Message Schemas
5. Message Schemas
Each MessageTypeId is defined by a corresponding JSON schema, along with usage metadata to guide developers, integrators, and permission systems.
Message schemas define:
- The structure and required fields for each
Payload - Which devices or roles may send or receive it
- Whether the message is text-only or binary-framed
- Validation rules used by W3S middleware
Schema Entry Format
Each entry includes:
| Field | Description |
|---|---|
| MessageTypeId | Unique identifier string |
| Name | Human-readable label |
| Description | Summary of message purpose |
| Direction | Who sends and receives the message (e.g. OSS8 → W3S, Client → W3S) |
| Schema | A versioned JSON schema definition |
| Example | An example message (text or header of binary) |
| Binary Payload? | Yes / No. Indicates whether this message uses the binary framing format |
| Notes | Special considerations (permissions, alarms, size limits, etc.) |
Alarm Notes (Binary Messages)
For binary message types (e.g., OSS_IMAGE_FRAME), the Payload inside the JSON header may include alarm data.
- This data is optional — present only when detections occur
- The field
alarmRegionsmust be omitted entirely if no detections are present - When included, these alarms are treated as primary payload content
- See Section 6 – Alarm Data for structure and semantics