db/message: split _render_part()

Rename it to _render_part_external() and make it only handle external
rendering. Move the other code -  dealing with text parts without an
external handler - to _MimeTree.render_str(). This takes into account
overridden content types, and also processes text/plain parts if that is
configured.

1 files changed, 51 insertions, 51 deletions

diff --git a/alot/db/message.py b/alot/db/message.py
index 0430025c..33b0f880 100644
--- a/alot/db/message.py
+++ b/alot/db/message.py
@@ -23,62 +23,56 @@ charset.add_charset('utf-8', charset.QP, charset.QP, 'utf-8')
 
 _APP_PGP_SIG = 'application/pgp-signature'
 _APP_PGP_ENC = 'application/pgp-encrypted'
-_TEXT_PLAIN  = 'text/plain'
 
-def _render_part(part, ctype, field_key='copiousoutput'):
+def _render_part_external(raw_payload, ctype, params, field_key='copiousoutput'):
     """
     renders a non-multipart email part into displayable plaintext by piping its
     payload through an external script. The handler itself is determined by
     the mailcap entry for this part's ctype.
     """
-    raw_payload = part.get_content()
-
     rendered_payload = None
     # get mime handler
     _, entry = settings.mailcap_find_match(ctype, key=field_key)
-    if entry is not None:
-        if isinstance(raw_payload, str):
-            raw_payload = raw_payload.encode('utf-8')
-
-        tempfile_name = None
-        stdin = None
-        handler_raw_commandstring = entry['view']
-        # in case the mailcap defined command contains no '%s',
-        # we pipe the files content to the handling command via stdin
-        if '%s' in handler_raw_commandstring:
-            # open tempfile, respect mailcaps nametemplate
-            nametemplate = entry.get('nametemplate', '%s')
-            prefix, suffix = parse_mailcap_nametemplate(nametemplate)
-            with tempfile.NamedTemporaryFile(
-                    delete=False, prefix=prefix, suffix=suffix) \
-                    as tmpfile:
-                tmpfile.write(raw_payload)
-                tempfile_name = tmpfile.name
-        else:
-            stdin = raw_payload
-
-        # read parameter, create handler command
-        parms = tuple('='.join(p) for p in part.get_params())
-
-        # create and call external command
-        cmd = mailcap.subst(entry['view'], ctype,
-                            filename=tempfile_name, plist=parms)
-        logging.debug('command: %s', cmd)
-        logging.debug('parms: %s', str(parms))
-        cmdlist = split_commandstring(cmd)
-        # call handler
-        stdout, _, _ = helper.call_cmd(cmdlist, stdin=stdin)
-        if stdout:
-            rendered_payload = stdout
-
-        # remove tempfile
-        if tempfile_name:
-            os.unlink(tempfile_name)
-    elif part.get_content_maintype() == 'text':
-        # return text parts without a handler as-is
-        rendered_payload = raw_payload
-        if not isinstance(rendered_payload, str):
-            rendered_payload = rendered_payload.decode('utf-8', errors = 'backslashreplace')
+    if entry is None:
+        return None
+
+    if isinstance(raw_payload, str):
+        raw_payload = raw_payload.encode('utf-8')
+
+    tempfile_name = None
+    stdin = None
+    handler_raw_commandstring = entry['view']
+    # in case the mailcap defined command contains no '%s',
+    # we pipe the files content to the handling command via stdin
+    if '%s' in handler_raw_commandstring:
+        # open tempfile, respect mailcaps nametemplate
+        nametemplate = entry.get('nametemplate', '%s')
+        prefix, suffix = parse_mailcap_nametemplate(nametemplate)
+        with tempfile.NamedTemporaryFile(
+                delete=False, prefix=prefix, suffix=suffix) \
+                as tmpfile:
+            tmpfile.write(raw_payload)
+            tempfile_name = tmpfile.name
+    else:
+        stdin = raw_payload
+
+    # read parameter, create handler command
+    parms = tuple('='.join(p) for p in params)
+
+    # create and call external command
+    cmd = mailcap.subst(entry['view'], ctype,
+                        filename=tempfile_name, plist=parms)
+    logging.debug('command: %s', cmd)
+    logging.debug('parms: %s', str(parms))
+    cmdlist = split_commandstring(cmd)
+    # call handler
+    stdout, _, _ = helper.call_cmd(cmdlist, stdin=stdin)
+    if stdout:
+        rendered_payload = stdout
+
+    # remove tempfile
+    if tempfile_name:
+        os.unlink(tempfile_name)
 
     return rendered_payload
 
@@ -177,12 +171,18 @@ class _MimeTree:
 
         content = self._part.get_content()
 
-        # no processing for plaintext
-        # XXX we may want to process plaintext as well
-        if self.content_type == _TEXT_PLAIN:
+        # try procesing content with an external program
+        rendered = _render_part_external(content, self.content_type, self._part.get_params())
+        if rendered:
+            return rendered
+
+        # return text parts without a handler as-is
+        if self.content_maintype == 'text':
+            if not isinstance(content, str):
+                content = content.decode('utf-8', errors = 'backslashreplace')
             return content
 
-        return _render_part(self._part, self.content_type)
+        return None
 
     @property
     def raw_data(self):