finish new blog post

Author: rieckpil

README.md

@@ -43,6 +43,7 @@
 * Deploy Java EE applications to Kubernetes ([Blog](https://rieckpil.de/howto-deploy-java-ee-applications-to-kubernetes), [Sources](https://github.com/rieckpil/blog-tutorials/tree/master/java-ee-kubernetes-deployment))
 * MicroProfile Rest Client for RESTful communication ([Blog](https://rieckpil.de/howto-microprofile-rest-client-for-restful-communication/), [Sources](https://github.com/rieckpil/blog-tutorials/tree/master/microprofile-rest-client-for-restful-communication))
 * Deploy a React application to Kuberntes ([Blog](https://dev.to/rieckpil/deploy-a-react-application-to-kubernetes-in-5-easy-steps-516j), [Sources](https://github.com/rieckpil/blog-tutorials/tree/master/react-app-kubernetes))
+* Intercept method calls using CDI interceptors ([Blog](https://rieckpil.de/howto-intercept-method-calls-using-cdi-interceptors/), [Sources](https://github.com/rieckpil/blog-tutorials/tree/master/intercept-methods-with-cdi-interceptors))
 
 ## WHATIS?:
 

intercept-methods-with-cdi-interceptors/Dockerfile

@@ -1,2 +1,2 @@
-FROM payara/server-full:latest
+FROM payara/server-full:5.192
 COPY target/intercept-methods-with-cdi-interceptors.war $DEPLOY_DIR

intercept-methods-with-cdi-interceptors/README.md

@@ -0,0 +1,18 @@
+# Codebase for the blog post [#HOWTO: Intercept method calls using CDI interceptors](https://rieckpil.de/howto-intercept-method-calls-using-cdi-interceptors/)
+
+Steps to run this project:
+
+1. Clone this Git repository
+2. Navigate to the folder `intercept-methods-with-cdi-interceptors`
+3. Start your Docker daemon
+4. Execute `buildAndRun.bat` (Windows) or `buildAndRun.sh` (`chmod +X ./buildAndRun.sh` required, Linux & Mac)
+5. Wait until the container is up and running
+6. Access http://localhost:8080/resources/payments/mike in your browser and you should get HTTP 400
+7. Access http://localhost:8080/resources/payments/mike with HTTP header `X-Secure-Payment` (either use Postman or curl) and you should get HTTP 200
+8. Access http://localhost:8080/resources/payments/duke with HTTP header `X-Secure-Payment` (either use Postman or cURL) and you should get HTTP 200 and you should see the manipulated amount in the logs
+
+```shell
+curl -XGET http://localhost:8080/resources/payments/mike
+curl -XGET --header "X-Secure-Payment: true" http://localhost:8080/resources/payments/mike
+curl -XGET --header "X-Secure-Payment: true" http://localhost:8080/resources/payments/duke
+```

intercept-methods-with-cdi-interceptors/buildAndRun.sh

@@ -13,25 +13,6 @@
 			<version>8.0</version>
 			<scope>provided</scope>
 		</dependency>
-		<dependency>
-			<groupId>org.eclipse.microprofile</groupId>
-			<artifactId>microprofile</artifactId>
-			<version>2.0.1</version>
-			<type>pom</type>
-			<scope>provided</scope>
-		</dependency>
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<version>4.12</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>org.mockito</groupId>
-			<artifactId>mockito-core</artifactId>
-			<version>2.23.0</version>
-			<scope>test</scope>
-		</dependency>
 	</dependencies>
 	<build>
 		<finalName>intercept-methods-with-cdi-interceptors</finalName>

intercept-methods-with-cdi-interceptors/pom.xml

@@ -1,4 +1,4 @@
-package sample;
+package de.rieckpil.blog;
 
 import javax.ws.rs.ApplicationPath;
 import javax.ws.rs.core.Application;

intercept-methods-with-cdi-interceptors/src/main/java/sample/JAXRSConfiguration.java intercept-methods-with-cdi-interceptors/src/main/java/de/rieckpil/blog/JAXRSConfiguration.java

@@ -0,0 +1,14 @@
+package de.rieckpil.blog;
+
+import javax.interceptor.InterceptorBinding;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.*;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+@InterceptorBinding
+@Target({TYPE, METHOD})
+@Retention(RUNTIME)
+public @interface ManipulatedPayment {
+}

intercept-methods-with-cdi-interceptors/src/main/java/de/rieckpil/blog/ManipulatedPayment.java

@@ -0,0 +1,52 @@
+package de.rieckpil.blog;
+
+import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
+import javax.inject.Inject;
+import javax.interceptor.AroundConstruct;
+import javax.interceptor.AroundInvoke;
+import javax.interceptor.Interceptor;
+import javax.interceptor.InvocationContext;
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+@Interceptor
+@ManipulatedPayment
+public class PaymentManipulationInterceptor {
+
+    @Inject
+    private PaymentManipulator paymentManipulator;
+
+    @AroundInvoke
+    public Object manipulatePayment(InvocationContext invocationContext) throws Exception {
+
+        if (invocationContext.getParameters()[0] instanceof String) {
+            if (((String) invocationContext.getParameters()[0]).equalsIgnoreCase("duke")) {
+                paymentManipulator.manipulatePayment();
+                invocationContext.setParameters(new Object[]{
+                        "Duke", new BigDecimal(999.99).setScale(2, RoundingMode.HALF_UP)
+                });
+            }
+        }
+
+        return invocationContext.proceed();
+    }
+
+    @AroundConstruct
+    public void aroundConstructInterception(InvocationContext invocationContext) throws Exception {
+        System.out.println(invocationContext.getConstructor().getDeclaringClass() + " will be manipulated");
+        invocationContext.proceed();
+    }
+
+    @PostConstruct
+    public void postConstructInterception(InvocationContext invocationContext) throws Exception {
+        System.out.println(invocationContext.getMethod().getDeclaringClass() + " is ready for manipulation");
+        invocationContext.proceed();
+    }
+
+    @PreDestroy
+    public void preDestroyInterception(InvocationContext invocationContext) throws Exception {
+        System.out.println("Stopped manipulating of class " + invocationContext.getMethod().getDeclaringClass());
+        invocationContext.proceed();
+    }
+}

intercept-methods-with-cdi-interceptors/src/main/java/de/rieckpil/blog/PaymentManipulationInterceptor.java

@@ -0,0 +1,12 @@
+package de.rieckpil.blog;
+
+import javax.enterprise.context.RequestScoped;
+
+@RequestScoped
+public class PaymentManipulator {
+
+    public void manipulatePayment() {
+        System.out.println("Manipulating payment...");
+    }
+
+}

intercept-methods-with-cdi-interceptors/src/main/java/de/rieckpil/blog/PaymentManipulator.java

@@ -0,0 +1,21 @@
+package de.rieckpil.blog;
+
+import javax.annotation.PostConstruct;
+import javax.ejb.Singleton;
+import javax.ejb.Startup;
+import java.math.BigDecimal;
+
+@Startup
+@Singleton
+@ManipulatedPayment
+public class PaymentProvider {
+
+    @PostConstruct
+    public void setUpPaymentProvider() {
+        System.out.println("Setting up payment provider ...");
+    }
+
+    public void withdrawMoneyFromCustomer(String customer, BigDecimal amount) {
+        System.out.println("Withdrawing money from " + customer + " - amount: " + amount);
+    }
+}

intercept-methods-with-cdi-interceptors/src/main/java/de/rieckpil/blog/PaymentProvider.java

@@ -0,0 +1,29 @@
+package de.rieckpil.blog;
+
+import javax.inject.Inject;
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.core.Response;
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+@Path("payments")
+public class PaymentResource {
+
+    @Inject
+    private PaymentProvider paymentProvider;
+
+    @GET
+    @Path("/{customerName}")
+    @SecurePayment(requiredHttpHeader = "X-Secure-Payment")
+    public Response getPaymentForCustomer(@PathParam("customerName") String customerName) {
+
+        paymentProvider
+                .withdrawMoneyFromCustomer(customerName,
+                        new BigDecimal(42.00).setScale(2, RoundingMode.HALF_UP));
+
+        return Response.ok("Payment was withdrawn from customer " + customerName).build();
+    }
+
+}

intercept-methods-with-cdi-interceptors/src/main/java/de/rieckpil/blog/PaymentResource.java

@@ -0,0 +1,20 @@
+package de.rieckpil.blog;
+
+import javax.enterprise.util.Nonbinding;
+import javax.interceptor.InterceptorBinding;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+@InterceptorBinding
+@Target({METHOD, TYPE})
+@Retention(RUNTIME)
+public @interface SecurePayment {
+
+   @Nonbinding String requiredHttpHeader() default "X-Duke";
+
+}
+

intercept-methods-with-cdi-interceptors/src/main/java/de/rieckpil/blog/SecurePayment.java

@@ -0,0 +1,35 @@
+package de.rieckpil.blog;
+
+import javax.annotation.Priority;
+import javax.interceptor.AroundInvoke;
+import javax.interceptor.Interceptor;
+import javax.interceptor.InvocationContext;
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.Context;
+import javax.ws.rs.core.HttpHeaders;
+import javax.ws.rs.core.Response;
+
+@Priority(42)
+@Interceptor
+@SecurePayment
+public class SecurePaymentInterceptor {
+
+    @Context
+    private HttpHeaders headers;
+
+    @AroundInvoke
+    public Object securePayment(InvocationContext invocationContext) throws Exception {
+
+        String requiredHttpHeader = invocationContext
+                .getMethod()
+                .getAnnotation(SecurePayment.class)
+                .requiredHttpHeader();
+
+        if (headers.getRequestHeaders().containsKey(requiredHttpHeader)) {
+            return invocationContext.proceed();
+        } else {
+            throw new WebApplicationException("Missing HTTP header: " + requiredHttpHeader, Response.Status.BAD_REQUEST);
+        }
+
+    }
+}

intercept-methods-with-cdi-interceptors/src/main/java/de/rieckpil/blog/SecurePaymentInterceptor.java

@@ -3,4 +3,7 @@
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
        bean-discovery-mode="all">
+<interceptors>
+    <class>de.rieckpil.blog.PaymentManipulationInterceptor</class>
+</interceptors>
 </beans>