JSON Schema Validator
Since Camel 2.20
Only producer is supported
The JSON Schema Validator component performs bean validation of the message body against JSON Schemas v4, v6, v7 and v2019-09 draft using the NetworkNT JSON Schema library (https://github.com/networknt/json-schema-validator).
Maven users will need to add the following dependency to their pom.xml
for this component:
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-json-validator</artifactId>
<version>x.y.z</version>
<!-- use the same version as your Camel core version -->
</dependency>
URI format
json-validator:resourceUri[?options]
Where resourceUri is some URL to a local resource on the classpath or a full URL to a remote resource or resource on the file system which contains the JSON Schema to validate against.
Configuring Options
Camel components are configured on two separate levels:
-
component level
-
endpoint level
Configuring Component Options
The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.
Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.
Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.
Configuring Endpoint Options
Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.
Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL as a type safe way of configuring endpoints.
A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.
The following two sections lists all the options, firstly for the component followed by the endpoint.
Component Options
The JSON Schema Validator component supports 2 options, which are listed below.
Name | Description | Default | Type |
---|---|---|---|
Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. |
false |
boolean |
|
Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. |
true |
boolean |
Endpoint Options
The JSON Schema Validator endpoint is configured using URI syntax:
json-validator:resourceUri
with the following path and query parameters:
Path Parameters (1 parameters)
Name | Description | Default | Type |
---|---|---|---|
Required Path to the resource. You can prefix with: classpath, file, http, ref, or bean. classpath, file and http loads the resource using these protocols (classpath is default). ref will lookup the resource in the registry. bean will call a method on a bean to be used as the resource. For bean you can specify the method name after dot, eg bean:myBean.myMethod. |
String |
Query Parameters (8 parameters)
Name | Description | Default | Type |
---|---|---|---|
Sets whether the context map should allow access to all details. By default only the message body and headers can be accessed. This option can be enabled for full access to the current Exchange and CamelContext. Doing so impose a potential security risk as this opens access to the full power of CamelContext API. |
false |
boolean |
|
Sets whether to use resource content cache or not. |
false |
boolean |
|
Whether to fail if no body exists. |
true |
boolean |
|
Whether to fail if no header exists when validating against a header. |
true |
boolean |
|
To validate against a header instead of the message body. |
String |
||
Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. |
false |
boolean |
|
To use a custom ValidatorErrorHandler. The default error handler captures the errors and throws an exception. |
JsonValidatorErrorHandler |
||
To use a custom schema loader allowing for adding custom format validation. The default implementation will create a schema loader that tries to determine the schema version from the $schema property of the specified schema. |
JsonUriSchemaLoader |
Example
Assuming we have the following JSON Schema
myschema.json
{
"$schema": "http://json-schema.org/draft-04/schema#",
"definitions": {},
"id": "my-schema",
"properties": {
"id": {
"default": 1,
"description": "An explanation about the purpose of this instance.",
"id": "/properties/id",
"title": "The id schema",
"type": "integer"
},
"name": {
"default": "A green door",
"description": "An explanation about the purpose of this instance.",
"id": "/properties/name",
"title": "The name schema",
"type": "string"
},
"price": {
"default": 12.5,
"description": "An explanation about the purpose of this instance.",
"id": "/properties/price",
"title": "The price schema",
"type": "number"
}
},
"required": [
"name",
"id",
"price"
],
"type": "object"
}
we can validate incoming JSON with the following Camel route, where myschema.json
is loaded from the classpath.
from("direct:start")
.to("json-validator:myschema.json")
.to("mock:end")
If you use the default schema loader, it will try to determine the schema version from the $schema property and instruct the validator appropriately. If it can’t find (or doesn’t recognize) the $schema property, it will assume your schema is version 2019-09.
If your schema is local to your application (e.g. a classpath location as opposed to URL), your schema can also contain $ref links to a relative subschema in the classpath. Per the JSON schema spec, your schema must not have an $id identifier property for this to work properly. See the unit test and schema for an example.
Spring Boot Auto-Configuration
When using json-validator with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:
<dependency>
<groupId>org.apache.camel.springboot</groupId>
<artifactId>camel-json-validator-starter</artifactId>
<version>x.x.x</version>
<!-- use the same version as your Camel core version -->
</dependency>
The component supports 3 options, which are listed below.
Name | Description | Default | Type |
---|---|---|---|
Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. |
true |
Boolean |
|
Whether to enable auto configuration of the json-validator component. This is enabled by default. |
Boolean |
||
Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. |
false |
Boolean |