Zig

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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Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // 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.

    const email = try chilkat.Email.init();
    defer email.deinit();
    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>");

    std.debug.print("NumRelatedItems before = {d}\n", .{email.getNumRelatedItems()});

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

    email.convertInlineImages() catch {
        std.debug.print("{s}\n", .{try email.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("NumRelatedItems after = {d}\n", .{email.getNumRelatedItems()});
}