Lua

Get a MIME Header Field Attribute

Demonstrates the Chilkat Mime.GetHeaderFieldAttribute method, which returns an attribute value parsed from a header field. The first argument is the header field name and the second is the attribute name. Surrounding quotes are removed.

Note: The file path is relative to the application's current working directory. Absolute paths may also be used. Supply the path to your own file.

Background: Many MIME headers pack extra parameters after the main value — Content-Type: multipart/mixed; boundary="xyz" or Content-Disposition: attachment; filename="report.pdf". This method extracts one of those named attributes directly, saving you from parsing the header string yourself and correctly stripping quotes and handling encoded values.

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Lua

local chilkat = require("chilkat")

local mime = chilkat.Mime.new()
local success = mime:load_mime_file("qa_data/message.eml")
if not success then
    print(mime.last_error_text)
    return
end

-- Return an attribute value parsed from a header field.  The 1st argument is the header field
-- name and the 2nd is the attribute name.  For example, the "boundary" attribute of the
-- Content-Type header, or the "filename" attribute of Content-Disposition.
local boundary = mime:get_header_field_attribute("Content-Type", "boundary")
if not mime.last_method_success then
    print(mime.last_error_text)
    return
end

print("Content-Type boundary: " .. boundary)