Create app.py

app.py

@@ -0,0 +1,60 @@
+from fastapi import FastAPI, Request, HTTPException
+from fastapi.responses import PlainTextResponse
+import os
+import requests
+
+# Default model used internally; the client only sends plain text
+DEFAULT_MODEL = "kwaipilot/kat-coder-pro:free"
+
+app = FastAPI()
+
+@app.get("/")
+def health():
+    return {"status": "ok"}
+
+@app.post("/chat")
+async def chat(request: Request):
+    # Accept plain text body; fallback to JSON {"text": "..."}
+    body = await request.body()
+    text = (body or b"").decode().strip()
+    if not text:
+        try:
+            data = await request.json()
+            text = str(data.get("text", "")).strip()
+        except Exception:
+            pass
+    if not text:
+        raise HTTPException(status_code=400, detail="Send plain text body or JSON {'text': '...'}")
+
+    api_key = os.getenv("OPENROUTER_API_KEY")
+    if not api_key:
+        raise HTTPException(status_code=500, detail="OPENROUTER_API_KEY not set")
+
+    try:
+        r = requests.post(
+            "https://openrouter.ai/api/v1/chat/completions",  # OpenRouter chat completions [web:21]
+            headers={
+                "Authorization": f"Bearer {api_key}",
+                "Content-Type": "application/json",
+            },
+            json={
+                "model": DEFAULT_MODEL,
+                "messages": [{"role": "user", "content": text}],
+            },
+            timeout=60,
+        )
+    except requests.RequestException as e:
+        raise HTTPException(status_code=502, detail=str(e))
+
+    # Try to extract assistant text; if not possible, return the raw body from OpenRouter
+    content = None
+    try:
+        data = r.json()
+        if r.status_code >= 400:
+            return PlainTextResponse(str(data), status_code=r.status_code)
+        content = data["choices"][0]["message"]["content"]
+    except Exception:
+        # Fall back to raw text (may be JSON or error text)
+        return PlainTextResponse(r.text, status_code=r.status_code)
+
+    return PlainTextResponse(content)