Validate Json schema with repeating json response in Python

Question

I am getting none when I try to validate my Json schema with my Json response using Validate from Jsonschema.validate, while it shows matched on https://www.jsonschemavalidator.net/

Json Schema

 {
        "KPI": [{
            "KPIDefinition": {
                "id": {
                    "type": "string"
                },
                "name": {
                    "type": "string"
                },
                "version": {
                    "type": "number"
                },
                "description": {
                    "type": "string"
                },
                "datatype": {
                    "type": "string"
                },
                "units": {
                    "type": "string"
                }
            },
            "KPIGroups": [{
                "id": {
                    "type": "number"
                },
                "name": {
                    "type": "string"
                }
            }]
        }],
        "response": [{
            "Description": {
                "type": "string"
            }
        }]
    }

JSON Response JSON Response

{
  "KPI": [
    {
      "KPIDefinition": {
        "id": "2",
        "name": "KPI 2",
        "version": 1,
        "description": "This is KPI 2",
        "datatype": "1",
        "units": "perHour"
      },
      "KPIGroups": [
        {
          "id": 7,
          "name": "Group 7"
        }
      ]
    },
    {
      "KPIDefinition": {
        "id": "3",
        "name": "Parameter 3",
        "version": 1,
        "description": "This is KPI 3",
        "datatype": "1",
        "units": "per Hour"
      },
      "KPIGroups": [
        {
          "id": 7,
          "name": "Group 7"
        }
      ]
    }
  ],
  "response": [
    {
      "Description": "RECORD Found"
    }
  ]
}

Code

json_schema2 = {"KPI":[{"KPIDefinition":{"id_new":{"type":"number"},"name":{"type":"string"},"version":{"type":"number"},"description":{"type":"string"},"datatype":{"type":"string"},"units":{"type":"string"}},"KPIGroups":[{"id":{"type":"number"},"name":{"type":"string"}}]}],"response":[{"Description":{"type":"string"}}]}

json_resp = {"KPI":[{"KPIDefinition":{"id":"2","name":"Parameter 2","version":1,"description":"This is parameter 2 definition version 1","datatype":"1","units":"kN"},"KPIGroups":[{"id":7,"name":"Group 7"}]},{"KPIDefinition":{"id":"3","name":"Parameter 3","version":1,"description":"This is parameter 3 definition version 1","datatype":"1","units":"kN"},"KPIGroups":[{"id":7,"name":"Group 7"}]}],"response":[{"Description":"RECORD FETCHED"}]}

print(jsonschema.validate(instance=json_resp, schema=json_schema2))

Validation is not being done correctly, I changed the dataType and key name in my response but still, it is not raising an exception or error.

Answer 1

jsonschema.validate(..) is not supposed to return anything.

Your schema object and the JSON object are both okay and validation has passed if it didn't raise any exceptions -- which seems to be the case here.

That being said, you should wrap your call within a try-except block so as to be able to catch validation errors.

Something like:

try:
    jsonschema.validate(...)
    print("Validation passed!")
except ValidationError:
    print("Validation failed")
# similarly catch SchemaError too if needed.

---

Update: Your schema is invalid. As it stands, it will validate almost all inputs. A schema JSON should be an object (dict) that should have fields like "type" and based on the type, it might have other required fields like "items" or "properties". Please read up on how to write JSONSchema.

Here's a schema I wrote for your JSON:

{
  "type": "object",
  "required": [
    "KPI",
    "response"
  ],
  "properties": {
    "KPI": {
        "type": "array",
        "items": {
          "type": "object",
            "required": ["KPIDefinition","KPIGroups"],
            "properties": {
              "KPIDefinition": {
                "type": "object",
                "required": ["id","name"],
                "properties": {
                  "id": {"type": "string"},
                  "name": {"type": "string"},
                  "version": {"type": "integer"},
                  "description": {"type": "string"},
                  "datatype": {"type": "string"},
                  "units": {"type": "string"},
                },
                "KPIGroups": {
                  "type": "array",
                  "items": {
                    "type": "object",
                    "required": ["id", "name"],
                    "properties": {
                      "id": {"type": "integer"},
                      "name": {"type": "string"}
                    }
                  }
                }
              }
            }
        }
    },
    "response": {
        "type": "array",
        "items": {
            "type": "object",
            "required": ["Description"],
            "properties": {
              "Description": {"type": "string"}
            }
        }
    }
  }
}