Tcl

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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Tcl


load ./chilkat.dll

set success 0

#  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.

set email [new_CkEmail]

CkEmail_put_Subject $email "Convert inline images"

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

puts "NumRelatedItems before = [CkEmail_get_NumRelatedItems $email]"

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

set success [CkEmail_ConvertInlineImages $email]
if {$success == 0} then {
    puts [CkEmail_lastErrorText $email]
    delete_CkEmail $email
    exit
}

puts "NumRelatedItems after = [CkEmail_get_NumRelatedItems $email]"

delete_CkEmail $email