json schema for a map of similar objects - json

Question

I wish to write a json schema to cover this (simplified) example
{
"errorMessage": "",
"nbRunningQueries": 0,
"isError": False,
"result": {
"foo": {"price":10.0, "country":"UK"},
"bar": {"price":100.2, "country":"UK"}
}
}
which can have this pretty trivial root schema
schema = {
"type":"object",
"required":True,
"properties":{
"errorMessage": {"type":"string", "required":True},
"isError": {"type":"boolean", "required":True},
"nbRunningQueries": {"type":"number", "required":True},
"result": {"type":"object","required":True}
}
}
The complication is the results {} element. Unlike a standard pattern where results would be an array of same objects - each with an id field or similar this response models a python dictionary which looks like this:
{
"foo": {},
"bar": {},
...
}
So given that a will be getting a results object of flexible size with no set keys how can I write json schema for this?
I don't control the input sadly or I'd rewrite it to be something like
{
"errorMessage": "",
"nbRunningQueries": 0,
"isError": False,
"result": [
{"id": "foo", "price":10.0, "country": "UK"},
{"id": "bar", "price":100.2, "country":"UK"}
]
}
Any help or links to pertinent examples would be great. Thanks.

Answer 1

With json-schema draft 4, you can use additionalProperties keyword to specify the schema of any new properties that you could receive in your results object.
"result" : {
"type" : "object"
"additionalProperties" : {
"type" : "number"
}
}
If you can restrict the allowed key names, then you may use "patternProperties" keyword and a regular expression to limit the permited key names.
Note that in json-schema draft 4 "required" must be an array which is bounded to the object, not to each property.