new_multipart

kumo.mimepart.new_multipart(CONTENT_TYPE, PARTS, OPTIONAL_BOUNDARY)

Since: Dev Builds Only

The functionality described in this section requires a dev build of KumoMTA. You can obtain a dev build by following the instructions in the Installation section.

Constructs a new multi-part MimePart with the Content-Type header set to CONTENT_TYPE, which is expected to have a multipart/ prefix, although any content type for which multipart semantics are expected by consumers is permitted.

The PARTS parameter is an array style table containing the set of MimePart objects that will form the children of the newly created part.

The OPTIONAL_BOUNDARY parameter is an optional string that can be used to define the MIME boundary for the various parts; you don't normally need to specify this as the default behavior is to generate a UUID to form the boundary string. You might wish to set the boundary if you are producing tests and need to make assertions on the resulting message content.

Example

This example shows how to produce a simple message with an attachment:

local kumo = require 'kumo'

local main =
  kumo.mimepart.new_text_plain 'Hello, I am the main message content'
local attachment =
  kumo.mimepart.new_binary('application/octet-stream', '\xbb\xaa', {
    file_name = 'binary.dat',
  })

local message =
  kumo.mimepart.new_multipart('multipart/mixed', { main, attachment })

print(message)

That will output a message looking something like this; the boundary will vary each time:

Content-Type: multipart/mixed;
 boundary="S53NSUR9QJam33WHBKAceA"

--S53NSUR9QJam33WHBKAceA
Content-Type: text/plain;
 charset="us-ascii"

Hello, I am the main message content
--S53NSUR9QJam33WHBKAceA
Content-Type: application/octet-stream
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
 filename="binary.dat"

u6o=
--S53NSUR9QJam33WHBKAceA--