Scripts to download files from google storage based on sha1 sums

third_party/gsutil/boto/contrib/m2helpers.py

+# Copyright (c) 2006,2007 Jon Colverson
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish, dis-
+# tribute, sublicense, and/or sell copies of the Software, and to permit
+# persons to whom the Software is furnished to do so, subject to the fol-
+# lowing conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
+# ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+# SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
+# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
+
+"""
+This module was contributed by Jon Colverson.  It provides a couple of helper
+functions that allow you to use M2Crypto's implementation of HTTPSConnection
+rather than the default version in httplib.py.  The main benefit is that
+M2Crypto's version verifies the certificate of the server.
+
+To use this feature, do something like this:
+
+from boto.ec2.connection import EC2Connection
+
+ec2 = EC2Connection(ACCESS_KEY_ID, SECRET_ACCESS_KEY,
+    https_connection_factory=https_connection_factory(cafile=CA_FILE))
+
+See http://code.google.com/p/boto/issues/detail?id=57 for more details.
+"""
+from M2Crypto import SSL
+from M2Crypto.httpslib import HTTPSConnection
+
+def secure_context(cafile=None, capath=None):
+    ctx = SSL.Context()
+    ctx.set_verify(SSL.verify_peer | SSL.verify_fail_if_no_peer_cert, depth=9)
+    if ctx.load_verify_locations(cafile=cafile, capath=capath) != 1:
+        raise Exception("Couldn't load certificates")
+    return ctx
+
+def https_connection_factory(cafile=None, capath=None):
+    def factory(*args, **kwargs):
+        return HTTPSConnection(
+            ssl_context=secure_context(cafile=cafile, capath=capath),
+                *args, **kwargs)
+    return (factory, (SSL.SSLError,))