README

TMQTTClient Library Version 1.01 for Delphi by Jamie I

INTRODUCTION:

TMQTTClient is a non-visual Delphi Client Library for the IBM Websphere MQ Transport Telemetry protocol ( http://mqtt.org ). It allows you to connect to a Message Broker that uses MQTT such as the Really Small Message Broker(http://alphaworks.ibm.com/tech/rsmbb which is freely available for evaluation purposes on IBM Alphaworks.

The Documentation of the protocol can be found here: http://publib.boulder.ibm.com/infocenter/wmbhelp/v6r0m0/index.jsp?topic=/com.ibm.etools.mft.doc/ac10840_.htm

LIMITATIONS:

This is not a reference implementation of the MQTT Protocol but does support both Publishing Messages and Subscribing to Topics with the following limitations:

• It only allows and supports QoS 0 Messages. I haven�t built QoS levels 1 or 2 in yet as I personally have no need for them but this is planned for future versions.
• You are required to schedule pinging the server yourself (using a TTimer for examples). The client library implements a ping command but doesn�t automatically ping the server itself at regular intervals.

Note: You should also be aware that it uses part of the Synapse Internet Communications Library for its Socket support so you�ll need to ensure that this is available on your search path.

USAGE:

There is a sample project included in the download but usage is relatively simple. This is a non-visual component so all you need to do is to put MQTT.pas and MQTTReadThread.pas into a directory that is in your compiler paths and then put MQTT in your uses.

uses MQTT;
var
    MQTTClient: TMQTTClient;
begin
    MQTTClient := TMQTTClient.Create('127.0.0.1', 1883);
    MQTTClient.Connect;
    MQTTClient.Publish('/dev/test', 'This is a test message.');
    MQTTClient.Disconnect;
    MQTTClient.Free;
end;

Special Thanks go to Andy Stanford-Clark and Nick O�Leary for their help on various �hiccups� that I encountered while developing and testing TMQTTClient.

If you are using my TMQTTClient in anything then I�d love to hear about how you�re using it, please contact me and let me know what you�re using it for.