So for the presentation, I am setting up a very basic Twitter clone; it’s meant to be simple yet it displays just enough of the productivity that Play! provides. I am gonna go through the steps to setup the demo application which should cover what was announced on Heroku’s blog post but with a little more depth.
First step let’s create the application
play new twitter
Add dependency to CRUD module (conf/dependencies.yml)
- play -> crud
Get the dependencies
play dependencies
IDE Integration
(for Eclipse)
play eclipsify
(for IntelliJ)
play idealize
(for Netbeans)
play netbeansify
Create Model (app/models/Tweet.java)
package models;
import java.util.Date;
import java.util.List;
import javax.persistence.Entity;
import play.data.validation.MaxSize;
import play.data.validation.Required;
import play.db.jpa.Model;
@Entity
public class Tweet extends Model {
@Required
@MaxSize(140)
public String tweet;
@Required
public Date createDate = new Date();
public static List findLatest() {
return Tweet.find(“order by createDate desc”).fetch();
}
@Override
public String toString() {
return this.tweet;
}
}
Define DB for JPA Models (conf/application.conf)
db=${DATABASE_URL}
Add Controller Actions (app/controllers/Application.java)
package controllers;
import java.util.List;
import models.Tweet;
import play.mvc.Controller;
public class Application extends Controller {
public static void index() {
List tweets = Tweet.findLatest();
render(tweets);
}
public static void create(String msg) {
Tweet tweet = new Tweet();
tweet.tweet = msg;
tweet.save();
render(tweet);
}
public static void tweets() {
List tweets = Tweet.findLatest();
renderJSON(tweets);
}
}
Define Main View (app/views/Application/index.html)
#{extends ‘main.html’ /}
#{set title:’Home’ /}
<!– Create Tweet Form –>
<form> <input name=”tweet” type=”text” />
<input type=”submit” value=”Tweet” /> </form><!– Latest Tweets List –>
<ul> #{list tweets}
<li>${_.tweet} (${_.createDate.since()})</li><p><p>
#{/list}</ul>
<!– JS –>
<script type=”text/javascript”>
// Capture Form Submit Event
$(‘form’).submit(function() {
// Define Create Action
var createAction = #{jsAction @create(‘:tweet’) /}
// Call Create Action
$.post(createAction({tweet: $(‘input:first’).val()}), function(data) {
// Prepend Results to the List
$(‘ul’).prepend(data);
$(‘input:first’).val(”);
});
// Don’t let the browser redirect
return false;
});
</script>
Define Create Action View (app/views/Application/create.html)
<li><code>${tweet.tweet} (${tweet.createDate.since()})</li>
Create Unit Test for Tweet Model
import models.Tweet;
import org.junit.Assert;
import org.junit.Test;
import play.test.UnitTest;
public class TweetTest extends UnitTest {
@Test
public void testModelSave() {
long count = Tweet.count();
Tweet t = new Tweet();
t.tweet = “my sample tweet”;
t.save();
long count2 = Tweet.count();
Assert.assertEquals(count + 1, count2);
}
}
Create CRUD Admin for Tweet Model
package controllers;
public class Tweets extends CRUD {
}
Add Routes (conf/routes)
* /admin module:crud GET /rest/tweets Application.tweets
Define Messages for CRUD Admin (conf/messages)
tweet=Tweet createDate=Date Created
Define Profile
web: play run –%$FRAMEWORK_ID –http.port=$PORT -DusePrecompiled=$USE_PRECOMPILED -DDATABASE_URL=mem
Run in Development
play run –%dev -DusePrecompiled=false -DDATABASE_URL=mem
Create Application on Heroku
heroku create play-twitter –stack cedar
heroku create play-twitter –stack cedar
Setup Git Repository
git init; git add .; git commit -a -m “Initial Commit”; git remote add heroku git@heroku.com:play-twitter.git
Setup Heroku Environment Variables
heroku config:add FRAMEWORK_ID=prod; heroku config:add USE_PRECOMPILED=true
Deploy to Heroku
git push heroku master
If anything went wrong you can always check the log
heroku logs
To Setup a Real Database on Heroku
heroku addons:add shared-database
You can checkout a live demo here, the admin interface here or clone the source code on Github.
Reference: Step-by-Step for a Simple Twitter with Play Framework, AJAX, CRUD and Heroku from our JCG partner Felipe Oliveira at Geek Are Totally In.
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