Camel Json Validation throws NoJsonBodyValidationException - rest

Question

I'm trying to perform Header validation for incoming GET request. I referred the Camel JSON schema validator component and followed below steps to implement in my project i.e.
Adding camel-json-validator-starter dependency in build.gradle
Adding Employee.json (YAML converted to JSON) in Resource folder of my Spring boot project. Here initially I had Open API 3.0 yaml specification file and I converted the same to json
Invoking validation with below code
rest(/employee).id("get-employee")
.produces(JSON_MEDIA_TYPE)
.get()
.description("The employee API")
.outType(EmployeeResponse.class)
.responseMessage()
.code(HttpStatus.OK.toString())
.message("Get Employee")
.endResponseMessage()
.route()
.to("json-validator:openapi.json")
.to("bean:employeeService?method=getEmployee()");
Running the project throws a org.apache.camel.component.jsonvalidator.NoJsonBodyValidationException, I'm using GET request but why is it expecting Request body, I just wanted to validate the Headers and request param from the incoming request. I'm not sure if my approach is right and what I'm missing.

Answer 1

I ran into this problem last year when adopting OpenAPI and came to the conclusion that it was too much work. I could not get FULL validation from the JSON validator using OpenAPI because there was some differences between the way OpenAPI declares schema definitions and the full JSON schema definitions.
Looking a the documentation of the JSON validation component you find this:
The JSON Schema Validator component performs bean validation of the message body against JSON Schemas v4 draft using the NetworkNT JSON Schema library (https://github.com/networknt/json-schema-validator). This is a full stand alone JSON Schema and if you read the github pages you find this.
OpenAPI Support
The OpenAPI 3.0 specification is using JSON schema to validate the request/response, but there are some differences. With a configuration file, you can enable the library to work with OpenAPI 3.0 validation.
OpenAPI schema appears to be a subset of the real JSON Schema.
Before I show you a more detailed example. Look at the example given in the camel documentation here: https://camel.apache.org/components/latest/json-validator-component.html. Compare that json schema file with the openAPI schema definitions and you will see they are not the same.
A useful tool here is https://jsonschema.net you can paste your json example here and infer a schema. I use this tool and the OpenAPI Pet Store example in the example below,
OpenAPI Petstore Pet Object Example:
{
"id": 0,
"category": {
"id": 0,
"name": "string"
},
"name": "doggie",
"photoUrls": [
"string"
],
"tags": [
{
"id": 0,
"name": "string"
}
],
"status": "available"
}
The openAPI specification saved in JSON produces this definition:
"Pet": {
"type": "object",
"required": [
"name",
"photoUrls"
],
"properties": {
"id": {
"type": "integer",
"format": "int64"
},
"category": {
"$ref": "#/definitions/Category"
},
"name": {
"type": "string",
"example": "doggie"
},
"photoUrls": {
"type": "array",
"xml": {
"name": "photoUrl",
"wrapped": true
},
"items": {
"type": "string"
}
},
"tags": {
"type": "array",
"xml": {
"name": "tag",
"wrapped": true
},
"items": {
"$ref": "#/definitions/Tag"
}
},
"status": {
"type": "string",
"description": "pet status in the store",
"enum": [
"available",
"pending",
"sold"
]
}
},
"xml": {
"name": "Pet"
}
}
When I convert this to proper JSON schema syntax the JSON Schema looks like this:
{
"definitions": {},
"$schema": "http://json-schema.org/draft-07/schema#",
"$id": "http://example.com/root.json",
"type": "object",
"title": "The Root Schema",
"required": [
"id",
"category",
"name",
"photoUrls",
"tags",
"status"
],
"properties": {
"id": {
"$id": "#/properties/id",
"type": "integer",
"title": "The Id Schema",
"default": 0,
"examples": [
0
]
},
"category": {
"$id": "#/properties/category",
"type": "object",
"title": "The Category Schema",
"required": [
"id",
"name"
],
"properties": {
"id": {
"$id": "#/properties/category/properties/id",
"type": "integer",
"title": "The Id Schema",
"default": 0,
"examples": [
0
]
},
"name": {
"$id": "#/properties/category/properties/name",
"type": "string",
"title": "The Name Schema",
"default": "",
"examples": [
"string"
],
"pattern": "^(.*)$"
}
}
},
"name": {
"$id": "#/properties/name",
"type": "string",
"title": "The Name Schema",
"default": "",
"examples": [
"doggie"
],
"pattern": "^(.*)$"
},
"photoUrls": {
"$id": "#/properties/photoUrls",
"type": "array",
"title": "The Photourls Schema",
"items": {
"$id": "#/properties/photoUrls/items",
"type": "string",
"title": "The Items Schema",
"default": "",
"examples": [
"string"
],
"pattern": "^(.*)$"
}
},
"tags": {
"$id": "#/properties/tags",
"type": "array",
"title": "The Tags Schema",
"items": {
"$id": "#/properties/tags/items",
"type": "object",
"title": "The Items Schema",
"required": [
"id",
"name"
],
"properties": {
"id": {
"$id": "#/properties/tags/items/properties/id",
"type": "integer",
"title": "The Id Schema",
"default": 0,
"examples": [
0
]
},
"name": {
"$id": "#/properties/tags/items/properties/name",
"type": "string",
"title": "The Name Schema",
"default": "",
"examples": [
"string"
],
"pattern": "^(.*)$"
}
}
}
},
"status": {
"$id": "#/properties/status",
"type": "string",
"title": "The Status Schema",
"default": "",
"examples": [
"available"
],
"pattern": "^(.*)$"
}
}
}
There is some differences between OpenAPI's schema definition and JSON Schema definition.

Answer 2

failOnNullBody (producer) - Whether to fail if no body exists.
Default is true
Try setting the option in your call:
.to("json-validator:openapi.json?failOnNullBody=false")