The following diagram shows the structure of a CoAP packet
Version (2 bits) - CoAP version. Always 01 T (2 bits) - Transaction type TKL (4 bits) - Token length Code (8 bits) - Request or response code
Request codes
Binary | Code | Type |
|---|---|---|
GET | 1 |
|
POST | 2 |
|
PUT | 3 |
|
DELETE | 4 |
|
Response codes
Type | Code | Binary |
|---|---|---|
Created | 2.01 | |
Deleted | 2.02 | |
Changed | 2.04 | |
Content | 2.05 | |
Bad Request | 4.00 | |
Unauthorized | 4.01 | |
Not found (resource) | 4.04 | |
Method not allowed | 4.05 |
Message ID (16 bits) - Unique identifier for the packet. Used for duplicate detection. Token (up to 64 bits) - Used to match a response with a request Options (x bits) - Both requests and responses may include a list of one or more options. Payload Marker (8 bits) - Marks the beginning of the payload. Always 11111111
Example for publishing an event
For this, we are going to show the packet structure of a device publishing an Event to Wia. The packet itself, along with the payload, should be transmitted in hex format.
This shows a POST request (Code: 02) being submitted to the path "events" with the payload structure {"accessToken":"d_sk_abc123","name":"hello-wia","data":"12345"}.
To test with your own device, make a request replacing d_sk_abc123 with your device's access token.