fastapi: implement server with same back compatibility as before

server/reflector/app.py

@@ -0,0 +1,15 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from reflector.views.rtc_offer import router as rtc_offer_router
+
+# build app
+app = FastAPI()
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# register views
+app.include_router(rtc_offer_router)