Lua

Convert Inline Data-URL Images to Related Parts

Demonstrates the Chilkat Email.ConvertInlineImages method, which converts images embedded inline within HTML (as base64 data URLs) into multipart/related MIME parts referenced from the HTML by cid:. This example sets an HTML body containing a data-URL image and converts it.

Background: HTML can embed an image two ways: as a data: URL (the base64 bytes sit right in the src attribute) or as a related part referenced by cid:. Many email clients don't render data: URLs for security reasons, so converting them to proper multipart/related parts — the traditional email way to embed images — greatly improves how reliably the images display.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the ConvertInlineImages method, which converts images embedded inline within
-- HTML (as base64 data URLs) into multipart/related MIME parts referenced from the HTML by
-- CID.

local email = chilkat.Email.new()
email.subject = "Convert inline images"

-- An HTML body with a base64 data-URL image (a 1x1 PNG).
email:set_html_body("<html><body><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==\"/></body></html>")

print("NumRelatedItems before = " .. email.num_related_items)

-- Convert the inline data-URL image(s) to multipart/related parts referenced by CID.

local success = email:convert_inline_images()
if not success then
    print(email.last_error_text)
    return
end

print("NumRelatedItems after = " .. email.num_related_items)