Direct Device MQTT Interaction Spec

Overview

This specification describes the technical requirements for connecting direct devices to the ThingsPanel platform via the MQTT protocol, defining the data interaction format and communication protocol between the device and the platform.

Core Concepts

Four Core Data Types

Before starting, understanding these four core concepts is crucial:

• 🔄 Telemetry - Real-time data reported by devices, usually measurements changing over time.
  • Example: Temperature readings reported periodically.
• 📋 Attributes - Static or less frequently changing characteristics of devices.
  • Example: Device IP, MAC address, or firmware version.
• 🎯 Events - Specific events or state changes occurring in devices.
  • Example: Motion detected or device boot completed.
• ⚡ Commands - Control instructions sent from the platform to devices.
  • Example: Turn on light or reboot device.

Key Parameters

📍 message_id

• Function: Unique message identifier to ensure no duplication. No length limit.
• Suggestion: Use the last 7 digits of the timestamp (ms).
• Requirement: Unique within a short period.

🏷️ device_number (Device ID)

• Function: Unique identifier of the device in the system.
• Requirement: Globally unique, no duplicates.

🎭 method

• Definition: String identifying a specific command or event type.
• Command Examples: "SetTemperature", "TurnOnLight", "RebootDevice"
• Event Examples: "TemperatureExceeded", "MotionDetected", "BatteryLow"

⚙️ params

• Function: Contains detailed info or data related to the method.
• Command Scenario: Provides specific parameters needed for command execution.
• Event Scenario: Contains data describing the event.

MQTT Authentication Rules

Auth Requirements

🔐 Uniqueness

• Username + Password combination must be globally unique.
• ClientID must be globally unique.

🔄 Consistency

• Devices must use the same auth info for every connection.
• Keep ClientID, Username, and Password consistent.

MQTT Topic Specification

Flexible Implementation

Important: Devices do not need to implement all listed MQTT topics. Selectively implement relevant topics based on specific device functions and scenarios.

Device Publish Topics

Topic	Description	Data Type	Required
devices/telemetry	Report telemetry data	Telemetry	Optional
devices/attributes/{message_id}	Report attributes	Attributes	Optional
devices/event/{message_id}	Report events	Events	Optional
ota/devices/progress	Report OTA progress	OTA	Optional
devices/command/response/{message_id}	Command response	Response	Optional
devices/attributes/set/response/{message_id}	Attribute set response	Response	Optional

Device Subscribe Topics

Topic Note

Note: + is a wildcard for message_id, {device_number} is the specific device ID.

Topic	Description	Data Type	Required
devices/telemetry/control/{device_number}	Receive control commands	Control	Optional
devices/attributes/set/{device_number}/+	Receive attribute set commands	Attribute Set	Optional
devices/attributes/get/{device_number}	Receive attribute get requests	Attribute Get	Optional
devices/command/{device_number}/+	Receive command execution requests	Command	Optional
ota/devices/inform/{device_number}	Receive OTA tasks	OTA	Optional
devices/attributes/response/{device_number}/+	Receive attribute response ack	Response Ack	Optional
devices/event/response/{device_number}/+	Receive event response ack	Response Ack	Optional

Data Interaction Format

🔄 Telemetry Reporting

Topic: devices/telemetry

Real-time Mode

Direct key-value pairs. System uses server reception time as timestamp.

Real-time Telemetry Example

{
  "temperature": 25.5,
  "humidity": 65.0,
  "switch": true
}

Historical Mode

Time-series array format. Each record contains timestamp and values.

Historical Telemetry Example

[
  {"ts": 1609459200, "values": {"temperature": 22.5, "humidity": 60.0}},
  {"ts": 1609462800, "values": {"temperature": 23.0, "humidity": 61.5}}
]

Format Recognition

• Real-time: Root level is key-value object.
• Historical: Root level is array, elements contain ts and values.

Field Description:

• ts: Unix timestamp (seconds).
• values: Telemetry key-value pairs at that time.

📋 Attribute Reporting

Topic: devices/attributes/{message_id}

Attribute Example

{
  "ip": "192.168.1.100",
  "mac": "00:11:22:33:44:55",
  "version": "1.0.0"
}

🎯 Event Reporting

Topic: devices/event/{message_id}

Real-time Mode

Real-time Event Example

{
  "method": "AlarmTriggered",
  "params": {
    "level": "high",
    "sensor": "temperature"
  }
}

Historical Mode

Historical Event Example

[
  {
    "ts": 1609459200000,
    "method": "AlarmTriggered",
    "params": {
      "level": "high",
      "sensor": "temperature"
    }
  },
  {
    "ts": 1609462800000,
    "method": "DeviceStarted",
    "params": {
      "version": "1.0.0",
      "mode": "normal"
    }
  }
]

Format Recognition

• Real-time: Root contains method and no ts.
• Historical: Root is array, elements contain ts and method.

Field Description:

• ts: Unix timestamp (milliseconds).
• method: Event name, required.
• params: Event parameters, optional.

📦 OTA Progress Reporting

Topic: ota/devices/progress

Success:

{
  "step": "100",
  "desc": "Upgrade 100%",
  "module": "MCU"
}

Failure:

{
  "step": "-1",
  "desc": "OTA Failed, download failed",
  "module": "MCU"
}

Step Description

Step	Description
1-100	Progress percentage
-1	Upgrade failed
-2	Download failed
-3	Verification failed
-4	Flash failed

⚡ Receive Control Commands

Topic: devices/telemetry/control/{device_number}

{
  "temperature": 25.0,
  "brightness": 80,
  "switch": true
}

📋 Receive Attribute Set

Topic: devices/attributes/set/{device_number}/+

{
  "ip": "192.168.1.100",
  "heartbeat": 30,
  "report_interval": 60
}

🔍 Receive Attribute Get

Topic: devices/attributes/get/{device_number}

Get All:

{
  "keys": []
}

Get Specific:

{
  "keys": ["temperature", "humidity"]
}

⚡ Receive Command Execution

Topic: devices/command/{device_number}/+

{
  "method": "Restart",
  "params": {
    "delay": 5,
    "mode": "safe"
  }
}

📦 Receive OTA Task

Topic: ota/devices/inform/{device_number}

OTA Task Params

Param	Type	Description
id	Long	Message ID
code	String	Status code
version	String	Version info
size	Long	Size in bytes
url	String	Download URL
sign	String	Signature
signMethod	String	SHA256, MD5
module	String	Module name
extData	Object	Extra info

{
  "id": "1001",
  "code": 200,
  "params": {
    "version": "2.0.1",
    "size": 1024000,
    "url": "https://example.com/firmware/device_v2.0.1.bin",
    "signMethod": "MD5",
    "sign": "d41d8cd98f00b204e9800998ecf8427e",
    "module": "MCU",
    "extData": {
      "description": "Fix temperature sensor bug",
      "mandatory": true
    }
  }
}

Response Format

Response Params

Param	Required	Type	Description
result	✅	number	Result: 0-Success, 1-Fail
errcode	❌	string	Error code (if fail)
message	✅	string	Message content
ts	❌	number	Timestamp (s)
method	❌	string	Method name

Examples

Success:

{
  "result": 0,
  "message": "success",
  "ts": 1609459200
}

Failure:

{
  "result": 1,
  "errcode": "INVALID_PARAM",
  "message": "Parameter validation failed",
  "ts": 1609459200,
  "method": "Restart"
}

Best Practices

Development Tips

1. Message ID: Suggest last 7 digits of timestamp.
2. Selective Implementation: Only implement necessary topics.
3. Auth Info: Keep consistent.
4. Error Handling: Implement full error response.
5. Data Validation: Validate JSON.
6. Keep Alive: Implement MQTT heartbeat.
7. Reconnection: Auto reconnect on network error.
8. OTA: Report progress.