How can I validate a json schema array that contains a MIXED type of objects?

Question

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.

Answer 1

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
}