Allow cid's in multipart/mixed

mbox2web

@@ -131,9 +131,25 @@ def render_body(msg, extra=None):
         if type(parts) == str:
             # mislabelled, assume text/plain
             return render_text_plain(msg)
+        # First, scan for parts with a content-id. A multipart/mixed shouldn't
+        # have them, but I've seen them in the wild and it should be harmless
+        # to support at least images. We don't want all content types, though,
+        # because save_part doesn't support nested parts and I don't want to
+        # fully implement what is really just a workaround for buggy software.
+        for i, part in enumerate(msg.get_payload()):
+            content_id = part.get("Content-Id")
+            content_type = part.get_content_type()
+            if content_id and content_type.startswith("image/"):
+                if extra is None:
+                    extra = {}
+                extra[content_id] = {
+                    "i": i,
+                    "part": part,
+                    "url": save_part(part, "_url"),
+                }
         partshtml = []
         for part in msg.get_payload():
-            partshtml.append(render_body(part))
+            partshtml.append(render_body(part, extra))
         bodytmpl = jenv.get_template("body_multipart_mixed.html")
         context = {
             "parts": partshtml