Zig

Convert a MIME Entity to multipart/mixed

Demonstrates the Chilkat Mime.ConvertToMultipartMixed method, which wraps the current entity in a new outer multipart/mixed, making the original the first child. It takes no arguments.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is how you turn an existing single-part message into one that can hold attachments — rather than rebuilding it, you wrap it, and its content becomes the first child of a new multipart/mixed. Message-level and custom headers are carried onto the new outer entity so the message identity is preserved. Afterward, AppendPartFromFile adds attachments beside the original body.

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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();

    const mime = try chilkat.Mime.init();
    defer mime.deinit();
    mime.loadMimeFile("qa_data/message.eml") catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    // Wrap the current entity in a new outer multipart/mixed entity.  The original entity becomes the
    // first child, which is what you do to add attachments to an existing single-part message.
    mime.convertToMultipartMixed() catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    // Now attachments can be appended alongside the original content.
    mime.appendPartFromFile("qa_data/report.pdf") catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("Number of parts: {d}\n", .{mime.getNumParts()});
}