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WebSocket simple example / server in go, client in JS
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| window.addEventListener("load", function(evt) { | |
| var output = document.getElementById("output"); | |
| var input = document.getElementById("input"); | |
| var ws; | |
| var print = function(message) { | |
| var d = document.createElement("div"); | |
| d.innerHTML = message; | |
| output.appendChild(d); | |
| }; | |
| document.getElementById("open").onclick = function(evt) { | |
| if (ws) { | |
| return false; | |
| } | |
| var loc = window.location, new_uri; | |
| if (loc.protocol === "https:") { | |
| new_uri = "wss:"; | |
| } else { | |
| new_uri = "ws:"; | |
| } | |
| new_uri += "//" + loc.host; | |
| new_uri += loc.pathname + "ws"; | |
| ws = new WebSocket(new_uri); | |
| ws.onopen = function(evt) { | |
| print("OPEN"); | |
| } | |
| ws.onclose = function(evt) { | |
| print("CLOSE"); | |
| ws = null; | |
| } | |
| ws.onmessage = function(evt) { | |
| print("RESPONSE: " + evt.data); | |
| } | |
| ws.onerror = function(evt) { | |
| print("ERROR: " + evt.data); | |
| } | |
| return false; | |
| }; | |
| document.getElementById("send").onclick = function(evt) { | |
| if (!ws) { | |
| return false; | |
| } | |
| print("SEND: " + input.value); | |
| ws.send(input.value); | |
| return false; | |
| }; | |
| document.getElementById("close").onclick = function(evt) { | |
| if (!ws) { | |
| return false; | |
| } | |
| ws.close(); | |
| return false; | |
| }; | |
| }); |
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| <!DOCTYPE html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <script type="text/javascript" src="app.js"></script> | |
| </head> | |
| <body> | |
| <table> | |
| <tr> | |
| <td valign="top" width="50%"> | |
| <p>Click "Open" to create a connection to the server, | |
| "Send" to send a message to the server and "Close" to close the connection. | |
| You can change the message and send multiple times. | |
| </p> | |
| <form> | |
| <button id="open">Open</button> | |
| <button id="close">Close</button> | |
| <p><input id="input" type="text" value="Hello world!"> | |
| <button id="send">Send</button> | |
| </form> | |
| </td> | |
| <td valign="top" width="50%"> | |
| <div id="output"></div> | |
| </td> | |
| </tr> | |
| </table> | |
| </body> | |
| </html> |
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| package main | |
| import ( | |
| "encoding/json" | |
| "errors" | |
| "github.com/gorilla/mux" | |
| "github.com/gorilla/websocket" | |
| "github.com/kelseyhightower/envconfig" | |
| "github.com/urfave/negroni" | |
| "log" | |
| "net/http" | |
| ) | |
| var ( | |
| config configuration | |
| upgrader = websocket.Upgrader{} // use default options | |
| ) | |
| type configuration struct { | |
| Debug bool `default:"true"` | |
| Scheme string `default:"http"` | |
| ListenAddress string `default:":8080"` | |
| PrivateKey string `default:"ssl/server.key"` | |
| Certificate string `default:"ssl/server.pem"` | |
| } | |
| type httpErr struct { | |
| Msg string `json:"msg"` | |
| Code int `json:"code"` | |
| } | |
| func handleErr(w http.ResponseWriter, err error, status int) { | |
| msg, err := json.Marshal(&httpErr{ | |
| Msg: err.Error(), | |
| Code: status, | |
| }) | |
| if err != nil { | |
| msg = []byte(err.Error()) | |
| } | |
| http.Error(w, string(msg), status) | |
| } | |
| func serveWs(w http.ResponseWriter, r *http.Request) { | |
| c, err := upgrader.Upgrade(w, r, nil) | |
| if err != nil { | |
| handleErr(w, err, http.StatusInternalServerError) | |
| return | |
| } | |
| defer c.Close() | |
| for { | |
| mt, msg, err := c.ReadMessage() | |
| if err != nil { | |
| handleErr(w, err, http.StatusInternalServerError) | |
| break | |
| } | |
| if mt != websocket.TextMessage { | |
| handleErr(w, errors.New("Only text message are supported"), http.StatusNotImplemented) | |
| break | |
| } | |
| var v message | |
| json.Unmarshal(msg, &v) | |
| err = c.WriteMessage(mt, []byte(msg)) | |
| if err != nil { | |
| handleErr(w, err, http.StatusInternalServerError) | |
| break | |
| } | |
| } | |
| } | |
| func main() { | |
| // Default values | |
| err := envconfig.Process("SOCKETCAM", &config) | |
| if err != nil { | |
| log.Fatal(err.Error()) | |
| } | |
| if config.Debug { | |
| log.Printf("==> SCHEME: %v", config.Scheme) | |
| log.Printf("==> ADDRESS: %v", config.ListenAddress) | |
| log.Printf("==> PRIVATEKEY: %v", config.PrivateKey) | |
| log.Printf("==> CERTIFICATE: %v", config.Certificate) | |
| } | |
| router := newRouter() | |
| n := negroni.Classic() | |
| n.UseHandler(router) | |
| if config.Scheme == "https" { | |
| log.Fatal(http.ListenAndServeTLS(config.ListenAddress, config.Certificate, config.PrivateKey, n)) | |
| } else { | |
| log.Fatal(http.ListenAndServe(config.ListenAddress, n)) | |
| } | |
| } | |
| // NewRouter is the constructor for all my routes | |
| func newRouter() *mux.Router { | |
| router := mux.NewRouter().StrictSlash(true) | |
| router. | |
| Methods("GET"). | |
| Path("/ws"). | |
| Name("Communication Channel"). | |
| HandlerFunc(serveWs) | |
| router. | |
| Methods("GET"). | |
| PathPrefix("/"). | |
| Name("Static"). | |
| Handler(http.FileServer(http.Dir("./htdocs"))) | |
| return router | |
| } |
Example don`t work, function c, err := upgrader.Upgrade(w, r, nil) always returns websocket: request origin not allowed by Upgrader.CheckOrigin
solutions
var wsUpgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool {
return true
},
}
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c, err := upgrader.Upgrade(w, r, nil)