JSONSchema v4 - 解析模式引用时出错 - 定义和参考

Question

尝试使用 http://www.jsonschemavalidator.net/、

验证以下架构时

{
    "id": "http://some.site.somewhere/entry-schema#",
    "$schema": "http://json-schema.org/draft-04/schema#",
    "description": "schema for the FormularSpecification",
    "definitions": {
        "elementId": {
            "id": "http://jsonschema.net/elementId",
            "type": "string"
        },
        "mappingKey": {
            "id": "http://jsonschema.net/mappingKey",
            "type": "string"
        },
        "elementType": {
            "id": "http://jsonschema.net/elementType",
            "type": "string"
        },
        "length": {
            "id": "http://jsonschema.net/length",
            "type": "integer"
        },
        "label": {
            "id": "http://jsonschema.net/label",
            "type": "string"
        },
        "content": {
            "id": "http://jsonschema.net/content",
            "type": "string"
        },
        "placeholder": {
            "id": "http://jsonschema.net/placeholder",
            "type": "string"
        },
        "date": {
            "id": "http://jsonschema.net/date",
            "type": "string"  
        },
        "option": {
            "id": "http://jsonschema.net/option",
            "type": "object",
            "properties": {
                "elementId": { "$ref": "#/definitions/elementId" },
                "label": { "$ref": "#/definitions/label" }
            },
            "required": ["elementId", "label"]
        },
        "options": {
            "id": "http://jsonschema.net/options",
            "type": "array",
            "items": { "$ref": "#/definitions/option" },
            "minItems": 1,
            "uniqueItems": true
        },
        "textfield": {
            "id": "http://jsonschema.net/textfield",
            "type": "object",
            "properties": {
                "elementId": { "$ref": "#/definitions/elementId" },
                "length": { "$ref": "#/definitions/length" },
                "label": { "$ref": "#/definitions/label" },
                "placeholder": { "$ref": "#/definitions/placeholder" },
                "textfieldType": {
                    "enum": [ "text", "ext4", "btrfs" ]
                }
            },
            "required": ["elementId", "length", "label", "placeholder", "textfieldType"]
        },
        "checkbox": {
            "id": "http://jsonschema.net/checkbox",
            "type": "object",
            "properties": {
                "label": { "$ref": "#/definitions/label" }
            },
            "required": ["label"]
        },
        "radio": {
            "id": "http://jsonschema.net/radio",
            "type": "object",
            "properties": {
                "label": { "$ref": "#/definitions/label" },
                "options": { "$ref": "#/definitions/options" }
            },
            "required": ["label", "options"]
        },
        "dropdown": {
            "id": "http://jsonschema.net/dropdown",
            "type": "object",
            "properties": {
                "label": { "$ref": "#/definitions/label" },
                "options": { "$ref": "#/definitions/options" }
            },
            "required": ["label", "options"]
        },
        "validator": {
            "id": "http://jsonschema.net/validator",
            "type": "object",
            "properties": {
                "elementId": { "$ref": "#/definitions/elementId" }
            }
        },
        "validators": {
            "id": "http://jsonschema.net/validators",
            "type": "array",
            "items": { "$ref": "#/definitions/validator" }
        },
        "interactiveDetails": {
            "type": "object",
            "oneOf": [
                { "textfield": { "$ref": "#/definitions/textfield" } },
                { "checkbox": { "$ref": "#/definitions/checkbox" } },
                { "radio": { "$ref": "#/definitions/radio" } },
                { "dropdown": { "$ref": "#/definitions/dropdown" } },
                { "date": { "$ref": "#/definitions/date" } }
            ]
        },
        "interactive": {
            "id": "http://jsonschema.net/interactive",
            "type": "object",
            "properties": {
                "elementId": { "$ref": "#/definitions/elementId" },
                "elementType": { "$ref": "#/definitions/elementType" },
                "mappingKey": { "$ref": "#/definitions/mappingKey" },
                "validators": { "$ref": "#/definitions/validators" },
                "interactiveDetails" : { "$ref": "#/definitions/interactiveDetails" }
            },
            "required": ["elementId", "elementType", "mappingKey", "validators"]
        },
        "interactives": {
            "id": "http://jsonschema.net/interactives",
            "type": "array",
            "items": { "$ref": "#/definitions/interactive" }
        },
        "description": {
            "id": "http://jsonschema.net/description",
            "type": "object",
            "properties": {
                "elementId": { "$ref": "#/definitions/elementId" },
                "elementType": { "$ref": "#/definitions/elementType" },
                "content": { "$ref": "#/definitions/content" }
            },
            "required": ["elementId", "elementType", "content"]
        },
        "descriptions": {
            "items": { "$ref": "#/definitions/description" }
        },
        "children": {
            "items": { 
                "anyOf": [
                    { "$ref": "#/definitions/group" },
                    { "$ref": "#/definitions/question" }
                ]
            },
            "minItems": 1
        },
        "question": {
            "type": "object",
            "properties": {
                "elementId": { "$ref": "#/definitions/elementId" },
                "descriptions": { "$ref": "#/definitions/descriptions" },
                "interactives": { "$ref": "#/definitions/interactives" }
            },
            "required": ["elementId", "descriptions", "interactives"]
        },
        "group": {
            "type": "object",
            "properties": {
                "elementId": { "$ref": "#/definitions/elementId" },
                "descriptions": { "$ref": "#/definitions/descriptions" },
                "children": { "$ref": "#/definitions/children"}
            },
            "required": ["elementId", "descriptions", "children"]
        }
    },
    "type": "object",
    "properties": {
        "elementId": { "$ref": "#/definitions/elementId" },
        "description": { "$ref": "#/definitions/descriptions" },
        "children": { "$ref": "#/definitions/children" }
    },
    "required": [
        "elementId",
        "descriptions",
        "children"
    ]
}

我收到以下错误：

Error when resolving schema reference '#/definitions/elementId'. Path 'definitions.description.properties.elementId', line 135, position 30.

我不知道是什么问题。翻了好几遍文档，也看了教程，但是一点头绪都没有。

Answer 1

id 关键字的语义有点混乱。我不确定我自己是否完全理解它。一般来说，在架构的根以外的任何地方包含 id 几乎都不是一个好主意。

The "id" keyword (or "id", for short) is used to alter the resolution scope. When an id is encountered, an implementation MUST resolve this id against the most immediate parent scope. The resolved URI will be the new resolution scope for this subschema and all its children, until another id is encountered.

http://json-schema.org/latest/json-schema-core.html#anchor27

考虑以下来自您的架构的摘录。因为您包含了 id 关键字，所以您的“elementId”和“label”$ref 不会像您期望的那样根据文档的根进行解析，它们会从最近的父架构 id.

"option": {
    "id": "http://jsonschema.net/option",
    "type": "object",
    "properties": {
        "elementId": { "$ref": "#/definitions/elementId" },
        "label": { "$ref": "#/definitions/label" }
    },
    "required": ["elementId", "label"],
    "definitions": { ... }  <-- your $refs expect values here
    }
},

我看到在某些圈子中，人们为每个子模式编写带有 id 的模式。我不确定他们认为这样做有什么好处，但我怀疑他们认为 id 只是一个标签，不明白它如何改变分辨率范围。

如果你确实有充分的理由在任何地方使用 ids 并且想保留它们，当你有冲突时你总是可以显式引用根 id。

{ "$ref": "http://some.site.somewhere/entry-schema#definitions/elementId" }

JSONSchema v4 - 解析模式引用时出错 - 定义和参考

JSONSchema v4 - Error when resolving schema reference - Definitions and References

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