Added: new function to FileBaseCaching, check() and refactored functions in caches.py

django/core/cache/backends/base.py

@@ -388,8 +388,11 @@ class BaseCache:
     async def aclose(self, **kwargs):
         pass
 
-    def check(self):
-        return []
+    def check(self, **kwargs):
+        raise NotImplementedError(
+            "subclasses may provide a check() method to verify the finder is "
+            "configured correctly."
+        )
 
 memcached_error_chars_re = _lazy_re_compile(r"[\x00-\x20\x7f]")
 

django/core/cache/backends/filebased.py

@@ -2,6 +2,7 @@
 import glob
 import os
 import pickle
+import pathlib
 import random
 import tempfile
 import time
@@ -11,7 +12,7 @@ from hashlib import md5
 from django.core.cache.backends.base import DEFAULT_TIMEOUT, BaseCache
 from django.core.files import locks
 from django.core.files.move import file_move_safe
-
+from django.core.checks import Warning
 
 class FileBasedCache(BaseCache):
     cache_suffix = ".djcache"
@@ -168,3 +169,21 @@ class FileBasedCache(BaseCache):
             os.path.join(self._dir, fname)
             for fname in glob.glob1(self._dir, "*%s" % self.cache_suffix)
         ]
+
+    @classmethod
+    def check(cls, cache, paths, name, alias_name='default'):
+        cache_path = pathlib.Path(cache._dir).resolve()
+        if any(path == cache_path for path in paths):
+            relation = "matches"
+        elif any(path in cache_path.parents for path in paths):
+            relation = "is inside"
+        elif any(cache_path in path.parents for path in paths):
+            relation = "contains"
+        else:
+            return None
+
+        return Warning(
+                    f"Your '{alias_name}' cache configuration might expose your cache "
+                    f"or lead to corruption of your data because its LOCATION "
+                    f"{relation} {name}.", id="caches.W002",
+                )

django/core/checks/caches.py

@@ -1,4 +1,5 @@
 import pathlib
+import json
 
 from django.conf import settings
 from django.core.cache import DEFAULT_CACHE_ALIAS, caches
@@ -21,6 +22,16 @@ def check_default_cache_is_configured(app_configs, **kwargs):
 
 @register(Tags.caches, deploy=True)
 def check_cache_location_not_exposed(app_configs, **kwargs):
+    cache = None
+    alias_name = ''
+    for alias, config in settings.CACHES.items():
+        if config.get('BACKEND').endswith("FileBasedCache"):
+            cache = caches[alias]
+            alias_name = alias
+
+    if cache is None:
+        return []
+
     errors = []
     for name in ("MEDIA_ROOT", "STATIC_ROOT", "STATICFILES_DIRS"):
         setting = getattr(settings, name, None)
@@ -34,43 +45,27 @@ def check_cache_location_not_exposed(app_configs, **kwargs):
                 paths.add(pathlib.Path(staticfiles_dir).resolve())
         else:
             paths = {pathlib.Path(setting).resolve()}
-        for alias in settings.CACHES:
-            cache = caches[alias]
-            if not isinstance(cache, FileBasedCache):
-                continue
-            cache_path = pathlib.Path(cache._dir).resolve()
-            if any(path == cache_path for path in paths):
-                relation = "matches"
-            elif any(path in cache_path.parents for path in paths):
-                relation = "is inside"
-            elif any(cache_path in path.parents for path in paths):
-                relation = "contains"
-            else:
-                continue
-            errors.append(
-                Warning(
-                    f"Your '{alias}' cache configuration might expose your cache "
-                    f"or lead to corruption of your data because its LOCATION "
-                    f"{relation} {name}.",
-                    id="caches.W002",
-                )
-            )
+
+        check_result = FileBasedCache.check(cache, paths, name, alias_name)
+        errors.append(check_result) if check_result else []
+
     return errors
 
 
 @register(Tags.caches)
 def check_file_based_cache_is_absolute(app_configs, **kwargs):
-    errors = []
+    alias_name = None
+    location = None
     for alias, config in settings.CACHES.items():
-        cache = caches[alias]
-        if not isinstance(cache, FileBasedCache):
-            continue
-        if not pathlib.Path(config["LOCATION"]).is_absolute():
-            errors.append(
-                Warning(
-                    f"Your '{alias}' cache LOCATION path is relative. Use an "
-                    f"absolute path instead.",
-                    id="caches.W003",
-                )
+        if config.get('BACKEND').endswith("FileBasedCache"):
+            alias_name = alias
+            location = config
+
+    if alias_name is not None and not pathlib.Path(location.get("LOCATION")).is_absolute():
+        return Warning(
+                f"Your '{alias_name}' cache LOCATION path is relative. Use an "
+                f"absolute path instead.",
+                id="caches.W003",
             )
-    return errors
+
+    return []