Remove unused cache engines (#12765)

Author: manrajs1

openlibrary/core/cache.py

@@ -25,7 +25,6 @@
     "Cache",
     "MemcacheCache",
     "MemoryCache",
-    "RequestCache",
     "get_memcache",
     "memcache_memoize",
     "memoize",
@@ -267,7 +266,11 @@ def delete(self, key):
 
 
 class MemoryCache(Cache):
-    """Cache implementation in memory."""
+    """Cache implementation in memory.
+
+    Note: expires is ignored. Values stay until deleted or cleared.
+    Use MemcacheCache if you need expiration.
+    """
 
     def __init__(self):
         self.d = {}
@@ -354,32 +357,8 @@ def delete(self, key):
         return value
 
 
-class RequestCache(Cache):
-    """Request-Local cache.
-
-    The values are cached only in the context of the current request.
-    """
-
-    @property
-    def d(self):
-        return web.ctx.setdefault("request-local-cache", {})
-
-    def get(self, key):
-        return self.d.get(key)
-
-    def set(self, key, value, expires=0):
-        self.d[key] = value
-
-    def add(self, key, value, expires=0):
-        return self.d.setdefault(key, value) is value
-
-    def delete(self, key):
-        return self.d.pop(key, None) is not None
-
-
 memory_cache = MemoryCache()
 memcache_cache = MemcacheCache()
-request_cache = RequestCache()
 
 
 def get_memcache():
@@ -390,8 +369,6 @@ def _get_cache(engine):
     d = {
         "memory": memory_cache,
         "memcache": memcache_cache,
-        "memcache+memory": memcache_cache,
-        "request": request_cache,
     }
     return d.get(engine)
 
@@ -411,7 +388,6 @@ def some_func(args):
         Engine to store the results. Available options are:
             * memory: stores the result in memory.
             * memcache: stores the result in memcached.
-            * request: stores the result only in the context of the current request.
 
     * key:
         key to be used in the cache. If this is a string, arguments are append
@@ -453,7 +429,7 @@ def get_page(key):
 
     def __init__(
         self,
-        engine: Literal["memory", "memcache", "request"],
+        engine: Literal["memory", "memcache"],
         key: str | Callable[..., str | tuple],
         expires: int = 0,
         background: bool = False,