Lua

Convert 8-bit MIME Parts to Base64

Demonstrates the Chilkat Mime.Convert8Bit method, which recursively converts every part whose Content-Transfer-Encoding is 8bit or binary to base64. It takes no arguments and is a void method.

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

Background: The original SMTP standard only guaranteed 7-bit transport, and some legacy servers still reject or mangle raw 8-bit and binary content. Converting those parts to base64 — a 7-bit-safe encoding — makes the whole message safe to relay through such systems without loss. It walks the entire tree, so a multipart message with several offending parts is fixed in one call.

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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

-- Recursively convert every part whose Content-Transfer-Encoding is 8bit or binary to base64.
-- This makes the MIME safe to transmit over channels that only support 7-bit text (such as some
-- legacy SMTP servers).
mime:convert8_bit()

print("8bit/binary parts converted to base64.")
local mimeText = mime:get_mime()
if not mime.last_method_success then
    print(mime.last_error_text)
    return
end

print(mimeText)