add experimental json key stuff

Author: Fabien Coelho

CacheToolsUtils.py

@@ -451,6 +451,38 @@ def cacheFunctions(
         globs[fun] = cached(cache=gen(cache, prefix))(f)
 
 
+# JSON-based key function
+# NOTE obviously this only works if parameters are json-serializable…
+def json_key(*args, **kwargs):
+    if kwargs:
+        return json.dumps({"*": args, "**": kwargs}, sort_keys=True)
+    else:  # array
+        return json.dumps(args)
+
+
+# Hmmm…
+class _HashJsonKey:
+    """A cache key with a persistant hash value."""
+
+    def __init__(self, *args, **kwargs):
+        self._hashed = None
+        self._args = args
+        self._kwargs = kwargs
+        self._key = json_key(*args, **kwargs)
+
+    def __hash__(self):
+        if self._hashed is None:
+            self._hashed = self._key.__hash__()
+        return self._hashed
+
+    def __str__(self):
+        return self._key
+
+
+def hash_json_key(*args, **kwargs):
+    return _HashJsonKey(*args, **kwargs)
+
+
 #
 # MEMCACHED
 #

README.md

@@ -7,7 +7,7 @@ Classes to add key prefix and stats to
 and other cache-related utils.
 
 ![Status](https://github.com/zx80/cachetools-utils/actions/workflows/cachetools-utils.yml/badge.svg?branch=main&style=flat)
-![Tests](https://img.shields.io/badge/tests-19%20✓-success)
+![Tests](https://img.shields.io/badge/tests-20%20✓-success)
 ![Coverage](https://img.shields.io/badge/coverage-100%25-success)
 ![Issues](https://img.shields.io/github/issues/zx80/cachetools-utils?style=flat)
 ![Python](https://img.shields.io/badge/python-3-informational)

docs/VERSIONS.md

@@ -19,6 +19,11 @@ Install [package](https://pypi.org/project/CacheToolsUtils/) from
   Maybe the existing client can do that with appropriate options?
 - `cached`: add `contains` and `delete` parameters to change names?
 
+## ? on ?
+
+Improve documentation.
+Add experimental `json_key` and `hash_json_key` cache key functions.
+
 ## 9.0 on 2024-10-27
 
 Add `stats` method to return a convenient `dict` of statistics.

test.py

@@ -25,29 +25,50 @@ def has_service(host="localhost", port=22):
         tcp_ip.close()
 
 
-def cached_fun(cache, cached=ct.cached):
+def cached_fun(cache, cached=ct.cached, key=ct.keys.hashkey):
     """return a cached function with basic types."""
 
-    @cached(cache=cache)
+    @cached(cache=cache, key=key)
     def fun(i: int, s: str|None, b: bool) -> int:
         return i + (10 * len(s) if s is not None else -20) + (100 if b else 0)
 
     return fun
 
+# reset cache contents and stats
+def reset_cache(cache):
+    try:
+        cache.clear()
+    except:  # fails on redis
+        pass
+    if hasattr(cache, "_cache") and hasattr(cache._cache, "reset"):
+        cache._cache.reset()
+    if hasattr(cache, "_cache2") and hasattr(cache._cache2, "reset"):
+        cache._cache2.reset()
+
+
+def run_cached_keys(cache):
+
+    for cached in (ct.cached, ctu.cached):
+        for keyfun in (ct.keys.hashkey, ct.keys.typedkey, ctu.hash_json_key, ctu.json_key):
+            reset_cache(cache)
+            fun = cached_fun(cache, cached, key=keyfun)
+            x = 0
+            for n in range(10):
+                for i in range(5):
+                    for s in ["a", "bb", "ccc", "", None]:
+                        for b in [False, True]:
+                            v = fun(i, s, b)
+                            # log.debug(f"fun{(i, s, b)} = {v} {type(v)}")
+                            x += v
+            assert x == 30000
+
 
 def run_cached(cache):
     """run something on a cached function."""
 
     for cached in (ct.cached, ctu.cached):
         # reset cache contents and stats
-        try:
-            cache.clear()
-        except:  # fails on redis
-            pass
-        if hasattr(cache._cache, "reset"):
-            cache._cache.reset()
-        if hasattr(cache, "_cache2") and hasattr(cache._cache2, "reset"):
-            cache._cache2.reset()
+        reset_cache(cache)
         fun = cached_fun(cache, cached)
         x = 0
         for n in range(10):
@@ -145,6 +166,14 @@ def test_stats_ct():
     setgetdel(cache)
 
 
+def test_caches():
+    n = 0
+    for Cache in (ct.LRUCache, ct.FIFOCache, ct.LFUCache, ct.RRCache):
+        n += 1
+        cache = Cache(maxsize=1024)
+        run_cached_keys(cache)
+    assert n == 4
+
 @pytest.mark.skipif(
     not has_service(port=11211),
     reason="no local memcached service available for testing",