{
  "schema": {
    "bsonType": "object",
    "required": [],
    "permission": {
      "read": "doc.user_id == auth.uid",
      "create": false,
      "update": "doc.user_id == auth.uid",
      "delete": false
    },
    "properties": {
      "_id": {
        "description": "ID，系统自动生成"
      },
      "id": {
        "description": "会话ID，由会话双方用户的id按一定规律排序后的哈希值",
        "permission": {
          "write": false
        }
      },
      "type": {
        "description": "会话类型，区分：群聊和单聊",
        "bsonType": "int",
        "label": "",
        "permission": {
          "write": false
        }
      },
      "user_id": {
        "description": "所属用户id",
        "bsonType": "string",
        "permission": {
          "write": false
        }
      },
      "friend_uid": {
        "description": "对话的好友的用户id",
        "permission": {
          "write": false
        }
      },
      "group_id": {
        "description": "对话的群id",
        "permission": {
          "write": false
        }
      },
      "unread_count": {
        "description": "未读消息数量",
        "bsonType": "int",
        "defaultValue": 0
      },
      "last_msg_note": {
        "description": "最后一条消息概述（文本消息的前n个字，消息为多媒体时只描述类型）"
      },
      "update_time": {
        "bsonType": "timestamp",
        "description": "最后一次会话时间",
        "defaultValue": {
          "$env": "now"
        }
      }
    }
  },
  "index": [
    {
      "IndexName": "id",
      "MgoKeySchema": {
        "MgoIndexKeys": [
          {
            "Name": "id",
            "Direction": "1"
          }
        ],
        "MgoIsUnique": false
      }
    }
  ]
}