feat : server response cache

server/sources/cache.py

@@ -0,0 +1,36 @@
+import os
+import json
+from pathlib import Path
+
+class Cache:
+    def __init__(self, cache_dir='.cache', cache_file='messages.json'):
+        self.cache_dir = Path(cache_dir)
+        self.cache_file = self.cache_dir / cache_file
+        self.cache_dir.mkdir(parents=True, exist_ok=True)
+        if not self.cache_file.exists():
+            with open(self.cache_file, 'w') as f:
+                json.dump([], f)
+
+        with open(self.cache_file, 'r') as f:
+            self.cache = set(json.load(f))
+
+    def add_message_pair(self, user_message: str, assistant_message: str):
+        """Add a user/assistant pair to the cache if not present."""
+        if not any(entry["user"] == user_message for entry in self.cache):
+            self.cache.append({"user": user_message, "assistant": assistant_message})
+            self._save()
+
+    def is_cached(self, user_message: str) -> bool:
+        """Check if a user msg is cached."""
+        return any(entry["user"] == user_message for entry in self.cache)
+
+    def get_cached_response(self, user_message: str) -> str | None:
+        """Return the assistant response to a user message if cached."""
+        for entry in self.cache:
+            if entry["user"] == user_message:
+                return entry["assistant"]
+        return None
+
+    def _save(self):
+        with open(self.cache_file, 'w') as f:
+            json.dump(self.cache, f, indent=2)