JSON Validate

履歴

リリース	内容
21 R2	Support of JSON Schema draft 2020-12

JSON Validate ( vJson : Object ; vSchema : Object ) : Object

引数	型		説明
vJson	Object	→	JSON object to validate
vSchema	Object	→	JSON schema used to validate JSON objects
戻り値	Object	←	Validation status and errors (if any)

説明

The JSON Validate command checks the compliance of the vJson JSON contents with the rules defined in the vSchema JSON schema. If the JSON is invalid, the command returns a detailed description of error(s).

In vJson, pass a JSON object containing the JSON contents to be validated.

Note: Validating a JSON string consists of checking that it follows the rules defined in a JSON schema. This is different from checking that the JSON is well-formed, which is done by the JSON Parse command.

In vSchema, pass the JSON schema to use for the validation. For more information on how to create a JSON schema, you may consult the json-schema.org web site.

Supported JSON schema validation drafts

To validate a JSON object, 4D uses the norm described in a JSON Schema Validation draft document. Several versions of these documents have been produced over time.

4D supports two versions of the draft:

• version 2020-12 (recommended). All parts of the norm are supported, except:
  • vocabulary
  • contentEncoding, contentMediaType, and contentSchema (validation of non-JSON content)
  • for references: $dynamicRef/$dynamicAnchor and references in https:...
• version 4 (legacy implementation, used by default). Note that the support of this norm has more limitations than version 2020-12.

Specifying the version to use

The version to use should be inserted in the schema using the $schema key:

• version 2020-12:

"$schema": "https://json-schema.org/draft/2020-12/schema",

• version 4:

"$schema": "http://json-schema.org/draft-04/schema#",

For compatibility reasons, the version 4 is used if the $schema key is omitted. However, it is recommended to use the version 2020-12 which provides the most reliable controls.

注

If you declare another schema version using the $schema key, an error is returned.

Validation result

If the JSON schema is not valid, 4D returns a Null object and throws an error that can be caught by an on error call method.

The JSON Validate returns an object that provides the status of the validation. このオブジェクトには、次のプロパティが格納されることがあります:

プロパティ名	型	Description
success	Boolean	True if vJson is validated, false otherwise. If false, the errors property is also returned
errors	Object collection	List of error objects if the vJson is not validated (see below)

Each error object of the errors collection contains the following properties:

プロパティ名	型	Description
code	Number	エラーコード
jsonPath	Text	JSON path that cannot be validated in vJson
line	Number	Line number of the error in the JSON file. This property is filled if the JSON has been parsed by JSON Parse with the * parameter. Otherwise, the property is omitted.
message	Text	エラーメッセージ
offset	Number	Line offset of the error in the JSON file. This property is filled if the JSON has been parsed by JSON Parse with the * parameter. Otherwise, the property is omitted.
schemaPaths	Text	JSON path in the schema that causes the validation error

Error list

Details

The following errors may be returned:

Code	JSON Keyword	Message
2	multipleOf	Error while validating against 'multipleOf' key.
3	最大	The value provided should not be greater than specified in the schema ("{s1}").
4	exclusiveMaximum	The value provided should be less than specified in the schema ("{s1}").
5	最小	The value provided should not be less than specified in the schema ("{s1}").
6	exclusiveMinimum	The value provided should be greater than specified in the schema ("{s1}").
7	maxLength	The string is longer than specified in the schema.
8	minLength	The string is shorter than specified in the schema.
9	パターン	The string "{s1}" does not match the pattern in the schema:{s2}.
10	additionalItems	Error while validating an array. JSON contains more elements than specified in the schema.
11	maxItems	The array contains more items than specified in the schema.
12	minItems	The array contains less items than specified in the schema.
13	uniqueItems	Error while validating an array. Elements are not unique. Another instance of "{s1}" is already in the array.
14	maxProperties	The number of properties is greater than specified in the schema.
15	minProperties	The number of properties is less than specified in the schema.
16	必須	The required property "{s1}" is missing.
17	additionalProperties	No additional properties allowed by the schema. The property(ies) {s1} should be removed.
18	依存関係	The property "{s1}" requires the property "{s2}".
19	enum	Error while validating against 'enum' key. "{s1}" does not match any enum element in the schema.
20	type	Incorrect type. Expected type is: {s1}
21	oneOf	The JSON matches more than one value.
22	oneOf	The JSON does not match any value.
23	not	The JSON is invalid against the value of 'not'.
24	format	The string does not match ("{s1}")
25	const	Value "{s1}" does not match the 'const' value in the schema.
26	unevalutedProperties	Unevaluated properties are not allowed by the schema. The property(ies) {s1} should be removed.
27	unevalutedItems	Unevaluated array items are not allowed. Item at index {s1} is not covered by any schema.
28	propertyNames	Property name "{s1}" does not validate against the 'propertyNames' schema.
29	contains	Array does not contain any items matching the 'contains' schema.
30	contains	Array must contain at least {s1} items matching the 'contains' schema, but only {s2} were found.
31	contains	Array must contain at most {s1} items matching the 'contains' schema, but {s2} were found.
32	必須	The property "{s1}" requires the property "{s2}" to be present.
35	prefixItems	Array items at the beginning do not match the 'prefixItems' schemas.
36	dependentSchemas	Validation failed against 'dependentSchemas'.
37	$ref	Reference could not be resolved.
38	$ref	Circular reference detected.

関連したblog 記事

Simplify JSON Validation and Boost Robustness

例題

You want to validate a JSON object with a schema and get the list of validation errors, if any, and store error lines and messages in a text variable:

 var $oResult : Object
 $oResult:=JSON Validate(JSON Parse(myJson;*);mySchema)
 If($oResult.success) //validation successful
    ...
 Else //validation failed
    var $vLNbErr : Integer
    var $vTerrLine : Text
    $vLNbErr:=$oResult.errors.length ///get the number of error(s)
    ALERT(String($vLNbErr)+" validation error(s) found.")
    For($i;0;$vLNbErr)
       $vTerrLine:=$vTerrLine+$oResult.errors[$i].message+" "+String($oResult.errors[$i].line)+Carriage return
    End for
 End if

参照

JSON Parse

プロパティ

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