Mule 4: JSON Schema Validation

JSON Schema is a specification for JSON based format for defining the structure of JSON data. It validates input data at runtime and verifies that they match a referenced schema or not. We can match against defined schemas that exist in local file or in an external URI.

If the payload is incorrect with given JSON schema, then compiler throws below Exception:

org.mule.module.json.validation.JsonSchemaValidationException: Json content is not compliant with schema

Use Case:

Validating the input JSON payload against with JSON Schema.

JSON Payload:

{
  "firstName": "Murali",
  "lastName": "Krishna",
  "age" : 26
}

JSON – Schema :

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "properties": {
    "firstName": {
      "type": "string"
    },
    "lastName": {
      "type": "string"
    },
    "age": {
      "type": "integer"
    }
  },
  "required": [
    "firstName",
    "lastName",
    "age"
  ]
}

Mule Flow:

Step -1 :

Configure the HTTP Listener with by giving hostname, port number and path along with this specify allowed methods (Optional) at an Advanced tab of HTTP connector.

Step-2:

Drag and Drop the JSON Validate Schema from Mule Palette to validate the input payload. And provide the schema path. In my case it is like below:

schemas/Sample-Schema.json

From above line,

schemas –> It is directory

Sample-Schema.json —> It is JSON-Schema structure for validation.

Syntax of JSON Validator as below:

<json:validate-schema doc:name="Validate schema" doc:id="5a8b10e1-59e8-4f68-9aaa-303c9cb5c9d6" schema="schemas/Sample-Schema.json">

Step-3:

Drag & Drop the Logger component to log the resultant payload after validation.

Final Config.xml:

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:json="http://www.mulesoft.org/schema/mule/json" xmlns:validation="http://www.mulesoft.org/schema/mule/validation"
  xmlns:ee="http://www.mulesoft.org/schema/mule/ee/core"
  xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
http://www.mulesoft.org/schema/mule/ee/core http://www.mulesoft.org/schema/mule/ee/core/current/mule-ee.xsd
http://www.mulesoft.org/schema/mule/validation http://www.mulesoft.org/schema/mule/validation/current/mule-validation.xsd
http://www.mulesoft.org/schema/mule/json http://www.mulesoft.org/schema/mule/json/current/mule-json.xsd">
  <http:listener-config name="HTTP_Listener_config" doc:name="HTTP Listener config" doc:id="8a601d72-5913-4ed7-99d3-707601301ec9" >
    <http:listener-connection host="0.0.0.0" port="8080" />
  </http:listener-config>
  <flow name="abcFlow" doc:id="30917fd1-0429-4ec7-9d7d-aa8d4d19413e" >
    <http:listener doc:name="Listener" doc:id="2b89fed0-69ce-47eb-93bf-3bd0628fe188" config-ref="HTTP_Listener_config" path="abc" allowedMethods="POST">
      <ee:repeatable-file-store-stream />
    </http:listener>
    <json:validate-schema doc:name="Validate schema" doc:id="5a8b10e1-59e8-4f68-9aaa-303c9cb5c9d6" schema="schemas/Sample-Schema.json">
    </json:validate-schema>
    <logger level="INFO" doc:name="Logger" doc:id="26b62866-2f25-4374-9d95-9fe14c052366" message="Payload is Validated ----&gt; #[message.payload]" />
  </flow>
</mule>

Success Scenario: