您将如何为任意键设计 JSON Schema？

Question

I have the following JSON output data:

{
   "label_name_0" : 0,
   "label_name_5" : 3,
   .
   .
   .
   "label_name_XXX" : 4
}

The output is simple: a key[1] name associated with integer value. If the key name doesn't change, I can easily come up with JSON Schema similar to this:

    {
        "type": "array"
        "title": "Data output",
        "items" :{ 
            "properties": {
                "label_name": {
                   "type": "integer",
                   "default": 0,
                   "readonly": True,
            }
        }
    },

Since the key name itself is not known and keep changing, I have to design schema for it. The only thing I know is that the key is string and not more than 100 characters. How do I define a JSON Schema for the key lable_name_xxx that keeps changing.

[1] Not sure if I am using the right terminology

Answer 1

On json-schema.org you will find something appropriate in the File System Example section. You can define patternProperties inside an object .

{
    "type": "object",
    "properties": {
        "/": {}
    },
    "patternProperties": {
        "^(label_name_[0-9]+)+$": { "type": "integer" }
    },
    "additionalProperties": false,
 }

The regular expression (label_name_[0-9]+)+ should fit your needs. In JSON Schema regular expressions are explicitly anchored with ^ and $ . The regular expressions defines, that there has to be at least one property ( + ). The property consists of label_name_ and a number between 0 and 9 whereas there has to be at least one number ([0-9]+) , but there can also arbitrary many of them.

By setting additionalProperties to false it constrains object properties to match the regular expression.

Answer 2

As Konrad's answer stated, use patternProperties . But use in place of properties , which is not needed, and I think Konrad just pasted from his reference example that was expecting a path starting with / . In the example below, the pattern match regex .* accepts any property name and I am allowing types of string or null only by using "additionalProperties": false .

  "patternProperties": {
    "^.*$": {
      "anyOf": [
        {"type": "string"},
        {"type": "null"}
      ]
    }
  },
  "additionalProperties": false

Answer 3

Simpler solution than patternProperties, since OP does not have any requirement on the key names ( documentation ):

{
    "type": "object",
    "additionalProperties": {
        "type": "integer",
        "default": 0,
        "readonly": true,
    }        
}

default and readonly included because they were included in the OP's initial suggestion, but they are not required.