MQTT KEKW

MQTT Kekw is a Node.js MQTT TCP client.

Example usage

Install

npm i @mqtt-kekw/tcp-client

Use

const { kekwClient } = require("@mqtt-kekw/tcp-client");

const client = new kekwClient(
  { hostAddress: "localhost", port: 1883 },
  (message) => {
    console.log("Connection Failed", message);
  }
);

Client Props

hostAddress

• Type: string
• Default: localhost
• Description: Broker address

port

• Type: number
• Default: 1883
• Description: Broker port

timeout

• Type: number
• Default: 5000
• Description: Timeout in ms. If no broker response within this time, client will destroy its connection.

onFailure

• Type: function (optional)
• Description: Callback function. Called after timeout.

Sending connection packet

Example usage

client.on("ready", () => {
  console.log("Client Ready !!");
  client.connectionUp({
    clientID: "MQTT_CLIENT",
  });
});

connectionUp

• Type: function

• Description: Sends a Connection packet to the broker

• Arguments:

• flags (optional):

• Type: object

• Description: Consists of following | Name | Type | Description | | :--- | :---- | :--- | | username | string | If username exists, it will be present in the payload | | password | string | If password exists, it will be present in the payload | | willFlag | boolean | ...more | | willQoS_1 | number | ...more | | willQoS_2 | number | ...more | | willRetain | boolean | ...more | | cleanSession | boolean | If cleanSession is set to 0, resume communications with the client based on state from the current Session |

• clientID (optional):

• Type: string

• Description: Client Identifier string. Part of the payload packet

• keepAlive (optional)::

• Type: object

• Description: How much longer should connection stay open between client and broker. Keep in mind that mosquitto broker adds +15 seconds to keepAlive | Name | Type | Description | | :--- | :---- | :--- | | hours | number | hours in number (0-23) | | minutes | number | minutes in number (0-60) | | seconds | number | seconds in number (0-60) |

• will:

• Type: object

• Description: Specify will topic and will message if willFlag is set to true | Name | Type | Description | | :--- | :---- | :--- | | willTopic | string | Will Topic | | willMessage | string | Will Message |

Emitted events

Events emitted with Node.js EventEmitter class. All events are created by following Oasis spesification @Docs-Oasis

| Event Name | Description | Args & Types | | :-------------------------------------------------------- | :-------------------------------------------------------------------- | -------------------------------------------- | | connect | TCP connection starts | --- | | ready | TCP connection ready | --- | | close | TCP connection closed | hadError: boolean | | end | TCP connection ended | --- | | error | TCP connection error | error: Error | | timeout | TCP timeout | --- | | connectionAccepted | Connection acknowledged by the Broker | {returnCode: string, message: string} | | connectionRefused | Connection did not acknowledged by the Broker | {returnCode: string, message: string} | | pingresp | Broker pinged back | message:string | | suback | Subscribe acknowledged by the Broker | {returnCodes: any[], packetID: number[]} | | unsuback | Unsubscribe acknowledged by the Broker | {packetID: number[]} | | puback | Publish acknowledged by the Broker(QoS = 1, At least once delivery) | {packetID: number[]} | | pubrec | Publish acknowledged by the Broker(QoS = 2, At most once delivery) | {packetID: number[]} | | received | Message from the Broker received | {topic: string, payload: string} |

Functions

• ping

  client.ping();

  Description: Sends a ping packet to the broker. pingresp should be triggered after client receives a ping back data packet.

• disconnect

  client.disconnect();

  Description: Sends a disconnect packet to the broker. Client closes it's connection after receiving disconnect acknowledgement packet.

• subscribeTo({topic,requestedQoS})

  Description: Sends a subscribe packet to the broker with topic or topics and requestedQoS. Client should receive suback packet.

  Arguments:

  topic:

  • Type: string | string[]
  • Description: Topic can be a string or a array of strings. Payload calculated accordingly

  requestedQoS:

  • Type: number (either 0 or 1)
  • Description: Requested QoS.(more later)

  client.subscribeTo({
    topic: "home/+/humidity",
    requestedQoS: 0,
  });

• unsubscribeFrom({topic,requestedQoS})

  Description: Sends an unsubscribe packet to the broker with topic or topics and requestedQoS. Client should receive unsuback packet.

  Arguments:

  topic:

  • Type: string | string[]
  • Description: Topic can be a string or a array of strings. Payload calculated accordingly

  packetIdentifier:

  • Type: number[]
  • Description: Packet identifier should be same as the packet identifier that client received in suback event

  client.unsubscribeFrom({
    topic: "home/+/humidity",
    packetIdentifier,
  });

• publishTo({topic,message,dupFlag,QoS1,QoS2,retain})

  Description: Sends a publish packet to the broker with necessarry arguments. Client should received puback or pubrec accordingly.

  Arguments:

  topic:

  • Type: string
  • Description: Topic is a string. Defines which topic that message will be published to

  message:

  • Type: string
  • Description: Message data with the related topic

  dupFlag:

  • Type: number
  • Description: Duplication flag should be set to 0 if it's first occasion. If it's a duplication, it should be set to 1

  QoS1:

  • Type: number
  • Description: ...

  QoS2:

  • Type: number
  • Description: ...

  retain:

  • Type: number
  • Description: ...

  client.unsubscribeFrom({
    topic: "home",
    packetIdentifier,
  });

Subscribe & Unsubscribe Example

Single-Level Wildcard '+'

Example topics

• home/room1/temperature
• home/room2/temperature
• home/room3/temperature

Example usage Subscribe to all topics with home/${any_topic}/temperature format

client.subscribeTo({
  topic: "home/+/temperature",
  //requestedQoS: 0,
});

If you want to unsubscribe from a single level wildcard

client.unsubscribeFrom({
  topic: "home/+/temperature",
  //requestedQoS: 0,
});

Multi-Level Wildcard '#'

Example topics

• home/room1/temperature
• home/room1/humidity
• home/room1/voltage

Example usage

Subscribe to all topics with home/room1/${any_topic} format

client.subscribeTo({
  topic: "home/room1/#",
  //requestedQoS: 0,
});

If you want to unsubscribe from a multi level wildcard

client.unsubscribeFrom({
  topic: "home/room1/#",
  //requestedQoS: 0,
});

Subscribe to multiple topics

client.subscribeTo({
  topic: ["home/room1/temperature", "home/room1/temperature"],
  //requestedQoS: 0,
});

Unsubscribe from multiple topics

client.unsubscribeFrom({
  topic: ["home/room1/temperature", "home/room1/temperature"],
  //packetIdentifier here
});