequest(remoteAddr, userAgent, w)
case ajaxSocketDataKeyPoll:
s.pollAjaxRequest(value, remoteAddr, userAgent, data, w)
case ajaxSocketDataKeyPush:
s.pushAjaxRequest(value, remoteAddr, userAgent, data, w)
default:
log.L.WithFields(logrus.Fields{
"remoteAddress": remoteAddr,
"userAgent": userAgent,
"key": key,
"value": value,
}).Warningf("ajax: invalid request.")
http.Error(w, "Bad Request", 400)
return
}
}