Zig

Add a Related String Resource to an Email

Demonstrates the Chilkat Email.AddRelatedString method, which adds a text-based related MIME resource, such as a style sheet, from an in-memory string and returns the generated Content-ID. The first argument is the MIME resource name, the second is the text content, and the third is the charset used to encode it. Because the Content-ID is generated by the call, this example adds the style sheet first, then builds an HTML body in a StringBuilder that references the style sheet by that cid:, and passes the result to SetHtmlBody.

Background: Related items are not always images loaded from disk — sometimes the resource is text you already have in memory, like a generated CSS style sheet or an SVG. AddRelatedString lets you embed such content directly without writing a temporary file first. As with other related items, it lives in the multipart/related enclosure and is referenced from the HTML by the Content-ID the method returns.

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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 AddRelatedString method, which adds a text-based related MIME resource
    // (such as a style sheet) from an in-memory string and returns the generated Content-ID.
    // The first argument is the resource name, the second is the text content, the third is the charset.

    const email = try chilkat.Email.init();
    defer email.deinit();
    email.setSubject("Email with a related style sheet");

    // Add the text-based related resource first; capture the generated Content-ID.
    const cid = email.addRelatedString(alloc, "styles.css", "body { color: navy; }", "utf-8") catch {
        std.debug.print("{s}\n", .{try email.getLastErrorText(alloc)});
        return;
    };

    // Build the HTML body, referencing the related style sheet by its Content-ID.  A
    // placeholder is used and then replaced with the actual Content-ID.
    const sb_html = try chilkat.StringBuilder.init();
    defer sb_html.deinit();
    sb_html.append("<html><head><link rel=\"stylesheet\" href=\"cid:PLACEHOLDER_CID\"/></head><body>Styled content.</body></html>") catch {};
    _ = sb_html.replace("PLACEHOLDER_CID", cid);
    email.setHtmlBody(try sb_html.getAsString(alloc));

    std.debug.print("Related Content-ID = {s}\n", .{cid});
    std.debug.print("NumRelatedItems = {d}\n", .{email.getNumRelatedItems()});
}