only try to play files that exist

app.py

@@ -208,19 +208,21 @@ def api_nowplaying():
 
 @app.route("/api/play/<filename>", methods=["POST"])
 def api_play_file(filename: str, error_str: str = "Could not play file '{filename}'"):
-    if not is_playing():
-        playback_start()
+    full_filename = music_path.joinpath(filename)
+    if full_filename.exists():
+        if not is_playing():
+            playback_start()
 
-    sock = mpv_socket_open()
-    if sock is not None:
-        mpv_socket_command(
-            sock, {"command": ["loadfile", str(music_path.joinpath(filename))]}
-        )
-        sock.close()
+        sock = mpv_socket_open()
+        if sock is not None:
+            mpv_socket_command(
+                sock, {"command": ["loadfile", str(full_filename)]}
+            )
+            sock.close()
 
-        time.sleep(0.1)
-        if is_playing():
-            return jsonify("ok")
+            time.sleep(0.1)
+            if is_playing():
+                return jsonify("ok")
 
     return jsonify(error_str.format(filename=filename)), 500