Data forwarding

platform provides a variety of data forwarding methods, Open OpenAPI, Online subscription to websocket data, and MQTT subscription

Use Websocket to subscribe to real-time device messages

You can subscribe to devices, device alarms and other related messages through websockets.

interface

The websocket unified interface is: `/messaging/{token}`,
`{token}` can be accessed by logging into the system or using OpenAPI. 

Take front-end js as an example:

var ws = new WebSocket("ws://localhost:8844/messaging/a872d8e6cf6ccd38deb0c8772f6040e3");
ws.onclose=function(e){console.log(e)};
ws.onmessage=function(e){console.log(e.data)}

If authentication fails, the message {"message": "authentication failed", "type":"authError"} is immediately returned, and the connection is disconnected.

Subscribe to messages

Send a message to the websocket in the format:

{
    "type": "sub", // fixed as sub
    "topic": "/device/*/*/**", // topic, see topic list.
    "parameter": { // parameter, different subscription requests, different supported parameters
        
},
    "id": "request-id" //request ID, the identity of the request, which the server will return when pushing the message.
}

Note

Passing in the same id multiple times is invalid before canceling the subscription and the subscription will not be repeated.

Platform push message:

{
    "payload": // message content, different topics, different content,
    "requestId": "request-id", // matches the id of the subscription request
    "topic": "/device/katch/123456789012345/offline", //topic, the topic that actually generated the data
    "type": "result" //type result: subscription result complete: end subscription error: error occurred 
}

prompt

A complete type indicates that the subscription has ended, and is usually returned when subscribing to a limited stream of data (such as sending device instructions), or when unsubscribing.

Unsubscribe

Send a message to the websocket in the format:

{
    "type": "unsub", // fixed as unsub
     "id": "request-id" // Consistent with subscription request ID
}

Subscribe to device messages

Consistent with the device topic in the message gateway, [View topic list] (.. /best-practices/start.md# device messages correspond to event bus topics).
The message payload (payload) is the same as the [device message type] (.. /best-practices/start.md# Platform Unified Device Message Definitions).

Send device instructions

Send a message to the websocket

{
    "type": "sub", // fixed as sub
    "topic": "/device-message-sender/katch/123456789012345,123456789012346", // Send messages to 123456789012345 and 123456789012346 devices under the katch model
    "parameter": {
        Message types, supported: READ_PROPERTY (read properties), WRITE_PROPERTY (modify properties), INVOKE_FUNCTION (invoke function)
        "messageType":"READ_PROPERTY" 
        Depending on the message, the parameters are also different. See: Platform Unified Messaging Definitions
        "properties":["temperature"],
        Header information
        "headers":{
            "async": false // whether asynchronous, when asynchronous, the platform does not wait for the device to return the command result.
        }
    },
    "id": "request-id" //request ID, the identity of the request, which the server will return when pushing the message.
}

The platform will push the results of the device back:

{
    "payload": { //The result varies depending on the request message type
        "deviceId": "123456789012345",
        "messageType": "READ_PROPERTY_REPLY",
        "success": true, // whether the instruction succeeded
        "properties": {
            "temperature": 28.21
        },
        "timestamp": 1588148129787
    },
    "requestId": "request-id", //ID of the subscription request
    "topic": "/device/katchu/123456789012345/offline",
    "type": "result"
}

prompt

deviceId supports * and comma , split, send messages to devices in batches. Such as: /device-message-sender/{productId}/{deviceId}.
If you want to terminate the sending, just cancel the subscription.

Batch sync device status

Send a message to the websocket

{
    "type": "sub", // fixed as sub
    "topic": "/device-batch/state-sync",
    "parameter": {
        "query":{"where":"productId is test-device"}//Query condition is dynamic query condition
    },
    "id": "request-id" //request ID, the identity of the request, which the server will return when pushing the message.
}

Platform push:

{
    "payload": { //The result varies depending on the request message type
        "deviceId": "123456789012345",
        "state": {
            "value":"offline",
            "text": "offline"
        }
    },
    "requestId": "request-id", //ID of the subscription request
    "topic": "/device-batch/state-sync",
    "type": "result" // for comlete means that the synchronization is complete.
}

Subscribe to device alarm data

Send a message to the websocket

{
    "type": "sub", // fixed as sub
    "topic": "/data-forwarding/device/alarm/{productId}/{deviceId}/{alarmId}",
    "parameter": {},
    "id": "request-id" //request ID, the identity of the request, which the server will return when pushing the message.
}

Platform push:

{
    "payload": { //Alarm related data
        "deviceId": "Device ID",
        "deviceName": "Device Name",
        "alarmId": "alarm ID",
        "alarmName": "Alarm Name"
        //... Other alarm data
    },
    "requestId": "request-id", //ID of the subscription request
    "topic": "/data-forwarding/device/alarm/{productId}/{deviceId}/{alarmId}",
    "type": "result" // for comlete means end of subscription.
}

Use MQTT to subscribe to platform messages

TIP provides the function of subscribing to platform messages in MQTT. You can subscribe to devices, device alarms and other related messages through MQTT.

Authentication

By default, token (you can use OpenAPI to apply for tokens) as clientId, username and password can be left unfilled in.

Subscribe to device messages

The following are common subscription topics:

• /device/*/*/message/event/trackerRealTime real-time data
• /device/*/*/message/event/trackerAlarm alerts
• /device/*/*/message/event/iccid ICCID changes
• /device/*/*/online device is online
• /device/*/*/offline device is ideal
• /_d_s/*/*/message/state/register device enabled
• /_d_s/*/*/message/state/unregister device disabled
• /_d_s/*/*/message/state/bind devices are bound to the tenant
• /_d_s/*/*/message/state/unbind devices are untied from the tenant