Zig

Socket Convert Existing TCP Connection to SSL/TLS

Demonstrates the Chilkat Socket ConvertToSsl method. Zig

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

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

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    const sock = try chilkat.Socket.init();
    defer sock.deinit();

    // --------------------------------------------------------------------
    // This example uses the public TCP/TLS echo service at https://tcpbin.com/
    // --------------------------------------------------------------------

    // The echo server at tcpbin.com expects to receive TCP connections on port 4242, and TLS connections on port 4243.
    // We could simply connect to port 4243 using TLS like this.
    // However, further below, this example shows how to initially make a TCP connection, and then convert the connection to TLS.
    var use_tls: bool = true;
    const port = 4243;
    const max_wait_ms = 5000;
    sock.connect("tcpbin.com", port, use_tls, max_wait_ms) catch {
        std.debug.print("{s}\n", .{try sock.getLastErrorText(alloc)});
        return;
    };

    // OK, we have a TLS connection.
    // Note: The server chooses the TLS protocol version.
    // We can see the version of the TLS connection that was established:
    std.debug.print("TLS version: {s}\n", .{try sock.getTlsVersion(alloc)});

    sock.close(max_wait_ms) catch {};

    // ---------------------------------------------------------------------
    // Now we'll do the same, except first we connect to port 4243 using TCP,
    // and then convert the connection to TLS.
    //
    // This may seem pointless, and it is for the case w/ this server.  However, there could be situations
    // where you're interacting with a server of some kind where there is a need to convert to/from TLS.
    // (This is common internal to many protocols, such as SMTP, IMAP, FTP, etc., and it is often called "explicit" SSL/TLS)

    // Connect again, except this time useTls is false, so we only have a simple TCP connection after this call.
    use_tls = false;
    sock.connect("tcpbin.com", port, use_tls, max_wait_ms) catch {
        std.debug.print("{s}\n", .{try sock.getLastErrorText(alloc)});
        return;
    };

    // Convert the existing TCP connection to TLS.
    // (The method name uses "SSL" because long ago, at the time of initial development, TLS 1.0 did not yet exist.)
    sock.convertToSsl() catch {
        std.debug.print("{s}\n", .{try sock.getLastErrorText(alloc)});
        return;
    };

    // OK, we now have a TLS connection.
    // Again, we can see the TLS version:
    std.debug.print("TLS version: {s}\n", .{try sock.getTlsVersion(alloc)});

    sock.close(max_wait_ms) catch {};
}