feat: Location-based routing

Author: Deskehs

server/handlers/mr.ts

@@ -16,19 +16,21 @@ const OPCODES = {
 async function handleIdentify(socket: any, packet: any) {
   const public_ip = packet.d.public_ip;
   const public_port = packet.d.public_port;
+  const lat = packet.d.lat || 0;
+  const lon = packet.d.lon || 0;
   const timestamp = packet.d.timestamp;
 
   global.mrServer.debug(`New media server has connected! Added to internal store.`);
 
-  //to-do find a proper & fast way to lookup these public ips to serve whats close to a user
-
   socket.public_ip = public_ip;
   socket.public_port = public_port;
   socket.emitter = new EventEmitter();
 
   global.mrServer.servers.set(public_ip, {
     socket: socket,
     port: public_port,
+    lat: lat,
+    lon: lon,
     seen_at: timestamp,
   });
 

server/handlers/rtc.ts

@@ -110,7 +110,26 @@ async function handleIdentify(socket: any, packet: any) {
       }),
     );
   } else {
-    const mediaServer = global.mrServer.getRandomMediaServer();
+    let lat = 0;
+    let lon = 0;
+    
+    try {
+        const userIp = socket._socket.remoteAddress || socket.upgradeReq?.connection?.remoteAddress;
+        if (userIp && userIp !== '127.0.0.1' && userIp !== '::1') {
+             const response = await fetch(`http://ip-api.com/json/${userIp}`);
+             if (response.ok) {
+                 const data = await response.json() as any;
+                 if (data.status === 'success') {
+                     lat = data.lat;
+                     lon = data.lon;
+                 }
+             }
+        }
+    } catch (e) {
+        // Ignore
+    }
+
+    const mediaServer = global.mrServer.getClosestMediaServer(lat, lon);
 
     if (mediaServer === null) {
       return;

server/protocol/mrserver.ts

@@ -15,7 +15,7 @@ const mrServer = {
       return;
     }
 
-    logText(message, 'MRA_CLIENT');
+    logText(message, 'MPA_CLIENT');
   },
   getRandomMediaServer() {
     const serverEntries = Array.from(this.servers.entries());
@@ -35,6 +35,58 @@ const mrServer = {
       port: serverObject.port,
     };
   },
+  getClosestMediaServer(lat, lon) {
+    const serverEntries = Array.from(this.servers.entries());
+
+    if (serverEntries.length === 0) {
+      return null;
+    }
+
+    if (!lat || !lon) {
+        return this.getRandomMediaServer();
+    }
+
+    let closestServer: any = null;
+    let minDistance = Infinity;
+
+    function getDistanceFromLatLonInKm(lat1, lon1, lat2, lon2) {
+        var R = 6371;
+        var dLat = deg2rad(lat2-lat1);
+        var dLon = deg2rad(lon2-lon1); 
+        var a = 
+            Math.sin(dLat/2) * Math.sin(dLat/2) +
+            Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * 
+            Math.sin(dLon/2) * Math.sin(dLon/2)
+            ; 
+        var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
+        var d = R * c;
+        return d;
+    }
+
+    function deg2rad(deg) {
+        return deg * (Math.PI/180)
+    }
+
+    for (const [ip, server] of serverEntries) {
+        if (server.lat === 0 && server.lon === 0) continue;
+
+        const dist = getDistanceFromLatLonInKm(lat, lon, server.lat, server.lon);
+        if (dist < minDistance) {
+            minDistance = dist;
+            closestServer = {
+                ip: ip,
+                socket: server.socket,
+                port: server.port
+            };
+        }
+    }
+
+    if (!closestServer) {
+        return this.getRandomMediaServer();
+    }
+
+    return closestServer;
+  },
   async handleClientConnect(socket) {
     this.debug(`Connected to a media server`);