Better socket handling, loadfile api update for mpv 0.38.0

backend/src/MediaPlayer.ts

@@ -38,8 +38,9 @@ enum UserEvent {
 }
 
 export class MediaPlayer { 
-    private playerProcess: ChildProcess;
-    private socket: Socket;
+    private playerProcess: ChildProcess | null = null;
+    private socket: Promise<Socket>;
+    
     private eventSubscribers: WebSocket[] = [];
     private favoritesStore: FavoritesStore;
 
@@ -49,9 +50,19 @@ export class MediaPlayer {
     private metadata: Map<string, LinkMetadata> = new Map();
 
     constructor() {
+        this.socket = this.tryRespawnPlayerProcess();
+        
+        this.favoritesStore = new FavoritesStore();
+        this.favoritesStore.onFavoritesChanged = (favorites) => {
+            this.handleEvent(UserEvent.FavoritesUpdate, { favorites });
+        };
+    }
+
+    private tryRespawnPlayerProcess(): Promise<Socket> {
         const socketFilename = Math.random().toString(36).substring(2, 10);
         const socketPath = `/tmp/mpv-${socketFilename}`;
         const enableVideo = process.env.ENABLE_VIDEO || false;
+        const logfilePath = `/tmp/mpv-logfile.txt`;
 
         console.log("Starting player process (video: " + (enableVideo ? "enabled" : "disabled") + ")");
         this.playerProcess = spawn("mpv", [
@@ -59,22 +70,26 @@ export class MediaPlayer {
             "--fullscreen",
             "--no-terminal",
             "--idle=yes",
-            "--input-ipc-server=" + socketPath
+            "--input-ipc-server=" + socketPath,
+            "--log-file=" + logfilePath,
+            "--msg-level=all=v"
         ]);
 
-        this.socket = new Socket();
+        
+        let socketReady!: (s: Socket) => void;
+        let socketPromise = new Promise<Socket>(resolve => {
+            socketReady = resolve;
+        });
         
         this.playerProcess.on("spawn", () => {
             console.log(`Player process spawned, opening socket @ ${socketPath}`);
             setTimeout(() => {
-                this.connectToSocket(socketPath);
+                let socket = this.connectToSocket(socketPath);
+                socketReady(socket);
             }, 500);
         });
 
-        this.favoritesStore = new FavoritesStore();
-        this.favoritesStore.onFavoritesChanged = (favorites) => {
-            this.handleEvent(UserEvent.FavoritesUpdate, { favorites });
-        };
+        return socketPromise;
     }
 
     public async getPlaylist(): Promise<PlaylistItem[]> {
@@ -247,7 +262,7 @@ export class MediaPlayer {
     }
 
     private async loadFile(url: string, mode: string, fetchMetadata: boolean = true, options: string[] = []) {
-        this.modify(UserEvent.PlaylistUpdate, () => this.writeCommand("loadfile", [url, mode, options.join(',')]));
+        this.modify(UserEvent.PlaylistUpdate, () => this.writeCommand("loadfile", [url, mode, "-1", options.join(',')]));
 
         if (fetchMetadata) {
             this.fetchMetadataAndNotify(url).catch(error => {
@@ -266,6 +281,9 @@ export class MediaPlayer {
     }
     
     private async writeCommand(command: string, args: any[]): Promise<any> {
+        // Wait for socket to become available. 
+        let socket = await this.socket;
+
         return new Promise((resolve, reject) => {
             const id = this.requestId++;
             
@@ -274,8 +292,13 @@ export class MediaPlayer {
                 request_id: id
             });
 
-            this.pendingCommands.set(id, { resolve, reject });
-            this.socket.write(commandObject + '\n');
+            try {
+                this.pendingCommands.set(id, { resolve, reject });
+                socket.write(commandObject + '\n');
+            } catch (e: any) {
+                console.error(`Error writing to socket: ${e}. Trying to respawn.`)
+                this.tryRespawnPlayerProcess();
+            }
 
             // Add timeout to prevent hanging promises
             setTimeout(() => {
@@ -313,9 +336,12 @@ export class MediaPlayer {
         }
     }
 
-    private connectToSocket(path: string) {
-        this.socket.connect(path);
-        this.socket.on("data", data => this.receiveData(data.toString()));
+    private connectToSocket(path: string): Socket {
+        let socket = new Socket();
+        socket.connect(path);
+        socket.on("data", data => this.receiveData(data.toString()));
+
+        return socket;
     }
 
     private handleEvent(event: string, data: any) {