fix issue with non-multipart messages

msg.get_boundary will return None in those cases,
so we cannot concatenate this with str untested.

Also, Generator.flatten(msg) causes msg to generate a boundary
string. So we don't need to call msg.as_string separately in case
we get the boundary after flattening
cf issue #469

1 files changed, 11 insertions, 11 deletions

diff --git a/alot/crypto.py b/alot/crypto.py
index b03cc2b8..97d13292 100644
--- a/alot/crypto.py
+++ b/alot/crypto.py
@@ -6,6 +6,7 @@ import re
 from email.generator import Generator
 from cStringIO import StringIO
 from alot.errors import GPGProblem
+from email.mime.multipart import MIMEMultipart
 import gpgme
 
 
@@ -17,22 +18,21 @@ def email_as_string(mail):
     :param mail: email to convert to string
     :rtype: str
     """
-    # Get the boundary for later. Before being able to call get_boundary(), we
-    # need to serialize the mail to string once.
-    mail.as_string()
-    boundary = mail.get_boundary()
-
     fp = StringIO()
     g = Generator(fp, mangle_from_=False)
     g.flatten(mail)
     as_string = RFC3156_canonicalize(fp.getvalue())
 
-    # Workaround for http://bugs.python.org/issue14983:
-    # Insert a newline before the outer mail boundary so that other mail
-    # clients (like KMail, Claws-Mail, mutt, …) can verify the signature when
-    # sending an email which contains attachments.
-    as_string = re.sub(r'--\n--' + boundary,
-        '--\n\n--' + boundary, as_string, flags=re.MULTILINE)
+    if isinstance(mail, MIMEMultipart):
+        # Get the boundary for later
+        boundary = mail.get_boundary()
+
+        # Workaround for http://bugs.python.org/issue14983:
+        # Insert a newline before the outer mail boundary so that other mail
+        # clients (like KMail, Claws-Mail, mutt, …) can verify the signature when
+        # sending an email which contains attachments.
+        as_string = re.sub(r'--\n--' + boundary,
+            '--\n\n--' + boundary, as_string, flags=re.MULTILINE)
     return as_string