Is there a way to validate that one of two properties (both arrays) are not empty?
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Kris Robison
Mar 19, 2015, 9:47:28 PM3/19/15
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Hi,
I've been digging through the specs for the last few days and I can't seem to find my question either in the docs or here or on StackOverflow.
Any of the following json objects are valid:
{ "id": 23, "foo": [1,2,3], "bar":[4,5,6] }
{ "id": 42, "foo": [1, 2, 3] } or { "id": 42, "foo": [1, 2, 3], "bar": [] }
{ "id": 42, "bar": [1] } or { "id": 42, "foo": [], "bar": [1] }
However the following are invalid:
{ "id": 11 }
{ "id": 11, "foo": [] } or { "id": 12, "bar": [] }
{ "id": 2, "foo": [], "bar": [] }
I would like to set up a json-schema-4 document which catches the invalid cases. I know the following doesn't quite catch it.
{"type": "object",
"$schema": "http://json-schema.org/draft-04/schema#",
"id": "#myObject",
"description": "The details of my object",
"additionalProperties": false,
"properties": {
"id": {
"type": "integer",
"description": "The ID of my object [Read Only Field]",
"minimum": 1
},
"foo": {
"type": "array",
"items": {
"type": "integer"
},
"description": "List of foo ids","minItems": 1},"bar": {
"type": "array","items": {
"type": "integer"
},
"description": "List of bar ids",
"minItems": 1}}}
Jason Desrosiers
Mar 20, 2015, 2:20:02 AM3/20/15
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It can be done, but it's not pretty. The syntax for requiring property "foo" OR "bar" is not great in json-schema, but it really gets weird when you allow the arrays to be empty.
The object is valid if it matches one of two objects;
1) The object requires an "id" and a "bar" array with at least one item. A "foo" array is optional and can be empty.
2) The object requires an "id" and a "foo" array with at least one item. A "bar" array is optional and can be empty.
I used "definitions" to avoid duplicating the definitions of "id", "foo", and "bar" in the "anyOf" construct.
I used "allOf" to mixin the "minItems" constraint to the "foo" and "bar" definitions.
{ "$schema": "http://json-schema.org/draft-04/schema#", "description": "The details of my object", "anyOf": [ { "type": "object", "properties": { "id": { "$ref": "#/definitions/id" }, "foo": { "$ref": "#/definitions/foo" }, "bar": { "allOf": [ { "$ref": "#/definitions/bar" }, { "minItems": 1 } ] } }, "additionalProperties": false, "required": [ "id", "bar" ] }, { "type": "object", "properties": { "id": { "$ref": "#/definitions/id" }, "foo": { "allOf": [ { "$ref": "#/definitions/foo" }, { "minItems": 1 } ] }, "bar": { "$ref": "#/definitions/bar" } }, "additionalProperties": false, "required": [ "id", "foo" ] } ], "definitions": { "id": { "type": "integer", "description": "The ID of my object [Read Only Field]", "minimum": 1 }, "foo": { "type": "array", "items": { "type": "integer" }, "description": "List of foo ids" },
Francis Galiegue
Mar 20, 2015, 5:28:33 AM3/20/15
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On Fri, Mar 20, 2015 at 7:20 AM, Jason Desrosiers <jdes...@gmail.com> wrote:
> It can be done, but it's not pretty. The syntax for requiring property
> "foo" OR "bar" is not great in json-schema, but it really gets weird when
> you allow the arrays to be empty.
>
There is much easier than that...
> It can be done, but it's not pretty. The syntax for requiring property
> "foo" OR "bar" is not great in json-schema, but it really gets weird when
> you allow the arrays to be empty.
>
{
"$schema": "http://json-schema/draftv4/schema#",
"type": "object",
"properties": {
"id": { "type": "integer" }
}
"additionalProperties": { "$ref": "#/definitions/nonEmptyArray" },
"oneOf": [
{
"required": [ "id", "foo" ],
"additionalProperties": false
},
{
"required": [ "id", "bar" ],
"additionalProperties": false
}
],
"definitions": {
"nonEmptyArray": {
"type": "array",
"minItems": 1,
"items": { /* schema for array items here */
}
}
}
--
Francis Galiegue, fgal...@gmail.com, https://github.com/fge
JSON Schema in Java: http://json-schema-validator.herokuapp.com
Parsers in pure Java: https://github.com/fge/grappa
Matt Jones
Mar 20, 2015, 12:20:08 PM3/20/15
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On Thursday, 19 March 2015 21:47:28 UTC-4, Kris Robison wrote:
Hi,I've been digging through the specs for the last few days and I can't seem to find my question either in the docs or here or on StackOverflow.Any of the following json objects are valid:{ "id": 23, "foo": [1,2,3], "bar":[4,5,6] }{ "id": 42, "foo": [1, 2, 3] } or { "id": 42, "foo": [1, 2, 3], "bar": [] }{ "id": 42, "bar": [1] } or { "id": 42, "foo": [], "bar": [1] }However the following are invalid:{ "id": 11 }{ "id": 11, "foo": [] } or { "id": 12, "bar": [] }{ "id": 2, "foo": [], "bar": [] }I would like to set up a json-schema-4 document which catches the invalid cases. I know the following doesn't quite catch it.
Is there some magical mixture of anyOf and oneOf that would help me get there? I only want one "foo" and one "bar" property in the resource.
I originally misinterpreted your question slightly as wanting to ensure that ONLY one of foo or bar was nonempty. Here's a schema that will detect that:
{
"type": "object",
"properties": {
"id": { "type": "integer" },
"foo": { "type": "array" },
"bar": { "type": "array" }
},
"additionalProperties": false,
"oneOf": [
{
"properties": {
"foo": { "minItems": 1 },
"bar": { "maxItems": 0 }
}
},
{
"properties": {
"foo": { "maxItems": 0 },
"bar": { "minItems": 1 }
}
}
]
}
Note that your first example will NOT validate according to this, as either foo or bar MUST be empty/missing for this schema.
The schema you want is actually simpler:
{
"type": "object",
"properties": {
"id": { "type": "integer" },
"foo": { "type": "array" },
"bar": { "type": "array" }
},
"additionalProperties": false,
"not":{
"properties": {
"foo": { "maxItems": 0 },
"bar": { "maxItems": 0 }
}
}
}
This one is just asserting that not both of the arrays are empty/missing; !(x & y) then simplifies to !x | !y, which is what was originally described.
Tested with the Ruby json_schema gem (v0.4.0) if it matters - I was slightly surprised that maxItems worked against an array that wasn't even in the payload...
--Matt Jones
Kris Robison
Mar 20, 2015, 12:56:50 PM3/20/15
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Thank you very much for looking at this. Testing it in the json_schema gem is perfect. I'm trying to set up a pacto server to look at our endpoints.
Kris Robison
Mar 20, 2015, 1:54:12 PM3/20/15
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Just an FYI Matt, the above schema allowed the {"id": 11 } scenario to successfully pass with the json-schema-v2.5.1 (note the hyphen) gem which is what pacto uses instead of json_schema. Now I need to figure out which interpretation is correct.
Jason Desrosiers
Mar 20, 2015, 1:55:26 PM3/20/15
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Matt,
Very clever use of "not" and "maxItems". I too was surprised at first that "maxItems" worked against an array that wasn't even in the payload. After thinking about it, it makes sense. It's actually not validating against the missing array at all. Because neither of these arrays are required properties, simply not being in the payload is enough to make it valid. It never has to check the number of items in the array because it has already been determined to be valid because it is missing.
On Friday, March 20, 2015 at 9:20:08 AM UTC-7, Matt Jones wrote:
Kris Robison
Mar 20, 2015, 2:19:01 PM3/20/15
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Actually both json_schema and json-schema pass the scenario: { "id": 11 }. At least one of the attributes is required and should be non-empty. I'm trying to add an anyOf clause now.
Kris Robison
Mar 20, 2015, 2:30:37 PM3/20/15
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I tried adding the following after the not definition, but it didn't help:
{"foo": { "type": "array", "minItems": 1} },
{"bar": { "type": "array", "minItems": 1} }
]
Jason Desrosiers
Mar 20, 2015, 2:55:02 PM3/20/15
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I think both validators are wrong for the reason I just described. If both "foo" and "bar" are not present, the "not" clause should be valid which should make the overall validation fail. Here are a couple validators that agree with me.
Anyway, you should be able to do this with "anyOf" instead of "not" like this:
{ "type": "object", "properties": { "id": { "type": "integer" }, "foo": { "type": "array" }, "bar": { "type": "array" } }, "additionalProperties": false, "anyOf": [ { "properties": { "foo": { "minItems": 1 } }, "required": [ "foo" ] }, { "properties": { "bar": { "minItems": 1 } }, "required": [ "bar" ] } ]}{ "type": "object", "properties": { "id": { "type": "integer" }, "foo": { "type": "array" }, "bar": { "type": "array" } }, "additionalProperties": false, "not": { "properties": { "foo": { "maxItems": 0 }, "bar": { "maxItems": 0 } } }, "minProperties": 2,
"required": ["id"]}Kris Robison
Mar 20, 2015, 4:58:54 PM3/20/15
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Thanks Jason. Your version works with the libraries, although I'm going to open tickets on them. I like the creativity of your golf solution, but of course my real object has more optional properties, so that would not work.
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