Added server status retrieval and implemented it on UI.

The player count on the landing page is now functional. If the server cannot be reached, the label and value will change to SERVER and OFFLINE, respectively. This behavior can be modified.

app/assets/js/actionbinder.js

@@ -6,8 +6,11 @@ const ConfigManager = require(path.join(__dirname, 'assets', 'js', 'configmanage
 const DiscordWrapper = require(path.join(__dirname, 'assets', 'js', 'discordwrapper.js'))
 const Mojang = require(path.join(__dirname, 'assets', 'js', 'mojang.js'))
 const AuthManager = require(path.join(__dirname, 'assets', 'js', 'authmanager.js'))
+const ServerStatus = require(path.join(__dirname, 'assets', 'js', 'serverstatus.js'))
+const {URL} = require('url')
 
 let mojangStatusListener
+let serverStatusListener
 
 // Launch Elements
 let launch_content, launch_details, launch_progress, launch_progress_label, launch_details_text
@@ -86,9 +89,36 @@ document.addEventListener('readystatechange', function(){
             document.getElementById('mojang_status_icon').style.color = Mojang.statusToHex(status)
         }
 
+        const refreshServerStatus = async function(){
+            console.log('Refreshing Server Status')
+            const serv = AssetGuard.resolveSelectedServer(ConfigManager.getGameDirectory())
+
+            let pLabel = 'SERVER'
+            let pVal = 'OFFLINE'
+
+            try {
+                console.log(serv)
+                const serverURL = new URL('my://' + serv.server_ip)
+                const servStat = await ServerStatus.getStatus(serverURL.hostname, serverURL.port)
+                if(servStat.online){
+                    pLabel = 'PLAYERS'
+                    pVal = servStat.onlinePlayers + '/' + servStat.maxPlayers
+                }
+
+            } catch (err) {
+                console.warn('Unable to refresh server status, assuming offline.')
+                console.debug(err)
+            }
+            document.getElementById('landingPlayerLabel').innerHTML = pLabel
+            document.getElementById('player_count').innerHTML = pVal
+        }
+
         refreshMojangStatuses()
+        refreshServerStatus()
+
         // Set refresh rate to once every 5 minutes.
         mojangStatusListener = setInterval(refreshMojangStatuses, 300000)
+        serverStatusListener = setInterval(refreshServerStatus, 300000)
 
     }
 }, false)

app/assets/js/assetguard.js

@@ -421,11 +421,11 @@ class AssetGuard extends EventEmitter {
         const servers = distro.servers
         for(let i=0; i<servers.length; i++){
             if(servers[i].default_selected){
-                return servers[i].id
+                return servers[i]
             }
         }
         // If no server declares default_selected, default to the first one declared.
-        return (servers.length > 0) ? servers[0].id : null
+        return (servers.length > 0) ? servers[0] : null
     }
 
     /**

app/assets/js/preloader.js

@@ -15,7 +15,7 @@ AssetGuard.retrieveDistributionDataSync(ConfigManager.getGameDirectory(), false)
 // Resolve the selected server if its value has yet to be set.
 if(ConfigManager.getSelectedServer() == null){
     console.log('Determining default selected server..')
-    ConfigManager.setSelectedServer(AssetGuard.resolveSelectedServer(ConfigManager.getGameDirectory()))
+    ConfigManager.setSelectedServer(AssetGuard.resolveSelectedServer(ConfigManager.getGameDirectory()).id)
     ConfigManager.save()
 }
 

app/assets/js/serverstatus.js

@@ -0,0 +1,65 @@
+const net = require('net')
+
+/**
+ * Retrieves the status of a minecraft server.
+ * 
+ * @param {string} address The server address.
+ * @param {number} port Optional. The port of the server. Defaults to 25565.
+ * @returns {Promise.<Object>} A promise which resolves to an object containing
+ * status information.
+ */
+exports.getStatus = function(address, port = 25565){
+
+    if(port == null || port == ''){
+        port = 25565
+    }
+    if(typeof port === 'string'){
+        port = parseInt(port)
+    }
+
+    return new Promise((resolve, reject) => {
+        const socket = net.connect(port, address, () => {
+            let buff = new Buffer([0xFE, 0x01])
+            socket.write(buff)
+        })
+
+        socket.setTimeout(2500, () => {
+            socket.end()
+            reject({
+                code: 'ETIMEDOUT',
+                errno: 'ETIMEDOUT',
+                address,
+                port
+            })
+        })
+
+        socket.on('data', (data) => {
+            if(data != null && data != ''){
+                let server_info = data.toString().split('\x00\x00\x00')
+                const NUM_FIELDS = 6
+                if(server_info != null && server_info.length >= NUM_FIELDS){
+                    resolve({
+                        online: true,
+                        version: server_info[2].replace(/\u0000/g, ''),
+                        motd: server_info[3].replace(/\u0000/g, ''),
+                        onlinePlayers: server_info[4].replace(/\u0000/g, ''),
+                        maxPlayers: server_info[5].replace(/\u0000/g,'')
+                    })
+                } else {
+                    resolve({
+                        online: false
+                    })
+                }
+            }
+            socket.end()
+        })
+
+        socket.on('error', (err) => {
+            socket.destroy()
+            reject(err)
+            // ENOTFOUND = Unable to resolve.
+            // ECONNREFUSED = Unable to connect to port.
+        })
+    })
+
+}

app/landing.ejs

@@ -102,7 +102,7 @@
         <div id="left">
             <div class="bot_wrapper">
                 <div id="content">
-                    <span class="bot_label">PLAYERS</span>
+                    <span class="bot_label" id="landingPlayerLabel">PLAYERS</span>
                     <span id="player_count">18/100</span>
                     <div class="bot_divider"></div>
                     <span class="bot_label">MOJANG STATUS</span>