Java tutorial
/* * Copyright 2015 MongoDB, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package course; import static spark.Spark.get; import static spark.Spark.setPort; import java.io.IOException; import java.io.StringWriter; import java.io.Writer; import java.util.ArrayList; import java.util.HashMap; import javax.servlet.http.Cookie; import org.apache.commons.lang3.StringEscapeUtils; import org.bson.Document; import com.mongodb.MongoClient; import com.mongodb.MongoClientURI; import com.mongodb.client.MongoDatabase; import freemarker.template.Configuration; import freemarker.template.SimpleHash; import freemarker.template.Template; import freemarker.template.TemplateException; import spark.Request; import spark.Response; import spark.Route; import static spark.Spark.get; import static spark.Spark.post; import static spark.Spark.setPort; /** * This class encapsulates the controllers for the blog web application. It * delegates all interaction with MongoDB to three Data Access Objects (DAOs). * <p/> * It is also the entry point into the web application. */ public class BlogController { private final Configuration cfg; private final UserDAO userDAO; private final SessionDAO sessionDAO; public static void main(String[] args) throws IOException { if (args.length == 0) { new BlogController("mongodb://localhost"); } else { new BlogController(args[0]); } } public BlogController(String mongoURIString) throws IOException { final MongoClient mongoClient = new MongoClient(new MongoClientURI(mongoURIString)); final MongoDatabase blogDatabase = mongoClient.getDatabase("blog"); userDAO = new UserDAO(blogDatabase); sessionDAO = new SessionDAO(blogDatabase); cfg = createFreemarkerConfiguration(); setPort(8082); initializeRoutes(); } abstract class FreemarkerBasedRoute extends Route { final Template template; /** * Constructor * * @param path * The route path which is used for matching. (e.g. /hello, * users/:name) */ protected FreemarkerBasedRoute(final String path, final String templateName) throws IOException { super(path); template = cfg.getTemplate(templateName); } @Override public Object handle(Request request, Response response) { StringWriter writer = new StringWriter(); try { doHandle(request, response, writer); } catch (Exception e) { e.printStackTrace(); response.redirect("/internal_error"); } return writer; } protected abstract void doHandle(final Request request, final Response response, final Writer writer) throws IOException, TemplateException; } private void initializeRoutes() throws IOException { // this is the blog home page get(new FreemarkerBasedRoute("/", "blog_template.ftl") { @Override public void doHandle(Request request, Response response, Writer writer) throws IOException, TemplateException { String username = sessionDAO.findUserNameBySessionId(getSessionCookie(request)); // this is where we would normally load up the blog data // but this week, we just display a placeholder. HashMap<String, String> root = new HashMap<String, String>(); template.process(root, writer); } }); // handle the signup post post(new FreemarkerBasedRoute("/signup", "signup.ftl") { @Override protected void doHandle(Request request, Response response, Writer writer) throws IOException, TemplateException { String email = request.queryParams("email"); String username = request.queryParams("username"); String password = request.queryParams("password"); String verify = request.queryParams("verify"); HashMap<String, String> root = new HashMap<String, String>(); root.put("username", StringEscapeUtils.escapeHtml4(username)); root.put("email", StringEscapeUtils.escapeHtml4(email)); if (validateSignup(username, password, verify, email, root)) { // good user System.out.println("Signup: Creating user with: " + username + " " + password); if (!userDAO.addUser(username, password, email)) { // duplicate user root.put("username_error", "Username already in use, Please choose another"); template.process(root, writer); } else { // good user, let's start a session String sessionID = sessionDAO.startSession(username); System.out.println("Session ID is" + sessionID); response.raw().addCookie(new Cookie("session", sessionID)); response.redirect("/welcome"); } } else { // bad signup System.out.println("User Registration did not validate"); template.process(root, writer); } } }); // present signup form for blog get(new FreemarkerBasedRoute("/signup", "signup.ftl") { @Override protected void doHandle(Request request, Response response, Writer writer) throws IOException, TemplateException { SimpleHash root = new SimpleHash(); // initialize values for the form. root.put("username", ""); root.put("password", ""); root.put("email", ""); root.put("password_error", ""); root.put("username_error", ""); root.put("email_error", ""); root.put("verify_error", ""); template.process(root, writer); } }); get(new FreemarkerBasedRoute("/welcome", "welcome.ftl") { @Override protected void doHandle(Request request, Response response, Writer writer) throws IOException, TemplateException { String cookie = getSessionCookie(request); String username = sessionDAO.findUserNameBySessionId(cookie); if (username == null) { System.out.println("welcome() can't identify the user, redirecting to signup"); response.redirect("/signup"); } else { SimpleHash root = new SimpleHash(); root.put("username", username); template.process(root, writer); } } }); // present the login page get(new FreemarkerBasedRoute("/login", "login.ftl") { @Override protected void doHandle(Request request, Response response, Writer writer) throws IOException, TemplateException { SimpleHash root = new SimpleHash(); root.put("username", ""); root.put("login_error", ""); template.process(root, writer); } }); // process output coming from login form. On success redirect folks to // the welcome page // on failure, just return an error and let them try again. post(new FreemarkerBasedRoute("/login", "login.ftl") { @Override protected void doHandle(Request request, Response response, Writer writer) throws IOException, TemplateException { String username = request.queryParams("username"); String password = request.queryParams("password"); System.out.println("Login: User submitted: " + username + " " + password); Document user = userDAO.validateLogin(username, password); if (user != null) { // valid user, let's log them in String sessionID = sessionDAO.startSession(user.get("_id").toString()); if (sessionID == null) { response.redirect("/internal_error"); } else { // set the cookie for the user's browser response.raw().addCookie(new Cookie("session", sessionID)); response.redirect("/welcome"); } } else { SimpleHash root = new SimpleHash(); root.put("username", StringEscapeUtils.escapeHtml4(username)); root.put("password", ""); root.put("login_error", "Invalid Login"); template.process(root, writer); } } }); // allows the user to logout of the blog get(new FreemarkerBasedRoute("/logout", "signup.ftl") { @Override protected void doHandle(Request request, Response response, Writer writer) throws IOException, TemplateException { String sessionID = getSessionCookie(request); if (sessionID == null) { // no session to end response.redirect("/login"); } else { // deletes from session table sessionDAO.endSession(sessionID); // this should delete the cookie Cookie c = getSessionCookieActual(request); c.setMaxAge(0); response.raw().addCookie(c); response.redirect("/login"); } } }); // used to process internal errors get(new FreemarkerBasedRoute("/internal_error", "error_template.ftl") { @Override protected void doHandle(Request request, Response response, Writer writer) throws IOException, TemplateException { SimpleHash root = new SimpleHash(); root.put("error", "System has encountered an error."); template.process(root, writer); } }); } // helper function to get session cookie as string private String getSessionCookie(final Request request) { if (request.raw().getCookies() == null) { return null; } for (Cookie cookie : request.raw().getCookies()) { if (cookie.getName().equals("session")) { return cookie.getValue(); } } return null; } // helper function to get session cookie as string private Cookie getSessionCookieActual(final Request request) { if (request.raw().getCookies() == null) { return null; } for (Cookie cookie : request.raw().getCookies()) { if (cookie.getName().equals("session")) { return cookie; } } return null; } // tags the tags string and put it into an array private ArrayList<String> extractTags(String tags) { // probably more efficent ways to do this. // // whitespace = re.compile('\s') tags = tags.replaceAll("\\s", ""); String tagArray[] = tags.split(","); // let's clean it up, removing the empty string and removing dups ArrayList<String> cleaned = new ArrayList<String>(); for (String tag : tagArray) { if (!tag.equals("") && !cleaned.contains(tag)) { cleaned.add(tag); } } return cleaned; } // validates that the registration form has been filled out right and // username conforms public boolean validateSignup(String username, String password, String verify, String email, HashMap<String, String> errors) { String USER_RE = "^[a-zA-Z0-9_-]{3,20}$"; String PASS_RE = "^.{3,20}$"; String EMAIL_RE = "^[\\S]+@[\\S]+\\.[\\S]+$"; errors.put("username_error", ""); errors.put("password_error", ""); errors.put("verify_error", ""); errors.put("email_error", ""); if (!username.matches(USER_RE)) { errors.put("username_error", "invalid username. try just letters and numbers"); return false; } if (!password.matches(PASS_RE)) { errors.put("password_error", "invalid password."); return false; } if (!password.equals(verify)) { errors.put("verify_error", "password must match"); return false; } if (!email.equals("")) { if (!email.matches(EMAIL_RE)) { errors.put("email_error", "Invalid Email Address"); return false; } } return true; } private Configuration createFreemarkerConfiguration() { Configuration retVal = new Configuration(); retVal.setClassForTemplateLoading(BlogController.class, "/freemarker"); return retVal; } }