Zig

Count the Related Items in an Email

Demonstrates the read-only Chilkat Email.NumRelatedItems property, which is the number of related MIME items in the email. Related items are resources — such as images or style sheets — embedded with an HTML body in a multipart/related enclosure, and are commonly referenced by the HTML using a cid: URL or a Content-Location. Indexes are zero-based. This example sets an HTML body, adds a related item, and prints the count.

Background: When an HTML email shows an image that travels inside the message (rather than being downloaded from the web), the image is a "related item." The HTML references it with <img src="cid:logo.png">, and a matching part carries a Content-ID of logo.png. The whole bundle lives in a multipart/related enclosure. This is different from an attachment: related items are meant to be displayed as part of the body, not saved as separate files.

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

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

    // Demonstrates the read-only Email.NumRelatedItems property.  Related items are
    // resources (such as images or style sheets) embedded alongside an HTML body in a
    // multipart/related enclosure, typically referenced from the HTML by a cid: URL.

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

    // Set an HTML body that references a related item by content-id.
    email.setHtmlBody("<html><body><img src=\"cid:logo.png\"/></body></html>");

    // Add the related item.  AddRelatedString returns the content-id assigned to it.
    // The empty charset argument means no charset conversion is applied.
    const cid = try email.addRelatedString(alloc, "logo.png", "(pretend this is image data)", "");
    std.debug.print("Related content-id = {s}\n", .{cid});

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