diff --git a/webagg/aggregator.py b/webagg/aggregator.py
index 0f148492..cb7cf10a 100644
--- a/webagg/aggregator.py
+++ b/webagg/aggregator.py
@@ -221,24 +221,53 @@ class BaseDirectoryIndexSource(BaseAggregator):
 
     def _load_files(self, glob_dir):
         for the_dir in glob.iglob(glob_dir):
-            for name in os.listdir(the_dir):
-                filename = os.path.join(the_dir, name)
+            for result in self._load_files_single_dir(the_dir):
+                yield result
 
-                if filename.endswith(self.CDX_EXT):
-                    print('Adding ' + filename)
-                    rel_path = os.path.relpath(the_dir, self.base_prefix)
-                    if rel_path == '.':
-                        full_name = name
-                    else:
-                        full_name = rel_path + '/' + name
+    def _load_files_single_dir(self, the_dir):
+        for name in os.listdir(the_dir):
+            filename = os.path.join(the_dir, name)
 
-                    yield full_name, FileIndexSource(filename)
+            if filename.endswith(self.CDX_EXT):
+                print('Adding ' + filename)
+                rel_path = os.path.relpath(the_dir, self.base_prefix)
+                if rel_path == '.':
+                    full_name = name
+                else:
+                    full_name = rel_path + '/' + name
+
+                yield full_name, FileIndexSource(filename)
 
     def __str__(self):
         return 'file_dir'
 
 
+#=============================================================================
 class DirectoryIndexSource(SeqAggMixin, BaseDirectoryIndexSource):
     pass
 
 
+#=============================================================================
+class CacheDirectoryIndexSource(DirectoryIndexSource):
+    def __init__(self, *args, **kwargs):
+        super(CacheDirectoryIndexSource, self).__init__(*args, **kwargs)
+        self.cached_file_list = {}
+
+    def _load_files_single_dir(self, the_dir):
+        try:
+            stat = os.stat(the_dir)
+        except Exception as e:
+            stat = 0
+
+        result = self.cached_file_list.get(the_dir)
+
+        if result:
+            last_stat, files = result
+            if stat and last_stat == stat:
+                print('Dir {0} unchanged'.format(the_dir))
+                return files
+
+        files = super(CacheDirectoryIndexSource, self)._load_files_single_dir(the_dir)
+        files = list(files)
+        self.cached_file_list[the_dir] = (stat, files)
+        return files
diff --git a/webagg/responseloader.py b/webagg/responseloader.py
index 4e7aeaf3..94a1f153 100644
--- a/webagg/responseloader.py
+++ b/webagg/responseloader.py
@@ -254,7 +254,7 @@ class LiveWebLoader(BaseLoader):
 
         try:
             fp = upstream_res.raw._fp.fp
-            if hasattr(fp, 'raw'):
+            if hasattr(fp, 'raw'):  #pragma: no cover
                 fp = fp.raw
             remote_ip = fp._sock.getpeername()[0]
         except:  #pragma: no cover
diff --git a/webagg/test/test_dir_agg.py b/webagg/test/test_dir_agg.py
index b55d3755..0da78bf3 100644
--- a/webagg/test/test_dir_agg.py
+++ b/webagg/test/test_dir_agg.py
@@ -7,7 +7,10 @@ from .testutils import to_path, to_json_list, TempDirTests, BaseTestClass
 
 from mock import patch
 
-from webagg.aggregator import DirectoryIndexSource, SimpleAggregator
+import time
+
+from webagg.aggregator import DirectoryIndexSource, CacheDirectoryIndexSource
+from webagg.aggregator import SimpleAggregator
 from webagg.indexsource import MementoIndexSource
 
 
@@ -44,6 +47,7 @@ class TestDirAgg(TempDirTests, BaseTestClass):
             fh.write('foo')
 
         cls.dir_loader = DirectoryIndexSource(dir_prefix, dir_path)
+        cls.cache_dir_loader = CacheDirectoryIndexSource(dir_prefix, dir_path)
 
     def test_agg_no_coll_set(self):
         res, errs = self.dir_loader(dict(url='example.com/'))
@@ -188,3 +192,25 @@ class TestDirAgg(TempDirTests, BaseTestClass):
 
 
 
+    def test_cache_dir_sources_1(self):
+        exp = {'sources': {'colls/A/indexes/example.cdxj': 'file',
+                           'colls/B/indexes/iana.cdxj': 'file',
+                           'colls/C/indexes/dupes.cdxj': 'file'}
+              }
+
+        res = self.cache_dir_loader.get_source_list({'url': 'example.com/', 'param.coll': '*'})
+        assert(res == exp)
+
+        res = self.cache_dir_loader.get_source_list({'url': 'example.com/', 'param.coll': '*'})
+        assert(res == exp)
+
+        new_file = os.path.join(self.root_dir, 'colls/C/indexes/empty.cdxj')
+
+        with open(new_file, 'a') as fh:
+            os.utime(new_file)
+
+        res = self.cache_dir_loader.get_source_list({'url': 'example.com/', 'param.coll': '*'})
+
+        # New File Included
+        exp['sources']['colls/C/indexes/empty.cdxj'] = 'file'
+        assert(res == exp)
diff --git a/webagg/test/test_upstream.py b/webagg/test/test_upstream.py
index 037b62e9..cd107811 100644
--- a/webagg/test/test_upstream.py
+++ b/webagg/test/test_upstream.py
@@ -36,7 +36,7 @@ class TestUpstream(LiveServerTests, BaseTestClass):
 
     def test_live_paths(self):
         res = requests.get(self.base_url + '/')
-        assert set(res.json().keys()) == {'/live/postreq', '/live'}
+        assert set(res.json().keys()) == {'/live/postreq', '/live', '/replay/postreq', '/replay'}
 
     def test_upstream_paths(self):
         res = self.testapp.get('/')
diff --git a/webagg/test/testutils.py b/webagg/test/testutils.py
index 4c5c42b6..c46e17f1 100644
--- a/webagg/test/testutils.py
+++ b/webagg/test/testutils.py
@@ -7,7 +7,7 @@ from multiprocessing import Process
 
 from wsgiref.simple_server import make_server
 
-from webagg.aggregator import SimpleAggregator
+from webagg.aggregator import SimpleAggregator, CacheDirectoryIndexSource
 from webagg.app import ResAggApp
 from webagg.handlers import DefaultResourceHandler
 from webagg.indexsource import LiveIndexSource
@@ -66,6 +66,12 @@ class LiveServerTests(object):
                                    {'live': LiveIndexSource()})
             )
         )
+        app.add_route('/replay',
+            DefaultResourceHandler(SimpleAggregator(
+                                   {'replay': CacheDirectoryIndexSource('./testdata/')}),
+                                   './testdata/'
+            )
+        )
         return app.application
 
     @classmethod