TCP/UDP Connectivity via Node-Red

Overview
Prerequisites
Setup TCP/UDP to MQTT Bridge on Node-RED
- Node-RED Configuration
- Specifying Application Version and Endpoint Token
Monitor the Data
About This Example

Overview

The Kaa platform currently supports HTTP(s) and MQTT(s) device protocols.
While it does not support direct communication via TCP or UDP, you can still communicate with Kaa by bridging TCP/UDP to HTTP or MQTT.
In this article, we will demonstrate how to bridge TCP/UDP into MQTT using Node-RED.
Node-RED will receive data over TCP/UDP on its own server and forward it over MQTT to the Kaa platform.

Prerequisites

You have installed Node-RED or are using the Kaa Node-RED managed service if you don’t want to host it yourself.
You have an account in the Kaa Cloud.

Setup TCP/UDP to MQTT Bridge on Node-RED

First, create an endpoint by following the Getting Started Tutorial.
You will need its application version and endpoint token.

Node-RED Configuration

Next, deploy the flow for the protocol of your choice. Copy the flow code for either TCP or UDP, and then import the flow into Node-RED.

[
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    "id": "4a8d6d5bb5991164",
    "type": "tab",
    "label": "TCP to MQTT flow",
    "disabled": false,
    "info": "",
    "env": []
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  {
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    "type": "inject",
    "z": "4a8d6d5bb5991164",
    "name": "",
    "props": [
      {
        "p": "payload"
      },
      {
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        "vt": "str"
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    ],
    "repeat": "5",
    "crontab": "",
    "once": false,
    "onceDelay": "5",
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    "server": "server",
    "host": "",
    "port": "5000",
    "datamode": "stream",
    "datatype": "utf8",
    "newline": "",
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    "base64": false,
    "tls": "",
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    "wires": []
  },
  {
    "id": "aa17bc8de5e6c2de",
    "type": "mqtt out",
    "z": "4a8d6d5bb5991164",
    "name": "kaa mqtt broker out",
    "topic": "",
    "qos": "",
    "retain": "",
    "respTopic": "",
    "contentType": "",
    "userProps": "",
    "correl": "",
    "expiry": "",
    "broker": "dc0deea1.ea5b2",
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    "wires": []
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    "func": "node.warn(\"Initializing flow variables\")\n\n// Set the application version and device token from here. \n// Don't forget to save and deploy your changes\nconst APP_VERSION = '<your-app-version>'\nconst TOKEN = '<your-endpoint-token>'\nconst SERVER_URL = 'cloud.kaaiot.com'\n\nflow.set('COUNT', 0)\nflow.set('APP_VERSION', APP_VERSION)\nflow.set('SERVER_URL', SERVER_URL)\nflow.set('TOKEN', TOKEN)\n",
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    "noerr": 0,
    "initialize": "",
    "finalize": "",
    "libs": [],
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    "y": 120,
    "wires": [],
    "icon": "node-red/alert.svg"
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    "crontab": "",
    "once": true,
    "onceDelay": 0.1,
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    "topic": "kp1/+/dcx/+/json/#",
    "qos": "2",
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    "noerr": 0,
    "initialize": "",
    "finalize": "",
    "libs": [],
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    "noerr": 0,
    "initialize": "",
    "finalize": "",
    "libs": [],
    "x": 620,
    "y": 240,
    "wires": [
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        "9a789498da90ae8d"
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    "y": 80,
    "wires": []
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    "wires": []
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    "info": "",
    "x": 190,
    "y": 320,
    "wires": []
  },
  {
    "id": "103bf5caccc0183c",
    "type": "comment",
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    "wires": []
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    "wires": []
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  {
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  {
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    "type": "function",
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    "outputs": 1,
    "noerr": 0,
    "initialize": "",
    "finalize": "",
    "libs": [],
    "x": 380,
    "y": 240,
    "wires": [
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    "active": true,
    "tosidebar": true,
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    "tostatus": false,
    "complete": "true",
    "targetType": "full",
    "statusVal": "",
    "statusType": "auto",
    "x": 710,
    "y": 580,
    "wires": []
  },
  {
    "id": "9a789498da90ae8d",
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    "z": "4a8d6d5bb5991164",
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    "host": "127.0.0.1",
    "port": "5000",
    "beserver": "client",
    "base64": false,
    "end": false,
    "tls": "",
    "x": 840,
    "y": 240,
    "wires": []
  },
  {
    "id": "dc0deea1.ea5b2",
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    "name": "mqtt.cloud.kaaiot.com",
    "broker": "mqtt.cloud.kaaiot.com",
    "port": "1883",
    "clientid": "",
    "autoConnect": true,
    "usetls": false,
    "protocolVersion": "4",
    "keepalive": "60",
    "cleansession": true,
    "birthTopic": "",
    "birthQos": "0",
    "birthPayload": "",
    "birthMsg": {},
    "closeTopic": "",
    "closeQos": "0",
    "closePayload": "",
    "closeMsg": {},
    "willTopic": "",
    "willQos": "0",
    "willPayload": "",
    "willMsg": {},
    "userProps": "",
    "sessionExpiry": ""
  }
]

[
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    "id": "4233a8e0fb20e448",
    "type": "tab",
    "label": "UDP to MQTT flow",
    "disabled": false,
    "info": "",
    "env": []
  },
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    "userProps": "",
    "correl": "",
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    "noerr": 0,
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    "finalize": "",
    "libs": [],
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    "icon": "node-red/alert.svg"
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    "finalize": "",
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    "finalize": "",
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    "finalize": "",
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    "port": "1883",
    "clientid": "",
    "autoConnect": true,
    "usetls": false,
    "protocolVersion": "4",
    "keepalive": "60",
    "cleansession": true,
    "birthTopic": "",
    "birthQos": "0",
    "birthPayload": "",
    "birthMsg": {},
    "closeTopic": "",
    "closeQos": "0",
    "closePayload": "",
    "closeMsg": {},
    "willTopic": "",
    "willQos": "0",
    "willPayload": "",
    "willMsg": {},
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    "sessionExpiry": ""
  }
]

In Node-RED, click the red Deploy button at the top right of the screen to deploy your flow. Then, from the dropdown menu, select Restart to apply the changes and start the flow.

deploy

Next, open the debug tab in the sidebar and check if any logs appear. If you see logs, it means everything is functioning correctly. However, you may encounter errors like statusCode: 400, which occur because the application version and endpoint token have not been provided yet. As a result, the Kaa platform cannot identify the endpoint from which the data is coming.

nodered error

Specifying Application Version and Endpoint Token

To resolve this issue above, open the init CONSTANTS node and paste your application version and endpoint token into the code.
After making these changes, save the code, redeploy the flow, and restart it.

code_fix

Monitor the Data

If everything was configured correctly, the statusCode error should no longer appear.
Go back to Kaa, open your device page, and you should see the count variable displayed on the graph.

device page

About This Example

This example runs both the client and server on port 5000 within a single flow.

You can use this flow to configure your own device to send data to Kaa. If you’re running Node-RED on your local network, configure your device to send data to the IP address of the machine running Node-RED, using port 5000 (the Node-RED TCP/UDP server port).