Matt RaibleMatt Raible is a writer with a passion for software. Connect with him on LinkedIn.

The Angular Mini-Book The Angular Mini-Book is a guide to getting started with Angular. You'll learn how to develop a bare-bones application, test it, and deploy it. Then you'll move on to adding Bootstrap, Angular Material, continuous integration, and authentication.

Spring Boot is a popular framework for building REST APIs. You'll learn how to integrate Angular with Spring Boot and use security best practices like HTTPS and a content security policy.

For book updates, follow @angular_book on Twitter.

The JHipster Mini-Book The JHipster Mini-Book is a guide to getting started with hip technologies today: Angular, Bootstrap, and Spring Boot. All of these frameworks are wrapped up in an easy-to-use project called JHipster.

This book shows you how to build an app with JHipster, and guides you through the plethora of tools, techniques and options you can use. Furthermore, it explains the UI and API building blocks so you understand the underpinnings of your great application.

For book updates, follow @jhipster-book on Twitter.

10+ YEARS


Over 10 years ago, I wrote my first blog post. Since then, I've authored books, had kids, traveled the world, found Trish and blogged about it all.
You searched this site for "play". 220 entries found.

You can also try this same search on Google.

Secure JSON Services with Play Scala and SecureSocial

AntwerpTownSquare Last November, I traveled to Antwerp to speak at Devoxx. After my talk on HTML5 with Play Scala, Mattias Karlsson approached me and we had a chat about doing the same talk at Jfokus in Stockholm. I agreed and we began talking details after Trish and I returned to the US.

Jfokus

I wrote this article on a plane between Denver and Seattle and will be hopping over the North Pole to Stockholm via Iceland tonight. For the past couple of weeks, I've been updating my Play More! HTML5/mobile app to add some new features. Most notably, I wanted to upgrade to Play 2.0, create JSON services and add authentication.

Upgrading to Play 2.0
My attempt to upgrade to Play 2.0 involved checking out the source from GitHub, building and installing the RC1 snapshot. As I tried to upgrade my app and started getting failed imports, I turned to the internet (specifically StackOverflow) to see if it was a good idea. The first answer for that question suggested I stay with 1.x.

If it's a critical project, to be finished before next March 2012, I would go with Play 1.x. If it's a less important project, which could be delayed, and that in any case won't be released before March 2012, try Play 2.0.

While I didn't plan on releasing Play More! before Jfokus, I decided upgrading didn't add a whole lot to the talk. Also, I couldn't find a Play Scala 0.9.1 to Play 2.0 upgrade guide and I didn't have enough time to create one. So I decided to stick with Play 1.2.4 and add some JSON services for my iPhone client.

JSON Servers
I found Manuel Bernhardt's Play! Scala and JSON. This led me to Jerkson, built by the now infamous @coda. I was able to easily get things working fairly quickly and wrote the following WorkoutService.scala:

package controllers.api

import play.mvc.Controller
import models._
import com.codahale.jerkson.Json._

object WorkoutService extends Controller {

  def workouts = {
    response.setContentTypeIfNotSet("application/json")
    generate(Workout.find().list())
  }
  def edit(id: Long) = {
    generate(Workout.byIdWithAthleteAndComments(id))
  }

  def create() = {
    var workout = params.get("workout", classOf[Workout])
    Workout.create(workout)
  }

  def save(id: Option[Long]) = {
    var workout = params.get("workout", classOf[Workout])
    Workout.update(workout)
  }

  def delete(id: Long) = {
    Workout.delete("id={id}").on("id" -> id).executeUpdate()
  }
}

Next, I added routes for my new API to conf/routes:

GET     /api/workouts               api.WorkoutService.workouts
GET     /api/workout/{id}           api.WorkoutService.edit
POST    /api/workout                api.WorkoutService.create
PUT     /api/workout/{id}           api.WorkoutService.save
DELETE  /api/workout/{id}           api.WorkoutService.delete

Then I created an ApiTest.scala class that verifies the first method works as expected.

import play.test.FunctionalTest
import play.test.FunctionalTest._
import org.junit._

class ApiTests extends FunctionalTest {
  
    @Test
    def testGetWorkouts() {
        var response = GET("/api/workouts");
        assertStatus(200, response);
        assertContentType("application/json", response)
        println(response.out)
    }
}

I ran "play test", opened my browser to http://localhost:9000/@tests and clicked ApiTests -> Start to verify it worked. All the green made me happy.

Play More API Tests

Finally, I wrote some CoffeeScript and jQuery to allow users to delete workouts and make sure delete functionality worked.

$('#delete').click ->
  $.ajax
    type: 'POST'
    url: $(this).attr('rel')
    error: ->
      alert('Delete failed, please try again.')
    success: (data) ->
      location.href = "/more"

I was very impressed with how easy Play made it to create JSON services and I smiled as my CoffeeScript skills got a refresher.

The Friday before we left for Devoxx, I saw the module registration request for SecureSocial.

SecureSocial with Play Scala
From SecureSocial's README:

SecureSocial allows you to add an authentication UI to your app that works with services based on OAuth1, OAuth2, OpenID and OpenID+OAuth hybrid protocols.

It also provides a Username and Password mechanism for users that do not wish to use existing accounts in other networks.

The following services are supported in this release:

  • Twitter (OAuth1)
  • Facebook (OAuth2)
  • Google (OpenID + OAuth Hybrid)
  • Yahoo (OpenID + OAuth Hybrid)
  • LinkedIn (OAuth1)
  • Foursquare (OAuth2)
  • MyOpenID (OpenID)
  • Wordpress (OpenID)
  • Username and Password

In other words, it sounded like a dream come true and I resolved to try it once I found the time. That time found me last Monday evening and I sent a direct message to @jaliss (the module's author) via Twitter.

Does Secure Social work with Play Scala? I'd like to use it in my Play More! project.

Jorge responded 16 minutes later saying that he hadn't used Play Scala and he'd need to do some research. At 8 o'clock that night (1.5 hours after my original DM), Jorge had a sample working and emailed it to me. 10 minutes later I was adding a Secure trait to my project.

package controllers

import play.mvc._
import controllers.securesocial.SecureSocial

/*
 * @author Jorge Aliss <[email protected]> of Secure Social fame.
 */
trait Secure {
  self: Controller =>

  @Before def checkAccess() {
    SecureSocial.DeadboltHelper.beforeRoleCheck()
  }

  def currentUser = {
    SecureSocial.getCurrentUser
  }
}

I configured Twitter and Username + Password as my providers by adding the following to conf/application.conf.

securesocial.providers=twitter,userpass

I also had to configure a number of securesocial.twitter.* properties. Next, I made sure my routes were aware of SecureSocial by adding the following to the top of conf/routes:

  *       /auth               module:securesocial

Then I specified it as a dependency in conf/dependencies.yml and ran "play deps".

    - play -> securesocial 0.2.4

After adding "with Secure" to my Profile.scala controller, I tried to access its route and was prompted to login. Right off the bat, I was shown an error about a missing jQuery 1.5.2 file in my "javascripts" folder, so I added it and rejoiced when I was presented with a login screen. I had to add the app on Twitter to use its OAuth servers, but I was pumped when both username/password authentication worked (complete with signup!) as well as Twitter.

The only issue I ran into with SecureSocial was that it didn't find the default implementation of SecureSocial's UserService.Service when running in prod mode. I was able to workaround this by adding a SecureService.scala implementation to my project and coding it to talk to my Athlete model. I didn't bother to hook in creating a new user when they logged in from Twitter, but that's something I'll want to do in the future. I was also pleased to find out customizing SecureSocial's views was a breeze. I simply copied them from the module into my app's views and voila!

package services

import play.db.anorm.NotAssigned
import play.libs.Codec
import collection.mutable.{SynchronizedMap, HashMap}
import models.Athlete
import securesocial.provider.{ProviderType, UserService, SocialUser, UserId}

class SecureService extends UserService.Service {
  val activations = new HashMap[String, SocialUser] with SynchronizedMap[String, SocialUser]

  def find(userId: UserId): SocialUser = {
    val user = Athlete.find("email={email}").on("email" -> userId.id).first()

    user match {
      case Some(user) => {
        val socialUser = new SocialUser
        socialUser.id = userId
        socialUser.displayName = user.firstName
        socialUser.email = user.email
        socialUser.isEmailVerified = true
        socialUser.password = user.password
        socialUser
      }
      case None => {
        if (!userId.provider.eq(ProviderType.userpass)) {
          var socialUser = new SocialUser
          socialUser.id = userId
          socialUser
        } else {
          null
        }
      }
    }
  }

  def save(user: SocialUser) {
    if (find(user.id) == null) {
      val firstName = user.displayName
      val lastName = user.displayName
      Athlete.create(Athlete(NotAssigned, user.email, user.password, firstName, lastName))
    }
  }

  def createActivation(user: SocialUser): String = {
    val uuid: String = Codec.UUID()
    activations.put(uuid, user)
    uuid
  }

  def activate(uuid: String): Boolean = {
    val user: SocialUser = activations.get(uuid).asInstanceOf[SocialUser]
    var result = false

    if (user != null) {
      user.isEmailVerified = true
      save(user)
      activations.remove(uuid)
      result = true
    }

    result
  }

  def deletePendingActivations() {
    activations.clear()
  }
}

Jorge was a great help in getting my authentication needs met and he even wrote a BasicAuth.scala trait to implement Basic Authentication on my JSON services.

package controllers

import _root_.securesocial.provider.{UserService, ProviderType, UserId}
import play._
import play.mvc._
import play.libs.Crypto

import controllers.securesocial.SecureSocial

/*
 * @author Jorge Aliss <[email protected]> of Secure Social fame.
 */
trait BasicAuth {
  self: Controller =>

  @Before def checkAccess = {
    if (currentUser != null) {
      // this allows SecureSocial.getCurrentUser() to work.
      renderArgs.put("user", currentUser)
      Continue
    }

    val realm =
      Play.configuration.getProperty("securesocial.basicAuth.realm", "Unauthorized")

    if (request.user == null || request.password == null) {
      Unauthorized(realm)
    } else {
      val userId = new UserId
      userId.id = request.user
      userId.provider = ProviderType.userpass
      val user = UserService.find(userId)

      if (user == null ||
        !Crypto.passwordHash(request.password).equals(user.password)) {
        Unauthorized(realm)
      } else {
        // this allows SecureSocial.getCurrentUser() to work.
        renderArgs.put("user", user)
        Continue
      }
    }
  }

  def currentUser = {
    SecureSocial.getCurrentUser()
  }
}

Summary
My latest pass at developing with Scala and leveraging Play to build my app was a lot of fun. While there were issues with class reloading every-so-often and Scala versions with Scalate, I was able to add the features I wanted. I wasn't able to upgrade to Play 2.0, but I didn't try that hard and figured it's best to wait until its upgrade guide has been published.

I'm excited to describe my latest experience to the developers at Jfokus this week. In addition, the conference has talks on Play 2.0, CoffeeScript, HTML5, Scala and Scalate. I hope to attend many of these and learn some new tricks to improve my skills and my app.

Update: The Delving developers have written an article on Migration to Play 2. While it doesn't provide specific details on what they needed to change, it does have good information on how long it took and things to watch for.

Posted in Java at Feb 12 2012, 04:02:43 PM MST 4 Comments

Twitter's Open Source Summit: Bootstrap 2.0 Edition

Every few months, Twitter hosts an Open Source Summit to talk about tools they're using. Since I happened to be near San Fransisco, I happily attended their latest #ossummit to learn about Bootstrap 2.0. Below are my notes from last night's event.

95% of Twitter's infrastructure is powered by open source. They hope to contributing back to open source by doing 2-3 summits per year. Without open source, there would be no Twitter. You can find a bunch of Twitter's open source contributions at twitter.github.com. They're also big fans of Apache and commit to a wide variety of projects there.

Bootstrap
Bootstrap is developed by two main guys: @mdo and @fat. Mark (@mdo) has been a designer at Twitter for 2 years. He started on the Revenue Team with ads, but has been working on redesign for last 4 months. Has been doing HTML and CSS for about 11 years. He used Notepad on Windows to build his GeoCities site.

boot·strap: simple and flexible HTML, CSS, and JavaScript for popular user interface components and interactions.

Work on Bootstrap started about a 1.5 years ago. Internal tools didn't get the proper attention they needed. They figured out there was a lot of people that wanted good looking UIs and interactions. It became Twitter Blueprint and was mostly used internally. Jacob (@fat) started shortly after first release and decided to add some JavaScript on top of it. The JavaScript for Bootstrap was originally the "Twitter Internal Toolkit" or "TIT" and was built on Moo Tools. Jacob was like "we gotta open source this, it's gonna be huge!" (he was right).

The 1.0 release supported Chrome, Safari and Firefox (everyone at Twitter was on Macs). 1.3 added cross-browser support and JavaScript plugins.

Now there's Bootstrap 2 (just released!). They rewrote all the documentation and components and removed legacy code.

So, what's new? The biggest thing is the docs. Previously had live examples, now shows live examples and why you would do something, as well as additional options. The "topbar" has been renamed to "navbar", but it's still got all the hotness. It's responsive with CSS media queries for small devices, tablets, small desktops and large desktops. This means the layout breaks at certain points and stacks elements to fit on smaller screens.

CSS: smarter defaults, better classes. In 1.4, all forms were stacked. Now they can flow horizontally. Tables are now namespaced so Bootstrap's styles don't apply to all tables. The available table, form and navigation classes are as follows:

// Tables
.table { ... }
.table-striped { ... }
.table-bordered { ... }
.table-condensed { ... }

// Forms
.form-inline { ... }
.form-search { ... }
.form-horizontal { ... }

// Nav
.nav { ... }
.nav-tabs { ... }
.nav-pills { ... }

The goals with 2.0 are consistency, simplification and future-proofing styles. With 1.4, buttons used "btn primary" and it caused problems if you wanted to have a "primary" class in your project. With 2.0, buttons and all elements are namespaced to avoid collisions (now it's .btn-primary).

After Mark finished talking about the design of Bootstrap, Jacob (@fat) started talking about Bootstrap's JavaScript. Jacob works on The Platform Team at Twitter and claims he made a lot of mistakes with 1.x. However, thanks to semantic versioning, 2.0 is a new version and he got to start over!

The biggest change in 2.0 is the use of data attributes (a.k.a. data-*). They were using them in 1.x, but not to the full potential of what they can be and should be. The first class API for Bootstrap JavaScript is data attributes (or HTML), not JavaScript.

With 1.x, you could add an anchor to close modals and alerts.

// 1.x closing modal/alerts
<a class="close" href="#">×</a>

However, if you put your alerts in your modals, you close them all when you likely only wanted to close one. 2.0 uses a "data-dismiss" attribute.

<a class="close" data-dismiss="model">×</a>

This allows you to target what you want closed (modals or alerts, etc.). You know exactly what's going to happen just by reading the code. Another example is the "href" attribute of an anchor. Rather than using "href", you can now use "data-target".

// 1.x href = target
<a href="#myModal" data-toggle="modal">Launch</a>

// 2.x data-target = target
<a data-target=".fat" data-toggle="modal">Launch</a>

If you'd rather turn off the data attribute API, or just part of it, you can do so by using the following:

// Turn off all data-api
$('body').off('.data-api')

// Turn off alert data-api
$('body).off('.alert.data-api')

2.0's JavaScript API has the same stuff, but better. You can turn off the data-api and do everything with JavaScript. They copied jQuery UI in a lot of ways (defaults, constructors, etc.). Bootstrap's JavaScript has 12 plugins. New ones include collapse, carousel and typeahead.

Customize - a new tab that lets you customize and download Bootstrap. It's basically an alternative to customizing .less files and allows you to choose components, select jQuery plugins, customize variables (colors, font-sizes, backgrounds) and download.

What does the future hold? Internationalization, improving responsiveness, more new features and bug fixes.

After both Mark and Jacob gave their talks, they talked together about Community and how great it's been. Even if you're not into writing CSS and JavaScript, they mentioned they still wanted to hear from you. To give an example of great community contributions, one guy opened 50 issues in the last 2 days.

Someone in the audience asked why they used LESS over SASS. Jacob said the main reason they use LESS is because they're good friends with the guy who invented it (Alexis). SASS turns CSS into a programming language, but they wanted to maintain the approachability of CSS, which LESS does. There's no plans to do an official SASS port, but there is talk of doing one. One advantage of the current LESS compiler is they rewrote it to have better output so it's far more readable.

NASA
After Mark and Jacob finished, there was a 5 minute break to grab beers and snacks. Then Sean Herron (@seanherron) (a.k.a. "NASA Bro") talked about Bootstrap at NASA. He actually didn't talk about Bootstrap much, except that they used it for code.NASA. He talked about NASA and how it's playing a key role in the movement towards open data, open source and open standards in our federal government. He mentioned how data.NASA was launched last August and that they helped develop OpenStack. Finally, he mentioned open.NASA, which is a collaborative approach to open, direct and transparent communication about our space program.

Hogan.js
Next up, Rob Sayre (@sayrer) talked about Hogan.js. Rob has been at Twitter for a few months, before that he wrote JavaScript at other places. Hogan.js is a compiler for Mustache templates.

Why Mustache? Because it's similar to HTML and easy to edit. You can mock data as JSON files and programmers are not required.

At Twitter, designers can do the CSS and Mustache without connecting to the backend. It has cross-language support in Ruby, Java and JavaScript. However, client-side template compilation has performance problems, especially in IE7 on a Windows XP box with 4 viruses.

So they had a few choices: work on mustache.js, or use Dust.js or Handlebars.js. The compilers are very nice for Dust.js and Handlebars.js, but they're huge. Handlebar's parser is 4000 lines. The entire Hogan.js file is 500 lines. They decided they were too large to send to the browser's of their users, so they chose to write a better compiler for Mustache.

Hogan.js's main features:

  • Compile on the server
  • Parser API
  • Performance

Performance is much better with Hogan.js than Mustache.js. On IE7 - Hogan is 5x faster than Mustache. On an iPhone, it's about the same (and an iPhone's browser is faster than IE7 on a decent computer). With modern browsers (Chrome 17, Safari 5 and Firefox 10), it's more than 10x faster.

Hogan.js is currently used at Twitter for Tweet embedding, the Bootstrap build process and soon, Twitter.com.

It's been awhile since I got excited about an open source project. Bootstrap has helped me a lot recently, in my Play More! mobile app, on some client projects and I'm in the process of refreshing AppFuse's UI to use it. I love how you can add a class or two to an element and all of a sudden they pop with good looks. The main problem with Bootstrap at this point is that a lot of Bootstrapped apps look the same. There's talk of adding themes in a future release to help alleviate this problem. In the meantime, there's a lot to get excited about with 2.0.

Thanks to Twitter for hosting this event and kudos to Mark and Jacob (and the community!) for such a fantastic project.

Posted in The Web at Feb 01 2012, 11:28:40 AM MST Add a Comment

Refreshing AppFuse's UI with Twitter Bootstrap

The last time AppFuse had an update done to its look and feel was in way back in 2006. I've done a lot of consulting since then, which has included a fair bit of page speed optimization, HTML5 development and integrating smarter CSS. It was way back in '05 when we first started looking at adding a CSS Framework to AppFuse. It was Mike Stenhouse's CSS Framework that provided the inspiration and my CSS Framework Design Contest that provided its current themes (puzzlewithstyle, andreas01 and simplicity).

Since then, a lot of CSS Frameworks have been invented, including Blueprint in 2007 and Compass in 2008. However, neither has taken the world by storm like Twitter Bootstrap. From Building Twitter Bootstrap:

A year-and-a-half ago, a small group of Twitter employees set out to improve our team’s internal analytical and administrative tools. After some early meetings around this one product, we set out with a higher ambition to create a toolkit for anyone to use within Twitter, and beyond. Thus, we set out to build a system that would help folks like us build new projects on top of it, and Bootstrap was conceived.
...
Today, it has grown to include dozens of components and has become the most popular project on GitHub with more than 13,000 watchers and 2,000 forks.

The fact that Bootstrap has become the most popular project on GitHub says a lot. For AppFuse.next, I'd like to integrate a lot of my learnings over the past few years, as well as support HTML5 and modern browsers as best we can. This means page speed optimizations, getting rid of Prototype and Scriptaculous in favor of jQuery, adding wro4j for resource optimization and integrating HTML5 Boilerplate. I've used Twitter Bootstrap for my Play More! app, as well as some recent client projects. Its excellent documentation has made it easy to use and I love the way you can simply add classes to elements to make them transform into something beautiful.

Last week, I spent a couple late nights integrating Twitter Bootstrap 2.0 into the Struts 2 and Spring MVC versions of AppFuse. The layout was pretty straightforward thanks to Scaffolding. Creating the Struts Menu Velocity template to produce dropdowns wasn't too difficult. I added class="table table-condensed" to the list screen tables, class="well form-horizontal" to forms and class="btn primary" to buttons.

I also added validation errors with the "help-inline" class. This is also where things got tricky with Struts and Spring MVC. For the form elements in Bootstrap, they recommend you use a "control-group" element that contains your label and a "controls" element. The control contains the input/select/textarea and also the error message if there is one. Here's a sample element waiting for data:

<div class="control-group">
    <label for="name" class="control-label">Name</label>
    <div class="controls">
        <input type="text" id="name" name="name">
    </div>
</div>

Below is what that element should look like to display a validation error:

<div class="control-group error">
    <label for="name" class="control-label">Name</label>
    <div class="controls">
        <input type="text" id="name" name="name" value="">
        <span class="help-inline">Please enter your name.</span>
    </div>
</div>

You can see this markup is pretty easy, you just need to add an "error" class to control-group and span to show the error message. With Struts 2, this was pretty easy thanks to its customizable templates for its tags. All I had to do was create a "template/css_xhtml" directory in src/main/webapp and modify checkbox.ftl, controlfooter.ftl, controlheader-core.ftl and controlheader.ftl to match Bootstrap's conventions.

Spring MVC was a bit trickier. Since its tags don't have the concept of writing an entire control (label and field), I had to do a bit of finagling to get things to work. In the current implementation, Struts 2 forms have a single line for a control-group and its control-label and controls.

<s:textfield key="user.firstName" required="true"/>

With Spring MVC, it's a bit more complex:

<spring:bind path="user.firstName">
<fieldset class="control-group${(not empty status.errorMessage) ? ' error' : ''}">
</spring:bind>
    <appfuse:label styleClass="control-label" key="user.firstName"/>
    <div class="controls">
        <form:input path="firstName" id="firstName" maxlength="50"/>
        <form:errors path="firstName" cssClass="help-inline"/>
    </div>
</fieldset>

You could probably overcome this verbosity with Tag Files.

Figuring out if a control-group needed an error class before the input tag was rendered was probably the hardest part of this exercise. This was mostly due to Bootstrap's great documentation and useful examples (viewed by inspecting the markup). Below are some screenshots of the old screens and new ones.

Old UI - Login Old UI - Users Old UI - Edit Profile

New UI - Login New UI - Users New UI - Edit Profile

Check out the full set on Flickr if you'd like a closer look.

Even though I like the look of the old UI, I can't help but think a lot of the themes are designed for blogs and content sites, not webapps. The old Wufoo forms were a lot better looking though. And if you're going to develop kick-ass webapps, you need to make them look good. Bootstrap goes a long way in doing this, but it certainly doesn't replace a good UX Designer. Bootstap simply helps you get into HTML5-land, start using CSS3 and it takes the pain out of making things work cross-browser. Its fluid layouts and responsive web design seems to work great for business applications, which I'm guessing AppFuse is used for the most.

I can't thank the Bootstrap developers enough for helping me make this all look good. With Bootstrap 2 dropping this week, I can see myself using this more and more on projects. In the near future, I'll be helping integrate Bootstrap into AppFuse's Tapestry 5 and JSF versions.

What do you think of this CSS change? Do you change your CSS and layout a fair bit when starting with AppFuse archetypes? What can we do to make AppFuse apps look better out-of-the-box?

Update: I updated AppFuse to the final Bootstrap 2.0 release. Also, Johannes Geppert wrote a Struts 2 Bootstrap Plugin. I hope to integrate this into AppFuse in the near future.

Posted in Java at Jan 31 2012, 05:12:17 PM MST 10 Comments

2011 - A Year in Review

2010 was an awesome year, but 2011 rocked the house! At the end of last year, I kept my goals simple:

In 2011, I plan on doing two main things: keep rockin' it with Trish and finishing The Bus. Everything else is gravy.

As predicted, it was a spectacular year, but I only accomplished 50% of my goals. That is, Trish and I had a great time skiing (especially in Utah), moving in together, traveling the world and getting engaged in Versailles. I even satisfied some 5-year goals: building a sauna in my basement and getting a ski shack in the mountains.

However, I didn't get much done with The Bus. Or rather, the guys at MotorWorks Restorations didn't drain me for all I'm worth in 2011. We did make good progress with estimating the final cost and obtaining many hard-to-find parts though. I now have a Porsche 911 Engine (1983 3.0L 6 cylinder), a Porsche 901 5 speed transmission, Porsche "Turbo Twist" wheels and a Custom Air Ride Front Beam from Franklin's VW Works. The thing that slowed our progress the most was the custom beam, as it took almost 6 months from order to delivery. When it arrived in September, I decided to put things on hold. I didn't want to get my bus back in the midst of winter and not be able to drive it.

[Read More]

Posted in Roller at Jan 11 2012, 09:45:20 AM MST 2 Comments

Our Engaging Trip to Paris and Antwerp

If you're a technologist, you should attend the Devoxx conference at least once in your life. It's one of the finest conferences on the planet. If you're a fan of Belgian beer, you owe it to yourself to visit Belgium to savor a taste. If you're a romantic, Paris is a recommended destination. Since I'm a technologist, love Belgian beer and consider myself a romantic, I went for the trifecta a couple weeks ago on what's becoming an annual trek to Devoxx. When Trish and I traveled to Devoxx last year, we flew to Amsterdam and took the train to Antwerp. This year, we decided to fly to Paris and take the train.

Much like last year, we witnessed another Broncos over Chiefs victory the Sunday before we left. That night, I stayed up until the wee hours of the morning finishing my Devoxx presentation. We left Denver around noon and met up with James Ward at the Red Carpet Club in Chicago. While sipping cocktails and catching up, I wrote a blog post about how PhoneGap rescued me a couple days earlier.

We slept soundly on the flight over, thanks to little sleep the night before. After arriving in Paris, we took the train to the the Notre Dame de Paris and had some breakfast nearby.

Notre Dame Cathedral Paris

We were planning on exploring throughout the day, but quickly realized that hauling our bags around was no fun and headed to Gare du Nord to catch a Thalys train to Brussels. We gasped at the cost of two first-class tickets, but soon forgot when we settled into our seats with free wi-fi, Belgian beers and power. After talking a local train to Antwerp, we finished our 21-hour journey by checking into the Hilton Antwerp in the city center. We were warmly welcomed with excellent Belgian beers on ice in our room and celebrated with a delicious meal at De Godevaart.

On Wednesday, I headed to Devoxx and attended a couple of great talks: Play 2.0, A web framework for a new era and PhoneGap for Hybrid App Development. As you can imagine, both talks were extremely interesting for me since I'd been using Play for several months and was recently saved by PhoneGap. Play 2.0 Beta was announced just before the Play talk and my blog post about the Play 2.0 session was picked up by Hacker News and the hits rolled in.

That afternoon, I headed back to my hotel with James Ward and met up with Trish for a couple beers. We spent a few hours in our hotel lobby updating presentations, editing videos, editing photos and getting ready for our talks on Thursday. That evening, we enjoyed a scrumptious dinner in the dungeon-like Pelgrom and conversations with Kevin Nilson, Sadek Drobi, Guillaume Bort and David Geary. I was pleased to find out from Sadek and Guillaume that Play 2.0 will include many fast website best practices, including concatenation, minification and gzipping of static assets. We retired early to get a good night's sleep before my talk on Thursday.

Kwak Kwak Kwak! Candle at Pelgrom

Matt Raible and Crew at Devoxx dinner Matt Raible at Pelgrom

On Thursday, both Trish and I journeyed to Devoxx to watch James Ward talk about how to deploy Java, Play Framework, and Scala apps on Heroku. My talk was an hour later and I gulped as I stood up front and watched the (very large) auditorium fill up with Devoxxians. Since I'd never rehearsed my talk or timed it, I was a bit nervous. Luckily, it ended up being one of my best-timed performances and there was even time for Q and A at the end. You can imagine the smile on my face as AC/DC's Thunderstruck blasted through the speakers during my video demo. After my talk finished, it was great to see all the positive feedback on Twitter and enjoy an "Atlas Beer" while watching Java Posse Live.

James Ward speaking on Heroku at Devoxx Matt Raible speaking at Devoxx Belgium 2011

Audience at Matt Raible's Presentation Devoxx Belgium

That evening, we had dinner with the Java Posse crew and James Ward before heading to the Devoxx Party @ Noxx.

Devoxx Party @ Noxx

Yes, we had an awesome time at Devoxx. I was pleased with the positive response from my talk and learned a bunch from the few talks I attended. Thanks to Stephan for inviting me and organizing one of the best conferences I've ever attended. For our last night in Antwerp, we dined at Huis De Colvenier and especially enjoyed our aperitif in the 19th-century wine cellar.

Huis De Colvenier Huis De Colvenier Huis De Colvenier Huis De Colvenier

Riverside in Antwerp Antwerp Town Square

Mmmm, Belgium Beer... We love Belgian Beer

Paris and Beyond
This brings us to my favorite part of this story. I was pretty stressed leading up to our departure to Devoxx because I had so many deadlines. I had a deadline with my current client to finish up some features before I left, I had to finish my Devoxx presentation (and app developed for the talk) and I had a secret deadline to finish my proposal to Trish. That's right, I was planning on proposing marriage to my dream girl. I mean, we were going to the diamond capital of the world (Antwerp) and one of Earth's most romantic cities (Paris). It seemed like the perfect opportunity to ask her to marry me. We did some ring shopping before we left Denver, but she didn't realize I had purchased one before we left.

We're both big music fans, so I decided months earlier that I would propose with lines from songs we both liked. Of course, I waited until the last minute to compose my prose, but I did finish it before we left for Europe. However, with all the Devoxx shenanigans, I didn't have time to memorize my proposal. Instead, I recorded it using the "Voice Memos" on my iPhone. I did this in the wee hours of the morning on Friday, while I was watching the Broncos game on the internet.

Saturday afternoon, we traveled to Paris via Thalys and checked into our hotel around sunset. When we stepped outside an hour later, I remember saying to Trish, "the Eiffel Tower looks pretty small, I thought it'd be bigger". After walking for a bit, it turned from small to big to huge. My plan that night was to propose on the tower. As Trish snapped pictures along our walk, I was taking out the piece of paper I had the proposal printed on and trying to memorize it. As you can imagine, I had to to this stealthily and by the time we reached the Eiffel Tower, I had enough memorized to propose. We arrived around midnight and were disappointed to find it was closed. This terminated my proposal plans for that night, but we still enjoyed the sparkling tower lights and took several pictures.

The Eiffel Tower The Eiffel Tower

The next day, Sunday, we traveled to the Château de Versailles. This was a recommendation from my good friend Eric, who had recently traveled to Paris with his wife, Heather. In fact, I owe a lot to Eric. He recommended we extend our trip to Paris (he'd traveled there disgruntled about not doing a beach vacation, then fell in love with the city) and suggested a number of great locations to visit. He also recommended proposing in the Gardens of Versailles, a very romantic location according to him. I had this in the back of my mind as we did an audio tour through the Palace of Versailles. As we ventured out into the Orangerie, I started hatching a plan to get Trish down to the gardens and try to rent bikes. We both love biking and the outdoors, so I figured it'd be a nice way to spend our memorable moment. As we strolled closer and I didn't see bikes to rent, I spotted the Grand Canal and noticed they had row boats.

The Versailles Orangerie Château de Versailles Gardens of Versailles Trees in the Versailles Gardens

Bassin d’Apollon – the Apollo Fountain

When we first arrived at the boat dock, there was a long line, but it magically disappeared moments later. We stepped into the boat, rowed to the center of the canal and paused for a bit to take in the beautiful day and the setting sun. Trish asked me to row to a better spot so she could photograph the sunset, but instead I said "here, listen to this" and handed her my headphones. I pressed play and watched her face light up as she heard my voice in her ears. 90 seconds later, I asked "Trish McGinity, will you marry me?" She responded with, "Of course!" :)

Happy Versailles Sunset

The rest of our trip in Paris was quite romantic and fun. We decided to wait until we got back to The States before telling anyone we were engaged. This meant we had three days of just us, Paris and some of the most beautiful art in the world. We explored the Louvre for 5-hours on Monday, marveling at the low-rider on display near the entrance and all the famous paintings.

Trish and the Louvre At The Louvre Lowrider in the Louvre Liberty Leading the People

Louvre

We imbibed in $40 martinis at The Hemingway Bar and scarfed down some delicious pizza at Gambino's. We had breakfast at Angelina's, toured La Sainte-Chapelle, hiked up Arc de Triomphe and wandered through the shopping districts Champs-Élysées and Faubourg St-Honoré. Yes, we fell in love with Paris and can't wait to return for Devoxx France in April.

Arc de Triumph

We departed Paris on the Wednesday morning before Thanksgiving and arrived in Boston that evening. We spent the next three days with Trish's family and our good friends, Chris, Julie, Lili and Wes. We did a 5K Turkey Trot on Thursday morning, followed by football watching and eating succulent turkey while basking in everyone's joy for us. We smiled, giggled, laughed, guffawed, smiled some more and had an all-around great time the rest of the weekend.

We returned home on Sunday evening, departing Boston's Logan airport only minutes after the Broncos kicked a field goal in overtime to beat the Chargers. Our flight was delayed just long enough (3 hours) that we got to watch almost the whole game. It was the perfect ending to a phenomenal trip.

To see more pictures from this adventure, see Trish's fantastic photos and mine on Flickr.

Posted in General at Dec 04 2011, 04:02:34 PM MST 12 Comments

My HTML5 with Play Scala, CoffeeScript and Jade Presentation from Devoxx 2011

This week, I had the pleasure of traveling to one of my favorite places in the world: Antwerp, Belgium. Like last year, I traveled with the lovely Trish McGinity and spoke at Devoxx 2011. This year, my talk was on developing a web/mobile app with HTML5, Play, Scala, CoffeeScript and Jade. I was inspired to learn Scala at the beginning of this year and added CoffeeScript and Jade to my learning list after talking to James Strachan at TSSJS 2011. You can read more about how my journey began in my first post about learning these technologies.

I started developing with these technologies in August and wrote about my learnings throughout the process. Last week, while writing my presentation, I decided it'd be fun to make my presentation into more of a story-telling-session than a learn-about-new-technologies session. To do this, I focused on talking a bit about the technologies, but more about my experience learning them. I also came up with a challenging idea: create a video that showed the development process, how hard it was to test the app and (hopefully) my success in getting it to work.

It was all a very close call, but I'm happy to say I pulled it off! I got the app to work on an iPhone (thanks to PhoneGap) last Saturday, finished the first draft of my presentation on Sunday night (after pulling an all-nighter) and finished editing the demo video on Wednesday night. My talk was on Thursday afternoon and I had a blast talking about my experience to such a large, enthusiastic audience. You can see the presentation below, on Slideshare or download the PDF.

You can find the "demo" for this talk on YouTube or watch it below.

One of the reasons I really enjoyed this talk is it only represents one milestone in my learning process. I plan on continuing to develop this application and learning more about HTML5, Scala, Play and CoffeeScript and Scalate/Jade. Now that Play 2.0 Beta has been released, I plan on upgrading to it and leveraging its native CoffeeScript and LESS support. I hope to continue using Scalate and its Jade format. And it's very likely PhoneGap will continue to be the bridge that allows everything to run in the background.

I've been talking with the Jfokus folks about doing this talk in Sweden in Feburary and Devoxx France about presenting there in April.

Learning all these technologies has been a challenging, but fun experience so far. As the last slide in my presentation says, I encourage you to do something similar. Pick something new to learn, have fun doing it, but more importantly - get out there and Play!

Update Dec. 20th: A video of this presentation is now available on Parleys.com.

Posted in Java at Nov 18 2011, 11:18:38 AM MST 7 Comments

Deploying Java and Play Framework Apps to the Cloud with James Ward

Yesterday, I attended James Ward's presentation on Deploying Java & Play Framework Apps to the Cloud at Devoxx. I arrived a bit late, but still managed to get there in time to see a lot of demos and learn more about Heroku. Below are my notes from James's talk.

When I arrived, James was doing a demo using Spring Roo. He was using Roo's Petclinic sample app and showed us how you could use Git to create a local repository of the new project and install Heroku's command line tool. From there, he ran the following command to create a new application on Heroku.

heroku create -s cedar

The Cedar Stack is what supports Java, Scala and Play Framework. It's the 3rd generation stack for Heroku. The command above created two endpoints, one for HTTP and one for Git. It picks from a list of randomly generated names, which all seem to have some humor in them. James ended up with "electric-sword-8877" for this demo.

From there, he ran git push heroku master to deploy the project to Heroku. Unfortunately, this resulted in a login error and there was an akward moment where we all thought the Demo Gods were angry. However, James was able to resolve this by using Heroku's sharing feature with the following command.

heroku sharing:add [email protected]

For Java projects, Heroku looks for a pom.xml file in the root directory and runs a Maven build on project. All the dependencies get downloaded on the cloud rather than put them into a WAR and requiring you to upload a large WAR file. You don't have to upload your source code to Heroku; James did it for the sake of the demo because it was faster.

After the build finishes, it creates a slug file. This file contains everything Heroku needs to run your application.

Next, James showed a demo of the running application and added a new Pet through its UI. Then he scaled it to two servers using the following command:

heroku scale web=2

He proved this was working by running heroku ps, which showed there were two running processes. He showed the app again, but noted that the record he added was missing. This is because when it started up a new dyno, Hibernate created the schema again and deleted all records. To fix, James changed Hibernate to only update the schema instead of create a new one. If you're a Hibernate user, you know this is as simple as changing:

hibernate.hbm2ddl.auto=create

to:

hibernate.hbm2ddl.auto=update

After committing this change, James redeployed using Git.

git push heroku master

The slug file got built again and Heroku deployed the new slug onto both dynos, automatically load balancing the app across two servers. James then ran heroku logs to see the logs of his dynos and prove that a request to his app's HTTP endpoint made requests to both dynos. The logging is powered by Logplex and you can read about how it works in the article Heroku Gets Sweet Logging.

James mentioned that Roo has a Heroku plugin, but after watching his talk and searching a bit on the internet, it seems it's just the jetty-runner setup as described in Getting Started with Spring MVC Hibernate on Heroku/Cedar.

What about autoscaling? There are some 3rd party tools that do this. Heroku's Management infrastructure has APIs that these tools talk too. Heroku hasn't built autoscaling into the platform because they don't know where the bottlenecks are in your application.

Heroku = Polyglot + PaaS + Cloud Components. It supports Ruby, node.js, Java, Clojure, Play and Scala and they're working on native Grails and Gradle support. There's currently 534,374 apps running on Heroku.

Heroku is a cloud application platform and there's 5 different components.

  1. Instant deployment
  2. HTTP Routing / Load Balancing
  3. Elastic Polyglot Runtime
  4. Management & Logging
  5. Component as a Service Ecosystem

For instant deployment, it's a pretty simple process:

  • You add files to a git repo
  • You provision the app on Heroku (heroku create)
  • You upload the files to Heroku (git push heroku master)
  • Heroku runs the build and assembles a "slug" file
  • Heroku starts a "dyno"
  • Heroku copies the "slug" to the "dyno"
  • Heroku starts the web application

Most apps will contain a Procfile that contains information about how to run the web process. For Spring Roo, it has:

web: java $JAVA_OPTS -jar target/dependency/jetty-runner.jar --port $PORT target/*.war

So how does Heroku decide what application server to use? It doesn't, you do. You need to get your application server into the slug file. The easiest way to do this is to specify your application server as a dependency in your pom.xml. In the Roo example, James uses the maven-dependency-plugin to get the jetty-runner dependency and copy it to the target directory. On Heroku, you bring your application server with you.

Heroku gives you 750 free dyno hours per app, per month. For developers, it's very easy to get started and use. Once you extend past one dyno, it's $.05 per dyno hour, which works out to around $30/month. It's only when you want to scale beyond one dyno where you get charged by Heroku, no matter how much data you transfer. Scalatest is running on Heroku. It has one dyno and is doing fine with that. Bill Venners doesn't have to pay anything for it.

java.herokuapp.com is a site James created that allows you to clone example apps and get started quickly with Heroku's Cedar Stack.

For HTTP Routing, Heroku uses an Erlang-based routing system to route all the HTTP requests across your dynos. Heroku doesn't support sticky sessions. Distributed session management does not work well, because it does not scale well. Heroku recommends you use a stateless web architecture or move your state into something like memcached. Jetty has (in the latest version) the ability to automatically serialize your session into a Mongo system. This works fine on Heroku. The problem with this is if you have 2 dynos running, each request can hit a different dyno and get different session state. Hence the recommendation for an external storage mechanism that can synchronize between dynos.

You can also run non-web applications on Heroku. You can have one web process, but as many non-web processes as you want.

Heroku has native support for the Play framework. To detect Play applications, it look for a conf/application.conf file. You don't need to have a Procfile in your root directory because Heroku knows how to start a Play application.

At this point, James created a new Play application, created a new Heroku app (he got "young-night-7104" this time) and pushed it to Heroku. He created a simple model object, a controller to allow adding new data and then wrote some jQuery to show new records via Ajax and JSON. He also showed how to configure the application to talk to Heroku's PostgreSQL database using the DATABASE_URL environment variable. He explained how you can use the heroku config command to see your environment variables.

The reason they use environment variables is so Heroku can update DATABASE_URL (and other variables) without having to call up all their customers and have them change them in their source code.

Play on Heroku supports Scala if you create your app with Scala. Play 2.0 uses Scala, Akka and SBT. Heroku added support for SBT a couple month ago, so everything will work just fine.

Heroku also supports Scala, detecting it by looking for the build.sbt file in the root directory. Heroku supports SBT 0.11.0 and it builds the 'stage' task. It currently does not support Lift because Lift uses an older version of SBT and because it's a very stateful framework that would require sticky sessions. Use Play, BlueEyes or Scalatra if you want Scala on Heroku.

Heroku has addons for adding functionality to your application, including Custom DNS, HTTPS, Amazon RDS, NoSQL and many more. They're also working on making their add-on and management APIs available via Java, so you'll (hopefully) be able to use them from your IDE in the future.

From there, James showed us how Heroku keeps slug files around so you can do rollbacks with heroku rollback. He also showed how you can use:

heroku run "your bash command"
to run any Bash command on the cloud.

Summary
I attended James's talk because he's a good friend, but also because I've been using Heroku to host my latest adventures with Play, Scala, CoffeeScript and Jade. I'm glad I attended because I learned some good tips and tricks and more about how Heroku works.

Heroku seems like a great development tool to me. In my experience, it's been really nice to have instant deployments using Git. In fact, I've created a 'push' alias so I can push to my project's repo and heroku at the same time.

alias push='git push origin master && git push heroku master'

I'd like to see more organizations embrace something like Heroku for developers. It'd be great if everyone had their own sandbox that business owners and product managers could see. I can't help but think this would be awesome for demos, prototyping, etc.

There were some other talks I wanted to attend at the same time, particularly Martin Odersky's What's in store for Scala? and WWW: World Wide Wait? A Performance Comparison of Java Web Frameworks. The WWW talk has posted their presentation but I'm sure it'd be more fun to watch.

It's pretty awesome that all the talks from Devoxx 2011 will be up on Parleys.com soon.

Update: James has posted his slides from this talk.

Posted in Java at Nov 18 2011, 08:14:45 AM MST 2 Comments

Play 2.0, A web framework for a new era

This week, I'm in Antwerp, Belgium for the annual Devoxx conference. After traveling 21 hours door-to-door yesterday, I woke up and came to the conference to attend some talks on Play and PhoneGap. I just got out of the session on Play 2.0, which was presented by Sadek Drobi and Guillaume Bort. Below are my notes from this presentation.

The Play 2.0 beta is out! You can read more about this release on the mailing list. This beta includes native support for both Scala and Java, meaning you can use both in the same project. The release also bundles Akka and SBT by default.

In other news, Play 2.0 is now part of the Typesafe Stack. Typesafe is the Scala company, started by the founder of Scala (Martin Odersky) and the founder of Akka (Jonas Bonér). Guillaume is also joining the Typesafe Advisory Board.

Sadek and Guillaume both work at zenexity, where Play is the secret weapon for the web applications they've built for the last decade. Play was born in the real world. They kept listening to the market to see what they should add to the project. At some point, they realized they couldn't keep adding to the old model and they needed to create something new.

The web has evolved from static pages to dynamic pages (ASP, PHP). From there, we moved to structured web applications with frameworks and MVC. Then the web moved to Ajax and long-polling to more real-time, live features. And this changes everything.

Now we need to adapt our tools. We need to handle tremendous flows of data. Need to improve expressiveness for concurrent code. We need to pick the appropriate datastore for the problem (not only SQL). We need to integrate with rapidly-evolving client side technologies like JavaScript, CoffeeScript, and Dart. We need to use elastic deployment that allows scaling up and scaling down.

zenexity wanted to integrated all of these modern web needs into Play 2.0. But they also wanted to keep Play approachable. They wanted to maintain fast turnaround so you can change your code and hit reload to see the changes. They wanted to keep it as a full stack framework with support for JSON, XML, Web Services, Jobs, etc. And they wanted to continue to use and conventions over configuration.

At this point, Guillaume did a Play 2.0 Beta demo, show us how it uses SBT and has a console so everything so it runs really fast. You can have both Scala and Java files in the same project. Play 2.0 templates are based on Scala, but you don't need to know Scala to use them. You might have to learn how to write a for loop in Scala, but it's just a subset of Scala for templates and views. SBT is used for the build system, but you don't have to learn or know SBT. All the old play commands still work, they're just powered by a different system.

After the demo, Sadek took over and started discussing the key features of Play 2.0.

To handle tremendous amounts of data, you need to do chunking of data and be able to process a stream of data, not just wait until it's finished. Java's InputStream is outdated and too low level. Its read() method reads the next byte of data from the input and this method can block until input data is available.

To solve this, Play includes a reactive programming feature, which they borrowed from Haskell. It uses Iteratee/Enumerator IO and leverages inversion of control (not like dependency injection, but more like not micro-managing). The feature allows you to have control when you need it so you don't have to wait for the input stream to complete. The Enumerator is the component that sends data and the Iteratee is the component that receives data. The Iteratee does incremental processing and can tell the Enumerator when it's done. The Iteratee can also send back a continuation, where it tells the Enumerator it wants more data and how to give it. With this paradigm, you can do a lot of cool stuff without consuming resources and blocking data flow.

Akka is an actor system that is a great model for doing concurrent code. An Actor could be both an Enumerator and an Iteratee. This vastly improves the expressiveness for concurrent code. For example, here's how you'd use Akka in Play:

def search(keyword: String) = Action {
  AsyncResult {
    // do something with result
  }
}

Play does not try to abstract data access because datastores are different now. You don't want to think of everything as objects if you're using something like MongoDB or navigating a Social Graph. Play 2.0 will provide some default modules for the different datastores, but they also expect a lot of contributed modules. Anorm will be the default SQL implementation for Play Scala and Ebean will be the default ORM implementation for Play Java. The reason they've moved away from Hibernate is because they needed something that was more stateless.

On the client side, there's so many technologies (LESS, CoffeeScript, DART, Backbone.js, jQuery, SASS), they didn't want to bundle any because they move too fast. Instead, there's plugins you can add that help you leverage these technologies. There's a lot of richness you can take advantage of on the client side and you need to have the tools for that.

Lastly, there's a new type of deployment: container-less deployment to the cloud. Akka allows you to distribute your jobs across many servers and Heroku is an implementation of elastic deployment that has built-in support for Play.

They've explained what they tried to design and the results of this new, clean architecture have been suprising. Side effects include: type-safety everywhere for rock-solid applications. There's an awesome performance boost from Scala. There's easier integration with existing projects via SBT. And it only takes 10 lines of code to develop an HTTP Server that responds to web requests.

The memory consumption is amazing: only 2MB of heap is used when a Play 2.0 app is started. Tests on Guillaume's laptop have shown that it can handle up to 40,000 requests per second, without any optimization of the JVM. Not only that, but after the requests subside, garbage collection cleans up everything and reduces the memory consumption back to 2MB.

At this point, Guillaume did another demo, showing how everything is type-safe in 2.0, including the routes file. If you mistype (or comment one out) any routes, the compiler will find it and notify you. Play 2.0 also contains a compiled assets feature. This allows you to use Google's Closure Compiler, CoffeeScript and LESS. If you put your LESS files in app/assets/stylesheets, compilation errors will show up in your browser. If you put JavaScript files in app/assets/javascripts, the Closure compiler will be used and compilation errors will show up in your browser.

Play 2.0 ships with 3 different sample applications, all implemented in both Java and Scala. HelloWorld is more than just text in a browser, it includes a form that shows how validation works. Another app is computer-database. When Guillaume started it, we saw how evolutions were used to create the database schema from the browser. The Play Team has done their best to make the development process a browser-based experience rather than having to look in your console. The computer-database is a nice example of how to do CRUD and leverages Twitter's Bootstrap for its look and feel.

The last sample application is zentasks. It uses Ajax and implements security so you can see how to create a login form. It uses LESS for CSS and CoffeeScript and contains features like in-place editing. If you'd like to see any of these applications in action, you can stop by the Typesafe booth this week at Devoxx.

Unfortunately, there will be no migrating path for Play 1.x applications. The API seems very similar, but there are subtle changes that make this difficult. The biggest thing is how templating has changed from Groovy to Scala. To migrate from 1.2.x would be mostly a copy/paste, modify process. There are folks working on getting Groovy templates working in 2.0. The good news is zenexity has hundreds of 1.x applications in production, so 1.x will likely be maintained for many years.

Summary
This was a great talk on what's new in Play 2.0. I especially like the native support for LESS and CoffeeScript and the emphasis on trying to keep developers using two tools: their editor and the browser. The sample apps look great, but the documentation look sparse. I doubt I'll get a chance to migrate my Play 1.2.3 app to 2.0 this month, but I hope to try migrating sometime before the end of the year.

Posted in Java at Nov 16 2011, 05:58:09 AM MST 11 Comments

PhoneGap to the Rescue!

This is the 7th article in a series about my adventures developing a web application with HTML5, Play Scala, CoffeeScript and Jade. Previous articles can be found at:

  1. Integrating Scalate and Jade with Play 1.2.3
  2. Trying to make CoffeeScript work with Scalate and Play
  3. Integrating HTML5 Boilerplate with Scalate and Play
  4. Developing with HTML5, CoffeeScript and Twitter's Bootstrap
  5. Play Scala's Anorm, Heroku and PostgreSQL Issues
  6. More Scalate Goodness for Play
A few weeks ago, I wrote about Developing a Stopwatch and Trip Meter with HTML5. I mentioned I'd run into a major issue when I discovered HTML5 Geo's watchPosition() feature didn't run in the background. From that article:

I tried out the trip meter that evening on a bike ride and noticed it said I'd traveled 3 miles when I'd really gone 6. I quickly figured out it was only calculating start point to end point and not taking into account all the turns in between. To view what was happening, I integrated my odometer.coffee with my map using Google Maps Polylines. Upon finishing the integration, I discovered two things, 1) HTML5 geolocation was highly inaccurate and 2) geolocation doesn't run in the background.

At the time, I opted to ignore this issue and use my app by setting Auto-Lock to Never. This worked, but if I happened to bump my phone while exercising, the app would get closed. Not to mention it really drained the battery and seemed to crash every-so-often.

Last week, I realized things were getting down to the wire and I was running out of time to finish my app's functionality for my Devoxx Talk. On Wednesday afternoon, I asked my office-mates (2 iOS developers) about developing a native app and installing it on my phone. They told me I had to be a iOS Certified Developer ($99/year) or jailbreak my iPhone to get an app on it. On Thursday, I downloaded PhoneGap and installed Xcode 4. As you can tell from the following image, PhoneGap seemed to be exactly what I was looking for.

PhoneGap

I spent some time going through PhoneGap's Getting Started Guide and was able to get my app rendering in a short amount of time. I was able to copy the webapp's generated HTML into my PhoneGap project's www directory and launch the app in the iOS Simulator. The only change I had to make was to convert my inline CoffeeScript (that used coffee-script.js for in-browser compilation) to JavaScript. It's possible the in-browser compiler works, but when things didn't work and I didn't see any error messages, it was the first thing I changed.

For getting the app onto a phone for testing, I opted for the easiest route and applied for an iOS Developer Account on Thursday afternoon. While waiting for approval on Friday, I briefly tried to jailbreak my phone, but encountered all kinds of version issues and gave up after 30 minutes. 24 hours after I applied for my account, Apple emailed asking for a business document to prove I was legit. I was unable to download any from the Colorado Secretary of State that were e-certified, so expeditiously switched my application from a business account to an individual one. Apple was great in helping me out before the weekend started and I had everything I needed as we drove to our Ski Shack on Friday evening.

On Friday night, I upgraded Trish's iPhone 4 to iOS 5 to make sure I had the latest and greatest platform for my app. Saturday morning, I woke up around 8 and started trying to figure out how to get my app on her phone. It took about an hour of fumbling, grumbling and searching to figure out how to do this. All the while, the troops were getting restless, noting that they were hungry for breakfast and groaning about Daddy taking so long. At 9:30, I finally got my PhoneGap app installed on Trish's phone and we drove to breakfast at Sharkey's.

I started the app when we left and checked it 5 minutes later when we arrived for breakfast. The blood drained from my face when I saw the app had drawn a straight line from our condo to the breakfast joint. We had taken several turns along the way and my new native app ignored them all. I assumed I had failed and my talk's conclusion at Devoxx would be "You can't develop a reliable Fitness Tracker app with HTML5". However, after a delicious Eggs Benedict, I became determined to succeed and returned home for some more hacking.

This is when I discovered Joel Dare's Play an MP3 Audio Stream in PhoneGap tutorial and the "Required background modes" key. This was the knowledge that saved the day and I anxiously added the key and the values to get location updates and allow audio to run in the background.

Required Background Modes

Saturday afternoon, I strapped on my recently purchased GoPro Camera, shot some video for my demo at Devoxx and had a blast skiing with Abbie, Jack and Trish. I celebrated that evening with an executive workout (15 minutes each in hot tub, sauna and steam room) at the Fraser Rec Center and again on Sunday when the Broncos whooped the Kansas City Chiefs just like last year.

Last night, I stayed up late to put the finishing touches on my Devoxx presentation. Now I'm sitting at the Red Carpet Club in Chicago's O'Hare getting ready to depart for Belgium. It's been a fun journey learning about HTML5, Scala, Play, CoffeeScript and Jade. If you're at Devoxx this week, I think I've got a presentation you're really going to like. ;-)

Posted in Java at Nov 14 2011, 04:32:19 PM MST 2 Comments

More Scalate Goodness for Play

Scalate This article is the 6th in a series on about my adventures developing a web application with HTML5, Play Scala, CoffeeScript and Jade. Previous articles can be found at:

  1. Integrating Scalate and Jade with Play 1.2.3
  2. Trying to make CoffeeScript work with Scalate and Play
  3. Integrating HTML5 Boilerplate with Scalate and Play
  4. Developing with HTML5, CoffeeScript and Twitter's Bootstrap
  5. Play Scala's Anorm, Heroku and PostgreSQL Issues

Last week, I wrote about my adventures with Anorm and mentioned I'd made some improvements to Scalate Play interoperability. First of all, I've been using a Scalate trait and ScalateTemplate class to render Jade templates in my application. I described this setup in my first article on Scalate and Play.

Adding SiteMesh Features and Default Variables
When I started making my app look good with CSS, I started longing for a feature I've used in SiteMesh. That is, to have a body id or class that can identify the page and allow per-page CSS rules. To do this with SiteMesh, you'd have something like the following in your page:

  
<body id="signup"/>

And then read it in your decorator:

<body<decorator:getProperty property="body.class" writeEntireProperty="true"/>>

As I started looking into how to do this, I came across Play Scala's ScalaController and how it was populating Play's default variables (request, response, flash, params, etc.). Based on this newfound knowledge, I added a populateRenderArgs() method to set all the default variables and my desired bodyClass variable.

def populateRenderArgs(args: (Symbol, Any)*): Map[String, Any] = {
  val renderArgs = Scope.RenderArgs.current();

  args.foreach {
    o =>
      renderArgs.put(o._1.name, o._2)
  }

  renderArgs.put("session", Scope.Session.current())
  renderArgs.put("request", Http.Request.current())
  renderArgs.put("flash", Scope.Flash.current())
  renderArgs.put("params", Scope.Params.current())
  renderArgs.put("errors", validationErrors)
  renderArgs.put("config", Play.configuration)

  // CSS class to add to body
  renderArgs.put("bodyClass", Http.Request.current().action.replace(".", " ").toLowerCase)
  renderArgs.data.toMap
}

implicit def validationErrors:Map[String,play.data.validation.Error] = {
  import scala.collection.JavaConverters._
  Map.empty[String,play.data.validation.Error] ++ 
    Validation.errors.asScala.map( e => (e.getKey, e) )
}

After adding this method, I was able to access these values in my templates by defining them at the top:

-@ val bodyClass: String 
-@ val params: play.mvc.Scope.Params
-@ val flash: play.mvc.Scope.Flash

And then reading their values in my template:

body(class=bodyClass)
...
- if (flash.get("success") != null) {
  div(class="alert-message success" data-alert="alert")
    a(class="close" href="#") &×
    | #{flash.get("success")}
- }
...
  fieldset
    legend Leave a comment →
    div.clearfix
      label(for="author") Your name:
      input(type="text" name="author" class="xlarge" value={params.get("author")})
    div.clearfix
      label(for="content") Your message:
      textarea(name="content" class="xlarge") #{params.get("content")}
    div.actions
      button(type="submit" class="btn primary") Submit your comment
      button(type="reset" class="btn") Cancel

For a request like Home/index, the body tag is now rendered as:

<body class="home index">
This allows you to group CSS styles by Controller names as well as by method names.

Next, I started developing forms and validation logic. I quickly discovered I needed an action() method like the one defined in ScalaTemplate's TemplateMagic class.

def action(action: => Any) = {
  new play.mvc.results.ScalaAction(action).actionDefinition.url
}

Since TemplateMagic is an inner class, I determined that copying the method into my ScalateTemplate class was the easiest workaround. After doing this, I was able to import the method and use it in my templates.

-import controllers.ScalateTemplate._
...
form(method="post" class="form-stacked" id="commentForm"
     action={action(controllers.Profile.postComment(workout._1.id()))})

After getting the proper URL written into my form's action attribute, I encountered a new problem. The Play Scala Tutorial explains validation flow as follows:

if (Validation.hasErrors) {
  show(postId)
} else {
  Comment.create(Comment(postId, author, content))
  Action(show(postId))
}

However, when I had validation errors, I end up with the following error:

Could not load resource: [Timeline/postComment.jade]

To fix this, I added logic to my Scalate trait that looks for a "template" variable before using Http.Request.current().action.replace(".", "/") for the name. After making this change, I was able to use the following code to display validation errors.

if (Validation.hasErrors) {
  renderArgs.put("template", "Timeline/show")
  show(postId)
} else {
  Comment.create(Comment(postId, author, content))
  Action(show(postId))
}

Next, I wanted to give child pages the ability to set content in parent pages. With SiteMesh, I could use the <content> tag as follows:

<content tag="underground">
  HTML goes here
</content>

This HTML could then be retrieved in the decorator using the <decorator:getProperty> tag:

<decorator:getProperty property="page.underground"/>

With Scalate, I found it equally easy using the captureAttribute() method. For example, here's how I captured a list of an athlete's workouts for display in a sidebar.

- captureAttribute("sidebar")
  - Option(older).filterNot(_.isEmpty).map { workouts =>
    .older-workouts
      h3
        | Older workouts
        span.from from this app
      - workouts.map { workout =>
        - render("workout.jade", Map('workout -> workout, 'mode -> "teaser"))
      - }
  - }
- }

Then in my layout, I was able to retrieve this and display it. Below is a snippet from the layout I'm using (copied from Twitter's Bootstrap example). You can see how the sidebar is included in the .span4 at the end.

-@ val sidebar: String = ""
...
.container
  .content
    .page-header
      h1
        = pageHeader
        small
          = pageTagline
    .row
      .span10
        !~~ body
      .span4
        = unescape(sidebar)
  footer

View vs. Render in Scalate
In the sidebar code above, you might notice the render() call. This is the Scalate version of server-side includes. It works well, but there's also a view() shortcut you can use if you want to have templates for rendering your model objects. I quickly discovered it might be difficult to use this feature in my app because my object was Option[(models.Workout, models.Athlete, Seq[models.Comment])] instead of a simple object. You can read the view vs. render thread on the Scalate Google Group if you're interested in learning more.

Scalate as a Module
The last enhancement I attempted to make was to put Scalate support into a Play module. At first, I tried overriding Play's Template class but ran into compilation issues. Then Guillaume Bort (Play's lead developer) recommended I stick with the trait approach and I was able to get everything working. I looked at the outdated play-scalate module to figure out how to add Scala support to build.xml and copied its 500.scaml page for error reporting.

In order to get line-precise error reporting working, I had to wrap a try/catch around calling Scalate's TemplateEngine.layout() method. Again, most of this code was copied from the outdated play-scalate module.

case class Template(name: String) {
  
  def render(args: (Symbol, Any)*) = {
    val argsMap = populateRenderArgs(args: _*)
    
    val buffer = new StringWriter()
    var context = new DefaultRenderContext(name, scalateEngine, new PrintWriter(buffer))
    
    try {
      val templatePath = new File(Play.applicationPath+"/app/views","/"+name).toString
        .replace(new File(Play.applicationPath+"/app/views").toString,"")
      scalateEngine.layout(templatePath + scalateType, argsMap)
    } catch {
      case ex:TemplateNotFoundException => {
        if(ex.isSourceAvailable) {
          throw ex
        }
        val element = PlayException.getInterestingStrackTraceElement(ex)
        if (element != null) {
           throw new TemplateNotFoundException(name, 
             Play.classes.getApplicationClass(element.getClassName()), element.getLineNumber());
        } else {
           throw ex
        }
      }  
      case ex:InvalidSyntaxException => handleSpecialError(context,ex)
      case ex:CompilerException => handleSpecialError(context,ex)
      case ex:Exception => handleSpecialError(context,ex)
    } finally {
      if (buffer.toString.length > 0)
        throw new ScalateResult(buffer.toString,name)
    }
  }
}
...
private def handleSpecialError(context:DefaultRenderContext,ex:Exception) {
  context.attributes("javax.servlet.error.exception") = ex
  context.attributes("javax.servlet.error.message") = ex.getMessage
  try {
    scalateEngine.layout(scalateEngine.load(errorTemplate), context)
  } catch {
    case ex:Exception =>
      // TODO use logging API from Play here...
      println("Caught: " + ex)
      ex.printStackTrace
  }
}

private def errorTemplate:String = {
  val fullPath = new File(Play.applicationPath,"/app/views/errors/500.scaml").toString 
  fullPath.replace(new File(Play.applicationPath+"/app/views").toString,"")
}

Once I had this in place, error messages from Scalate are much better. Not only do I see the error in my browser, but I can click on the offending line to open it directly in TextMate.

Play Scalate Error Reporting

I've published my play-scalate module on GitHub so others can try it out. To give it a whirl, add the following to your dependencies.yml:

    - upgrades -> play-scalate 0.1

repositories:
    - upgrades:
        type: http
        artifact: "http://static.raibledesigns.com/[module]-[revision].zip"
        contains:
            - upgrades -> *

Then add with play.modules.scalate.Scalate to your controllers and call the render() method.

Summary
After using Scalate and Play for almost 3 months, I'm really enjoying the combination. When I first integrated Scalate with a simple trait, the error messages were always in the console. Now that I've borrowed some smarts from Play's ScalaController and play-scalate's error reporting, I feel like it's practically a built-in solution. I was easily able to integrate my desired SiteMesh features and it even allows reusable template blocks. In the end, it's just Scala and Scalate does a good job of allowing you to leverage that.

Other thoughts:

  • If you're writing a lot of Jade and familiar with HTML, Don Park's html2jade is a great tool that comes with Scalate support.
  • I'm really enjoying writing CSS with LESS, particularly the ability to nest rules and have programming features. The only issue I've seen is IntelliJ's LESS plugin only does code-completion for variables rather than CSS values.
  • The Play Framework Cookbook is a great reference for learning how to write modules. Not only does it explain how to create modules, it has some great real-world examples for doing bytecode enhancement, implementing message queues, using Solr and how to do production monitoring.

If this series of articles has intrigued you and you'll be at Devoxx next week, you should stop by my talk on Thursday afternoon. In addition, there's several other Play talks at Devoxx and a possible meetup on Wednesday. Check out the Devoxx, anyone? thread for more information.

Update: There's one thing I forgot to mention about the Play Scalate Module. When I had Scalate integrated in my app with a trait, I only included the scalate-core and scalate-util JARs in dependencies.yml:

- org.fusesource.scalate -> scalate-core 1.5.2-scala_2.8.1:
    transitive: false
- org.fusesource.scalate -> scalate-util 1.5.2-scala_2.8.1:
    transitive: false

However, when I created the play-scalate module, I allowed more dependencies.

- org.fusesource.scalate -> scalate-core 1.5.2-scala_2.8.1:
    exclude:
        - javax.servlet -> *
        - com.sun.jersey -> *
        - org.osgi -> *
- org.fusesource.scalate -> scalate-util 1.5.2-scala_2.8.1
Because Scalate depends on Logback, debug messages started showing up in my console. To fix this, I created conf/logback.xml in my project and filled it with the following XML.

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
      <encoder>
          <pattern>%msg%n</pattern>
      </encoder>
  </appender>

  <root level="info">
    <appender-ref ref="STDOUT" />
  </root>
</configuration>

This reduces the logging and allows me to increase Scalate's logging if I ever have the need.

Posted in Java at Nov 07 2011, 02:07:40 PM MST Add a Comment