From 3abed698897f01f7b9d71675ea038e21bff39c56 Mon Sep 17 00:00:00 2001
From: "W. Trevor King" <wking@tremily.us>
Date: Sat, 21 Apr 2012 13:20:00 -0400
Subject: [PATCH] Add `allow_default_signer` to `sign_and_encrypt_bytes`.

This allows you to fall back to your configured default signer
(`default-key` in `~/.gnupg/gpg.conf`).  `sign_and_encrypt_bytes` will
sign (and possibly encrypt) content when either `signers` is non-empty
or `allow_default_signer` is set.

The signing PGP/MIME wrappers around `sign_and_encrypt_bytes` (`sign`
and `sign_and_encrypt`) both expose the new option to their callers.
---
 pgp_mime/crypt.py | 14 ++++++++------
 pgp_mime/pgp.py   | 10 ++++++----
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/pgp_mime/crypt.py b/pgp_mime/crypt.py
index d326d24..40d4572 100644
--- a/pgp_mime/crypt.py
+++ b/pgp_mime/crypt.py
@@ -72,7 +72,8 @@ def _write(fd, data):
 
 
 def sign_and_encrypt_bytes(data, signers=None, recipients=None,
-                           always_trust=False, mode='detach'):
+                           always_trust=False, mode='detach',
+                           allow_default_signer=False):
     r"""Sign ``data`` with ``signers`` and encrypt to ``recipients``.
 
     Just sign:
@@ -116,11 +117,12 @@ def sign_and_encrypt_bytes(data, signers=None, recipients=None,
         client.make_request(
             _common.Request('OUTPUT', 'FD={}'.format(output_write)))
         parameters = []
-        if signers and recipients:
-            command = 'SIGN_ENCRYPT'
-        elif signers:
-            command = 'SIGN'
-            parameters.append('--{}'.format(mode))
+        if signers or allow_default_signer:
+            if recipients:
+                command = 'SIGN_ENCRYPT'
+            else:
+                command = 'SIGN'
+                parameters.append('--{}'.format(mode))
         elif recipients:
             command = 'ENCRYPT'
         else:
diff --git a/pgp_mime/pgp.py b/pgp_mime/pgp.py
index 498428a..8a7df52 100644
--- a/pgp_mime/pgp.py
+++ b/pgp_mime/pgp.py
@@ -12,7 +12,7 @@ from .email import email_targets as _email_targets
 from .email import strip_bcc as _strip_bcc
 
 
-def sign(message, signers=None):
+def sign(message, signers=None, allow_default_signer=False):
     r"""Sign a ``Message``, returning the signed version.
 
     multipart/signed
@@ -92,7 +92,8 @@ def sign(message, signers=None):
     """
     body = message.as_string().encode('us-ascii')
     signature = str(_sign_and_encrypt_bytes(
-            data=body, signers=signers), 'us-ascii')
+            data=body, signers=signers,
+            allow_default_signer=allow_default_signer), 'us-ascii')
     sig = _MIMEApplication(
         _data=signature,
         _subtype='pgp-signature; name="signature.asc"',
@@ -202,7 +203,7 @@ def encrypt(message, recipients=None, always_trust=True):
     return msg
 
 def sign_and_encrypt(message, signers=None, recipients=None,
-                     always_trust=False):
+                     always_trust=False, allow_default_signer=False):
     r"""Sign and encrypt a ``Message``, returning the encrypted version.
 
     multipart/encrypted
@@ -278,7 +279,8 @@ def sign_and_encrypt(message, signers=None, recipients=None,
         _LOG.debug('extracted encryption recipients: {}'.format(recipients))
     encrypted = str(_sign_and_encrypt_bytes(
             data=body, signers=signers, recipients=recipients,
-            always_trust=always_trust), 'us-ascii')
+            always_trust=always_trust,
+            allow_default_signer=allow_default_signer), 'us-ascii')
     enc = _MIMEApplication(
         _data=encrypted,
         _subtype='octet-stream; name="encrypted.asc"',
-- 
2.26.2