Make togglesign accept an optional keyid (like 4AC8EE1D) which will be used for signing

4 files changed, 53 insertions, 5 deletions

diff --git a/alot/buffers.py b/alot/buffers.py
index 266b3e11..199bb6b2 100644
--- a/alot/buffers.py
+++ b/alot/buffers.py
@@ -123,7 +123,11 @@ class EnvelopeBuffer(Buffer):
 
         # sign/encrypt lines
         if self.envelope.sign:
-            self.crypto_wgt = widgets.HeadersList([ ('sign', 'yes') ])
+            description = 'yes'
+            sign_key = self.envelope.sign_key
+            if sign_key is not None and len(sign_key.subkeys) > 0:
+                description += ', with key ' + sign_key.subkeys[0].keyid
+            self.crypto_wgt = widgets.HeadersList([ ('sign', description) ])
             displayed_widgets.append(self.crypto_wgt)
 
         #display attachments
diff --git a/alot/commands/envelope.py b/alot/commands/envelope.py
index 7d3caceb..26271148 100644
--- a/alot/commands/envelope.py
+++ b/alot/commands/envelope.py
@@ -1,3 +1,4 @@
+import argparse
 import os
 import re
 import glob
@@ -11,6 +12,7 @@ from alot.account import SendingMailFailed
 from alot.db.errors import GPGProblem
 from alot import buffers
 from alot import commands
+from alot import crypto
 from alot.commands import Command, registerCommand
 from alot.commands import globals
 from alot.helper import string_decode
@@ -330,9 +332,26 @@ class ToggleHeaderCommand(Command):
         ui.current_buffer.toggle_all_headers()
 
 
-@registerCommand(MODE, 'togglesign')
+@registerCommand(MODE, 'togglesign', arguments=[
+    (['keyid'], {'nargs':argparse.REMAINDER, 'help':'which key id to use'})])
 class ToggleSignCommand(Command):
     """toggle signing this email"""
+    def __init__(self, keyid, **kwargs):
+        """
+        :param keyid: which key id to use
+        :type keyid: str
+        """
+        self.keyid = keyid
+        Command.__init__(self, **kwargs)
+
     def apply(self, ui):
+        if len(self.keyid) > 0:
+            keyid = str(' '.join(self.keyid))
+            try:
+                key = crypto.CryptoContext().get_key(keyid)
+            except GPGProblem, e:
+                ui.notify(e.message, priority='error')
+                return
+            ui.current_buffer.envelope.sign_key = key
         ui.current_buffer.envelope.sign = not ui.current_buffer.envelope.sign
         ui.current_buffer.rebuild()
diff --git a/alot/crypto.py b/alot/crypto.py
index 2e417060..b9196590 100644
--- a/alot/crypto.py
+++ b/alot/crypto.py
@@ -81,7 +81,26 @@ class CryptoContext(pyme.core.Context):
         self.set_engine_info(pyme.constants.PROTOCOL_OpenPGP, gpg_path)
         self.set_armor(1)
 
-    def detached_signature_for(self, plaintext_str):
+    def get_key(self, keyid):
+        """
+        Gets a key from the keyring by filtering for the specified keyid, but
+        only if the given keyid is specific enough (if it matches multiple
+        keys, an exception will be thrown).
+
+        :param keyid: filter term for the keyring (usually a key ID)
+        :rtype: pyme.pygpgme._gpgme_key
+        """
+        result = self.op_keylist_start(keyid, 0)
+        key = self.op_keylist_next()
+        if self.op_keylist_next() is not None:
+            # Deferred import to avoid a circular import dependency
+            from alot.db.errors import GPGProblem
+            raise GPGProblem(("More than one key found matching this filter."
+                " Please be more specific (use a key ID like 4AC8EE1D)."))
+        self.op_keylist_end()
+        return key
+
+    def detached_signature_for(self, plaintext_str, key=None):
         """
         Signs the given plaintext string and returns the detached signature.
 
@@ -101,8 +120,12 @@ class CryptoContext(pyme.core.Context):
                 return
 
         :param plaintext_str: text to sign
+        :param key: gpgme_key_t object representing the key to use
         :rtype: tuple of pyme.pygpgme._gpgme_op_sign_result and str
         """
+        if key is not None:
+            self.signers_clear()
+            self.signers_add(key)
         plaintext_data = pyme.core.Data(plaintext_str)
         signature_data = pyme.core.Data()
         self.op_sign(plaintext_data, signature_data,
diff --git a/alot/db/envelope.py b/alot/db/envelope.py
index a2a17117..9d8e2599 100644
--- a/alot/db/envelope.py
+++ b/alot/db/envelope.py
@@ -26,7 +26,7 @@ from utils import encode_header
 class Envelope(object):
     """a message that is not yet sent and still editable"""
     def __init__(self, template=None, bodytext=u'', headers={}, attachments=[],
-            sign=False, encrypt=False):
+            sign=False, sign_key=None, encrypt=False):
         """
         :param template: if not None, the envelope will be initialised by
                          :meth:`parsing <parse_template>` this string before
@@ -52,6 +52,7 @@ class Envelope(object):
         self.headers.update(headers)
         self.attachments = list(attachments)
         self.sign = sign
+        self.sign_key = sign_key
         self.encrypt = encrypt
         self.sent_time = None
         self.modified_since_sent = False
@@ -164,7 +165,8 @@ class Envelope(object):
             logging.info('signing plaintext: ' + plaintext)
 
             try:
-                result, signature_str = context.detached_signature_for(plaintext)
+                result, signature_str = context.detached_signature_for(
+                        plaintext, self.sign_key)
                 if len(result.signatures) != 1:
                     raise GPGProblem(("Could not sign message "
                             "(GPGME did not return a signature)"))