Lua

Add a Content-Length Header to MIME

Demonstrates the Chilkat Mime.AddContentLength method, which computes the byte length of the entity's serialized body and adds or updates its Content-Length header. It takes no arguments and is a void method. The count is based on the transfer-encoded serialized body.

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: Some protocols and consumers want a Content-Length declaring the body size up front. This computes it correctly from the encoded body — the bytes actually written — rather than the decoded content, and updates any existing header so it stays accurate. Call it after the body is final; if you change the body afterward, call it again, or remove the header, since a stale length is worse than none.

Chilkat Lua Downloads

Download Chilkat for Lua

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

-- Compute the byte length of the entity's serialized body and add (or update) its Content-Length
-- header.  The count is based on the transfer-encoded serialized body.  It is a void method.
mime:add_content_length()

local contentLength = mime:get_header_field("Content-Length")
if not mime.last_method_success then
    print(mime.last_error_text)
    return
end

print("Content-Length: " .. contentLength)