initial commit

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 = Buffer.from([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.
+        })
+    })
+
+}