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![Receiving a chat message
protected void doPost(HttpServletRequest req,
HttpServletResponse resp)
throws ServletException, IOException {
XMPPService xmpp = XMPPServiceFactory.getXMPPService();
Message message = xmpp.parseMessage(req);
JID fromJid = message.getFromJid();
String body = message.getBody();
String emailAddress = fromJid.getId().split("/")[0];
if (body.equalsIgnoreCase("hello")) {
...
return;
}
...](https://image.slidesharecdn.com/gaeoverviewphnompenh2-111026045035-phpapp01/85/Google-App-Engine-Overview-BarCamp-Phnom-Penh-2011-41-320.jpg)
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Google App Engine Overview - BarCamp Phnom Penh 2011
Guy Flysher gave a presentation on Google App Engine at Barcamp Phnom Penh 2011. He began with an introduction of himself and his work at Google. The agenda included explaining what App Engine is, how to use App Engine products, and demonstrating how to use App Engine through a hello world example and code samples. He discussed key App Engine services like Datastore, URL Fetch, Mail, and Images. He also showed how App Engine can be used for non-web applications through backend processing. Finally, he demonstrated sending chat messages and emails using the XMPP and Mail services.
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Google App Engine Overview - BarCamp Phnom Penh 2011
- 1. Guy Flysher Google AppEngine (Google App Engine Overview) Barcamp Phnom Penh 2011 Phnom Penh, Cambodia
- 2. About me ● Developerin the Emerging markets team. ● Joined Google in 2007. ● Previously worked on Social graphs, Gmail and Google Accounts. ● Currently work on SMS products (Chat SMS, G+ SMS and more to come...) ● G+ profile: http://gplus.name/GuyFlysher
- 3. Agenda ● Part I:What is App Engine? ● Part II: App Engine Product Usage ● Part III: How to use App Engine ○ Hello world example ○ App Engine Services ○ Code examples ○ Demos of non web uses
- 4. Why does AppEngine exist?
- 5. App Engine isa full development platform App Engine provides great Hosting tools, APIs & hosting Easy to build APIs Easy to manage Easy to scale Tools
- 6. Language Runtime Options GO Experimental Java
- 7. App Engine APIs/Services Memcache Datastore URL Fetch Mail XMPP Task Queue Images Blobstore User Service
- 8.
- 9. Agenda ● Part I:What is App Engine? ● Part II: App Engine Product Usage ● Part III: How to use App Engine ○ Hello world example ○ App Engine Services ○ Code examples ○ Demos of non web uses
- 10. App Engine -A Larger Number 1,500,000,000+ Page views per day
- 11. Notable App EngineCustomers
- 12. Royal Wedding -Scalability Success Official blog & live stream apps hosted on App Engine On Wedding day... Blog app served: ● Up to 2k requests per second ● 15 million pageviews ● 5.6 million visitors Live stream app served: ● Up to 32k requests per second ● 37.7 million pageviews ● 13.7 million visitors http://goo.gl/F1SGc
- 13. Not all appsuser-facing or web-based! ● Need backend server processing? Want to build your own? ● Go cloud with App Engine! ● No UI needed for app to talk to App Engine, just need HTTP or XMPP ● Great place for user info e.g., high scores, contacts, levels/badges, etc. ● Better UI: move user data off phone & make universally available
- 14. Agenda ● Part I:What is App Engine? ● Part II: App Engine Product Usage ● Part III: How to use App Engine ○ Servlets and JSP files ○ Hello world example ○ App Engine Services and code examples ○ Demos of non web uses
- 15. Java HttpServlet ● Abstractclass for processing HTTP requests. ● Override its methods for processing various HTTP requests, e.g: ○ doGet ○ doPost ○ doHead ○ etc ● Part of Java (not App Engine specific)
- 16. HttpServlet example public classHello_worldServlet extends HttpServlet { public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException { String userIp = req.getRemoteAddr(); resp.setContentType("text/plain"); resp.getWriter().println("Hello, " + userIp); } }
- 17. JSP - JavaServerPages ● Used to create dynamically generated web pages based on HTML. ● A mix of Java and HTML. ● Can be though of as the Java equivalent of PHP.
- 18. JSP example <%@ pagecontentType="text/html;charset=UTF-8" language="java" %> <html><head> <title> Welcome!</title></head><body> <% if (request.getParameter("name") != null) { %> <p>Hello, <%= request.getParameter("name") %> </p> <% } else { %> <p>Hello, stranger. </p> <% } %>
- 19. Hello World Demo Deploy from scratch (In under 3 minutes)
- 20. App Engine setup Servlets and other Java code JSP, html and other static files
- 21. App Engine setup Configuration files
- 22. web.xml Used to mapURLs to the servlets that will handle them:
- 23.
- 24. web.xml Used to mapURLs to the servlets that will handle them:
- 25. App Engine Services The User Service
- 26. The user system Buildingyour own user system is a lot of work ● Needs to be very secure - destructive result if broken into. ● Needs to be very reliable - if it is down your app can't be used. ● Lots of other services you need to build - a recovery mechanism etc.
- 27. The Google usersystem App Engine User Service lets you use Google's user system for your app. Benefits: ● Users don't need to create a new account to use your app, they can use their Google account ● Very secure, highly reliable. ● Already has recovery mechanisms etc. ● Very easy to use!
- 28. The User Service Checkingif a user is logged in: <% UserService userService = UserServiceFactory.getUserService(); User user = userService.getCurrentUser(); if (user != null) { %> <p>Hello, <%= user.getNickname() %> </p>! <p>Our records show your email as: <%= user.getEmail() %> </p> <% } else { %> <p>Hello! Please log in. </p> <% } %>
- 29. The User Service Creatinga sign in/out links <% UserService userService = UserServiceFactory.getUserService(); User user = userService.getCurrentUser(); if (user != null) { %> <p>Hello, <%= user.getNickname() %>! <p> <a href="<%= userService.createLogoutURL(request.getRequestURI()) %>">Sign out </a></p> <% } else { %> <p><a href="<%= userService.createLoginURL(request.getRequestURI()) %>">Sign in</a</p> ...
- 33. App Engine Services The XMPP (chat) Service
- 34. Sending a chatmessage ... JID fromJid = new JID("gday-chat@appspot.com"); JID toJid = new JID("chatty.cathy@gmail.com"); Message msg = new MessageBuilder() .withRecipientJids(toJid) .withFromJid(fromJid) .withBody("Hi there. Is this easy or what?") .build(); XMPPService xmpp = XMPPServiceFactory.getXMPPService(); SendResponse status = xmpp.sendMessage(msg); boolean messageSent = (status.getStatusMap().get(toJid) == SendResponse.Status.SUCCESS); ...
- 35. App Engine Services The Mail Service
- 36. Sending an emailmessage ... Properties props = new Properties(); Session session = Session.getDefaultInstance(props, null); try { Message msg = new MimeMessage(session); msg.setFrom(new InternetAddress( "anything@my-app-name.appspotmail.com", "Guy's App Engine App")); msg.addRecipient(Message.RecipientType.TO, new InternetAddress("my.client@gmail.com")); msg.setSubject("You confirmation email"); msg.setText("..."); Transport.send(msg); } catch (AddressException e) { ... } catch (MessagingException e) { ... } catch (UnsupportedEncodingException e) { ... } ...
- 37.
- 38. ! Q&A More documentation and information: http://code.google.com/appengine
- 39.
- 40. Receiving a chatmessage Signup your app to receive chat messages appengine-web.xml <inbound-services> <service>xmpp_message</service> </inbound-services> web.xml <servlet> <servlet-name>xmppreceiver</servlet-name> <servlet-class>gday.ReceiveChatMessageServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>xmppreceiver</servlet-name> <url-pattern>/_ah/xmpp/message/chat/</url-pattern> </servlet-mapping>
- 41. Receiving a chatmessage protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { XMPPService xmpp = XMPPServiceFactory.getXMPPService(); Message message = xmpp.parseMessage(req); JID fromJid = message.getFromJid(); String body = message.getBody(); String emailAddress = fromJid.getId().split("/")[0]; if (body.equalsIgnoreCase("hello")) { ... return; } ...