Lua

Get the Nth Binary Part of a Content-Type into BinData

Demonstrates the Chilkat Email.GetNthBinaryPartOfTypeBd method, which loads the binary bytes of the Nth MIME sub-part matching a content-type pattern into a BinData object. The arguments are the zero-based index among the matching parts, the content-type pattern, an inlineOnly flag, an excludeAttachments flag, and the BinData that receives the bytes. This example extracts the first image/png part.

Background: This is the binary, type-targeted way to pull a specific part out of a message — ideal for extracting, say, every image/png or the one application/pdf from a complex MIME tree without caring whether it is an attachment, an inline image, or a body part. Reading into a BinData keeps the raw bytes exact, ready to save, hash, or re-transmit.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the GetNthBinaryPartOfTypeBd method, which loads the binary bytes of the Nth
-- MIME sub-part matching a Content-Type pattern into a BinData object.  The arguments are
-- the zero-based index among matching parts, the Content-Type pattern, inlineOnly,
-- excludeAttachments, and the BinData that receives the bytes.

local email = chilkat.Email.new()
email.subject = "GetNthBinaryPartOfTypeBd example"
email.body = "See the attached image."

-- Load the image from a file into a BinData object and attach it (binary data belongs
-- in a BinData, never in a string).
local bdImage = chilkat.BinData.new()
local success = bdImage:load_file("qa_data/images/photo.png")
if not success then
    print(bdImage.last_error_text)
    return
end

success = email:add_attachment_bd("photo.png", bdImage, "image/png")
if not success then
    print(email.last_error_text)
    return
end

-- Load the bytes of the first (index 0) image/png part into a BinData object.
local bd = chilkat.BinData.new()
success = email:get_nth_binary_part_of_type_bd(0, "image/png", false, false, bd)
if not success then
    print(email.last_error_text)
    return
end

print("image/png part size (bytes) = " .. bd.num_bytes)

-- Note: The path "qa_data/images/photo.png" is a relative local filesystem path,
-- relative to the current working directory of the running application.