212 lines
4.6 KiB
JavaScript
212 lines
4.6 KiB
JavaScript
/* classe client WebSocket */
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class WSClient{
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/* (1) Constructor
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*
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* @server_url<String> The url of the desired server
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* @channel_uri<String> The url of the desired channel
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*
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---------------------------------------------------------*/
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constructor(server_url, channel_uri){
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/* (1) Store & create data
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---------------------------------------------------------*/
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/* (1) Store the arguments */
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this.server_url = server_url;
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this.channel_uri = channel_uri;
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/* (2) Initialise event data */
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this.is_opened = false; // Set to TRUE when connection opened
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this.pending = null; // Next message to send through connection
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this.handler = []; // On reveice handlers
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/* (3) Create the websocket connection */
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this.ws = new WebSocket(this.server_url+'/'+channel_uri);
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/* (2) Bind events
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---------------------------------------------------------*/
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/* (1) OPEN: when connection is established */
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this.ws.onopen = this._onopen.bind(this);
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/* (2) MESSAGE: when message received */
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this.ws.onmessage = this._onmessage.bind(this);
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/* (3) ERROR: when websocket error */
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this.ws.onerror = this._onerror.bind(this);
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/* (4) CLOSE: when websocket closes */
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this.ws.onclose = this._onclose.bind(this);
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}
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/* (2) Binds a handle to the onReceive event (global only)
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*
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* @callback<Function> Callback function(message, error)
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*
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---------------------------------------------------------*/
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listen(callback){
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/* (1) Check @callback type (default value) */
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if( !(callback instanceof Function) )
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throw new Error('WSClient.bind(callback) expected argument *callback* to be a function');
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/* (2) Store callback */
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this.on_receive = callback;
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return this;
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}
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/* (3) Sends a message through the socket
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*
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* @message<String> The data to send
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* <Object> The data to send (will be serialized)
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*
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---------------------------------------------------------*/
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send(message){
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/* (1) Manage arguments
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---------------------------------------------------------*/
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/* (2) Check @message type */
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if( typeof message != 'string' && typeof message != 'object' ){
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this.on_receive(null, 'wrong message type');
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return this;
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}
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/* (2) Stringify JSON if object */
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if( typeof message == 'object' )
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message = JSON.stringify(message);
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/* (2) Send process
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---------------------------------------------------------*/
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/* (1) If not opened -> store message (will send when onopen()) */
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if( !this.is_opened )
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this.pending = message;
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/* (2) If already opened -> send now */
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else
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this.ws.send(message);
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return this;
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}
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/* (4) PRIVATE: Open handler
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*
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---------------------------------------------------------*/
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_onopen(){
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/* (1) Set @is_opened status variable */
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this.is_opened = true;
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/* (2) If message pending */
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if( this.pending != null ){
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this.ws.send(this.pending); // send message
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this.pending = null; // reset message (optional)
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}
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}
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/* (5) PRIVATE: Receive handler
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*
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---------------------------------------------------------*/
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_onmessage(msg_event){
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/* (1) If not trusted -> error */
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if( !msg_event.isTrusted ){
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this.on_receive(null, 'not trusted');
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return;
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}
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/* (2) If wrong origin -> error */
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if( msg_event.origin != this.server_url ){
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this.on_receive(null, 'unknown origin');
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return;
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}
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/* (3) Try to JSON parse */
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var parsedMsg = null;
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try{
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parsedMsg = JSON.parse(msg_event.data);
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}catch(e){
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this.on_receive(null, 'JSON error');
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return;
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}
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/* (4) If all right -> success */
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this.on_receive(parsedMsg, null);
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}
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/* (6) PRIVATE: Error handler
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*
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---------------------------------------------------------*/
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_onerror(){
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/* (1) Remove other handlers (only 1 error) */
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this.ws.onmessage = null;
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this.ws.onclose = null;
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/* (2) Send error */
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this.on_receive(null, 'websocket error');
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}
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/* (7) PRIVATE: Close handler
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*
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---------------------------------------------------------*/
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_onclose(){
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/* (1) Remove onmessage (not to catch messages) */
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this.ws.onmessage = null;
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/* (2) Send end */
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this.on_receive(null, 'websocket closed');
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}
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}
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class WSClientBuilder{
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/* (1) Constructor
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*
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* @server_url<String> The url of the desired server
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*
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---------------------------------------------------------*/
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constructor(server_url){
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/* (1) Store the server url */
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this.server_url = server_url;
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}
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/* (2) Builds a WSClient with desired channel
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*
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* @channel_uri<String> The uri of the desired channel
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*
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---------------------------------------------------------*/
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channel(channel_uri=''){
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return new WSClient(this.server_url, channel_uri);
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}
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}
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export{ WSClient, WSClientBuilder } |