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| """Serve the original music studio and proxy StepFun using a Space Secret.""" | |
| import asyncio | |
| import os | |
| import time | |
| from collections import deque | |
| from pathlib import Path | |
| import httpx | |
| from fastapi import FastAPI, Request | |
| from fastapi.responses import JSONResponse, RedirectResponse | |
| from fastapi.staticfiles import StaticFiles | |
| app = FastAPI(docs_url=None, redoc_url=None, openapi_url=None) | |
| UPSTREAM = 'https://api.stepfun.com' | |
| MAX_BODY = 30 * 1024 * 1024 | |
| submissions = deque() | |
| submit_lock = asyncio.Lock() | |
| def error(status: int, kind: str, message: str) -> JSONResponse: | |
| return JSONResponse({'error': {'type': kind, 'message': message}}, status_code=status) | |
| async def studio(): | |
| return RedirectResponse('/studio/app.html') | |
| async def health() -> dict: | |
| return {'status': 'ok', 'configured': bool(os.environ.get('STEPFUN_API_KEY'))} | |
| async def music(action: str, request: Request): | |
| """Forward only music submission and polling; never return the API key.""" | |
| if action not in ('submit', 'query'): | |
| return error(404, 'not_found', 'Unknown endpoint') | |
| key = os.environ.get('STEPFUN_API_KEY', '').strip() | |
| if not key: | |
| return error(503, 'service_unavailable', 'Music service is not configured yet') | |
| raw = bytearray() | |
| async for chunk in request.stream(): | |
| raw.extend(chunk) | |
| if len(raw) > MAX_BODY: | |
| return error(413, 'request_params_invalid', 'Payload too large') | |
| import json | |
| try: | |
| body = json.loads(raw) | |
| if not isinstance(body, dict): | |
| raise ValueError() | |
| except (ValueError, UnicodeDecodeError): | |
| return error(400, 'request_params_invalid', 'Expected a JSON object') | |
| if action == 'submit': | |
| if body.get('task') not in ('text_to_music', 'vocal_to_music', 'music_cover'): | |
| return error(400, 'request_params_invalid', 'Unsupported task') | |
| if not isinstance(body.get('caption'), str) or not body['caption'].strip(): | |
| return error(400, 'request_params_invalid', 'Caption is required') | |
| body['model_id'] = 'step-music' | |
| async with submit_lock: | |
| now = time.monotonic() | |
| while submissions and submissions[0] < now - 60: | |
| submissions.popleft() | |
| if len(submissions) >= int(os.environ.get('SUBMITS_PER_MINUTE', '6')): | |
| return error(429, 'rate_limited', 'Please wait before generating again') | |
| submissions.append(now) | |
| elif not isinstance(body.get('task_id'), str) or not body['task_id']: | |
| return error(400, 'request_params_invalid', 'Task ID is required') | |
| try: | |
| async with httpx.AsyncClient(timeout=httpx.Timeout(230, connect=15)) as client: | |
| res = await client.post(f'{UPSTREAM}/v1/audio/music/{action}', json=body, | |
| headers={'Authorization': f'Bearer {key}'}) | |
| payload = res.json() | |
| # Never echo upstream error messages or arbitrary response headers. | |
| if res.is_error: | |
| kind = payload.get('error', {}).get('type', 'service_unavailable') | |
| if kind not in ('not_allowed', 'request_params_invalid', 'model_invalid', 'rate_limited', 'service_unavailable'): | |
| kind = 'service_unavailable' | |
| return error(res.status_code, kind, 'Music API request failed') | |
| return JSONResponse(payload, headers={'Cache-Control': 'no-store'}) | |
| except (httpx.HTTPError, ValueError): | |
| return error(502, 'service_unavailable', 'Music API is temporarily unavailable') | |
| app.mount('/studio', StaticFiles(directory=Path(__file__).parent / 'static', html=True), name='studio') | |