Java tutorial
/* * Copyright 2013-2015 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 final_exam; import com.mongodb.MongoClient; import com.mongodb.MongoClientURI; import com.mongodb.client.MongoDatabase; import freemarker.template.Configuration; import freemarker.template.SimpleHash; import org.apache.commons.lang3.StringEscapeUtils; import org.bson.Document; import spark.ModelAndView; import spark.Request; import spark.template.freemarker.FreeMarkerEngine; import javax.servlet.http.Cookie; import java.io.IOException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import static spark.Spark.*; /** * 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 BlogPostDAO blogPostDAO; private final UserDAO userDAO; private final SessionDAO sessionDAO; public BlogController(String mongoURIString) throws IOException { final MongoClient mongoClient = new MongoClient(new MongoClientURI(mongoURIString)); final MongoDatabase blogDatabase = mongoClient.getDatabase("blog"); blogPostDAO = new BlogPostDAO(blogDatabase); userDAO = new UserDAO(blogDatabase); sessionDAO = new SessionDAO(blogDatabase); cfg = createFreemarkerConfiguration(); setPort(8082); initializeRoutes(); } public static void main(String[] args) throws IOException { if (args.length == 0) { new BlogController("mongodb://localhost"); } else { new BlogController(args[0]); } } private void initializeRoutes() throws IOException { final Configuration configuration = new Configuration(); configuration.setClassForTemplateLoading(BlogController.class, "/final_exam/freemarker"); // this is the blog home page get("/", (request, response) -> { String username = sessionDAO.findUserNameBySessionId(getSessionCookie(request)); List<Document> posts = blogPostDAO.findByDateDescending(10); SimpleHash root = new SimpleHash(); root.put("myposts", posts); if (username != null) { root.put("username", username); } return new ModelAndView(root, "blog_template.ftl"); }, new FreeMarkerEngine(configuration)); // used to display actual blog post detail page get("/post/:permalink", (request, response) -> { String permalink = request.params(":permalink"); System.out.println("/post: get " + permalink); Document post = blogPostDAO.findByPermalink(permalink); if (post == null) { response.redirect("/post_not_found"); } else { // empty comment to hold new comment in form at bottom of blog entry detail page SimpleHash newComment = new SimpleHash(); newComment.put("name", ""); newComment.put("email", ""); newComment.put("body", ""); SimpleHash root = new SimpleHash(); root.put("post", post); root.put("comment", newComment); return new ModelAndView(root, "entry_template.ftl"); } return null; }, new FreeMarkerEngine(configuration)); // handle the signup post post("/signup", (request, response) -> { 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"); return new ModelAndView(root, "signup.ftl"); } 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"); return new ModelAndView(root, "signup.ftl"); } return null; }, new FreeMarkerEngine(configuration)); // present signup form for blog get("/signup", (request, response) -> { 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", ""); return new ModelAndView(root, "signup.ftl"); }, new FreeMarkerEngine(configuration)); // will present the form used to process new blog posts get("/newpost", (request, response) -> { // get cookie String username = sessionDAO.findUserNameBySessionId(getSessionCookie(request)); if (username == null) { // looks like a bad request. user is not logged in response.redirect("/login"); } else { SimpleHash root = new SimpleHash(); root.put("username", username); return new ModelAndView(root, "newpost_template.ftl"); } return null; }, new FreeMarkerEngine(configuration)); // handle the new post submission post("/newpost", (request, response) -> { String title = StringEscapeUtils.escapeHtml4(request.queryParams("subject")); String post = StringEscapeUtils.escapeHtml4(request.queryParams("body")); String tags = StringEscapeUtils.escapeHtml4(request.queryParams("tags")); String username = sessionDAO.findUserNameBySessionId(getSessionCookie(request)); if (username == null) { response.redirect("/login"); // only logged in users can post to blog } else if (title.equals("") || post.equals("")) { // redisplay page with errors HashMap<String, String> root = new HashMap<String, String>(); root.put("errors", "post must contain a title and blog entry."); root.put("subject", title); root.put("username", username); root.put("tags", tags); root.put("body", post); return new ModelAndView(root, "newpost_template.ftl"); } else { // extract tags ArrayList<String> tagsArray = extractTags(tags); // substitute some <p> for the paragraph breaks post = post.replaceAll("\\r?\\n", "<p>"); String permalink = blogPostDAO.addPost(title, post, tagsArray, username); // now redirect to the blog permalink response.redirect("/post/" + permalink); } return null; }, new FreeMarkerEngine(configuration)); get("/welcome", (request, response) -> { 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); return new ModelAndView(root, "welcome.ftl"); } return null; }, new FreeMarkerEngine(configuration)); // process a new comment post("/newcomment", (request, response) -> { String name = StringEscapeUtils.escapeHtml4(request.queryParams("commentName")); String email = StringEscapeUtils.escapeHtml4(request.queryParams("commentEmail")); String body = StringEscapeUtils.escapeHtml4(request.queryParams("commentBody")); String permalink = request.queryParams("permalink"); Document post = blogPostDAO.findByPermalink(permalink); if (post == null) { response.redirect("/post_not_found"); } // check that comment is good else if (name.equals("") || body.equals("")) { // bounce this back to the user for correction SimpleHash root = new SimpleHash(); SimpleHash comment = new SimpleHash(); comment.put("name", name); comment.put("email", email); comment.put("body", body); root.put("comment", comment); root.put("post", post); root.put("errors", "Post must contain your name and an actual comment"); return new ModelAndView(root, "entry_template.ftl"); } else { blogPostDAO.addPostComment(name, email, body, permalink); response.redirect("/post/" + permalink); } return null; }, new FreeMarkerEngine(configuration)); // present the login page get("/login", (request, response) -> { SimpleHash root = new SimpleHash(); root.put("username", ""); root.put("login_error", ""); return new ModelAndView(root, "login.ftl"); }, new FreeMarkerEngine(configuration)); // 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("/login", (request, response) -> { 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"); return new ModelAndView(root, "login.ftl"); } return null; }, new FreeMarkerEngine(configuration)); // Show the posts filed under a certain tag get("/tag/:thetag", (request, response) -> { String username = sessionDAO.findUserNameBySessionId(getSessionCookie(request)); SimpleHash root = new SimpleHash(); String tag = StringEscapeUtils.escapeHtml4(request.params(":thetag")); List<Document> posts = blogPostDAO.findByTagDateDescending(tag); root.put("myposts", posts); if (username != null) { root.put("username", username); } return new ModelAndView(root, "blog_template.ftl"); }, new FreeMarkerEngine(configuration)); // will allow a user to click Like on a post post("/like", (request, response) -> { String permalink = request.queryParams("permalink"); String commentOrdinalStr = request.queryParams("comment_ordinal"); // look up the post in question int ordinal = Integer.parseInt(commentOrdinalStr); // TODO: check return or have checkSession throw String username = sessionDAO.findUserNameBySessionId(getSessionCookie(request)); Document post = blogPostDAO.findByPermalink(permalink); // if post not found, redirect to post not found error if (post == null) { response.redirect("/post_not_found"); } else { blogPostDAO.likePost(permalink, ordinal); response.redirect("/post/" + permalink); } return null; }, new FreeMarkerEngine(configuration)); // tells the user that the URL is dead get("/post_not_found", (request, response) -> { SimpleHash root = new SimpleHash(); return new ModelAndView(root, "post_not_found.ftl"); }, new FreeMarkerEngine(configuration)); // allows the user to logout of the blog get("/logout", (request, response) -> { 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"); } return null; }, new FreeMarkerEngine(configuration)); // used to process internal errors get("/internal_error", (request, response) -> { SimpleHash root = new SimpleHash(); root.put("error", "System has encountered an error."); return new ModelAndView(root, "error_template.ftl"); }, new FreeMarkerEngine(configuration)); } // 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) { 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; } }