Lua

Get a Header Attribute of an Attached Message

Demonstrates the Chilkat Email.GetAttachedMessageAttr method, which returns a header-field attribute value for the Nth attached (embedded) email. The first argument is the zero-based attached-message index, the second is the header field name, and the third is the attribute name. This example attaches an email and reads the filename attribute of its Content-Disposition header.

Background: MIME header fields can carry named attributes (parameters) after the main value — for example Content-Disposition: attachment; filename="report.eml", where filename is an attribute. Rather than parsing the raw header yourself, this method extracts a single named attribute from a chosen header of a specific embedded message, which is convenient when a message forwards other emails as nested message/rfc822 parts.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the GetAttachedMessageAttr method, which returns a header-field attribute
-- value for the Nth attached (embedded) email.  The first argument is the zero-based
-- attached-message index, the second is the header field name, and the third is the attribute name.

-- Build an inner email to attach.
local innerEmail = chilkat.Email.new()
innerEmail.subject = "Embedded message"
innerEmail.from = "alice@example.com"
innerEmail:add_to("Bob", "bob@example.com")

-- Attach it to an outer email as a message/rfc822 part.
local email = chilkat.Email.new()
email.subject = "Has an attached message"
local success = email:attach_email(innerEmail)
if not success then
    print(email.last_error_text)
    return
end

-- Get the "filename" attribute of the "Content-Disposition" header of the first
-- attached message (index 0).
local fname = email:get_attached_message_attr(0, "Content-Disposition", "filename")
print("Attached message filename attribute: " .. fname)