Add support for message/partial

This doesn't handle the case where total isn't present on all parts, but
I don't actually expect to encounter that (and if I do, it will crash
and I can fix it).

mbox2web

@@ -1,5 +1,6 @@
 #!/usr/bin/python3
 
+import email.parser
 import html
 import html.parser
 import mailbox
@@ -45,6 +46,8 @@ def render_message(msg):
     msghtml = msgtmpl.render(context)
     return jinja2.Markup(msghtml)
 
+partial_message_cache = {}
+
 def render_body(msg):
     content_type = msg.get_content_type()
 
@@ -88,6 +91,32 @@ def render_body(msg):
     elif content_type == "text/enriched":
         tepart = TextEnrichedPart(msg.get_payload())
         bodyhtml = tepart.as_string()
+    elif content_type == "message/partial":
+        # Default header for get_param is Content-Type
+        whole_msg_id = msg.get_param("id")
+        if not whole_msg_id in partial_message_cache:
+            # For now we assume that total is present on all parts. This
+            # isn't guarantueed, however, and we may need to handle the 
+            # case where total is only present on the last part.
+            partial_message_cache[whole_msg_id] = [None] * int(msg.get_param("total"))
+        payload = msg.get_payload()
+        s = payload[0].as_string() # Only one part
+        partial_message_cache[whole_msg_id][int(msg.get_param("number"))-1] = s
+        if not None in partial_message_cache[whole_msg_id]:
+            p = email.parser.Parser()
+            whole_msg = p.parsestr("".join(partial_message_cache[whole_msg_id]))
+            whole_msg_embedded_id = whole_msg["Message-Id"]
+            if not whole_msg_embedded_id:
+                whole_msg.add_header("Message-Id", "<" + whole_msg_id + ">")
+                whole_msg_embedded_id = whole_msg_id
+            archive(whole_msg)
+            del partial_message_cache[whole_msg_id]
+        bodyhtml = "<p>This is part %d of %d of <a href='../%s/'>%s</a></p>" % (
+                        int(msg.get_param("number")),
+                        int(msg.get_param("total")),
+                        encode_message_id(whole_msg_id),
+                        html.escape(whole_msg_id))
+
     else:
         raise RuntimeError("Content-type " + content_type + " not implemented yet")