Raise JSON Schema Validation Error when key does not exist in API Gateway

Question

Having some issues trying to get to AWS API Gateway to error. Validation errors raise correctly for keys that have been defined when provided the wrong type, but if I add a random key to the request body that has not been defined in the model then API Gateway just carries on processing the request and returns a 200 Success response.

How can I define, in the model, that random keys are not allowed?

Model

{
  "type" : "object",
  "properties" : {
    "bool" : {
      "type" : "boolean"
    },
    "string" : {
      "type" : "string"
    },
    "int" : {
      "type" : "integer",
      "format" : "int32"
    }
  }
}

Request Body API GW Correctly Gives 200 Response

{
    "bool": true,
    "string": "foo",
    "int": 123
}

Invalid Request Body API GW Correctly Gives 400 Response

{
    "bool": "foo",
    "string": 123,
    "int": false
}

Invalid Request Body API GW Incorrectly Gives 200 Response

{
    "bool": true,
    "string": "foo",
    "int": 123,
    "bar":""
}

Any ideas on what I'm missing in the JSON schema?

score 3 · Accepted Answer · answered Feb 06 '21 at 05:56

I needed to add the following to the model

"additionalProperties":false

Model

{
  "type" : "object",
  "additionalProperties":false,
  "properties" : {
    "bool" : {
      "type" : "boolean"
    },
    "string" : {
      "type" : "string"
    },
    "int" : {
      "type" : "integer",
      "format" : "int32"
    }
  }
}

from this issue Only allow properties that are declared in JSON schema

Raise JSON Schema Validation Error when key does not exist in API Gateway

1 Answers1