== Authorization Client API

If you are using Java, you can access all {{book.project.name}} {{book.project.module}} using a client API.

=== Maven Dependency

```xml
<dependencies>
    <dependency>
        <groupId>org.keycloak</groupId>
        <artifactId>keycloak-authz-client</artifactId>
        <version>${KEYCLOAK_VERSION}</version>
    </dependency>
</dependencies>
```

=== Configuration

The client configuration is defined in a JSON file as follows:

```json
{
  "realm": "hello-world-authz",
  "auth-server-url" : "http://localhost:8080/auth",
  "resource" : "hello-world-authz-service",
  "credentials": {
    "secret": "secret"
  }
}
```

* *realm* (required)
+
The name of the realm.

* *auth-server-url* (required)
+
The base URL of the Keycloak server. All other Keycloak pages and REST service endpoints are derived from this. It is usually in the form https://host:port/auth. 

* *resource* (required)
+
The client-id of the application. Each application has a client-id that is used to identify the application. 

* *credentials* (required)
Specifies the credentials of the application. This is an object notation where the key is the credential type and the value is the value of the credential type. Currently only secret/password is supported. 

=== Obtaining User Entitlements

Here is an example illustrating how to obtain user entitlements:

```java
// create a new instance based on the configuration defined in keycloak-authz.json
AuthzClient authzClient = AuthzClient.create();

// obtain an Entitlement API Token to get access to the Entitlement API.
// this token is an access token issued to a client on behalf of an user
// with a scope = kc_entitlement
String eat = getEntitlementAPIToken(authzClient);

// send the entitlement request to the server to
// obtain an RPT with all permissions granted to the user
EntitlementResponse response = authzClient.entitlement(eat)
    .getAll("hello-world-authz-service");
String rpt = response.getRpt();

System.out.println("You got a RPT: " + rpt);

// now you can use the RPT to access protected resources on the resource server
```

Here is an example illustrating how to obtain user entitlements for a set of one or more resources:

```java
// create a new instance based on the configuration defined in keycloak-authz.json
AuthzClient authzClient = AuthzClient.create();

// obtain an Entitlement API Token to get access to the Entitlement API.
// this token is an access token issued to a client on behalf of an user
// with a scope = kc_entitlement
String eat = getEntitlementAPIToken(authzClient);

// create an entitlement request
EntitlementRequest request = new EntitlementRequest();
PermissionRequest permission = new PermissionRequest();

permission.setResourceSetName("Hello World Resource");

request.addPermission(permission);

// send the entitlement request to the server to obtain an RPT
// with all permissions granted to the user
EntitlementResponse response = authzClient.entitlement(eat)
    .get("hello-world-authz-service", request);
String rpt = response.getRpt();

System.out.println("You got a RPT: " + rpt);
```

=== Creating a Resource Using the Protection API

```java
// create a new instance based on the configuration defined in keycloak-authz.json
AuthzClient authzClient = AuthzClient.create();

// create a new resource representation with the information we want
ResourceRepresentation newResource = new ResourceRepresentation();

newResource.setName("New Resource");
newResource.setType("urn:hello-world-authz:resources:example");

newResource.addScope(new ScopeRepresentation("urn:hello-world-authz:scopes:view"));

ProtectedResource resourceClient = authzClient.protection().resource();
Set<String> existingResource = resourceClient
    .findByFilter("name=" + newResource.getName());

if (!existingResource.isEmpty()) {
    resourceClient.delete(existingResource.iterator().next());
}

// create the resource on the server
RegistrationResponse response = resourceClient.create(newResource);
String resourceId = response.getId();

// query the resource using its newly generated id
ResourceRepresentation resource = resourceClient.findById(resourceId).getResourceDescription();
```