matrix-spec-proposals/event-schemas/schema/v1/core

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "definitions": {
    "event": {
      "title": "Event",
      "description": "The basic set of fields all events must have.",
      "type": "object",
      "properties": {
        "event_id": {
          "type": "string",
          "description": "The globally unique event identifier."
        },
        "user_id": {
          "type": "string"
        },
        "content": {
          "type": "object",
          "description": "The fields in this object will vary depending on the type of event."
        },
        "type": {
          "type": "string",
          "description": "The type of event. This SHOULD be namespaced similar to Java package naming conventions e.g. 'com.example.subdomain.event.type'"
        }
      },
      "required": ["event_id", "user_id", "content", "type"]
    },
    "room_event": {
        "type": "object",
        "title": "Room Event",
        "description": "The basic set of fields all room events must have.",
        "allOf":[{
            "$ref": "#/definitions/event"
        }],
        "properties": {
            "room_id": {
                "type": "string"
            }
        },
        "required": ["room_id"]
    },
    "state_event": {
        "type": "object",
        "title": "State Event",
        "description": "The basic set of fields which define a room state event.",
        "allOf":[{
            "$ref": "#/definitions/room_event"
        }],
        "properties": {
            "state_key": {
                "type": "string",
                "description": "A unique key which defines the overwriting semantics for this piece of room state. This value is often a 0-length string."
            },
            "prev_content": {
                "type": "object",
                "description": "The previous content if this event has overwritten another event."
            }
        },
        "required": ["state_key"]
    }
  }
}