Drop httplib2 in RemoteRepoCache, use custom HeadRequest and urllib2.

With a neat little trick, urllib2 can be made to only perform a HEAD
request in urllib2.urlopen(). This is done by creating a dedicated
HeadRequest class for HEAD requests and by passing such a HeadRequest to
urllib2.urlopen().

This also means we no longer have to check the response status ourselves
again as urllib2 will raise an exception on negative HTTP responses like
404 or 500.

1 files changed, 13 insertions, 6 deletions

diff --git a/morphlib/remoteartifactcache.py b/morphlib/remoteartifactcache.py
index 6df91a4e..e2101b5d 100644
--- a/morphlib/remoteartifactcache.py
+++ b/morphlib/remoteartifactcache.py
@@ -15,11 +15,16 @@
 
 
 import cliapp
-import httplib2
 import urllib2
 import urlparse
 
 
+class HeadRequest(urllib2.Request): # pragma: no cover
+
+    def get_method(self):
+        return 'HEAD'
+
+
 class GetError(cliapp.AppException):
 
     def __init__(self, cache, artifact):
@@ -81,10 +86,12 @@ class RemoteArtifactCache(object):
 
     def _has_file(self, filename): # pragma: no cover
         url = self._request_url(filename)
-        http = httplib2.Http()
-        response = http.request(url, 'HEAD')
-        status = response[0]['status']
-        return status >= 200 and status < 400
+        request = HeadRequest(url)
+        try:
+            urllib2.urlopen(request)
+            return True
+        except urllib2.HTTPError:
+            return False
 
     def _get_file(self, filename): # pragma: no cover
         url = self._request_url(filename)
@@ -95,4 +102,4 @@ class RemoteArtifactCache(object):
         if not server_url.endswith('/'):
             server_url += '/'
         return urlparse.urljoin(
-                server_url, '/1.0/artifacts/filename=%s' % filename)
+                server_url, '/1.0/artifacts?filename=%s' % filename)