Getting KeyCloakContext From ServletRequest

When REST APIs are protected with keycloak authentication, we might need to get user realm in the backend to get some user information.

In the ServletRequestFilter implementation,

public class ApplicationFilter implements Filter {

private Base64 decoder = new Base64(true);

        @Inject

ServletRequestHolder requestHolder;

@Override

public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)

throws IOException, ServletException {

try {

checkAuthentication(req);

....

//TODO

}

/**

* Get the logged in user info from the request.

* 

* @param request

*/

private void checkAuthentication(ServletRequest request) {

HttpServletRequest httpServletRequest = (HttpServletRequest) request;

KeycloakSecurityContext kContext = (KeycloakSecurityContext) httpServletRequest

.getAttribute(KeycloakSecurityContext.class.getName());

String bearerToken;

if (kContext != null) {

bearerToken = kContext.getTokenString();

String[] jwtToken = bearerToken.split("\\.");

byte[] decodedClaims = decoder.decode(jwtToken[1]);

JSONObject jsonObj = new JSONObject(new String(decodedClaims));

.....

//TODO

}

JAX-RS Custom Exception Mapper

When the service(backend) throws any custom exception, using <javax.ws.rs.ext.ExceptionMapper> we can catch it , and send a relevant message to the client (/caller).

import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.ExceptionMapper;
import javax.ws.rs.ext.Provider;

/**
 * Map the server exceptions to return to the client
 *
 */

@Provider
public class CustomJaxRsExceptionMapper implements ExceptionMapper {

@Override

     @Produces("application/json")

public Response toResponse(ServiceException e) {

          Map map = new HashMap();

  map.put("Exception", e.getMessage());

Response response = Response.status(500).entity(map).build();
return response;
}
}

RESTEASY003875: Unable to find a constructor that takes a String param or a valueOf() or fromString() method

The error[1] occurs when we use complex types in our GET querys.  JAXRS understands simple data types. If we use complex types, we might need to have our own (de)serialisation for the complex types.

import java.lang.annotation.Annotation;

import java.lang.reflect.Type;

import java.math.BigDecimal;

import javax.money.Monetary;

import javax.ws.rs.ext.ParamConverter;

import javax.ws.rs.ext.ParamConverterProvider;

import javax.ws.rs.ext.Provider;

import org.javamoney.moneta.Money;

@Provider

public class MoneyConverterProvider  implements ParamConverterProvider {

    private final MoneyConverter converter = new MoneyConverter();

    @Override

    public ParamConverter getConverter(Class rawType, Type genericType, Annotation[] annotations) {

        if (!rawType.equals(Money.class)) return null;

        return (ParamConverter) converter; 

    }

    public class MoneyConverter implements ParamConverter {

        public Money fromString(String value) {

            if (value == null ||value.isEmpty()) return null; 

   

            return Money.of(new BigDecimal(value), Monetary.getCurrency("AUD"));

        }

        public String toString(Money value) {

            if (value == null) return "";

            return value.toString(); 

        }

    }

}

[1]


0:42:46,435 ERROR [org.jboss.msc.service.fail] (ServerService Thread Pool -- 86) MSC000001: Failed to start service jboss.undertow.deployment.default-server.default-host./apidb: org.jboss.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./apidb: java.lang.RuntimeException: RESTEASY003875: Unable to find a constructor that takes a String param or a valueOf() or fromString() method for javax.ws.rs.QueryParam("money") on public javax.ws.rs.core.Response com.rest.autogen.SalesTransactionEndpoint.getItems(java.lang.Integer,java.lang.Integer,java.lang.String,java.lang.Long,java.lang.String, org.javamoney.moneta.Money) for basetype: org.javamoney.moneta.Money

at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploymentService.java:85)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
at org.jboss.threads.JBossThread.run(JBossThread.java:320)
Caused by: java.lang.RuntimeException: RESTEASY003875: Unable to find a constructor that takes a String param or a valueOf() or fromString() method for javax.ws.rs.QueryParam("money") on public javax.ws.rs.core.Response com.rest.autogen.SalesTransactionEndpoint.getItems(java.lang.Integer,java.lang.Integer,java.lang.String,java.lang.Long,java.lang.String,org.javamoney.moneta.Money) for basetype: org.javamoney.moneta.Money
at org.jboss.resteasy.core.StringParameterInjector.initialize(StringParameterInjector.java:220)
at org.jboss.resteasy.core.StringParameterInjector.(StringParameterInjector.java:64)
at org.jboss.resteasy.core.QueryParamInjector.(QueryParamInjector.java:30)
at org.jboss.resteasy.core.InjectorFactoryImpl.createParameterExtractor(InjectorFactoryImpl.java:86)
at org.jboss.resteasy.cdi.CdiInjectorFactory.createParameterExtractor(CdiInjectorFactory.java:52)
at org.jboss.resteasy.core.MethodInjectorImpl.(MethodInjectorImpl.java:44)
at org.jboss.resteasy.core.InjectorFactoryImpl.createMethodInjector(InjectorFactoryImpl.java:77)
at org.jboss.resteasy.cdi.CdiInjectorFactory.createMethodInjector(CdiInjectorFactory.java:58)
at org.jboss.resteasy.core.ResourceMethodInvoker.(ResourceMethodInvoker.java:99)
at org.jboss.resteasy.core.ResourceMethodRegistry.processMethod(ResourceMethodRegistry.java:281)
at org.jboss.resteasy.core.ResourceMethodRegistry.register(ResourceMethodRegistry.java:252)
at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:222)
at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:194)
at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:180)
at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:157)
at org.jboss.resteasy.core.ResourceMethodRegistry.addPerRequestResource(ResourceMethodRegistry.java:76)
at org.jboss.resteasy.spi.ResteasyDeployment.registration(ResteasyDeployment.java:434)
at org.jboss.resteasy.spi.ResteasyDeployment.start(ResteasyDeployment.java:245)
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.init(ServletContainerDispatcher.java:113)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.init(HttpServletDispatcher.java:36)
at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:117)
at org.wildfly.extension.undertow.security.RunAsLifecycleInterceptor.init(RunAsLifecycleInterceptor.java:78)
at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:103)
at io.undertow.servlet.core.ManagedServlet$DefaultInstanceStrategy.start(ManagedServlet.java:231)
at
io.undertow.servlet.core.ManagedServlet.createServlet(ManagedServlet.java:132)
at io.undertow.servlet.core.DeploymentManagerImpl.start(DeploymentManagerImpl.java:526)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(UndertowDeploymentService.java:101)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploymentService.java:82)