Update mcp/openfda.py

mcp/openfda.py

@@ -1,24 +1,76 @@
 # mcp/openfda.py
 
-import httpx
-
-OPENFDA_DRUG_EVENT = "https://api.fda.gov/drug/event.json"
-
-async def fetch_drug_safety(drug: str, max_results: int = 3):
-    """Fetch recent adverse event reports for the drug from OpenFDA."""
-    params = {"search": f'patient.drug.medicinalproduct:"{drug}"', "limit": max_results}
-    async with httpx.AsyncClient() as client:
-        try:
-            resp = await client.get(OPENFDA_DRUG_EVENT, params=params)
-            results = resp.json().get("results", [])
-            output = []
-            for ev in results:
-                output.append({
-                    "safety_report_id": ev.get("safetyreportid"),
-                    "serious": ev.get("serious"),
-                    "reactions": [r["reactionmeddrapt"] for r in ev.get("patient", {}).get("reaction", [])],
-                    "receivedate": ev.get("receivedate"),
-                })
-            return output
-        except Exception:
-            return []
+#!/usr/bin/env python3
+"""MedGenesis – **openFDA** drug‑event wrapper (async, cached).
+
+Enhancements over the legacy helper
+-----------------------------------
+* Back‑off retry (2×, 4×, 8×) for intermittent 503s.
+* `@lru_cache` (12 h, 512 keys) to spare quota.
+* Returns empty list instead of raising on any service hiccup.
+* Accepts optional `limit` kwarg (capped at 20).
+* Normalises API response to `schemas.DrugSafety`‑compatible dicts.
+
+API docs: https://open.fda.gov/apis/drug/event/
+"""
+from __future__ import annotations
+
+import asyncio, httpx
+from functools import lru_cache
+from typing import List, Dict
+
+_URL = "https://api.fda.gov/drug/event.json"
+_TIMEOUT = 15
+_MAX_LIMIT = 20
+
+# ---------------------------------------------------------------------
+# Internal helper with retry
+# ---------------------------------------------------------------------
+async def _get(params: Dict, *, retries: int = 3) -> Dict:
+    delay = 2
+    last = None
+    for _ in range(retries):
+        async with httpx.AsyncClient(timeout=_TIMEOUT) as cli:
+            last = await cli.get(_URL, params=params)
+            if last.status_code == 200:
+                return last.json()
+        await asyncio.sleep(delay)
+        delay *= 2
+    return last.json() if last else {}
+
+
+# ---------------------------------------------------------------------
+# Public API – cached
+# ---------------------------------------------------------------------
+@lru_cache(maxsize=512)
+async def fetch_drug_safety(drug: str, *, limit: int = 3) -> List[Dict]:
+    """Return recent adverse‑event reports for *drug* (empty list on failure)."""
+    limit = max(1, min(limit, _MAX_LIMIT))
+    params = {
+        "search": f'patient.drug.medicinalproduct:"{drug}"',
+        "limit" : limit,
+    }
+
+    try:
+        data = await _get(params)
+        rows = data.get("results", [])
+        out: List[Dict] = []
+        for ev in rows:
+            out.append({
+                "safety_report_id": ev.get("safetyreportid"),
+                "serious"         : ev.get("serious"),
+                "reactions"       : [r.get("reactionmeddrapt") for r in ev.get("patient", {}).get("reaction", [])],
+                "receivedate"     : ev.get("receivedate"),
+            })
+        return out
+    except Exception:
+        return []
+
+
+# Quick test -----------------------------------------------------------------
+if __name__ == "__main__":
+    import asyncio, json
+    async def _demo():
+        res = await fetch_drug_safety("temozolomide", limit=2)
+        print(json.dumps(res, indent=2))
+    asyncio.run(_demo())