jsonschema - dynamic properties with static properties - json

Question

I have a schema to validate a json.
For certain properties i need them to have values of certain types.
If "attr" property is "a" then "val" property should be "integer"
If "attr" property is "x" then "val" property should be "boolean"
If "attr" property is "b" then "val" property should be "string" with
format "ipv4"
and so on...
This, I can define with oneOff. For all other "attr" properties i need to them to be of a certain format, sort of like a catch all, with "val" property to be "string".
If "attr" matches pattern then "val" property should be "string".
can this be done.
This is the schema that i have at the moment.
{
"$schema": "http://json-schema.org/draft-04/schema#",
"type": "object",
"properties": {
"name": {
"title": "name",
"type": "string"
},
"attribute": {
"title": "attributes",
"type": "object",
"$ref": "#/definitions/expr",
}
},
"definitions": {
"expr": {
"properties": {
"attr": {
"title": "attribute"
},
"val": {
"title": "val"
}
},
"required": ["val", "attr"],
"oneOf": [
{
"properties": {
"attr": {"enum": ["a","b"]},
"val": {"type": "integer"}
}
},
{
"properties": {
"attr": {"enum": ["x"]},
"val": {"type": "boolean"}
}
},
{
"properties": {
"attr": {"pattern": "^[-A-Za-z0-9_]*$", "maxLength": 255},
"val": {"type": "string"}
}
}
]
}
},
"additionalProperties": false,
"required": [
"name",
"attribute"
]
}
The problem is the properties for which i am trying to restrict the value type, also match the catchall format. so when i am expecting an integer value, it is passing with string value.
For Example:
the below json will pass the schema, based on the first item of oneOff
{
"name": "shouldpass",
"attribute": {
"attr": "a",
"val": 1
}
}
the below json will pass, based on the last item of oneOff.
{
"name": "shouldpass2",
"attribute": {
"attr": "h",
"val": "asd"
}
}
the below json should fail, based on the first item of oneOff, but it is also passing, because it is matching the last item of oneOff.
{
"name": "shouldfail",
"attribute": {
"attr": "a",
"val": "string"
}
}
how to acheive this?

Answer 1

You schema for attr in the last subschema could be:
{
"pattern": "^[-A-Za-z0-9_]*$",
"not": { "enum": ["a", "b", "x"] },
"maxLength": 255
}
Alternatively, instead of "oneOf" you can use "switch" keyword from the next JSON-schema version proposals: http://epoberezkin.github.io/ajv/keywords.html#switch-v5-proposal
It's implemented in Ajv (I am the author).