Introduction

See Official Readme for more informations.

Rationale for this fork

I've made this fork to extend MQTT Publish/Subscribe capability with Geo Location filtering for a University Project.

By setting a subscription on a specific subpath of a topic, it must be possible to receive all of messages sent on a defined range.

Usage samples

• Creating and connecting an MQTT client with default options:

    var configuration = new MqttConfiguration();	
    var client = await MqttClient.CreateAsync("192.168.1.10", configuration);
    var sessionState = await client.ConnectAsync (new `MqttClientCredentials`(clientId: "foo"));
  

  The ConnectAsync method returns once the CONNACK packet has been received from the Server.

  The session state value contains information about if the session has been re used or cleared

• Creating and connecting an MQTT client specifying configuration and clean session:

    var configuration = new MqttConfiguration {
  
    		BufferSize = 128 * 1024,
    		Port = 1883,
    		KeepAliveSecs = 10,
    		WaitTimeoutSecs = 2,
    		MaximumQualityOfService = MqttQualityOfService.AtMostOnce,
    		AllowWildcardsInTopicFilters = true,
    		AllowLocationSubscription = true // Addition to enable Geo Location filtering
  
    };
    var client = await MqttClient.CreateAsync("192.168.1.10", configuration);
    var sessionState = await client.ConnectAsync (new `MqttClientCredentials`(clientId: "foo"), cleanSession: true);
  

• Subscribing and unsubscribing to normal topics has not changed:

    await client.SubscribeAsync("foo/bar/topic1", MqttQualityOfService.AtMostOnce); //QoS0
    await client.SubscribeAsync("foo/bar/topic2", MqttQualityOfService.AtLeastOnce); //QoS1
    await client.SubscribeAsync("foo/bar/topic3", MqttQualityOfService.ExactlyOnce); //QoS2
  

  The SubscribeAsync method returns once the SUBACK packet has been received from the Server

    await client.UnsubscribeAsync("foo/bar/topic1");
    await client.UnsubscribeAsync("foo/bar/topic2");
    await client.UnsubscribeAsync("foo/bar/topic3");
  

  The UnsubscribeAsync method returns once the UNSUBACK packet has been received from the Server

• Subscribing to geo location topics is done in the following way:

   var topic = "topics/loc/ll=xx.xx,yy.yy&s=circle&r=15&u=(m|km)&t=(timestamp)";
   client.SubscribeAsync(topic, MqttQualityOfService.AtMostOnce); //QoS0

  • The first part of the topic must be "topics/loc/";
  • The separator for the parameters is the "&";
  • The ll (LatLon) parameter must be followed by the double value of the latitude and the second one by the longitude value separated by a comma ",";
  • The s (shape) parameter must be one of the following values (circle) (for now is the only supported, sorry)
  • The u (unit) parameter must be one of the following values (m, km);
  • The t (timestamp) parameter must be the timestamp of the current time

More

For more specific information about the MQTT protocol, please see the latest Oasis spec.