support multiple recipients in encryption

Multiple recipient-keys can be specified. They are shown in the envelope buffer.
A new command is introduced: 'rmencrypt' do remove a key from the encryption
lsit. Unfortunately pygpgme doesn't implement __cmp__() so we have to either
write something similar on our own or use this solution (index of the key in
encryption list)

4 files changed, 53 insertions, 13 deletions

diff --git a/alot/buffers.py b/alot/buffers.py
index 117eecce..8f344081 100644
--- a/alot/buffers.py
+++ b/alot/buffers.py
@@ -154,9 +154,20 @@ class EnvelopeBuffer(Buffer):
 
         if self.envelope.encrypt:
             description = 'Yes'
-            encrypt_key = self.envelope.encrypt_key
-            if encrypt_key is not None and len(encrypt_key.subkeys) > 0:
-                description += ', with key ' + encrypt_key.subkeys[0].keyid
+            encrypt_keys = self.envelope.encrypt_keys
+            if  len(encrypt_keys) == 1:
+                description += ', with key '
+            elif len(encrypt_keys) > 1:
+                description += ', with keys '
+            first_key = True
+            for key in encrypt_keys: 
+                if key is not None:
+                    if first_key:
+                        first_key = False
+                    else:
+                        description += ', '
+                    if len(key.subkeys) > 0:
+                        description += key.subkeys[0].keyid
             lines.append(('GPG encrypt', description))
 
         # add header list widget iff header values exists
diff --git a/alot/commands/envelope.py b/alot/commands/envelope.py
index 618bdc10..af0705bc 100644
--- a/alot/commands/envelope.py
+++ b/alot/commands/envelope.py
@@ -453,13 +453,19 @@ class SignCommand(Command):
 
 
 @registerCommand(MODE, 'encrypt', forced={'action': 'encrypt'}, arguments=[
-    (['keyid'], {'help': 'keyid of the key to encrypt with'})])
+    (['keyids'], {'nargs':argparse.REMAINDER, 
+                 'help': 'keyid of the key to encrypt with'})])
 @registerCommand(MODE, 'unencrypt', forced={'action': 'unencrypt'})
 @registerCommand(MODE, 'toggleencrypt', forced={'action': 'toggleencrypt'},
                  arguments=[
-                 (['keyid'], {'help':'keyid of the key to encrypt with'})])
+                     (['keyids'], {'nargs': argparse.REMAINDER, 
+                      'help':'keyid of the key to encrypt with'})])
+@registerCommand(MODE, 'rmencrypt', forced={'action': 'rmencrypt'},
+                 arguments=[
+                     (['keyids'], {'nargs': argparse.REMAINDER, 
+                      'help':'keyid of the key to encrypt with'})])
 class EncryptCommand(Command):
-    def __init__(self, action=None, keyid=None, **kwargs):
+    def __init__(self, action=None, keyids=None, **kwargs):
         """
         :param action: wether to encrypt/unencrypt/toggleencrypt
         :type action: str
@@ -467,13 +473,30 @@ class EncryptCommand(Command):
         :type keyid: str
         """
 
-        self.encrypt_key = keyid
+        self.encrypt_keys = keyids
         self.action = action
         Command.__init__(self, **kwargs)
 
     def apply(self, ui):
         envelope = ui.current_buffer.envelope
-        if self.action == 'encrypt':
+        if self.action == 'rmencrypt':
+            try:
+                for keyid in self.encrypt_keys:
+                    # this is not so nice, but pygpgme doesn't supply a
+                    # __cmp__() operator so list.remove(x) doesn't work
+                    del envelope.encrypt_keys[int(keyid) - 1]
+            except gpgme.GpgmeError as e:
+                if e.code == gpgme.ERR_INV_VALUE:
+                    raise GPGProblem("Can not find key to encrypt.")
+                raise GPGProblem(str(e))
+            except ValueError as e:
+                raise Warning("Enter a the index of the key as argument to " +
+                              "rmencrypt.")
+            except IndexError as e:
+                raise Warning("There are not so many encryption keys.")
+            ui.current_buffer.rebuild()
+            return
+        elif self.action == 'encrypt':
             encrypt = True
         elif self.action == 'unencrypt':
             encrypt = False
@@ -482,7 +505,13 @@ class EncryptCommand(Command):
         envelope.encrypt = encrypt
         if encrypt:
             try:
-                envelope.encrypt_key = crypto.get_key(self.encrypt_key)
+                # cache all keys before appending to envelope, since otherwise
+                # we get an error message but all earlier keys are added, but
+                # not shown
+                keys = []
+                for keyid in self.encrypt_keys:
+                    keys.append(crypto.get_key(keyid))
+                envelope.encrypt_keys.extend(keys)
             except gpgme.GpgmeError as e:
                 if e.code == gpgme.ERR_INV_VALUE:
                     raise GPGProblem("Can not find key to encrypt.")
diff --git a/alot/crypto.py b/alot/crypto.py
index dfa8491f..be7e83e2 100644
--- a/alot/crypto.py
+++ b/alot/crypto.py
@@ -153,7 +153,7 @@ def detached_signature_for(plaintext_str, key=None):
     return sigs, signature
 
 
-def encrypt(plaintext_str, key=None):
+def encrypt(plaintext_str, keys=None):
     """
     Encrypts the given plaintext string and returns a PGP/MIME compatible
     string
@@ -166,7 +166,7 @@ def encrypt(plaintext_str, key=None):
     encrypted_data = StringIO()
     ctx = gpgme.Context()
     ctx.armor = True
-    ctx.encrypt([key], gpgme.ENCRYPT_ALWAYS_TRUST, plaintext_data,
+    ctx.encrypt(keys, gpgme.ENCRYPT_ALWAYS_TRUST, plaintext_data,
                 encrypted_data)
     encrypted_data.seek(0, 0)
     encrypted = encrypted_data.read()
diff --git a/alot/db/envelope.py b/alot/db/envelope.py
index 83050d03..00f7a22f 100644
--- a/alot/db/envelope.py
+++ b/alot/db/envelope.py
@@ -58,7 +58,7 @@ class Envelope(object):
         self.sign = sign
         self.sign_key = sign_key
         self.encrypt = encrypt
-        self.encrypt_key = None
+        self.encrypt_keys = []
         self.tags = tags  # tags to add after successful sendout
         self.sent_time = None
         self.modified_since_sent = False
@@ -214,7 +214,7 @@ class Envelope(object):
 
 
             try:
-                encrypted_str = crypto.encrypt(plaintext, self.encrypt_key)
+                encrypted_str = crypto.encrypt(plaintext, self.encrypt_keys)
             except gpgme.GpgmeError as e:
                 raise GPGProblem(str(e))