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https://github.com/mailscope/kumomta.git
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Wez Furlong
78 lines
3.0 KiB
Markdown
78 lines
3.0 KiB
Markdown
# get_simple_structure
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```lua
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local structure = mimepart:get_simple_structure()
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```
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{{since('2025.10.06-5ec871ab')}}
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A MIME message is an encoding of a tree of pieces of content which makes things
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relatively complex to script around in various processing work flows,
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especially because there can be multiple ways to encode similar information
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that result in different tree structures.
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This method will walk the tree structure starting from `mimepart` and collect
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together the main points of interest, returning a lua table holding that
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simplified and flattened view. The following fields are present in the
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simplified structure:
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* `text_part` - The first `text/plain` [MimePart](index.md) found in the walk, if any.
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* `html_part` - The first `text/html` [MimePart](index.md) found in the walk, if any.
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* `header_part` - The "main" part from the perspective of header analysis
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* `attachments` - An array style table holding a list of all the attachments.
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* `amp_html_part` - The first `text/x-amp-html` [MimePart](index.md) found in the walk, if any. {{since('2026.03.04-bb93ecb1', inline=True)}}
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Each attachment table entry has the following fields:
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* `file_name` - The suggested name to use when saving the attachment. If the
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`Content-Disposition` header defined the file name, then that will be used.
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Otherwise, the `Content-Type` `name` parameter will be used. If neither is
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present, then the `file_name` field will not be set (effectively `nil`).
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* `inline` - will be `true` if the attachment was marked as having an inline
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disposition, `false` otherwise.
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* `content_id` - if the `Content-ID` header is defined, this field will hold
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its value.
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* `part` - the [MimePart](index.md) for the attachment. You can use this to
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access its body (eg: [mimepart.body](body.md) or headers.
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## Example of modifying incoming message content
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This example prepends text to both the text and html parts of incoming messages:
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```lua
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kumo.on('smtp_server_message_received', function(message, conn_meta)
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local mime_part = message:parse_mime()
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local structure = mime_part:get_simple_structure()
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if structure.text_part then
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structure.text_part.body = 'PREPENDED!\r\n' .. structure.text_part.body
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end
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if structure.html_part then
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structure.html_part.body = '<B>PREPENDED!</B>\r\n'
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.. structure.html_part.body
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end
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-- Apply the changed content to the message
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message:set_data(tostring(mime_part))
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end)
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```
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## Example of dumping incoming attachments
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This example logs the attachment information and contents during reception.
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It is not recommended for production workflows, as the contents can be
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large and unsuitable for capture in the diagnostic log, but can be helpful
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in some debugging scenarios.
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```lua
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kumo.on('smtp_server_message_received', function(message, conn_meta)
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local mime_part = message:parse_mime()
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local structure = mime_part:get_simple_structure()
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for _, attachment in ipairs(structure.attachments) do
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print(attachment.file_name, attachment.content_type, attachment.part.body)
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end
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end)
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```
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