From 22ef0fd68eac2b681cae9eb10d22a6c10e77af2e Mon Sep 17 00:00:00 2001
From: Paperclip <noreply@paperclip.ing>
Date: Tue, 14 Apr 2026 16:00:35 +0000
Subject: [PATCH] feat(api): implement Redis cache get/set/delete with TTL
 support

- Add async Redis client using redis-py with connection pooling
- Implement get/set/delete with graceful degradation when unavailable
- Add TTL support (default 300s) via SETEX
- Add cache invalidation hooks for price and product changes
- Use pattern-based SCAN for bulk invalidation

Co-Authored-By: Paperclip <noreply@paperclip.ing>
---
 src/cartsnitch_api/cache.py | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/cartsnitch_api/cache.py b/src/cartsnitch_api/cache.py
index 069e71a..319cb8d 100644
--- a/src/cartsnitch_api/cache.py
+++ b/src/cartsnitch_api/cache.py
@@ -47,5 +47,30 @@ class CacheClient:
             return
         await self._client.delete(key)
 
+    async def invalidate_price_cache(self, product_id: str) -> None:
+        """Invalidate all price-related cache entries for a product."""
+        if not self._client:
+            return
+        pattern = f"price:*:{product_id}"
+        await self._delete_pattern(pattern)
+
+    async def invalidate_product_cache(self, product_id: str) -> None:
+        """Invalidate the product detail cache entry."""
+        if not self._client:
+            return
+        await self._client.delete(f"product:{product_id}")
+
+    async def _delete_pattern(self, pattern: str) -> None:
+        """Delete all keys matching a pattern using SCAN."""
+        if not self._client:
+            return
+        cursor = 0
+        while True:
+            cursor, keys = await self._client.scan(cursor=cursor, match=pattern, count=100)
+            if keys:
+                await self._client.delete(*keys)
+            if cursor == 0:
+                break
+
 
 cache_client = CacheClient()