feat: add auto-start functionality for last used audio device on server startup

src/auracast/server/multicast_server.py

@@ -7,6 +7,8 @@ import sys
 from datetime import datetime
 import asyncio
 import numpy as np
+from dotenv import load_dotenv
+
 from pydantic import BaseModel
 from fastapi import FastAPI, HTTPException
 from fastapi.middleware.cors import CORSMiddleware
@@ -21,7 +23,7 @@ from auracast.utils.sounddevice_utils import (
     list_usb_pw_inputs,
     list_network_pw_inputs,
 )
-
+load_dotenv()
 
 PTIME = 40 # TODO: seems to have no effect at all
 pcs: Set[RTCPeerConnection] = set()      # keep refs so they don’t GC early
@@ -85,22 +87,19 @@ global_config_group = auracast_config.AuracastConfigGroup()
 multicaster1: multicast_control.Multicaster | None = None
 multicaster2: multicast_control.Multicaster | None = None
 
+
+# Raspberry Pi UART transports
+TRANSPORT1 = os.getenv('TRANSPORT1', 'serial:/dev/ttyAMA3,1000000,rtscts')  # transport for raspberry pi gpio header
+TRANSPORT2 = os.getenv('TRANSPORT2', 'serial:/dev/ttyAMA4,1000000,rtscts')  # transport for raspberry pi gpio header
+
 @app.post("/init")
 async def initialize(conf: auracast_config.AuracastConfigGroup):
     """Initializes the primary broadcaster (multicaster1)."""
     global global_config_group
     global multicaster1
     try:
-        if conf.transport == 'auto':
-            serial_devices = glob.glob('/dev/serial/by-id/*')
-            log.info('Found serial devices: %s', serial_devices)
-            for device in serial_devices:
-                if 'usb-ZEPHYR_Zephyr_HCI_UART_sample' in device:
-                    log.info('Using: %s', device)
-                    conf.transport = f'serial:{device},115200,rtscts'
-                    break
-        if conf.transport == 'auto':
-            raise HTTPException(status_code=500, detail='No suitable transport found.')
+
+        conf.transport = TRANSPORT1
         # Derive audio_mode and input_device from first BIG audio_source
         first_source = conf.bigs[0].audio_source if conf.bigs else ''
         if first_source.startswith('device:'):
@@ -132,6 +131,8 @@ async def initialize(conf: auracast_config.AuracastConfigGroup):
             'input_device': input_device_name,
             'program_info': [getattr(big, 'program_info', None) for big in conf.bigs],
             'gain': [getattr(big, 'input_gain', 1.0) for big in conf.bigs],
+            'auracast_sampling_rate_hz': conf.auracast_sampling_rate_hz,
+            'octets_per_frame': conf.octets_per_frame,
             'timestamp': datetime.utcnow().isoformat()
         })
         global_config_group = conf
@@ -155,16 +156,7 @@ async def initialize2(conf: auracast_config.AuracastConfigGroup):
     """Initializes the secondary broadcaster (multicaster2). Does NOT persist stream settings."""
     global multicaster2
     try:
-        if conf.transport == 'auto':
-            serial_devices = glob.glob('/dev/serial/by-id/*')
-            log.info('Found serial devices: %s', serial_devices)
-            for device in serial_devices:
-                if 'usb-ZEPHYR_Zephyr_HCI_UART_sample' in device:
-                    log.info('Using: %s', device)
-                    conf.transport = f'serial:{device},115200,rtscts'
-                    break
-        if conf.transport == 'auto':
-            raise HTTPException(status_code=500, detail='No suitable transport found.')
+        conf.transport = TRANSPORT2
         # Patch device name to index for sounddevice
         for big in conf.bigs:
             if big.audio_source.startswith('device:'):
@@ -242,6 +234,90 @@ async def get_status():
     return status
 
 
+async def _autostart_from_settings():
+    """Background task: auto-start last selected device-based input at server startup.
+
+    Skips Webapp (webrtc) and Demo (file) modes. Polls every 2 seconds until the
+    saved device name appears in either USB or Network lists, then builds a config
+    and initializes streaming.
+    """
+    try:
+        settings = load_stream_settings() or {}
+        audio_mode = settings.get('audio_mode')
+        input_device_name = settings.get('input_device')
+        rate = settings.get('auracast_sampling_rate_hz')
+        octets = settings.get('octets_per_frame')
+        channel_names = settings.get('channel_names') or ["Broadcast0"]
+        program_info = settings.get('program_info') or channel_names
+        languages = settings.get('languages') or ["deu"]
+        original_ts = settings.get('timestamp')
+
+        # Only auto-start device-based inputs; Webapp and Demo require external sources/UI
+        if not input_device_name:
+            return
+        if rate is None or octets is None:
+            # Not enough info to reconstruct stream reliably
+            return
+
+        # Avoid duplicate start if already streaming
+        if multicaster1 and multicaster1.get_status().get('is_streaming'):
+            return
+
+        while True:
+            try:
+                # Do not interfere if user started a stream manually in the meantime
+                if multicaster1 and multicaster1.get_status().get('is_streaming'):
+                    return
+                # Abort if saved settings changed to a different target while we were polling
+                current_settings = load_stream_settings() or {}
+                if current_settings.get('timestamp') != original_ts:
+                    # Settings were updated (likely by user via /init)
+                    # If the target device or mode changed, stop autostart
+                    if (
+                        current_settings.get('input_device') != input_device_name or
+                        current_settings.get('audio_mode') != audio_mode
+                    ):
+                        return
+                # Avoid refreshing PortAudio while we poll
+                usb = [d for _, d in list_usb_pw_inputs(refresh=False)]
+                net = [d for _, d in list_network_pw_inputs(refresh=False)]
+                names = {d.get('name') for d in usb} | {d.get('name') for d in net}
+                if input_device_name in names:
+                    # Build a minimal config based on saved fields
+                    bigs = [
+                        auracast_config.AuracastBigConfig(
+                            name=channel_names[0] if channel_names else "Broadcast0",
+                            program_info=program_info[0] if isinstance(program_info, list) and program_info else program_info,
+                            language=languages[0] if languages else "deu",
+                            audio_source=f"device:{input_device_name}",
+                            input_format=f"int16le,{rate},1",
+                            iso_que_len=1,
+                            sampling_frequency=rate,
+                            octets_per_frame=octets,
+                        )
+                    ]
+                    conf = auracast_config.AuracastConfigGroup(
+                        auracast_sampling_rate_hz=rate,
+                        octets_per_frame=octets,
+                        transport=TRANSPORT1,
+                        bigs=bigs,
+                    )
+                    # Initialize and start
+                    await initialize(conf)
+                    return
+            except Exception:
+                log.warning("Autostart polling encountered an error", exc_info=True)
+            await asyncio.sleep(2)
+    except Exception:
+        log.warning("Autostart task failed", exc_info=True)
+
+
+@app.on_event("startup")
+async def _startup_autostart_event():
+    # Spawn the autostart task without blocking startup
+    asyncio.create_task(_autostart_from_settings())
+
+
 @app.post("/refresh_audio_inputs")
 async def refresh_audio_inputs(force: bool = False):
     """Triggers a re-scan of audio devices.