{
    "categories": {
        ".read": true,
        ".update": "$role === 'admin'",
        ".add": "$role === 'admin'",
        ".remove": "$role === 'admin'"
    },
    "articles": {
        ".read": true,
        ".update": {
            "condition": "$admin === true",
            "data": {
                "title": {"length": [1, 64], "required": true },
                "content": {"length": [1, 20480]},
                "password": { "match": "^\\d{6,10}$"},
                "author_id": "value == $userid"
            },
            "query": {
                "_id": "get($value).author_id === $userid"
            }
        },
        ".add": {
            "condition": "$admin === true",
            "data": { 
                "type": {"required": true, "in": ["choice", "fill"]}, 
                "title": {"length": [4, 64], "required": true, "unique": true},
                "content": {"length": [4, 20480]},
                "total": {"number": [0, 100], "default": 0, "required": true},
                "author_id": { "condition": "$value == $userid" }
            }
        },
        ".remove": {
            "condition":"$admin === true",
            "query": {
                "id": "get($value).author_id === $userid // TODO 尚未实现 get 函数"
            }
        }
    }
}