Zig

Count the Messages in a multipart/digest Email

Demonstrates the read-only Chilkat Email.NumDigests property, which is the number of message/rfc822 parts contained within a multipart/digest enclosure. If no such enclosure exists, the value is 0. Digest indexes are zero-based; use GetDigestEmail to retrieve an individual bundled message as its own Email object. This example loads a digest email and lists each message's subject.

Background: A multipart/digest is a way to package many separate emails inside one carrier message — historically used by mailing lists to send a single daily "digest" containing all of that day's posts. Each bundled item is a complete message/rfc822 email with its own headers and body. This differs from NumAttachedMessages, which counts nested messages attached to an ordinary email rather than the members of a digest enclosure.

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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 read-only Email.NumDigests property, which is the number of
    // message/rfc822 parts contained within a multipart/digest enclosure.  If there is no
    // multipart/digest enclosure, the value is 0.  Digest indexes are zero-based.

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

    // Load a multipart/digest email (a single email that bundles many messages).
    email.loadEml("qa_data/eml/digest.eml") catch {
        std.debug.print("{s}\n", .{try email.getLastErrorText(alloc)});
        return;
    };

    const n = email.getNumDigests();
    std.debug.print("NumDigests = {d}\n", .{n});

    // Retrieve each bundled message as its own Email object.
    const digest_email = try chilkat.Email.init();
    defer digest_email.deinit();
    var i: i32 = 0;
    i = 0;
    while (i < n) : (i += 1) {
        try email.getDigestEmail(i, digest_email);
        std.debug.print("Digest {d} subject: {s}\n", .{ i, try digest_email.getSubject(alloc) });
    }

    // Note: Paths such as "qa_data/..." are relative local filesystem paths,
    // relative to the current working directory of the running application.
}