--- a/fetch/main.py	Sun Sep 18 18:27:57 2011 -0700
+++ b/fetch/main.py	Sun Sep 18 18:37:02 2011 -0700
@@ -8,6 +8,8 @@
 import sys
 import optparse
 
+__all__ = ['Fetcher', 'FileFetcher', 'main']
+
 class Fetcher(object):
   """abstract base class for resource fetchers"""
 
@@ -21,8 +23,11 @@
   def __call__(self, dest):
     raise NotImplementedError
 
+### standard dispatchers - always available
 
+import tarfile
 import urllib2
+from StringIO import StringIO
 
 class FileFetcher(Fetcher):
   """fetch a single file"""
@@ -47,6 +52,14 @@
 
   type = 'tar'
 
+  def __call__(self, dest):
+    assert os.path.isdir(dest)
+    buffer = StringIO()
+    buffer.write(self.download(self.url))
+    buffer.seek(0)
+    tf = tarfile.open(mode='r', fileobj=buffer)
+    tf.extract(dest)
+
 class HgFetcher(Fetcher):
   """checkout a mercurial repository"""