Molodetz blogrol volgens DPP-template

molodetz/database/settings.py

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+# retoor <retoor@molodetz.nl>
+import logging
+
+from molodetz.cache import TTLCache
+from molodetz.constants import SETTINGS_DEFAULTS
+from molodetz.database.core import db, now_iso
+
+logger = logging.getLogger(__name__)
+
+_settings_cache = TTLCache(ttl=60, max_size=100)
+_version_cache = TTLCache(ttl=1, max_size=100)
+_local_versions = {}
+
+
+def read_cache_version(name):
+    cached = _version_cache.get(name)
+    if cached is not None:
+        return cached
+    try:
+        if "cache_state" not in db.tables:
+            return 0
+        row = db["cache_state"].find_one(name=name)
+        version = int(row["version"]) if row else 0
+    except Exception as exc:
+        logger.warning("cache version read failed for %s: %s", name, exc)
+        return 0
+    _version_cache.set(name, version)
+    return version
+
+
+def sync_local_cache(name, cache):
+    version = read_cache_version(name)
+    if _local_versions.get(name) != version:
+        cache.clear()
+        _local_versions[name] = version
+
+
+def bump_cache_version(name, cache=None):
+    try:
+        with db:
+            db.query(
+                "INSERT INTO cache_state (name, version, updated_at) VALUES (:name, 1, :stamp) "
+                "ON CONFLICT(name) DO UPDATE SET version = version + 1, updated_at = excluded.updated_at",
+                name=name,
+                stamp=now_iso(),
+            )
+    except Exception as exc:
+        logger.warning("cache version bump failed for %s: %s", name, exc)
+    _version_cache.pop(name)
+    if cache is not None:
+        cache.clear()
+    _local_versions.pop(name, None)
+
+
+def get_setting(key, default=None):
+    if default is None:
+        default = SETTINGS_DEFAULTS.get(key, "")
+    sync_local_cache("settings", _settings_cache)
+    cached = _settings_cache.get(key)
+    if cached is not None:
+        return cached
+    value = default
+    if "site_settings" in db.tables:
+        row = db["site_settings"].find_one(uid=f"setting_{key}")
+        if row is None:
+            row = db["site_settings"].find_one(uid=f"default_{key}")
+        if row is not None and row.get("value") is not None:
+            value = str(row["value"])
+    _settings_cache.set(key, value)
+    return value
+
+
+def get_int_setting(key, default):
+    try:
+        return int(get_setting(key, str(default)))
+    except (TypeError, ValueError):
+        return default
+
+
+def set_setting(key, value):
+    db["site_settings"].upsert(
+        {"uid": f"setting_{key}", "key": key, "value": str(value), "updated_at": now_iso()},
+        ["uid"],
+    )
+    bump_cache_version("settings", _settings_cache)
+
+
+def all_settings():
+    return {key: get_setting(key, default) for key, default in SETTINGS_DEFAULTS.items()}