Layers: Allow handler to avoid caching

volatility3/framework/layers/resources.py

@@ -13,7 +13,7 @@ import ssl
 import urllib.parse
 import urllib.request
 import zipfile
-from typing import Optional, Any, IO
+from typing import Optional, Any, IO, List
 from urllib import error
 
 from volatility3 import framework
@@ -79,7 +79,15 @@ class ResourceAccessor(object):
         """Determines whether a URLs contents should be cached"""
         parsed_url = urllib.parse.urlparse(url)
 
-        return not parsed_url.scheme in ['file', 'jar']
+        return not parsed_url.scheme in self._non_cached_schemes()
+
+    @staticmethod
+    def _non_cached_schemes() -> List[str]:
+        """Returns the list of schemes not to be cached"""
+        result = ['file']
+        for clazz in framework.class_subclasses(VolatilityHandler):
+            result += clazz.non_cached_schemes()
+        return result
 
     # Current urllib.request.urlopen returns Any, so we do the same
     def open(self, url: str, mode: str = "rb") -> Any:
@@ -201,7 +209,14 @@ class ResourceAccessor(object):
         return curfile
 
 
-class JarHandler(urllib.request.BaseHandler):
+class VolatilityHandler(urllib.request.BaseHandler):
+
+    @classmethod
+    def non_cached_schemes(cls) -> List[str]:
+        return []
+
+
+class JarHandler(VolatilityHandler):
     """Handles the jar scheme for URIs.
 
     Reference used for the schema syntax:
@@ -211,6 +226,10 @@ class JarHandler(urllib.request.BaseHandler):
     http://developer.java.sun.com/developer/onlineTraining/protocolhandlers/
     """
 
+    @classmethod
+    def non_cached_schemes(cls) -> List[str]:
+        return ['jar']
+
     @staticmethod
     def default_open(req: urllib.request.Request) -> Optional[Any]:
         """Handles the request if it's the jar scheme."""