Introduction in the play framework

Web development with the Play! framework Java web development is fun again Alexander Reelsen alexander@reelsen.net June 2010 Alexander Reelsen Web development with the Play! framework June 2010 1 / 35

Agenda 1 Introduction Overview 2 Core concepts Architecture Conventions Conﬁguring routes Model Controller View Testing Jobs Running Play in production 3 Ongoing development Features for Play 1.1 Module repository Development forecast Alexander Reelsen Web development with the Play! framework June 2010 2 / 35

Introduction Agenda 1 Introduction Overview 2 Core concepts Architecture Conventions Conﬁguring routes Model Controller View Testing Jobs Running Play in production 3 Ongoing development Features for Play 1.1 Module repository Development forecast Alexander Reelsen Web development with the Play! framework June 2010 3 / 35

Introduction Overview Speaking... About me Studied information systems 10 years linux system engineering, converted to software engineering Just another java developer Web framework enthusiast Fed up with complex java environment for simple webapps Non development life Basketball/Streetball Web 2.0 Alexander Reelsen Web development with the Play! framework June 2010 4 / 35

Introduction Overview The web taking over Ubiquitous web Web as ubiquitous platform Providing data, not web pages Browser as the operating system JavaScript gains steam, toolkits as well as engines Web applications are alive Alexander Reelsen Web development with the Play! framework June 2010 5 / 35

Core concepts Agenda 1 Introduction Overview 2 Core concepts Architecture Conventions Conﬁguring routes Model Controller View Testing Jobs Running Play in production 3 Ongoing development Features for Play 1.1 Module repository Development forecast Alexander Reelsen Web development with the Play! framework June 2010 6 / 35

Core concepts Architecture Play in 10 seconds Quick overview No compile, deploy, restart cycle - Fix the bug and hit reload! Share nothing system - no state in the server Clean templating system - using groovy Exact errors (including line numbers, even for templates) Lots of builtin features for fast development Pure Java Starts fast, runs fast Extensible by modules Alexander Reelsen Web development with the Play! framework June 2010 7 / 35

Core concepts Architecture Roots and fundamentals History Exists since 2008, by Guillaume Bort from zenexity Release 1.0 was in October 2009 Current: 1.0.3 + development tree A framework imposes its own style of architecture REST as architectural paradigm for ressources URLs are the entry point (and implicit interface) to your application Do not work against HTTP (stateless protocol) Convention over conﬁguration Only fractions of diﬀerences between development and production mode Alexander Reelsen Web development with the Play! framework June 2010 8 / 35

Core concepts Architecture Play architecture Source: http://www.playframework.org/documentation/1.0.1/main Alexander Reelsen Web development with the Play! framework June 2010 9 / 35

Core concepts Architecture Play is a lot of glue code Includes the following libraries Hibernate Oval Lucene Google gson Eclipse compiler Commons: ﬁleupload, httpclient, email, logging, beanutils MINA and Asyncweb EhCache JAMon Groovy Alexander Reelsen Web development with the Play! framework June 2010 10 / 35

Core concepts Architecture Play specialties Interesting to know No support for servlet API (yes, in a web framework) Sharing objects via memcached through several nodes Everything is UTF-8 Full text indexing with 2 annotations No anemic domain model - logic is in the object DAOs and ﬁnders are not external Textmate, eclipse bundles, also support for IDEA and netbeans Alexander Reelsen Web development with the Play! framework June 2010 11 / 35

Core concepts Conventions Application layout Creating a new app play new myapp Application structure ./ conf ./ conf / routes ./ conf / a p p l i c a t i o n . conf ./ conf / messages ./ test ./ l i b ./ public . / app . / app / m o d e l s . / app / c o n t r o l l e r s . / app / v i e w s Alexander Reelsen Web development with the Play! framework June 2010 12 / 35

Core concepts Conventions Application config file conf/application.conf Configure database access db=fs, db=mem db=mysql:user:pwd@database_name Any JDBC connection Specify modules Supported languages Logger memcached setup mail configuration mode/system specific settings Alexander Reelsen Web development with the Play! framework June 2010 13 / 35

Core concepts Conﬁguring routes The conf/routes ﬁle Interface contract to the outer world GET / Application . index GET / u s e r /{ username } Application . showUser POST / user Application . createUser DELETE / u s e r /{ username } Application . deleteUser GET / public staticDir : public Alexander Reelsen Web development with the Play! framework June 2010 14 / 35

Core concepts Model Designing a domain model A simple user @Entity public class User extends Model { @Required @Column(unique = true) public String username; @Required @Email public String email; @Required public String password; public void setPassword(String password) { this.pass = Crypto.passwordHash(pass); } } Alexander Reelsen Web development with the Play! framework June 2010 15 / 35

Core concepts Model The Model class is a helper Finders and Entity actions // Query by property User user = User.find("byUsername", username).first(); // Calls a setter user.password = "foobar"; user.save(); List<User> users = User.findAll(); users.get(0).delete(); // JPA queries are possible as well, so are joins List<String> names = User.find("select u.username from User u order by u.username desc").fetch(); Alexander Reelsen Web development with the Play! framework June 2010 16 / 35

Core concepts Controller Calling business logic User controller public class Application extends Controller { public static void index() { List<User> users = User.findAll(); render(users); } public static void showUser(String username) { User user = User.find("byUsername", username).first(); notFoundIfNull(user); render(user); } ... Alexander Reelsen Web development with the Play! framework June 2010 17 / 35

Core concepts Controller Calling business logic User controller (ctd.) ... public static void deleteUser(String username) { User user = User.find("byUsername", username).first(); notFoundIfNull(user); user.delete(); Application.index(); } public static void createUser(@Valid User user) { if (validation.hasErrors()) { flash.error("Invalid user data"); Application.index(); } user = user.save(); Application.showUser(user.username) } } Alexander Reelsen Web development with the Play! framework June 2010 18 / 35

Core concepts Controller Calling business logic Example: Accessing the session public class AuthController extends Controller { @Before(unless = "login") public static void checkSession() { if (!request.session.contains("username")) { forbidden("You are not authorized"); } } public void login(String username, String password) { String pass = Crypto.passwordHash(password); User user = User.find("byUsernameAndPassword", username, pass).first(); notFoundIfNull(user); request.session.put("username", user); Application.index(); } } Alexander Reelsen Web development with the Play! framework June 2010 19 / 35

Core concepts View The templating system List users (app/views/Application/index.html) #{ extends ’ main . html ’ /} #{ set title : ’ Index ’ /} < ul > #{ list items : users , as : ’ user ’} < li > #{ a @Application . showUser ( user . username )} $ { user . username } #{/ a } with email address $ { user . email } </ li > #{/ list } </ ul > Alexander Reelsen Web development with the Play! framework June 2010 20 / 35

Core concepts View The templating system Add user #{ form @Application . createUser ()} < div > Username : < input type = " text " name = " user . username " / > </ div > < div > Password : < input type = " pass " name = " user . password " / > </ div > < div > Email : < input type = " text " name = " user . email " / > </ div > < input type = " submit " value = " Add user " / > #{/ form } Alexander Reelsen Web development with the Play! framework June 2010 21 / 35

Core concepts View The templating system More tags doLayout, extends, include if, ifnot, else, elseif &{’i18nVariable’} out of conf/messages.de Always access to: session, flash, request, params, lang, messages, out, play Alexander Reelsen Web development with the Play! framework June 2010 22 / 35

Core concepts View The templating system Extending objects using mixins public class SqrtExtension extends JavaExtensions { public static Double sqrt(Number number) { return Math.sqrt(number.doubleValue()); } } The template code < div > Square root of x value is : $ { x . sqrt ()} </ div > Alexander Reelsen Web development with the Play! framework June 2010 23 / 35

Core concepts Testing Testing Providing test data YAML formatted ﬁle provides testdata User ( a l e r e e ) : username : a l r password : t e s t email : a l e x a n d e r @ r e e l s e n . net Loading test data... @Before public void setUp() { Fixtures.deleteAll(); Fixtures.load("data.yml"); } Alexander Reelsen Web development with the Play! framework June 2010 24 / 35

Core concepts Testing Testing Unit tests Standard junit tests Extend from UnitTest, which needs a JPA environment Functional tests Integration tests Checks the external responses (http response) Selenium tests GUI tests Very nice controllable, playback recorder Possibility of doing step-by-step slow debugging Alexander Reelsen Web development with the Play! framework June 2010 25 / 35

Core concepts Testing Testing CI with Calimoucho Poor mans hudson Checks out the project and runs play auto-test, which needs a graphical layer for selenium tests Check it under http://integration.playframework.org Code coverage with cobertura Enable the cobertura module in application.conf Run the tests, check the results Alexander Reelsen Web development with the Play! framework June 2010 26 / 35

Core concepts Jobs Jobs - being asynchronous Doing the right thing at the right time Scheduled jobs (housekeeping) Bootstrap jobs (initial data providing) Suspendable requests (rendering a PDF report without blocking the connection thread pool) /* @Every("1h") */ @OnApplicationStart public class LoadDataJob extends Job { public void doJob() { /* .. do whatever you want */ } } Alexander Reelsen Web development with the Play! framework June 2010 27 / 35

Core concepts Running Play in production Putting play into production The setup A redirector like nginx or apache is preferred Also eliminates the need to serve static files Redirect to different nodes would be the main task Profile per nodes possible (very useful for server farms) Alexander Reelsen Web development with the Play! framework June 2010 28 / 35

Core concepts Running Play in production Monitoring play application Partial Output of play status Monitors: Application.showLatestRecipesRss(), ms. -> 4120 hits; 41.0 avg; 20.0 min; 260.0 max; /app/views/Application/showLatestRecipesRss.html, ms. -> 4120 hits; 34.9 avg; 19.0 min; 235.0 max; Datasource: Job execution pool: Scheduled jobs: Alexander Reelsen Web development with the Play! framework June 2010 29 / 35

Ongoing development Agenda 1 Introduction Overview 2 Core concepts Architecture Conventions Conﬁguring routes Model Controller View Testing Jobs Running Play in production 3 Ongoing development Features for Play 1.1 Module repository Development forecast Alexander Reelsen Web development with the Play! framework June 2010 30 / 35

Ongoing development Features for Play 1.1 Play 1.1 is on its way Core features Bug ﬁxes Scala support More modules through module repository Alexander Reelsen Web development with the Play! framework June 2010 31 / 35

Ongoing development Module repository Useful modules Slowly but steadily growing Scala, Scalate, Akka PDF, excel modules Guice and Spring modules Netty and grizzly support GWT support, GAE support Extended CSS, SASS Ivy and Maven support Siena, Ebean ORM, MongoDB Database migration module Hosting: stax, playapps Alexander Reelsen Web development with the Play! framework June 2010 32 / 35

Ongoing development Development forecast TODO Open issues NoSQL support (Siena, MongoDB) Amazon Cloud Integration Hosting platform (playapps.net has just launched) Lucene Solr Support for shared environments Tighter integration with JavaScript Toolkits like Dojo Far more modules - check out the rich grails ecosystem The ﬁrst book... is coming! Alexander Reelsen Web development with the Play! framework June 2010 33 / 35

Finish Done! Thanks for listening. Questions? Job oﬀers regarding Java Scalability or new technologies like Play and/or MongoDB? Talk to me or send mail to alexander@reelsen.net Alexander Reelsen Web development with the Play! framework June 2010 34 / 35

Finish URLs Further information This presentation: http://www.slideshare.net/areelsen/ http://www.playframework.org http://twitter.com/playframework http://it-republik.de/jaxenter/artikel/ Webanwendungen-mit-dem-Java-Framework-Play!-2813.html http://www.bookware.de/kaffeeklatsch/archiv/ KaffeeKlatsch-2009-11.pdf http://www.bookware.de/kaffeeklatsch/archiv/ KaffeeKlatsch-2009-12.pdf http://www.zenexity.fr/frameworks/ anatomie-dun-framework-de-developpement-web/ Alexander Reelsen Web development with the Play! framework June 2010 35 / 35

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Introduction in the play framework

by Alexander Reelsen on Jun 20, 2010

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Introduction in the play framework — Presentation Transcript