从外部 JSON 模式导入所有定义

Question

我一直在尝试使用JSON Pointers 来引用和重用JSON schemas。

按照这些示例，我能够引用在另一个 JSON 模式中声明的特定属性，并且一切都按预期进行，但是我还没有找到一种方法来使用另一个基本模式的定义来扩展基本 JSON 模式，而无需显式引用每个属性。

似乎这会很有用，但我还没有发现它可能或不可能的迹象。

想象一下基本架构things：

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "id": "http://example.com/thing.json",
    "type": "object",
    "additionalProperties": false,
    "properties": {
        "url": {
            "id": "url",
            "type": "string",
            "format": "uri"
        },
        "name": {
            "id": "name",
            "type": "string"
        }
    },
    "required": ["name"]
}

如果我想要一个更具体的 person 架构，它可以重用 thing 的两个属性，我可以这样做：

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "id": "http://example.com/thing/person.json",
    "type": "object",
    "additionalProperties": false,
    "properties": {
        "url": {
            "$ref": "http://example.com/thing.json#/properties/url",
        },
        "name": {
            "$ref": "http://example.com/thing.json#/properties/name",
        },
        "gender": {
            "id": "gender",
            "type": "string",
            "enum": ["F", "M"]
        },
        "nationality": {
            "id": "nationality",
            "type": "string"
        },
        "birthDate": {
            "id": "birthDate",
            "type": "string",
            "format": "date-time"
        }
    },
    "required": ["gender"]
}

但是，我发现这种方法存在两个问题：

1. 更新超定义后，也必须更新相关架构
2. 手动维护所有这些引用变得繁琐/冗长
3. 规则（如required: name）不是引用定义的一部分

有没有办法通过使用单个全局引用来获得以下有效 JSON 模式？

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "id": "http://example.com/thing/person.json",
    "type": "object",
    "additionalProperties": false,
    "properties": {
        "url": {
            "id": "url",
            "type": "string",
            "format": "uri"
        },
        "name": {
            "id": "name",
            "type": "string"
        }
        "gender": {
            "id": "gender",
            "type": "string",
            "enum": ["F", "M"]
        },
        "nationality": {
            "id": "nationality",
            "type": "string"
        },
        "birthDate": {
            "id": "birthDate",
            "type": "string",
            "format": "date-time"
        }
    },
    "required": ["name", "gender"]
}

我尝试在架构的根目录中包含 $ref，如下所示：

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "id": "http://jsonschema.net/thing/person",
    "type": "object",
    "additionalProperties": false,
    "$ref": "http://example.com/thing.json",
    "properties": {
        "gender": {/* ... */},
        "nationality": {/* ... */},
        "birthDate": {/* ... */}
    },
    "required": ["gender"]
}

这具有继承thing 属性但忽略所有其他属性的效果：

gender: Additional property gender is not allowed
nationality: Additional property nationality is not allowed
birthDate: Additional property birthDate is not allowed

Answer 1

您正在寻找allOf 关键字。 JSON Schema 不像我们许多人习惯的那样进行继承。相反，您可以告诉它数据需要对父模式（事物）和子模式（人）都有效。

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "id": "http://example.com/thing.json",
    "type": "object",
    "properties": {
        "url": {
            "id": "url",
            "type": "string",
            "format": "uri"
        },
        "name": {
            "id": "name",
            "type": "string"
        }
    },
    "required": ["name"]
}

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "id": "http://example.com/thing/person.json",
    "allOf": [
        { "$ref": "http://example.com/thing.json" },
        {
            "type": "object",
            "properties": {
                "gender": {
                    "id": "gender",
                    "type": "string",
                   "enum": ["F", "M"]
                },
                "nationality": {
                    "id": "nationality",
                    "type": "string"
                },
                "birthDate": {
                    "id": "birthDate",
                    "type": "string",
                    "format": "date-time"
                }
            },
            "required": ["gender"]
        }
    ],
}

或者，我更喜欢写得更简洁

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "id": "http://example.com/thing/person.json",
    "allOf": [{ "$ref": "http://example.com/thing.json" }],
    "properties": {
        "gender": {
            "id": "gender",
            "type": "string",
            "enum": ["F", "M"]
        },
        "nationality": {
            "id": "nationality",
            "type": "string"
        },
        "birthDate": {
            "id": "birthDate",
            "type": "string",
            "format": "date-time"
        }
    },
    "required": ["gender"]
}

请注意，使用这种方法，您不能使用"additionalProperties": false。正是出于这个原因，我总是建议人们最好的做法是忽略其他属性，而不是明确禁止它们。