[tor-commits] [bridgedb/master] Add crypto.gpgSignMessage() utility function.

[isis at torproject.org]

commit b2c7a2a20ca07dec8dd7c9a812f8173127c45b3a
Author: Isis Lovecruft <isis at torproject.org>
Date:   Wed Apr 16 22:41:48 2014 +0000

    Add crypto.gpgSignMessage() utility function.
---
 lib/bridgedb/EmailServer.py |    1 +
 lib/bridgedb/crypto.py      |   26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/lib/bridgedb/EmailServer.py b/lib/bridgedb/EmailServer.py
index eed96bf..65a3ccd 100644
--- a/lib/bridgedb/EmailServer.py
+++ b/lib/bridgedb/EmailServer.py
@@ -29,6 +29,7 @@ from bridgedb import Dist
 from bridgedb import I18n
 from bridgedb import safelog
 from bridgedb.crypto import getGPGContext
+from bridgedb.crypto import gpgSignMessage
 from bridgedb.Filters import filterBridgesByIP6
 from bridgedb.Filters import filterBridgesByIP4
 from bridgedb.Filters import filterBridgesByTransport
diff --git a/lib/bridgedb/crypto.py b/lib/bridgedb/crypto.py
index 5c68794..ebab733 100644
--- a/lib/bridgedb/crypto.py
+++ b/lib/bridgedb/crypto.py
@@ -347,6 +347,32 @@ def getGPGContext(cfg):
 
     return ctx
 
+def gpgSignMessage(gpgmeCtx, messageString, mode=None):
+    """Sign a **messageString** with a GPGME context.
+
+    :param gpgmeCtx: A ``gpgme.Context`` initialised with the appropriate
+        settings.
+    :param str messageString: The message to sign.
+    :param mode: The signing mode. (default: ``gpgme.SIG_MODE_CLEAR``)
+    :rtype: tuple
+    :returns: A 2-tuple of ``(signature, list)``, where:
+        * ``signature`` is the ascii-armored signature text.
+        * ``list`` is a list of ``gpgme.NewSignature``s.
+
+    .. warning:: The returned signature text and list *may* be empty, if no
+        signature was created.
+    """
+    if not mode:
+        mode = gpgme.SIG_MODE_CLEAR
+
+    msgFile = io.StringIO(unicode(messageString))
+    sigFile = io.StringIO()
+    sigList = gpgmeCtx.sign(msgFile, sigFile, mode)
+    sigFile.seek(0)
+    signature = sigFile.read()
+
+    return (signature, sigList)
+
 
 class SSLVerifyingContextFactory(ssl.CertificateOptions):
     """``OpenSSL.SSL.Context`` factory which does full certificate-chain and