Preserve filename of inline attachments

For ESPs that support both content-id and filename,
don't drop the filename.

Author: medmunds

anymail/backends/mailgun.py

@@ -111,9 +111,14 @@ def set_html_body(self, body):
 
     def add_attachment(self, attachment):
         # http://docs.python-requests.org/en/v2.4.3/user/advanced/#post-multiple-multipart-encoded-files
-        field = "inline" if attachment.inline else "attachment"
+        if attachment.inline:
+            field = "inline"
+            name = attachment.cid
+        else:
+            field = "attachment"
+            name = attachment.name
         self.files.append(
-            (field, (attachment.name, attachment.content, attachment.mimetype))
+            (field, (name, attachment.content, attachment.mimetype))
         )
 
     def set_metadata(self, metadata):

anymail/backends/mandrill.py

@@ -118,10 +118,15 @@ def set_html_body(self, body):
         self.data["message"]["html"] = body
 
     def add_attachment(self, attachment):
-        key = "images" if attachment.inline else "attachments"
-        self.data["message"].setdefault(key, []).append({
+        if attachment.inline:
+            field = "images"
+            name = attachment.cid
+        else:
+            field = "attachments"
+            name = attachment.name or ""
+        self.data["message"].setdefault(field, []).append({
             "type": attachment.mimetype,
-            "name": attachment.name or "",
+            "name": name,
             "content": attachment.b64content
         })
 

anymail/utils.py

@@ -100,11 +100,12 @@ class Attachment(object):
     """A normalized EmailMessage.attachments item with additional functionality
 
     Normalized to have these properties:
-    name: attachment filename; may be empty string; will be Content-ID (without <>) for inline attachments
-    content
+    name: attachment filename; may be empty string
+    content: bytestream
     mimetype: the content type; guessed if not explicit
     inline: bool, True if attachment has a Content-ID header
-    content_id: for inline, the Content-ID (with <>)
+    content_id: for inline, the Content-ID (*with* <>)
+    cid: for inline, the Content-ID *without* <>
     """
 
     def __init__(self, attachment, encoding):
@@ -114,6 +115,7 @@ def __init__(self, attachment, encoding):
         self.encoding = encoding  # should we be checking attachment["Content-Encoding"] ???
         self.inline = False
         self.content_id = None
+        self.cid = ""
 
         if isinstance(attachment, MIMEBase):
             self.name = attachment.get_filename()
@@ -123,7 +125,7 @@ def __init__(self, attachment, encoding):
             if attachment.get_content_maintype() == "image" and attachment["Content-ID"] is not None:
                 self.inline = True
                 self.content_id = attachment["Content-ID"]  # including the <...>
-                self.name = self.content_id[1:-1]  # without the <, >
+                self.cid = self.content_id[1:-1]  # without the <, >
         else:
             (self.name, self.content, self.mimetype) = attachment