​
Overview

Event subscription is a mechanism that allows clients to receive real-time updates from the server. This is particularly useful for applications that require live data, such as chat applications, stock tickers, or any other application where data changes frequently.

​
Lifecycle

The following flow represents message exchanges between a client and a server during the subscription process.

​
Targets

The server can send events to the following targets (highlighted in bold):

​
Reference

​
Messages

​
subscription/add Message

Request to subscribe to a specific event type sent by a client. 
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "subscription/add",
  "params": {
    "scope": "revision",
    "scope_id": "0A06AB3A-DD72-4D42-939A-61DC4EF69418",
    "target": "session",
    "target_id": "28E70055-DBB4-4CA8-88BC-133D6CEA68E6",
    "types": [
      "execution_started",
      "execution_ended"
    ]
  }
}
Server is expected to respond with a confirmation message indicating success: 
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {}
}
Or an error message indicating failure: 
{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": 403,
    "message": "Access forbidden"
  }
}

​
subscription/remove Message

Request to unsubscribe from a specific event type sent by a client. 
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "subscription/remove",
  "params": {
    "scope": "revision",
    "scope_id": "0A06AB3A-DD72-4D42-939A-61DC4EF69418",
    "target": "session",
    "target_id": "28E70055-DBB4-4CA8-88BC-133D6CEA68E6",
    "types": [
      "execution_started",
      "execution_ended"
    ]
  }
}
Request processing confirmation is delivered back to the client.

​
subscription/event Message

Notification sent by the server to indicate that an event has occurred. 
{
  "jsonrpc": "2.0",
  "method": "subscription/event",
  "params": {
    "scope": "revision",
    "scope_id": "0A06AB3A-DD72-4D42-939A-61DC4EF69418",
    "target": "session",
    "target_id": "28E70055-DBB4-4CA8-88BC-133D6CEA68E6",
    "type": "execution_started",
    "execution": {
      "id": "452CDAC7-2ED0-4D24-8436-C6D45B34B331"
    }
  }
}

​
Events

​
Workflow Blob - session Target

{
  "jsonrpc": "2.0",
  "method": "subscription/event",
  "params": {
    "scope": "revision",
    "scope_id": string,
    "target": "session",
    "target_id": string,
    "type": string,
    ...
    }
  }
}