Java

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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import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Email;

public class ChilkatExample {

    public static void main(String[] args) {
        // 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.

        Email email = new Email();
        email.setSubject("Convert inline images");

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

        System.out.println("NumRelatedItems before = " + email.getNumRelatedItems());

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

        try {
            email.convertInlineImages();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("NumRelatedItems after = " + email.getNumRelatedItems());
    }
}