move get_mime_headers() function to Message object where it belongs.

also simplify creating a mime object from the headers ...

python/src/deltachat/account.py

@@ -2,7 +2,6 @@
 
 from __future__ import print_function
 import threading
-import six
 import re
 import time
 import requests
@@ -223,26 +222,6 @@ class Account(object):
         """ return Message instance. """
         return Message.from_db(self._dc_context, msg_id)
 
-    def get_mime_headers(self, msg):
-        """ return mime-header object for an incoming message.
-
-        This only returns a non-None object if ``save_mime_headers``
-        config option was set and ``msg_id`` refers to an incoming
-        message.
-
-        :param msg_id: integer message id
-        :returns: email-mime message object.
-        """
-        import email.parser
-        msg_id = getattr(msg, "id", msg)
-        mime_headers = lib.dc_get_mime_headers(self._dc_context, msg_id)
-        if mime_headers:
-            s = ffi.string(mime_headers)
-            if isinstance(s, bytes):
-                s = s.decode("ascii")
-            fp = six.StringIO(s)
-            return email.parser.Parser().parse(fp)
-
     def mark_seen_messages(self, messages):
         """ mark the given set of messages as seen.
 

python/src/deltachat/message.py

@@ -109,6 +109,22 @@ class Message(object):
         if ts:
             return datetime.utcfromtimestamp(ts)
 
+    def get_mime_headers(self):
+        """ return mime-header object for an incoming message.
+
+        This only returns a non-None object if ``save_mime_headers``
+        config option was set and the message is incoming.
+
+        :returns: email-mime message object (with headers only, no body).
+        """
+        import email.parser
+        mime_headers = lib.dc_get_mime_headers(self._dc_context, self.id)
+        if mime_headers:
+            s = ffi.string(mime_headers)
+            if isinstance(s, bytes):
+                s = s.decode("ascii")
+            return email.message_from_string(s)
+
     @property
     def chat(self):
         """chat this message was posted in.

python/tests/test_account.py

@@ -291,15 +291,14 @@ class TestOnlineAccount:
         lp.sec("sending text message from ac1 to ac2")
         msg_out = chat.send_text("message1")
         ac1._evlogger.get_matching("DC_EVENT_MSG_DELIVERED")
-        assert ac1.get_mime_headers(msg_out.id) is None
+        assert msg_out.get_mime_headers() is None
 
         lp.sec("wait for ac2 to receive message")
         ev = ac2._evlogger.get_matching("DC_EVENT_MSGS_CHANGED")
         in_id = ev[2]
-        mime = ac2.get_mime_headers(in_id)
+        mime = ac2.get_message_by_id(in_id).get_mime_headers()
         assert mime.get_all("From")
         assert mime.get_all("Received")
-        assert ac2.get_mime_headers(ac2.get_message_by_id(in_id)).get_all("From")
 
     def test_send_and_receive_image(self, acfactory, lp, data):
         lp.sec("starting accounts, waiting for configuration")