init

backend/src/agent/app.py

@@ -0,0 +1,61 @@
+# mypy: disable - error - code = "no-untyped-def,misc"
+import pathlib
+from fastapi import FastAPI, Request, Response
+from fastapi.staticfiles import StaticFiles
+import fastapi.exceptions
+
+# Define the FastAPI app
+app = FastAPI()
+
+
+def create_frontend_router(build_dir="../frontend/dist"):
+    """Creates a router to serve the React frontend.
+
+    Args:
+        build_dir: Path to the React build directory relative to this file.
+
+    Returns:
+        A Starlette application serving the frontend.
+    """
+    build_path = pathlib.Path(__file__).parent.parent.parent / build_dir
+    static_files_path = build_path / "assets"  # Vite uses 'assets' subdir
+
+    if not build_path.is_dir() or not (build_path / "index.html").is_file():
+        print(
+            f"WARN: Frontend build directory not found or incomplete at {build_path}. Serving frontend will likely fail."
+        )
+        # Return a dummy router if build isn't ready
+        from starlette.routing import Route
+
+        async def dummy_frontend(request):
+            return Response(
+                "Frontend not built. Run 'npm run build' in the frontend directory.",
+                media_type="text/plain",
+                status_code=503,
+            )
+
+        return Route("/{path:path}", endpoint=dummy_frontend)
+
+    build_dir = pathlib.Path(build_dir)
+
+    react = FastAPI(openapi_url="")
+    react.mount(
+        "/assets", StaticFiles(directory=static_files_path), name="static_assets"
+    )
+
+    @react.get("/{path:path}")
+    async def handle_catch_all(request: Request, path: str):
+        fp = build_path / path
+        if not fp.exists() or not fp.is_file():
+            fp = build_path / "index.html"
+        return fastapi.responses.FileResponse(fp)
+
+    return react
+
+
+# Mount the frontend under /app to not conflict with the LangGraph API routes
+app.mount(
+    "/app",
+    create_frontend_router(),
+    name="frontend",
+)