Raible Designs

LinkedIn's Engineering Blog

Have you been curious about LinkedIn's architecture or how they're using Grails and Rails? If so, you might be interested in LinkedIn's Engineering Blog. Over the past couple of weeks, a few Engineers have starting writing about our architecture, OpenSocial, RailsConf, YUI, Grails and OSGi. Below is a complete listing of Engineering posts.

• OSGi at LinkedIn: Java Compilation in OSGi
• Grails at LinkedIn
• OSGi at LinkedIn
• LinkedIn Speaks YUI
• Enlightenments from RailsConf 2008
• Google I/O and LinkedIn's Open Social Integration
• LinkedIn at JavaOne 2008

If there are topics you'd like to see us blog about, please let me know. I've somehow landed in the role of Editor for the Engineering Blog, so I should be able to hook you up if I can find an engineer to blog about what you're interested in.

On a related note, Rob Getzschman's entry LinkedIn discovers the truth about Cannes is quite entertaining. Highly recommended.

RE: Which is the Hottest Java Web Framework?

The "Break it Down" Blog has a lengthy post on Which is the Hottest Java Web Framework? Or Maybe Not Java? Comparing Java Web Frameworks is hard because so many people are passionate about the framework they know best. Add a couple more like Flex and Ruby on Rails and its downright difficult. Nevertheless, this post is good in that it contains a lot of pretty trend graphs and it looks like the author has done some good research. It's likely the folks that will scream foul are the ones that did poor in the comparison (Tapestry and Stripes, I'm talking about you).

Surprising among the top Java Web Frameworks is the rise of Struts 2:

To quote:

Which is much more interesting I think is how Wicket adoption has stayed almost flat while Struts 2 adoption has spiked. Spring MVC/WebFlow seems to be going no where fast and racing JBoss Seam there.

The popularity of Struts 2 really caught me off guard with it being quite a bit different from Struts 1, I figured it got thrown into the "just another web framework" category, but I guess there is something in a name and it's doing quite well.

Regardless of what you think of the post and trends, you have to appreciate the amount of time the author put into it.

What's a good RIA to develop in 20 hours?

In less than two months, I'm making my annual trek to Portland, Oregon to speak at OSCON. To prepare for my talk, I'd like to develop the same application with two different combinations: Flex + Rails and GWT + Grails.

As luck would have it, I'm having a hard time coming up with a good application to write. I'd like to time-box it so I only spend 10 hours on the backend (for each) and 10 hours on the front-end, for a total of 40 hours for both applications.

Can you think of any good applications that would warrant a rich front-end and wouldn't take too long to create? I'd like to put both applications in production and generate enough traffic to be faced with scalability issues.

Over the next several weeks, I hope to start creating the applications and blog about what I've learned along the way. At some point, I hope to post an outline and a rough draft. With your help, I believe this can be an excellent presentation. If the presentation and applications are as good as I hope they'll be, it's likely I'll open source them for everyone to use.

Thanks in advance for any advice.

Update: Thanks for all the great feedback. I've posted a survey to narrow the choices.

Talks for the Colorado Software Summit

I'm looking forward to another great year at the Colorado Software Summer in October. I submitted a couple abstracts back in April and have recently been granted the opportunity to change one.

The reason for the change is Yan Pujante (founder at LinkedIn) is going to do my talk on Building LinkedIn's Next Generation Architecture with OSGi and Spring. Since he's been very integral in writing the existing codebase, as well as the move to OSGi, it seemed more appropriate for him to do this talk. I'd like to keep my talk on Appcelerator, but I'm having a hard time deciding between four other options.

If you're planning on attending CSS this year, let me know which one you'd like to see most.

• What's New (or coming) in Spring 3.0
• Implementing Spring Security, OpenID and OAuth
• Comparing RESTful Web Frameworks: Struts 2 vs. Spring MVC
• How Yahoo's Rules for High Performance Web Sites made LinkedIn 50% Faster

I could see changing the first option to Spring Web specifically. I could also see adding Rails and Grails to the 3rd choice. The 4th one is a lofty goal as the project has just begun. If we succeed, it could be a great talk.

Should we change AppFuse to be Struts 2-specific?

Dusty recently posted an interesting idea to the AppFuse developers mailing list:

After thinking/coding/reading for a while I think the more interesting task is: Retool AppFuse to be one or more Struts2 plugins based on various higher level app patterns. (AppFuse Facebook, AppFuse Employee DB, AppFuse Blog, AppFuse Basic LDAP, AppFuse Basic Crowd).

This all comes from the fact, that I have been wanting to refactor the AppFuse web layer for Struts. One of the interesting aspects of AppFuse is that it works pretty much the same across all its web frameworks. It does so with some lowest common denominator abstractions that can be ported and look and work the same across frameworks. I have picked my tool(s): Struts 2 and Ruby On Rails when I want to pretend I am young again. I know Spring MVC, JSF, etc. but I have no desire to build significant apps on those platforms. It's not because they suck and Struts2 rules, it is because I know Struts 2 the best, I am most efficient there and it provides everything I need to build great webapps (Let's not devolve to a framework debate). So, I would rather have a more Struts 2-specific web stack, that really leverages conventions born and raised there. The nice thing about the Struts 2 web stack is that it is complemented nicely by AppFuse's data/service layer, since unlike Grails or Rails, Struts 2 has no data or service layer. [Read More »]

Seems like a good idea to me. What do you think?

Someday I'd like to come up with a "compatibility test" that allows others to improve upon the ideas in AppFuse and develop their stacks independently. A suite of Selenium tests that require extensionless URLs might be a good start.

Extensionless URLs with Java Web Frameworks

Last week, I had a go of making a Spring MVC application use extensionless URLs. I did some googling, found some tips on the Spring Forums and believe I arrived at a solid solution. Using the UrlRewriteFilter (version 3), I was able to create a rule that looks for any URLs without an extension. If it finds one, it appends the extension and forwards to the controllers. This rule is as follows (where *.html is my servlet-mapping for DispatcherServlet in web.xml):

  <rule>
    <from>^([^?]*)/([^?/\.]+)(\?.*)?$</from>
    <to last="true">$1/$2.html$3</to>
  </rule>

As long as I hand-write all my URLs without an extension (<a href="home"> vs. <a href="home.html">), this seems to work. To combat developers that use "home.html", one solution is to require all links to be wrapped with <c:url value="url"/> (or some other macro that call response.encodeURL()). If you can convince everyone to do this, you can write an outbound-rule that strips the .html extension from URLs.

  <outbound-rule>
    <from>^(.*)\.html(\?.*)?$</from>
    <to last="false">$1$2</to>
  </outbound-rule>

In an ideal world, it'd be possible to modify the <a> tag at the very core of the view framework you're using to automatically encode the URL of any "href" attributes. I don't think this is possible with JSP, FreeMarker, Facelets or any other Java Web Framework templates (i.e. Tapestry or Wicket). If it is, please let me know.

Below is my final urlrewrite.xml with these rules, as well as my "welcome-file" rule at the top.

<?xml version="1.0" encoding="utf-8"?>
<!DOCENGINE urlrewrite PUBLIC "-//tuckey.org//DTD UrlRewrite 3.0//EN"
  "http://tuckey.org/res/dtds/urlrewrite3.0.dtd">

<urlrewrite>
  <rule>
    <from>/$</from>
    <to type="forward">home</to>
  </rule>

  <rule>
    <from>^([^?]*)/([^?/\.]+)(\?.*)?$</from>
    <to last="true">$1/$2.html$3</to>
  </rule>

  <outbound-rule>
    <from>^(.*)\.html(\?.*)?$</from>
    <to last="false">$1$2</to>
  </outbound-rule>

</urlrewrite>

If you have other solutions for extensionless URLs with Java web frameworks, I'd love to hear about them. With any luck, 2008 will be the year we drop extensions (and path-mappings) from our URLs. The stat packages might not like it, but I do.

Upgrading to Spring Security 2.0

This evening I spent a few hours and upgraded AppFuse to use Acegi Spring Security 2.0. The upgrade was fairly straightforward:

• %s/org.acegisecurity/org.springframework.security/g
• Upgraded dependencies (exclusions are necessary if you're using Spring 2.5.x and don't want 2.0.x dependencies pulled in):

  <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-core-tiger</artifactId>
      <version>${spring.security.version}</version>
      <exclusions>
          <exclusion>
              <groupId>org.springframework</groupId>
              <artifactId>spring-core</artifactId>
          </exclusion>
          <exclusion>
              <groupId>org.springframework</groupId>
              <artifactId>spring-support</artifactId>
          </exclusion>
      </exclusions>
  </dependency>
  ...
  <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-taglibs</artifactId>
      <version>${spring.security.version}</version>
      <exclusions>
          <exclusion>
              <groupId>org.springframework</groupId>
              <artifactId>spring-web</artifactId>
          </exclusion>
      </exclusions>
  </dependency>
  

• Changed taglib prefix from "authz" to "security" and change the associated taglib declaration to:

  <%@ taglib uri="http://www.springframework.org/security/tags" 
      prefix="security" %>
  

• In web.xml, I changed <filter-class> to org.springframework.web.filter.DelegatingFilterProxy. Since I didn't name my filter springSecurityFilterChain, I also had to add the following <init-param>:

      <init-param>
          <param-name>targetBeanName</param-name>
          <param-value>springSecurityFilterChain</param-value>
      </init-param>
  

• Lastly, I modified security.xml to use the new syntax. AppFuse's security.xml went from 175 lines to 33 with the new security namespace configuration!

It's hard to believe I first looked at Acegi almost 4 years ago. At that time, I said it contained too much XML for my needs. Ben's reaction:

Seriously, the "whole lotta XML" gives you exponentially more power and flexibility than a method such as this could ever hope to provide you.

It's nice to see that Spring Security 2.0 gives you exponentially more power and flexibility without all the XML. Thanks guys!

P.S. You can also view the full changelog for this upgrade.

Update: If you're using <authz:authentication property="fullName"/> in your JSPs, you'll need to change it to <security:authentication property="principal.fullName"/>.

History Meme

From my 17" MacBook Pro that sits at home and I don't use much on a day-to-day basis:

powers:~ mraible$ history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head
148 mvn
71 cd
46 sudo
40 ls
27 java
23 ll
17 svn
16 echo
13 vi
10 mate

From my 15" MacBook Pro that I use on a daily basis:

mraible-mn:~ mraible$ history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head
83 cd
81 ls
79 sudo
65 mvn
39 mate
28 svn
19 vi
15 rm
12 open
7 tail

Nothing too exciting.

The Web Framework Smackdown Questions

I'm doing my Web Frameworks Smackdown this morning at TheServerSide Conference. A few weeks ago, I asked What Would You Ask the Web Framework Experts? on Javalobby and LinkedIn. Here's a summary of those questions:

• What is the overall performance of your framework as it compares to others?
• How does your web framework position themselves in relation to Web Beans?
• How easy is it to create a re-useable component in your framework? Is it as easy as sub-classing an existing component?
• What is the key differentiating characteristic of your framework that makes it better than the rest?
• What do you think about the various scopes introduced by Seam, e.g. conversation vs request or session? If you support these additional scopes, do you also provide some sort of concurrency control?
• Why can't we, the Java Community, come together and adopt the best application framework and settle the web development subject?
• What are you doing to help with developer productivity?
• 2008 is a huge year for the mobile web. How do you help developers build great mobile web applications?
• If you couldn't use your framework, what would you use and why?
• How do you enable rich Ajax applications?
• Can a developer make a change to source, and hit RELOAD in the browser to see the change? If not, why not?
• What do you think about the whole Flex revolution, and do you think you are competitors to this technology?
• How easy is it to create a module and plug it into a bigger application, complete with configuration, code, and view?

Of course, there's many more questions on the aforementioned pages, these are just some that I hope to ask during the panel. Sitting on the panel: Don Brown (Struts 2), Keith Donald (Spring MVC), Ed Burns (JSF), David Geary (GWT), Geert Bevin (RIFE/OpenLaszlo) and Justin Gehtland (Rails). I tried to get Flex and Grails folks, but they'd either left the conference already or are speaking at the same time.

Update: InfoWorld has some modest coverage of this event in Web frameworks debated at TheServerSide Java Symposium.

Proposal accepted for OSCON 2008

From an e-mail I received earlier this afternoon:

We are pleased to accept the following proposal for OSCON 2008.

* Web Frameworks of the Future: Flex, GWT, Grails and Rails

It has been scheduled for 16:30 on 23 Jul 2008.

My Abstract:

What if the choices in web framework was reduced to 4? If RIA are the way of the future, it's possible that these 4 frameworks are the best choices for this development paradigm. This session will explore these frameworks, as well as entertain many other's opinions on the future of web development.

RESTful backends are easy to create with both Rails and Grails. Ajax frontends are simple to create and maintain with GWT. Flex gives you flash and a pretty UI. If you're an HTML developer, Rails allows you to quickly develop MVC applications. If you're a Java Developer, GWT + Grails might be a match made in heaven. This session is designed to help you learn more about each framework and decide which combination is best for your project.

I'm really looking forward to learning about GWT and Flex in the coming months. If you have any experience (or opinions) about the abstract above, I'd love to hear it. The louder the better.

For those who haven't been, OSCON is one of those truly special conferences. Possible reasons:

• It's only an hour from my parent's house
• It's a beautiful time of year in Portland
• It's always the same weekend as the Oregon Brewers Festival
• It's a kickass conference with the greatest diversity of Open Source Committers

I'm going for all 4 reasons and even made a reservation to stay at The Kennedy School. Should be a fun show.