{ "$schema": "http://json-schema.org/draft-04/schema#", "definitions": { "event": { "type": "object", "properties": { "event_id": { "type": "string" }, "user_id": { "type": "string" }, "content": { "type": "object" }, "type": { "type": "string" } }, "required": ["event_id", "user_id", "content", "type"] }, "room_event": { "type": "object", "allOf":[{ "$ref": "#/definitions/event" }], "properties": { "room_id": { "type": "string" } }, "required": ["room_id"] } } }