zmqd 0.1.0-alpha1

∅MQD – a ∅MQ wrapper for the D programming language

∅MQD is a D library that wraps the low-level C API of the ∅MQ messaging framework. It is a rather thin wrapper that maps closely to the C API, while making it safer, easier and more pleasant to use. Here's how:

• Errors are signalled by means of exceptions rather than return codes.
• Functions are appropriately marked with @safe/@trusted/@system, pure and nothrow.
• Memory and resources (i.e. contexts, sockets and messages) are automatically managed, thus preventing leaks.
• Context, socket and message options are implemented as properties.

The names of functions and types in ∅MQD are very similar to those in ∅MQ, but they follow the D naming conventions. For example, zmq_msg_send() becomes zmqd.Message.send() and so on. Thus, the library should feel both familiar to ∅MQ users and natural to D users.

The documentation may be browsed online at http://kyllingstad.github.io/zmqd/.

Requirements

What you need is:

• An up-to-date D compiler (last tested with DMD 2.064)
• The ∅MQ libraries
• The ∅MQ bindings from Deimos

Tell the compiler where to find the libraries and the import files, and you're good to go.

Example: Hello World server

The C implementation of the "Hello World server" from the ∅MQ Guide looks like this:

// Hello World server

#include <zmq.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>

int main (void)
{
    // Socket to talk to clients
    void *context = zmq_ctx_new ();
    void *responder = zmq_socket (context, ZMQ_REP);
    int rc = zmq_bind (responder, "tcp://*:5555");
    assert (rc == 0);

    while (1) {
        char buffer [10];
        zmq_recv (responder, buffer, 10, 0);
        printf ("Received Hello\n");
        sleep (1); // Do some 'work'
        zmq_send (responder, "World", 5, 0);
    }
    return 0;
}

The equivalent ∅MQD program looks like this:

import core.thread, core.time, std.stdio;
import zmqd;

void main()
{
    auto responder = Socket(SocketType.rep);
    responder.bind("tcp://*:5555");

    while (true) {
        char[10] buffer;
        responder.receive(buffer[]);
        writeln("Received Hello");
        Thread.sleep(seconds(1)); // Do some 'work'
        responder.send("World");
    }
}

Note how Socket does not need a context, because the library creates a global "default context", since this is what the majority of programs will do anyway. Of course, if we wanted to, we could replace the first line of main() with the following:

auto context = Context();
auto responder = Socket(context, SocketType.rep);