BAEL-3091: The Prototype Pattern in Java (changed code based on valid comments from a reader)

oauth2-framework-impl/oauth2-client/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>oauth2-client</artifactId>
+    <packaging>war</packaging>
+    <name>oauth2-client</name>
+
+    <parent>
+        <groupId>com.baeldung.oauth2</groupId>
+        <artifactId>oauth2-framework-impl</artifactId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>net.wasdev.wlp.maven.plugins</groupId>
+                <artifactId>liberty-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <httpPort>9180</httpPort>
+        <httpsPort>9543</httpsPort>
+    </properties>
+</project>

oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/AbstractServlet.java

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+package com.baeldung.oauth2.client;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.Base64;
+
+public abstract class AbstractServlet extends HttpServlet {
+
+    protected void dispatch(String location, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        RequestDispatcher requestDispatcher = request.getRequestDispatcher(location);
+        requestDispatcher.forward(request, response);
+    }
+
+    protected String getAuthorizationHeaderValue(String clientId, String clientSecret) {
+        String token = clientId + ":" + clientSecret;
+        String encodedString = Base64.getEncoder().encodeToString(token.getBytes());
+        return "Basic " + encodedString;
+    }
+}

oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/AuthorizationCodeServlet.java

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+package com.baeldung.oauth2.client;
+
+import org.eclipse.microprofile.config.Config;
+
+import javax.inject.Inject;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.UUID;
+
+@WebServlet(urlPatterns = "/authorize")
+public class AuthorizationCodeServlet extends HttpServlet {
+
+    @Inject
+    private Config config;
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        //...
+        request.getSession().removeAttribute("tokenResponse");
+        String state = UUID.randomUUID().toString();
+        request.getSession().setAttribute("CLIENT_LOCAL_STATE", state);
+
+        String authorizationUri = config.getValue("provider.authorizationUri", String.class);
+        String clientId = config.getValue("client.clientId", String.class);
+        String redirectUri = config.getValue("client.redirectUri", String.class);
+        String scope = config.getValue("client.scope", String.class);
+
+        String authorizationLocation = authorizationUri + "?response_type=code"
+                + "&client_id=" + clientId
+                + "&redirect_uri=" + redirectUri
+                + "&scope=" + scope
+                + "&state=" + state;
+        response.sendRedirect(authorizationLocation);
+    }
+}

oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/CallbackServlet.java

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+package com.baeldung.oauth2.client;
+
+import org.eclipse.microprofile.config.Config;
+
+import javax.inject.Inject;
+import javax.json.JsonObject;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.ws.rs.client.Client;
+import javax.ws.rs.client.ClientBuilder;
+import javax.ws.rs.client.Entity;
+import javax.ws.rs.client.WebTarget;
+import javax.ws.rs.core.Form;
+import javax.ws.rs.core.HttpHeaders;
+import javax.ws.rs.core.MediaType;
+import java.io.IOException;
+
+@WebServlet(urlPatterns = "/callback")
+public class CallbackServlet extends AbstractServlet {
+
+    @Inject
+    private Config config;
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+        String clientId = config.getValue("client.clientId", String.class);
+        String clientSecret = config.getValue("client.clientSecret", String.class);
+
+        //Error:
+        String error = request.getParameter("error");
+        if (error != null) {
+            request.setAttribute("error", error);
+            dispatch("/", request, response);
+            return;
+        }
+        String localState = (String) request.getSession().getAttribute("CLIENT_LOCAL_STATE");
+        if (!localState.equals(request.getParameter("state"))) {
+            request.setAttribute("error", "The state attribute doesn't match !!");
+            dispatch("/", request, response);
+            return;
+        }
+
+        String code = request.getParameter("code");
+
+        Client client = ClientBuilder.newClient();
+        WebTarget target = client.target(config.getValue("provider.tokenUri", String.class));
+
+        Form form = new Form();
+        form.param("grant_type", "authorization_code");
+        form.param("code", code);
+        form.param("redirect_uri", config.getValue("client.redirectUri", String.class));
+
+        try {
+            JsonObject tokenResponse = target.request(MediaType.APPLICATION_JSON_TYPE)
+                    .header(HttpHeaders.AUTHORIZATION, getAuthorizationHeaderValue(clientId, clientSecret))
+                    .post(Entity.entity(form, MediaType.APPLICATION_FORM_URLENCODED_TYPE), JsonObject.class);
+            request.getSession().setAttribute("tokenResponse", tokenResponse);
+        } catch (Exception ex) {
+            System.out.println(ex.getMessage());
+            request.setAttribute("error", ex.getMessage());
+        }
+        dispatch("/", request, response);
+    }
+}

oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/DownstreamCallServlet.java

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+package com.baeldung.oauth2.client;
+
+import org.eclipse.microprofile.config.Config;
+
+import javax.inject.Inject;
+import javax.json.JsonObject;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.ws.rs.client.*;
+import java.io.IOException;
+import java.io.PrintWriter;
+
+@WebServlet(urlPatterns = "/downstream")
+public class DownstreamCallServlet extends HttpServlet {
+
+    @Inject
+    private Config config;
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse resp) throws ServletException, IOException {
+        resp.setContentType("text/html;charset=UTF-8");
+        String action = request.getParameter("action");
+        Client client = ClientBuilder.newClient();
+        WebTarget webTarget = client.target(config.getValue("resourceServerUri", String.class));
+        WebTarget resourceWebTarget;
+        String response = null;
+        JsonObject tokenResponse = (JsonObject) request.getSession().getAttribute("tokenResponse");
+        if ("read".equals(action)) {
+            resourceWebTarget = webTarget.path("resource/read");
+            Invocation.Builder invocationBuilder = resourceWebTarget.request();
+            response = invocationBuilder
+                    .header("authorization", tokenResponse.getString("access_token"))
+                    .get(String.class);
+        } else if ("write".equals(action)) {
+            resourceWebTarget = webTarget.path("resource/write");
+            Invocation.Builder invocationBuilder = resourceWebTarget.request();
+            response = invocationBuilder
+                    .header("authorization", tokenResponse.getString("access_token"))
+                    .post(Entity.text("body string"), String.class);
+        }
+        PrintWriter out = resp.getWriter();
+        out.println(response);
+        out.flush();
+        out.close();
+    }
+}

oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/RefreshTokenServlet.java

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+package com.baeldung.oauth2.client;
+
+import org.eclipse.microprofile.config.Config;
+
+import javax.inject.Inject;
+import javax.json.JsonObject;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.ws.rs.client.Client;
+import javax.ws.rs.client.ClientBuilder;
+import javax.ws.rs.client.Entity;
+import javax.ws.rs.client.WebTarget;
+import javax.ws.rs.core.Form;
+import javax.ws.rs.core.HttpHeaders;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+import java.io.IOException;
+
+@WebServlet(urlPatterns = "/refreshtoken")
+public class RefreshTokenServlet extends AbstractServlet {
+
+    @Inject
+    private Config config;
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+        String clientId = config.getValue("client.clientId", String.class);
+        String clientSecret = config.getValue("client.clientSecret", String.class);
+
+        JsonObject actualTokenResponse = (JsonObject) request.getSession().getAttribute("tokenResponse");
+        Client client = ClientBuilder.newClient();
+        WebTarget target = client.target(config.getValue("provider.tokenUri", String.class));
+
+        Form form = new Form();
+        form.param("grant_type", "refresh_token");
+        form.param("refresh_token", actualTokenResponse.getString("refresh_token"));
+
+        String scope = request.getParameter("scope");
+        if (scope != null && !scope.isEmpty()) {
+            form.param("scope", scope);
+        }
+
+        Response jaxrsResponse = target.request(MediaType.APPLICATION_JSON_TYPE)
+                .header(HttpHeaders.AUTHORIZATION, getAuthorizationHeaderValue(clientId, clientSecret))
+                .post(Entity.entity(form, MediaType.APPLICATION_FORM_URLENCODED_TYPE), Response.class);
+        JsonObject tokenResponse = jaxrsResponse.readEntity(JsonObject.class);
+        if (jaxrsResponse.getStatus() == 200) {
+            request.getSession().setAttribute("tokenResponse", tokenResponse);
+        } else {
+            request.setAttribute("error", tokenResponse.getString("error_description", "error!"));
+        }
+        dispatch("/", request, response);
+    }
+}

oauth2-framework-impl/oauth2-client/src/main/liberty/config/server.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<server description="${project.artifactId}">
+
+    <featureManager>
+        <feature>localConnector-1.0</feature>
+        <feature>cdi-2.0</feature>
+        <feature>jsp-2.3</feature>
+        <feature>mpConfig-1.3</feature>
+        <feature>jaxrsClient-2.1</feature>
+        <feature>jsonp-1.1</feature>
+    </featureManager>
+
+    <httpEndpoint id="defaultHttpEndpoint" httpPort="${httpPort}" httpsPort="${httpsPort}"/>
+
+    <applicationManager autoExpand="true"/>
+    <applicationMonitor updateTrigger="mbean"/>
+    <application type="war" location="${project.build.finalName}.war" context-root="/"/>
+
+</server>

oauth2-framework-impl/oauth2-client/src/main/resources/META-INF/microprofile-config.properties

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+#Client registration
+client.clientId=webappclient
+client.clientSecret=webappclientsecret
+client.redirectUri=http://localhost:9180/callback
+client.scope=resource.read resource.write
+
+#Provider
+provider.authorizationUri=http://127.0.0.1:9080/authorize
+provider.tokenUri=http://127.0.0.1:9080/token
+
+#Resource Server
+resourceServerUri=http://localhost:9280/api

oauth2-framework-impl/oauth2-client/src/main/webapp/WEB-INF/beans.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+       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_2_0.xsd"
+       bean-discovery-mode="all">
+</beans>

oauth2-framework-impl/oauth2-client/src/main/webapp/WEB-INF/web.xml

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+<web-app xmlns="http://java.sun.com/xml/ns/javaee" version="3.0">
+    <welcome-file-list>
+        <welcome-file>index.jsp</welcome-file>
+    </welcome-file-list>
+</web-app>

oauth2-framework-impl/oauth2-client/src/main/webapp/index.jsp

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+<%@ page import="org.eclipse.microprofile.config.Config" %>
+<%@ page import="org.eclipse.microprofile.config.ConfigProvider" %>
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <meta charset="UTF-8">
+    <title>OAuth2 Client</title>
+    <style>
+        body {
+            margin: 0px;
+        }
+
+        input[type=text], input[type=password] {
+            width: 75%;
+            padding: 4px 0px;
+            display: inline-block;
+            border: 1px solid #502bcc;
+            box-sizing: border-box;
+        }
+
+        .container-error {
+            padding: 16px;
+            border: 1px solid #cc102a;
+            background: #f50307;
+            width: 75%;
+            margin-left: 25px;
+            margin-bottom: 25px;
+        }
+
+        .container {
+            padding: 16px;
+            border: 1px solid #130ecc;
+            background: #eaecf5;
+            width: 75%;
+            margin-left: 25px;
+            margin-bottom: 25px;
+        }
+    </style>
+</head>
+
+<body>
+
+<%
+    Config config1 = ConfigProvider.getConfig();
+%>
+
+<div class="container-error" style="visibility: <%=request.getAttribute("error")!=null?"visible":"hidden"%>">
+    <span>Error : ${error}</span>
+</div>
+
+<div class="container">
+    <span><h4>OAuth2 Authorization Server</h4></span>
+    <hr>
+    <p>Client Registration :</p>
+    <ul>
+        <li>client_id: <%=config1.getValue("client.clientId", String.class)%>
+        </li>
+        <li>client_secret: <%=config1.getValue("client.clientSecret", String.class)%>
+        </li>
+        <li>redirect_uri: <%=config1.getValue("client.redirectUri", String.class)%>
+        </li>
+        <li>scope: <%=config1.getValue("client.scope", String.class)%>
+        </li>
+    </ul>
+    <p>Authorization Server :</p>
+    <ul>
+        <li>authorization_uri: <%=config1.getValue("provider.authorizationUri", String.class)%>
+        </li>
+        <li>token_uri: <%=config1.getValue("provider.tokenUri", String.class)%>
+        </li>
+    </ul>
+</div>
+<div class="container">
+    <span><h4>OAuth2 Client</h4></span>
+    <hr>
+    <p>Token Request :</p>
+    <ul>
+        <li><a class="btn btn-primary" href="/authorize">Get Access Token</a></li>
+    </ul>
+
+    <p>Token Response:</p>
+    <ul>
+        <li>access_token: ${tokenResponse.getString("access_token")}</li>
+        <li>scope: ${tokenResponse.getString("scope")}</li>
+        <li>Expires in (s): ${tokenResponse.getInt("expires_in")}</li>
+        <li>refresh_token: ${tokenResponse.getString("refresh_token")}</li>
+    </ul>
+</div>
+
+<div class="container">
+    <span><h4>Refresh Token</h4></span>
+    <hr>
+    <ul>
+        <li><a href="refreshtoken">Refresh token (original scope)</a></li>
+        <li><a href="refreshtoken?scope=resource.read">Refresh token (scope: resource.read)</a></li>
+        <li><a href="refreshtoken?scope=resource.write">Refresh token (scope: resource.write)</a></li>
+    </ul>
+</div>
+
+<div class="container">
+    <span><h4>OAuth2 Resource Server Call</h4></span>
+    <hr>
+    <ul>
+        <li><a href="downstream?action=read">Read Protected Resource</a></li>
+        <li><a href="downstream?action=write">Write Protected Resource</a></li>
+    </ul>
+</div>
+
+</body>
+</html>