add exec_shellCmd func + improve doc

README.md

@@ -72,11 +72,37 @@ JETSONJSCLIENT.send_value({
 })
 ```
 
-`JETSONJSCLIENT.shutdown()` : shutdown the Jetson. It is an hardware shutdown (equivalent to the Unix command `shutdown -h now`)
-
+`JETSONJSCLIENT.exec_shellCmd()` : execute a shell command. It can be useful to switch ON/OFF the Jetson GPIOs
 
+`JETSONJSCLIENT.shutdown()` : shutdown the Jetson. It is an hardware shutdown (equivalent to the Unix command `shutdown -h now`)
 
 
+### Final webapp
+The final web application (not running in the Jetson but on the user's browser) connects to the Jetson through websockets and get the values.
+There is no buffering : if a value is sent from the Jetson when the user is not connected, this value will be lost. We would rather drop some values than introducing a latency. The [test application](/test/index.html), served statically by the NodeJS server on port 3000 show how to connect externally to the Jetson websocket server and read the values :
+```javascript
+var socket=new WebSocket('ws://'+jetsonIP+':8888') //port hould be server.serviceExtWSPort in settings.js
+
+// Connection opened
+socket.addEventListener('open', function (event) {
+	console.log('Connected!')
+});
+
+// Listen for messages
+var domLogs=document.getElementById('logs');
+domLogs.value='';
+socket.addEventListener('message', function (event) {
+    var dataParsed=JSON.parse(event.data);
+    var typeLabel=dataParsed.t;
+    var data=dataParsed.m;
+
+    switch(typeLabel){
+    	case 'VAL':
+    		domLogs.value+=JSON.stringify(data)+'\n'
+    		break;
+    }
+});
+```
 
 
 
@@ -96,4 +122,4 @@ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLI
 ## References
 * [Jeeliz official website](https://jeeliz.com)
 * [Nvidia Jetson Download center](https://developer.nvidia.com/embedded/downloads)
-
+* Nvidia Jetson GPIOS (eLinux.org): [hardware](https://elinux.org/Jetson/GPIO), [software](https://elinux.org/Jetson/Tutorials/GPIO)

client/JetsonJSClient.js

@@ -274,6 +274,13 @@ const JETSONJSCLIENT=(function(){
 			}
 		},
 
+		'exec_shellCmd': function(cmd){
+			if (_state!==_states.idle){
+				return false
+			}
+			return send('SHELLCMD', cmd)
+		},
+
 		'shutdown': function(){
 			console.log('INFO in JetsonJSClient.js : shutdown() launched. THE DEVICE WILL SHUTDOWN BRO!!!')
 			send('CMD', 'SHUTDOWN')

server/services/AppWS.js

@@ -67,13 +67,20 @@ const onMessage=(typeLabel, dataDict)=>{
 			console.log('INFO in AppWS : CMD received - CMD =', dataDict)
 			switch(dataDict){
 				case 'SHUTDOWN':
-				exec('shutdown -h now', (isSuccess)=>{
-
+				exec('shutdown -h now', (isSuccess, stdOut, stdErr)=>{
+					
 				})
 				break
 			}
 			break;
 
+		case 'SHELLCMD':
+			console.log('INFO in AppWS : SHELLCMD received - SHELLCMD =', dataDict)
+			exec(dataDict, (isSuccess, stdOut, stdErr)=>{
+
+				})
+			break
+
 		default:
 			console.log('WARNING in AppWS - onMessage : unknow message type ', typeLabel)
 		break
@@ -84,15 +91,15 @@ const exec_cmd=(shellCmd, callback)=>{
 	exec(shellCmd, (err, stdout, stderr) => {
 	  if (err) {
 	  	console.log('WARNING in AppWS - exec_cmd() : cannot execute the command ', shellCmd, 'err =', err)
-	  	callback(false)
+	  	callback(false, '', '')
 	    return
 	  }
 
 	  // the *entire* stdout and stderr (buffered)
 	  console.log('INFO in AppWS - exec_cmd() : ', shellCmd, 'results:')
 	  console.log(`stdout: ${stdout}`)
 	  console.log(`stderr: ${stderr}`)
-	  callback(true)
+	  callback(true, stdout, stderr)
 	})
 }