HTTP Integration

• Data Flow Overview
• Prerequisites
• Create SENTIENT Integration
• Create ST-RMQTT HTTP Integration
  • Topic Filters
  • Configuration
  • Events
• Sending an Uplink Message

ST-RMQTT HTTP Integration provides a simple and efficient way to forward MQTT messages from devices to an external system using the HTTP protocol. It acts as a bridge between ST-RMQTT and external applications, ensuring seamless and reliable data exchange.

Data Flow Overview

ST-RMQTT HTTP Integration enables forwarding MQTT messages to an external HTTP service:

1. Device (client) publishes an MQTT message to a topic that matches the Integration’s Topic Filters.
2. ST-RMQTT broker receives the message and forwards to ST-RMQTT Integration Executor.
3. ST-RMQTT Integration Executor processes the message, formats it as an HTTP request, and forwards it to the external service.
4. External service receives the request and processes the data accordingly.

Prerequisites

Before setting up the integration, ensure the following:

• A running ST-RMQTT instance.
• An external service ready to receive HTTP requests (e.g., SENTIENT Cloud).
• A client capable of publishing MQTT messages (e.g., ST-RMQTT WebSocket Client).

Create SENTIENT Integration

In this tutorial, we use SENTIENT as the external service receiving HTTP requests from ST-RMQTT. However, any other HTTP-compatible service can be used.

Follow the official SENTIENT HTTP Integration Guide to create an integration on SENTIENT Cloud.

Once the HTTP Integration is created:

1. Open the details page and enable debug mode to verify data reception.
2. Copy the HTTP endpoint URL, as this will be needed in the next step.

Create ST-RMQTT HTTP Integration

1. Go to the Integrations page and click the “+” button to create a new integration.
2. Select HTTP as the integration type and click Next.
3. On the Topic Filters page click Next to subscribe to the default topic st-rmqtt/#.
4. In the Configuration step, paste the Endpoint URL from the SENTIENT Integration.
5. Open Advanced settings and set Payload content type to JSON.
6. Click Add to save the integration.

You can test the connectivity to the configured HTTP endpoint by sending a HEAD request using the ‘Check connection’ button.

Topic Filters

Topic filters define MQTT-based subscriptions and act as triggers for ST-RMQTT HTTP Integration. When the broker receives a message matching configured topic filters, the integration processes it and forwards the data to the specified external system.

If the integration is configured with the topic filter:

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st-rmqtt/devices/+/status

Then, any message matching this pattern will trigger the integration, including:

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st-rmqtt/devices/device-01/status
st-rmqtt/devices/gateway-01/status

Configuration

Events

ST-RMQTT provides logging for integration-related events, allowing users to debug and troubleshoot integration behavior. Below are three ‘Event’ types:

• Lifecycle Events – Logs events such as Started, Created, Updated, Stopped, etc.

• Statistics – Provides insights into integration performance, including the number of processed messages and occured errors.

• Errors – Captures failures related to authentication, timeouts, payload formatting, or connectivity issues with the external service.

Sending an Uplink Message

To send a message, follow these steps:

1. Navigate to the WebSocket Client page.
2. Select ‘WebSocket Default Connection’ or any other available working connection, then click Connect. Make sure the ‘Connection status’ is shown as Connected.
3. Set the ‘Topic’ field to st-rmqtt/http-integration to match the Integration’s ‘Topic Filter’ st-rmqtt/#.
4. Click the Send icon to publish the message.
5. If successfull, the message should appear in the ‘Messages’ table.

Once the message is published:

1. In the SENTIENT Cloud open the HTTP Integration details.
2. Go to the Events tab.
3. If the setup is correct, you should see an event with the status ‘OK’ and a message payload similar to:

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{
    "payload": {
        "temperature": 25
    },
    "topicName": "st-rmqtt/http-integration",
    "clientId": "st-rmqtt_7QUvZzow",
    "eventType": "PUBLISH_MSG",
    "qos": 1,
    "retain": false,
    "st-rmqttIeNode": "st-rmqtt_ie_node",
    "st-rmqttNode": "st-rmqtt_node",
    "ts": 1742553324248,
    "props": {},
    "metadata": {
        "integrationName": "HTTP integration"
    }
}

Message description:

• payload: Content of the MQTT message.
• topicName: The MQTT topic to which the message was published.
• clientId: The ID of the MQTT client that published the message.
• eventType: Type of MQTT event, here it’s a published message (the only supported type for now).
• qos: Quality of Service level used for the incoming message.
• retain: Indicates if the message is a retained MQTT message.
• st-rmqttIeNode: Node ID of the Integration Executor service that handled the message.
• st-rmqttNode: Node ID of the ST-RMQTT broker that received the message.
• ts: Timestamp (in milliseconds) when the message was received.
• props: MQTT 5.0 user properties or other MQTT properties.
• metadata: Additional metadata added from integration configuration, e.g., the name of the integration that handled the message, added by default.