使用 Ban Unknown Properties 根据架构验证 JSON

Question

This answer from 2013 says that JSON validators (validating against a schema) should/can allow a ban unknown properties parameter to only allow properties that exist in the schema, even if the schema does not contain additionalProperties false . However as far as I can see all paths to this property seem to go cold.

Is there any validator that I can use in C# that will fail extra properties even without the additionalProperties false directive?

Answer 1

I do not have control of the schema, it does not contain additionalProperties and I cannot add it.

You can write your own schema, that says "use this schema over here: " and then add on additional keywords to it. Note that this requires an implementation that supports the draft 2019-09 specification:

{
  "$schema": "https://json-schema.org/draft/2019-09/schema",
  "$ref": "... uri to the schema you wish to modify",
  "unevaluatedProperties": false
}

"unevaluatedProperties" is a new keyword in this draft that takes other schemas evaluated at the same data location into account -- any property that was not earlier mentioned with a "properties", "additionalProperties", "patternProperties" or "unevaluatedProperties" keyword will be considered by this "unevaluatedProperties" keyword here. Since its value is false , any such matching properties will be disallowed.