Zig
Force Quoted-Printable Encoding for Email

Demonstrates how to force the quoted-printable encoding for email.
Chilkat Zig Downloads

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

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

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

    email.setSubject("test");
    email.setFrom("bob@example.com");
    email.addTo("Mary", "mary@example.com") catch {};

    // Add plain-text and HTML alternative bodies.
    // Include some "=" chars so we can see the quoted-printable encoding when used..
    email.addPlainTextAlternativeBody("This is a test == Hello World!") catch {};
    email.addHtmlAlternativeBody("<html><body>This is a test == Hello World!</body></html>") catch {};

    // Examine the MIME of the email to see that it does not use quoted-printable.
    // (If the email contained non-usascii chars, it would automatically use quoted-printable.)
    const mailman = try chilkat.MailMan.init();
    defer mailman.deinit();
    std.debug.print("{s}\n", .{try mailman.renderToMime(alloc, email)});

    // Here is the MIME before forcing quoted-printable.
    // Notice the Content-Transfer-Encoding is "7bit" (not "quoted-printable")

    // MIME-Version: 1.0
    // Date: Tue, 29 Sep 2020 12:26:52 -0500
    // Message-ID: <CF274FC0A2F82B98A05B7507DF7DFB966A2C0EB8@CHILKATSLICE>
    // Content-Type: multipart/alternative;
    //  boundary="------------080901080902080000030208"
    // X-Priority: 3 (Normal)
    // Subject: test
    // From: bob@example.com
    // To: Mary <mary@example.com>
    //
    // --------------080901080902080000030208
    // Content-Transfer-Encoding: 7bit
    // Content-Type: text/plain; charset=us-ascii; format=flowed
    //
    // This is a test == Hello World!
    // --------------080901080902080000030208
    // Content-Transfer-Encoding: 7bit
    // Content-Type: text/html; charset=us-ascii
    //
    // <html><body>This is a test == Hello World!</body></html>
    // --------------080901080902080000030208--

    std.debug.print("----\n", .{});

    // To force quoted-printable, set the Content-Transfer-Encoding header.
    // It will automatically propagate as needed to the MIME sub-parts.
    email.addHeaderField("Content-Transfer-Encoding", "quoted-printable");
    std.debug.print("{s}\n", .{try mailman.renderToMime(alloc, email)});

    // MIME-Version: 1.0
    // Date: Tue, 29 Sep 2020 12:26:52 -0500
    // Message-ID: <F36B276E3A720FE5111D15CE9142C8909E1F5AB9@CHILKATSLICE>
    // Content-Type: multipart/alternative;
    //  boundary="------------080901080902080000030208"
    // X-Priority: 3 (Normal)
    // Subject: test
    // From: bob@example.com
    // To: Mary <mary@example.com>
    //
    // --------------080901080902080000030208
    // Content-Transfer-Encoding: quoted-printable
    // Content-Type: text/plain; charset=us-ascii; format=flowed
    //
    // This is a test =3D=3D Hello World!
    // --------------080901080902080000030208
    // Content-Transfer-Encoding: quoted-printable
    // Content-Type: text/html; charset=us-ascii
    //
    // <html><body>This is a test =3D=3D Hello World!</body></html>
    // --------------080901080902080000030208--
}