how can I override the validation rules which are defined in a json schema which is inherited by the "allOf" keyword?
Example:
{
"$schema": "http://json-schema.org/draft-06/schema",
"title": "My JSON Schema",
"description": "",
"definitions": {
"a": {
"type": "object",
"properties": {
"b": {
"type": "object",
"properties": {
"c": {
"type": "string",
"minLength": 1,
"maxLength": 100
}
},
"required": [
"c"
]
}
},
"required": [
"b"
]
}
},
"properties": {
"main": {
"type": "object",
"allOf": [
{
"$ref": "#/definitions/a"
}
]
},
"sub": {
"type": "object",
"allOf": [
{
"$ref": "#/definitions/a"
}
]
}
}
}
The json schema defines two objects:
main
sub
Both objects inherit their properties from the defined object "a"
But the object "sub" should have other validation rules for property b.c (currently it is minLength 1 and maxLength 100).
So of course following json is invalid:
{
"main" :{
"b": {
"c": "This property has a min length"
}
},"sub" : {
"b": {
"c": ""
}
}
}
How can I override the validation rules for property b.c?
There is currently no way to do this perscribed by the JSON Schema specification.
Related
We want to validate an array of elements with a JSON Schema Validator (https://github.com/networknt/json-schema-validator if that makes any difference).
Unfortunately we get quite ambiguous error messages if the validation fails and I am wondering if there is a way to improve this.
To make it clearer, I have created a small sample:
Each element in the array has a property "pet_type" which we can be sure to be there all the time (yeah I know that is discussable, but for the sake of argument let's ignore that for now). Each element has then some other properties.
This is the json schema right now.
Envelope (Basically with an array of elements)
{
"title": "Envelope",
"type": "object",
"properties": {
"pets": {
"type": "array",
"items": {
"anyOf": [
{
"$ref": "./Cat.json"
},
{
"$ref": "./Dog.json"
}
]
}
}
}
}
Cat (one of the elements in the array)
{
"title": "Cat",
"allOf": [
{
"$ref": "Pet.json"
},
{
"type": "object",
"properties": {
"hunts": {
"type": "boolean"
},
"age": {
"type": "integer"
},
"pet_type": {
"type": "string",
"enum": [
"Cat"
],
"pattern": "Cat"
}
},
"required": [
"pet_type",
"age"
]
}
]
}
Dog:
{
"title": "Dog",
"allOf": [
{
"$ref": "Pet.json"
},
{
"type": "object",
"properties": {
"bark": {
"type": "boolean"
},
"breed": {
"type": "string"
},
"pet_type": {
"type": "string",
"enum": [
"Dog"
],
"pattern": "Dog"
}
},
"required": [
"bark"
]
}
]
}
And the Pet.json, which specifies that "pet_type" is required on each of the elements.
{
"title": "Pet",
"type": "object",
"discriminator": {
"propertyName": "pet_type"
},
"properties": {
"pet_type": {
"type": "string",
"enum": [
"Cat",
"Dog"
]
}
},
"required": [
"pet_type"
]
}
The problem I have is that the error messages get very long, because the element is validated against all of the constraints, without narrowing it down a bit.
Let's say the JSON to validate looks like this:
{
"pets": [
{
"pet_type": "Cat",
"hunts": true
}
]
}
"pet_type" is set to "Cat", so for a human it is "clear" that it should only validate against the Cat JSON Schema and then show that "age" is missing.
What really happens is that there are 4 violations:
age is missing (from the Cat JSON Schema)
bark is missing (from the Dog JSON Schema)
pet_type is violating the "Dog" enum contstraint (from the Dog JSON Schema)
pet_type is violating the "Dog" regex pattern (from the Dog JSON Schema)
Note: I have added the enum/regex pattern in an act of trying to change the behavior, but it did not work.
I understand from a technical standpoint why it behaves like it does, I just want to know if it is possible to tell the validator somehow to first narrow down the validation based on pet_type and then keep validating?
What I tried to get it working:
I have tried to set the pet_type to string with an enum "Cat" and "Dog" and added one of those values to the Cat/Dog JSON Schema respectively in an attempt to make it clear which event has which pet_type.
I have tried to remove the Pet.json Schema completely, but that did not change anything.
I have tried to use if/then, but somehow this gets rid of all validation errors:
{
"title": "Envelope",
"type": "object",
"properties": {
"pets": {
"type": "array",
"items": {
"anyOf": [
{
"if": {
"properties": {
"pet_type": {
"const": "Cat"
}
}
},
"then": {
"$ref": "./Cat.json"
}
},
{
"if": {
"properties": {
"pet_type": {
"const": "Dog"
}
}
},
"then": {
"$ref": "./Dog.json"
}
}
]
}
}
}
}
My sample I tried to validate gives no errors anymore:
{
"pets": [
{
"pet_type": "Cat",
"hunts": true
}
]
}
Turns out the solution with if/then was correct, and the json-schema-validator actually detects the problems, but has some code that should improve the error messages, but gets rid of the validation errors instead.
I will bring the problem to their attention.
For now I have found a workaround to use nested if/then/else statements:
{
"title": "Envelope",
"type": "object",
"properties": {
"pets": {
"type": "array",
"items": {
"if": {
"properties": {
"pet_type": {
"const": "Cat"
}
}
},
"then": {
"$ref": "./Cat.json"
},
"else": {
"if": {
"properties": {
"pet_type": {
"const": "Dog"
}
}
},
"then": {
"$ref": "./Dog.json"
},
"else": {
"properties": {
"pet_type": {
"type": "string",
"enum": [
"Cat",
"Dog"
]
}
}
}
}
}
}
},
"additionalProperties": false
}
The following is a sample schema to depict the issue
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"definitions": {
"person": {
"type": "object",
"properties": {
"age": {
"type": "string"
}
}
}
},
"properties": {
"child": {
"$ref": "#/definitions/person"
}
},
"required": [
"child"
],
"if": {
"properties": {
"person/age": {
"const": "3"
}
}
},
"then": {
"properties": {
"guardian": {
"$ref": "#/definitions/person"
}
},
"required": [
"guardian"
]
}
}
Is there a way to refer age inside the person object?
{"child":{"age":"3"}}. Should fail as guardian tag is missing
The above data should fail as the guardian object is missing.
Remember that if is just a regular schema validating against the instance. Just nest your properties like you would with any nested object structure.
{
"type": "object",
"properties": {
"child": {
"type": "object",
"properties": {
"age": { "const": "3" }
},
"required": ["age"]
}
},
"required": ["child"]
}
Note that the type and required keywords are necessary to not inadvertently trigger the then schema. For example, with out them, these would cause the then to trigger when you probably didn't want it to.
{}
{ "child": null }
{ "child": {} }
I have searched and haven't quite found a solution.
I would like to do a schema as so:
...
"bag": {
"type": "array",
"items": {
"anyOf": [
{"$ref": "#/definitions/obj1"},
{"$ref": "#/definitions/obj2"},
{"$ref": "#/definitions/obj3"}
]
},
"required": ["items"],
"minItems": 1
}
...
With objects defined:
...
"definitions": {
"obj1": {
"type": "object",
"properties": {
"obj1": {
"type": "object",
"properties": {
"a": {
"type": "string"
}
},
"required": ["a"]
}
}
},
"obj2": {
"type": "object",
"properties": {
"obj1": {
"type": "object",
"properties": {
"b": {
"type": "string"
}
},
"required": ["b"]
}
}
},
"obj3": {
"type": "object",
"properties": {
"obj1": {
"type": "object",
"properties": {
"c": {
"type": "string"
}
},
"required": ["c"]
}
}
}
}
...
Ideally, I would like to validate against a schema that looks like this:
...
"bag": [
{
"obj1": {"a": "test1"}
},
{
"obj3": {"c": "test1"}
}
]
...
In this context, if someone passes obj1 and obj3 into bag. By the schema, obj1 requires property a and obj3 requires property c.
I'm having trouble actually executing this as the validation doesn't seem to enforce correctly.
Any tips? Thanks in advance.
From your current schema and example data, I can't tell exactly what you want, but making an educated guess...
I suspect you want to use oneOf as opposed to anyOf.
anyOf allows you to match multiple subschemas, and it looks like you only want to allow matching one of the subschemas, obj1, 2, or 3.
This would help you debug the issue, but it's not the cause of your always passing validation.
For each definition subschema, you need to add "additionalProperties": false.
Here's the key: JSON Schema is constraints based, meaning anything not constrained is allowed.
additionalProperties restricts the allowed properties of an object to those defined in properties (and patternProperties).
Here's the example schema. You can see it working with your instance here: https://jsonschema.dev/s/MjBUp
{
"$schema": "http://json-schema.org/draft-07/schema",
"definitions": {
"obj1": {
"type": "object",
"properties": {
"obj1": {
"type": "object",
"properties": {
"a": {
"type": "string"
}
},
"required": ["a"]
}
},
"additionalProperties": false
},
"obj2": {
"type": "object",
"properties": {
"obj1": {
"type": "object",
"properties": {
"b": {
"type": "string"
}
},
"required": ["b"]
}
},
"additionalProperties": false
}
},
"type": "array",
"items": {
"anyOf": [
{"$ref": "#/definitions/obj1"},
{"$ref": "#/definitions/obj2"}
]
},
"required": ["items"],
"minItems": 1
}
I've been struggling with "switch" in JSON Schema. Went through couple of GitHub and SO discussions on this topic but haven't find solution.
My intention is to vary "payload" object properties based on "id" enum that will have 30 different mappings ("payload" definitions per enum "id").
For example first message json object will have amount and other properties but for the demo purpose let's go only with one property (amout):
{
"message": {
"id": 1,
"correlationId": "a0011e83-280e-4085-b0f1-691059aaae61",
"payload": {
"amount": 100
}
}
}
And second json:
{
"message": {
"id": 2,
"correlationId": "a0011e83-280e-4085-b0f1-691059aaae61",
"payload": {
"code": "xyz"
}
}
}
Is there a way to build JSON Schema (draft 7 or any other) in this manner?
What you're asking for is a fairly common requirement. Using oneOf/anyOf should get you where you want.
In those cases where the alternatives are mutually exclusive (due to the different "id" values), I'm in favour of anyOf to allow Schema Validator to stop checking when encountering the first matching subschema – whereas oneOf implies that all other alternatives must not match, e.g. in case of "id": 1 a validator would only have to check against the first subschema in an anyOf to indicate that it is valid while for oneOf it'd have to check against the other 29 to ensure that those aren't also valid. But you may find oneOf more expressive for human consumers of your schema.
For your particular scenario, I'd imagine something along the lines of the following schema:
{
"type": "object",
"required": ["message"],
"properties": {
"message": {
"type": "object",
"required": ["id", "correlationId", "payload"],
"properties": {
"id": { "enum": [1, 2, 3] },
"correlationId": { "type": "string" },
"payload": { "type": "object" }
},
"anyOf": [
{
"properties": {
"id": { "const": 1 },
"payload": { "$ref": "#/definitions/payload1" }
}
},
{
"properties": {
"id": { "const": 2 },
"payload": { "$ref": "#/definitions/payload2" }
}
},
{
"properties": {
"id": { "const": 3 },
"payload": { "$ref": "#/definitions/payload3" }
}
},
]
}
},
"definitions": {
"payload1": {
"type": "object",
"required": ["amount"],
"properties": {
"amount": { "type": "integer" }
}
},
"payload2": {
"type": "object",
"required": ["code"],
"properties": {
"code": { "type": "string" }
}
},
"payload3": {
"type": "object",
"required": ["foo"],
"properties": {
"foo": { "type": "string" }
}
}
}
}
I've been working on a json schema to validate the answers from one of my webservices.
The answer is splitted in two properties: data and status. If status.code is set to 0, then data will have to respect a specific schema. Else, if status.code is set to -1, data won't be read, so I don't want to check if it respects the schema.
Here is the schema :
{
"$schema": "http://json-schema.org/schema#",
"id": "file://registration.json",
"type": "object",
"properties": {
"status": {
"$ref": "#/definitions/classes/status"
}
},
"anyOf": [
{
"$ref": "#/definitions/conditions/status-is-ok"
},
{
"$ref": "#/definitions/conditions/status-is-nok"
}
],
"definitions": {
"classes": {
"status": {
"type": "object",
"properties": {
"code": {
"type": "integer"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
]
},
"data": {
"type": "object",
"properties": {
"propertyA": {
"type": "#/definitions/classes/metadatauser"
},
"propertyB": {
"type": "#/definitions/classes/membreinfo"
}
},
"required": ["propertyA", "propertyB"]
}
},
"conditions": {
"status-is-ok": {
"status": {
"properties": {
"code": 0
}
},
"data": {
"$ref": "#/definitions/classes/data"
}
},
"status-is-nok": {
"status": {
"properties": {
"code": -1
}
},
"data": {
"type": "object"
}
}
}
}
}
And here's an example of what should not be validated:
{
"data": {},
"status": {
"code": 0,
"message": "OK"
}
}
At the moment, this portion of code passes, and I don't know why.
You've got a few things wrong here, so I'll try to explain all of them. You were on the right track!
"properties": {
"code": 0
}
The value of "properties" MUST be an object. Each value of this object
MUST be a valid JSON Schema.
http://json-schema.org/latest/json-schema-validation.html#rfc.section.6.5.4
You can't put the value you expect as the value for a property key.
You CAN however use the [const]1 keyword to achive a specific value validation.
"$ref": "#/definitions/conditions/status-is-ok"
...
"conditions": {
"status-is-ok": {
"status": {
"properties": {
[The definitions] keyword's value MUST be an object. Each member value of this
object MUST be a valid JSON Schema.
https://datatracker.ietf.org/doc/html/draft-handrews-json-schema-validation-01#section-9
This means that you need to treat each value of each key in a defintions as a JSON Schema. If you had a JSON Schema where you did not nest "status" inside a properties object, no validation would take place. The same is true for "data".
(Strictly, according to the definitions section of the spec, you MUST NOT nest schemas deeply in the definitions object, but this seems to be supported by some implementations anyway, and resolves using the correct resolution rules. Prefixing may be better.)
The complete fixed schema is as follows.
{
"$schema": "http://json-schema.org/schema#",
"id": "file://registration.json",
"type": "object",
"properties": {
"status": {
"$ref": "#/definitions/classes/status"
}
},
"anyOf": [
{
"$ref": "#/definitions/conditions/status-is-ok"
},
{
"$ref": "#/definitions/conditions/status-is-nok"
}
],
"definitions": {
"classes": {
"status": {
"type": "object",
"properties": {
"code": {
"type": "integer"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
]
},
"data": {
"type": "object",
"properties": {
},
"required": [
"propertyA",
"propertyB"
]
}
},
"conditions": {
"status-is-ok": {
"properties": {
"status": {
"properties": {
"code": {
"const": 0
}
}
},
"data": {
"$ref": "#/definitions/classes/data"
},
},
"additionalProperties": false
},
"status-is-nok": {
"properties": {
"status": {
"properties": {
"code": {
"const": -1
}
}
},
"data": {
"type": "object"
},
},
"additionalProperties": false
}
}
}
}
Please do let me know if any of this doesn't make sense.
Feel free to join the JSON Schema slack server should you want to discuss any aspects further! Happy to also comment here.