Manolo Carrasco Moñino (Tux & Tuna)

Enabling Desktop Notifications in IE with chromeframe

2011-06-21T07:55:00.000-07:00

Chrome comes with interesting features to improve the user experience. One of them is the 'Desktop Notifications', which allows you to display nice notifications in your desktop using javascript.

Gmail was one of the first applications making use of it, but there are many other applications like Talkwheel using it. These applications are able to detect when the user is running chrome and they offer a link to the user to enable the feature.

Unfortunately there are many companies which only permit the usage of IE in their desktops, if this is your case, don't worry, there is a nice project called chromeframe which embeds the chrome engine in IE as an extension, making IE render faster, perform better when executing javascript, and adding many html5 features like canvas, svg, etc.

A last problem, is that chromeframe has a bug which prevents to show the info bar to authorise websites to use notifications, so you have to follow these steps to enable notifications in IE:

Open IE and Install chromeframe from this URL, if you did not it before.
Add the entry below to your windows registry. You can do either, import the key by clicking over this link, or run 'regedit' and add the entry by hand as is shown in the screenshot below.

HKCU\Software\Google\ChromeFrame\AllowUnsafeURLs=dword:1

Now you can open the chrome settings page just typing: gcf:chrome://settings/content in the url box.

Finally you have to enable notifications.

It seems that FireFox will support 'Desktop notifications' soon, since it is part of the html5 specification, in the meanwhile you can install the ff-html5notification plugin by clicking on this link.

GwtQuery CSS Selectors Performance

2011-01-22T00:19:00.000-08:00

Lately I've been working on the gwtquery opensource project, a rewrite in Gwt of the popular jquery javascript library.

Like jquery, which helps javascript developers to handle DOM elements and events, gquery helps java developers to do the same, and both share the same API with almost the same methods and behaviour.

One of the most powerful features in jquery is the ability to select elements using css selectors. In this matter, gquery improves the performance using two gwt techniques:

Generating permutations and selecting the more suitable engine selector for each browser .

Being able to analyse the css selector at compile-time and optimize the generated code.

Based on these, Gquery generates the most appropriate strategy for each browser, not only considering performance but the final javascript size.

One of the tasks I've faced along this time working with gquery, is to improve the performance of selectors adding new engines, testing them, and choosing the faster one for each browser.

There is a benchmarking application in gwtquery to compare the performance between each engine implementation. It is inspired in the Slickspeed test, taking from it the list of selectors to compare and the DOM document.

I have run this benchmark in several combinations of browsers and operating systems, and finally I have put the results into a spreadsheet to easily compare it and generate some charts.

Premises

I have used the browsers most used nowadays, and the operating systems I have in my virtualbox machines.
I have selected a bunch of the most popular javascript frameworks (jquery_1.3.1, dojo_1.4.3, prototype_1.6.0.3) and javascript selectors (sizzle_1.0, domassistant_2.7).
Gquery can run in two modes, gwt_compiled meaning that the compiler is able to parse each selector used in the application and generate optimized js code, and gwt_dynamic which evaluates selectors in runtime time like the rest of libraries.
In browsers where native optimizations are not available, Gquery falls back to a pure JSNI implementation based on Sizzle.
During my testing, I realised that there are browsers performing worse than others, so I had to make three groups, and each group has a different time scale to easily see the results.
Newer IE8 releases comes with a native selector which is only available in standard mode.
The unit used in all tables and charts is the millisecond, meaning the accumulated time spent to run each single slickspeed css selector.

Comparison between frameworks

This table shows the results of my tests. As you can see, gwtquery in compiled mode always beats, and in general gwtquery dynamic performs better than any other library.

Comparison between browsers:

This table demonstrates that there are browsers performing better than others. In general, opera, chrome, safari and firefox-3.6 handle DOM selectors very well, firefox-3.0 and IE8 (in standars mode) performs acceptable, and other versions of IE performs quite bad.

Conclusions

GwtQuery in compiled mode is the faster javascript library to select dom elements.
GwtQuery dynamic selectors are, in most cases, faster or equal than any other library.
GwtQuery performs better than its brother jQuery.
Sizzle is faster than other libraries, this is the reason why gwtquery fall back js implementation is based on it.
The javascript produced by the Gwt compiler performs well, and normally better than the javascript written by hand.
There are considerable differences between the performance of different browsers. The most significant is the behaviour of IE, although last changes introduced in IE8 are promising.
Gecko browsers perform worst than browsers based on webkit, nevertheless the version used in FF-3.6 has many improvements.

Minino linux 1.2 comes with LXP wm.

2010-11-24T05:37:00.000-08:00

Some time ago I was involved in a project to develop a Linux windows manager almost identical to Windows XP, I took as base icewm and developed LookXP a.k.a. LXP.
The main reason to do that was to install computers in public areas like hotels and business centers, and most people don't realise any difference with the computers they were in the habit of using.

Minino which is a Spanish pet name for little cats, is a lightweight linux distribution thought to be installed in computers with low resources and especially designed for schools, it is easy to use, it is plenty of features, and it is supported by many Spanish foundations and organizations.
In its last release, Minino developers have decided to include LXP because it has few resources requirements, and it is fully configurable. They have made a good work creating a new customized theme as you can see in this screen-shot:

You can download and try Minino from here.

If you are curious, here you have a screen-shot of LXP running a XP theme:

Giving a GWT talk in Castellon

2010-10-27T06:58:00.000-07:00

This week I'm giving a conference in the event 'IV Encuentros de Programadores Java'.

This year the topic of the event is RIA applications, a matter awakening much interest lately.

If you are interested in the event visit this page to register. Also, you should pre-configure your laptop to attend the workshop.

[EDITED]

Using maven with the milestone of GWT-2.1.0

2010-07-09T11:19:00.000-07:00

Gwt version 2.1.0 is coming soon with many improvements, as I already said in other post, now it is possible to create a new maven project using the provided command webAppCreator.

But right now, there are a couple of things you must put in your pom in order to use the new feature:

You have to add the Gwt repository until the new release was published in the Central maven repositories.
You have to use the snapshot version of the maven-gwt-plugin since the last version does not recognize 2.1.0 as a valid gwt version.

NOTE: You have to camellize the tags because blogger sometimes convert it to lowercase.


    com.google.gwt
    gwt-user
    2.1-SNAPSHOT
    provided
  

  
    
      gwt.milestone
      http://google-web-toolkit.googlecode.com/svn/2.1.0.M3/gwt/maven
    
  

  
    
      codehaus.snapshots
      http://snapshots.repository.codehaus.org/
    
  

  
    
      
        org.codehaus.mojo
        gwt-maven-plugin
        1.3-SNAPSHOT
        [...]

Counting lines of code

2010-06-22T01:11:00.000-07:00

A mate of mine asked me how could he count the lines of a project. I said that an easy way is just to use unix command line utilities and I proposed just this line:

find . -name *.java -exec grep -v -P \
    "^[\s]*(\*|//|/\*|import|$)" \
    '{}' ';' | wc -l

But what does it?
- First if finds all java files an print them to the standard output.
- Then it removes empty, import and comment lines.
- Finally it count the lines.

After a while, I though that perl could be used to discard comments more accurately. So I produced this command line replacing grep by perl:

find . -name "*.java" -exec perl -n -e \
   '$i=1 if(/^\s*\/\*/);print $_ if(!$i && !/^\s*(\/\/|import|$)/);$i=0 if($i && /\*\//)' \
   '{}' ';' | wc -l

Finally someone pointed to me to check sloccount, a command-line tool able not only to count lines but also to estimate the effort and the cost in dollars. Take a look to the results of the gwtupload library:

$ sloccount gwtupload-project
[...] 
SLOC Directory SLOC-by-Language (Sorted)
4346    samples-gae     java=3966,xml=380
3048    core            java=2956,xml=92
1360    jsupload        java=608,perl=551,xml=201
704     gae             java=614,xml=81,sh=9
615     samples         java=403,xml=212
569     tomcat          xml=569
512     top_dir         xml=482,sh=30

Totals grouped by language (dominant language first):
java:          8547 (76.63%)
xml:           2017 (18.08%)
perl:           551 (4.94%)
sh:              39 (0.35%)

Total Physical Source Lines of Code (SLOC)                = 11,154
Development Effort Estimate, Person-Years (Person-Months) = 2.52 (30.20)
 (Basic COCOMO model, Person-Months = 2.4 * (KSLOC**1.05))
Schedule Estimate, Years (Months)                         = 0.76 (9.13)
 (Basic COCOMO model, Months = 2.5 * (person-months**0.38))
Estimated Average Number of Developers (Effort/Schedule)  = 3.31
Total Estimated Cost to Develop                           = $ 339,973
 (average salary = $56,286/year, overhead = 2.40).
[...]
Please credit this data as "generated using David A. Wheeler's 'SLOCCount'."

Podcasts about Security

2010-06-21T23:45:00.000-07:00

A podcast in two parts has been published at Javahispano. In this podcast Abraham, Jorge and me talk about different kinds of vulnerabilities, anecdotes, and many interesting issues related with the security not only at big Companies or in the Internet, but those problems at home (wifi, phising, etc).
The podcasts are a bit large, but quite fun.

We spoke in Spanish and you can get they from these links: Part_I & Part_II

Hope you like them.

Latest GWT 'webAppCreator' is able to produce maven projects.

2010-05-25T11:56:00.000-07:00

"webAppCreator" is the utility provided by GWT to create new projects. It creates a new module with the name and namespace the user desires and put enought stuff to start a new GWT project: static html page, css sheet, entry point, rpcs, tests, ant and eclipse configuraion files, and so on.

I have missed ever in this tool the ability to setup the pom.xml file for a maven project. Maven is widely used in most java projects, and it was a pain to create your pom.xml file from scratch each time you create a new GWT project.

Last time I gave a talk about the basis of GWT I had to explain how to do this by hand, and I said that It would be easy to add this feature, so I went ahead with it and I produced a patch which has been included lately in the GWT core.

Although the feature will not be abailable until the next GWT release, fortunately GWT-2.1.0 is comming soon since millestone one has been already published.

To start a new GWT project from scratch just type:

$ webAppCreator -maven -noant com.example.MyApplication

GWT MVP, blending stuff: presenter, dispatch, gin, guice, tests, maven

2010-05-09T23:28:00.000-07:00

Lately, GWT is being considered one of the best alternatives to produce large client side web applications. Maybe, the main reason to this is the use of patterns like Model-View-Presenter (MVP), EventBus, Command-Pattern, etc, which makes the Gwt development really easy and fast.
These rules and best practices were presented by Ray Ryan at last Google I/O, and the main consecuence was the growth of nice libraries which incredibly help you to produce huge Gwt applications.

Unfortunately there is not good documentation nor examples to learn how to blend all these components in your project. Taking the project Hupa as a reference, I have re-factored the Google Contacts MVP project in order to show how to integrate gwt-presenter, gwt-dispatch, google-gin and google-guice. I have coded JRE tests covering all the presenters, and GWT tests to demonstrate that views and RPCs can also be tested with functional tests. I have put everything in a project handled with maven and eclipse.

I prepared this work to my last Gwt presentation and it is shared in google code:

svn checkout http://gwt-workshop.googlecode.com/svn/trunk/GwtWsMvpContacts
mvn clean test gwt:run package

The main reason to adopt this patterns is the ability to tests almost the code of your application in the JVM. This report in Hudson demonstrate that almost everything can be tested in GWT.

Spanish translation of Hudson

2010-04-05T01:09:00.000-07:00

Many weeks ago I started the task of translating Hudson to Spanish.
Although it is a hard work it has helped me to know and understand all the corners of this awesome CI application.

Instead of having an unique repository of key-values pairs, Hudson has hundreds of internationalizable files distributed along the sources which you have to copy and edit by hand, making the work very heavy.
This was the reason why I decided to code a small tool: translation-tool.pl which has helped me a lot, and which is able to look for missing keys and files, print statistics about the progress, batch edition, and much more.

Another problem in translating an application is to find the adequate words in your language to express the original idea; for instance the words `build`, `Dashboard`, `fingerprint` in English sound weird in Spanish for this context. I have written a wiki page with the status of the Spanish translation where people can leave their opinions and suggestions, so if you speak Spanish, please feel free to collaborate.

Podcasts in JavaHispano

2010-03-16T02:14:00.000-07:00

JavaHispano.org is one of the best sites in Internet about technologies related with java. The site uses Spanish as the official language because there are many people interested in technologies which are not good at English. One of the best points in the site are the podcasts they normally publish once a week.

JavaHispano guys have given me the opportunity to collaborate with them and I have participated in two podcasts, one about GWT and another about Continuous Integration.

I encourage them to continue doing this invaluable work.

Jetty includes my fix for a bug in URL session tracking

2010-03-11T07:32:00.000-08:00

Months ago I sent a patch to jetty guys which fixes an issue I spotted related with the URL session tracking.
Basically the the origin of the problem was that Jetty didn't expect more than one parameter in the URI part reserved for the session identifier, even though there are several applications using this part for handling special parameters, and not only the session id.

Hudson JMeter-plugin renamed to Performance-plugin

2010-03-06T01:25:00.000-08:00

JMeter-plugin is a nice way of running jmeter tests and publishing the performance data in Hudson, take a look to this post I did sometime ago.
Said that, the good news are that we have added to the plugin the ability to collect and parse data from other sources like junit xml reports, and this is the reason why the plugin has been renamed to Performance-plugin which is a more generic name.
In the plugin's page you have a procedure to migrate your existing data from jmeter to performance plugin.

Running and monitoring batch processes in Hudson

2010-02-22T14:36:00.000-08:00

Hudson is not only an excellent tool for running and monitoring software builds, but also for running any periodic process: software updates, batch and maintenance scripts, backups, etc.

Last week I participated in a 'javahispano.org' podcast where I talked about the goodness of Continuous Integration and Hudson, and I said that it is recommendable to move most automatic maintenance scripts from crontabs to Hudson.

This can be easily achieved by writing a simple shell script which contains the set of processes to execute periodically and which saves results into junit reports, so that Hudson will be able to record the exit status, the standard and error outputs, and the time lasted by each command, as is shown in this screenshot:

I use a simple shell script library I wrote time ago. It generates a junit report using the same technique that surefire does in maven putting all xml files in a folder. You can get the script library from here.

The usage of the library is very easy, just include it at the beginning of your shell script and call the method 'juLog' each time you want to report anything to Hudson. I think a simple example is a bit more instructive:

#/bin/sh

#### Include the library
. `dirname $0`/sh2ju.sh

#### Clean old reports
juLogClean
#### Success command
juLog  -name=myTrueCommand true
#### Failure
juLog  -name=myFalseCommand false
#### Sleep
juLog  -name=mySleepCommand sleep 5
#### The test fails because the word 'world' is found in command output
juLog  -name=myErrorCommand -ierror=world   echo Hello World
#### A sql command
juLog  -name=mySqlCommand psql -h localhost -U postgres -c 'select now()'
#### A call to a customized method
myCmd() {
   ls -l $*
   return 0
}
juLog  -name=myCustomizedMethod myCmd '*.sh'

Finally configure Hudson folowing these steps:

Create a free-style project

Put your script and the library in SCM

Chosse execute a shell as build method

Run it periodically

Publish Junit results

Hudson and Jetty, avoiding the error: IllegalStateException, Form too large

2010-01-07T01:12:00.000-08:00

Hudson comes packed in an 'out of the box' war file which works fine just putting it in the 'webapps' folder of any servlet container. Unfortunately jetty has a restriction which makes some hudson's features fail, this constrain is the max size allowed for a posted form request, which comes configured with a default value of 200,000 Bytes, since hudson sends sometimes ajax requests quite larger. This failure produces messages in jetty log files like:

java.lang.IllegalStateException: Form too large 218722>200000
 at org.eclipse.jetty.server.Request.extractParameters(Request.java:256)

To avoid this error, just create a configuration file for hudson in the contexts folder of jetty:

<Configure class="org.eclipse.jetty.webapp.WebAppContext">
  <Set name="contextPath">/hudson</Set>
  <Set name="war"><Systemproperty name="jetty.home" default="."/>/webapps/hudson.war</Set>
  <Set name="maxFormContentSize" type="int">600000</Set>
 </Configure>

Hudson's Jmeter plugin 0.3.0 released

2009-12-19T23:09:00.000-08:00

I'm pleased to announce release 0.3.0 of Hudson's Jmeter plugin. It includes some fixes, and very cool features. For instance, the plugin is now able to handle multiple tests in the same job and it can be configured using threshold parameters to mark a build as unstable or failed.

The simpler way to use it is with ant, follow these simple steps to create a new job:

Install jMeter an run it in graphic mode.
Create as many jmeter tests as services you want to check, and add to each test the assertions which would make it fail.
Put all these tests together in the folder 'test/jmeter'
Create a build.xml specifying the path to jmeter:

<project default="all">
  <property name="jmeter-home" location="/usr/local/jmeter"/>
  <path id="ant.jmeter.classpath">
    <pathelement
       location="${jmeter-home}/extras/ant-jmeter-1.0.9.jar" />
  </path>
  <taskdef
    name="jmeter"
    classname="org.programmerplanet.ant.taskdefs.jmeter.JMeterTask"
    classpathref="ant.jmeter.classpath" />
  <target name="clean">
    <delete dir="results"/>
    <delete file="jmeter.log"/>
    <mkdir dir="results/jtl"/>
    <mkdir dir="results/html"/>
  </target>
  <target name="test" depends="clean">
    <jmeter
       jmeterhome="${jmeter-home}"
       resultlogdir="results/jtl">
      <testplans dir="test/jmeter" includes="*.jmx"/>
    </jmeter>
  </target>
  <target name="report" depends="test">
    <xslt
       basedir="results/jtl"
       destdir="results/html"
       includes="*.jtl"
       style="${jmeter-home}/extras/jmeter-results-detail-report_21.xsl"/>
  </target>
  <target name="all" depends="report"/>
</project>

In Hudson, create a new free-style software project and configure it:

Apache-Hupa webmail

2009-12-07T01:24:00.000-08:00

Hupa is the name of Apache-James' webmail. The name has been selected in respect to the American tribe, and it means in its native language 'the tribe on both ways'.

This cool webmail is being developed using java in the server side and GWT for the javascript, and the idea is to have an open-source email client with most of the best characteristics of gmail and usable with any email server.

Right now, Hupa supports IMAP message sources and it performances well, but it is thought to support any James-server storage system in order to improve speed and produce an out-of-the-box package which includes james email server and the webmail.

There is not any official version yet, but the svn code is quite usable. If you want to play with Hupa, you can get the code from svn and package the application with maven. Take a look to the README.txt file in the root folder in order to know how to configure it to use your own server. By default it comes configured to use gmail imap enabled accounts.

Become a Hudson committer

2009-11-23T03:14:00.000-08:00

As you know, weeks ago I sent a large patch modifing Hudson's jmeter plugin. I wrote an entry in this blog explaining what this patch does. Hudson's guys have accepted it, and they have given me write access to the repository.

Definitively, I think that the fact of allowing people to commit code easily, helps opensource growth.

Apache Software Foundation (ASF) Committer

2009-11-23T02:39:00.000-08:00

I'm pleased to announce that I've become being an ASF committer.

I've been contributing actively in Hupa project last months. Hupa is a webmail client written in java and it uses the most innovative technologies in Rich Internet Applications (RIA) design: Google web tookkit (GWT) and Model View Presenter (MVP). The project has been included in the Apache-James project recently.

I want to thank to Norman Maurer and the other James team members for selecting me.

GWT: Client-side vs Server-side locale selection

2009-11-15T15:28:00.000-08:00

When you deploy a GWT application which uses I18N, gwt's compiler generates a file for each browser-language pair. So, before the application is loaded, it is necessary to load a minimal amount of javascript code which figures out which is the appropriate file for this user to load.

Right now, the Gwt algorithm used for language detection, only considers the language parameter in the url, the locale meta-tag, and the javascript variable __gwt_Locale. With these options, the developer has to provide whether links to the user to select the adequate language, or server-side code able to read the Accept-Language header, which has to be called before the gwt application is loaded. Take a look to this post to know exactly how to do the server-side language detection.

However, it is possible to know the language the user is using asking the browser as is explained in this page.
The language reported by the browser is just the language used for the application (menus, messages, etc), and not the Accept-Language header, but it covers a hight percentage of cases. It works fine when an user selects the language at login time in linux, Mac, other un*x, and with the default user's language in windows.

So, simply adding the code below to your .gwt.xml file, your application will select the correct language for most user cases, and you don't need to add complex stuff to do the selection in server side.

I have sent a patch to gwt guys which I expect could be included soon in the official trunk.

<property-provider name="locale">
    <![CDATA[
      try {
      var locale;
      // Look for the locale as a url argument
      if (locale == null) {
        var args = location.search;
        var startLang = args.indexOf("locale=");
        if (startLang >= 0) {
          var language = args.substring(startLang);
          var begin = language.indexOf("=") + 1;
          var end = language.indexOf("&");
          if (end == -1) {
            end = language.length;
          }
          locale = language.substring(begin, end);
        }
      }
      if (locale == null) {
        // Look for the locale on the web page
        locale = __gwt_getMetaProperty("locale")
      }
      if (locale == null) {
        // Look for an override computed by other means in the selection script
        locale = $wnd['__gwt_Locale'];
      }
      if (locale == null) {
        // Use the browser's locale
        locale = navigator.browserLanguage ? navigator.browserLanguage : navigator.language;
        if (locale != null) {
           locale = locale.replace(/-/g, '_');
        }
      }
      if (locale == null) {
        return "default";
      }
      while (!__gwt_isKnownPropertyValue("locale",  locale)) {
        var lastIndex = locale.lastIndexOf("_");
        if (lastIndex == -1) {
              locale = "default";
          break;
        } else {
          locale = locale.substring(0,lastIndex);
        }
      }
      return locale;
    } catch(e){
      alert("Unexpected exception in locale detection, using default: " + e);
      return "default";
    }
  ]]>
  </property-provider>

Jetty bug in url session tracking

2009-11-04T15:05:00.000-08:00

Jetty is an amazing servlet container with an excellent architecture and splendid code. But it is not free of bugs. Weeks ago when I was working on porting an old application, which has been running in Tomcat for years, to Jetty, I realised that the code about tracking sessions using url instead of cookies is erroneous.

The origin of the problem is that Jetty doesn't expect more than one parameter in the url part reserved for the session identifier.

For instance, this url is correctly handled:

http://www.example.com/MyApp/MyAction.do;jsessionid=blablabla?query_string

But this one fails:

http://www.example.com/MyApp/MyAction.do;jsessionid=blablabla;ramdomstr=123123?query_string

I've reported this problem to Jetty's guys.

Tip: Enabling JSP support in Jetty.7.0.0

2009-09-15T02:13:00.000-07:00

Jetty7, doesn't enable jsp support by default, so after one hour trying to understand what was happening, I got the reason.

If you get jetty from eclipse's site, it doesn't come with the needed jsp libraries, so you have to put these libraries manually or download jetty with jsp libraries from codehaus.

But, this is not enough, if you start the server you get an error like this:

INFO::NO JSP Support for /, did not find org.apache.jasper.servlet.JspServlet

So you have to enable jsp support in jetty passing additional undocumented options to the jetty start script:

$ java -jar jetty.jar OPTIONS=Server,jsp

The best option to start jetty and customize it is using the provided script: bin/jetty.sh. But you have to do these steps:

# change the permissions of the provided script.
 $ chmod u+x bin/jetty.sh

 # create a file where you can put customized options.
 $ cat /etc/default/jetty
JETTY_PORT=80
JETTY_HOME=/usr/local/jetty
JAVA_OPTIONS="$JAVA_OPTIONS -Dartifactory.home=/mirai/DATA/artifactory"
JETTY_ARGS=OPTIONS=Server,jsp
 
 # create the link in /etc/init.d
 $ sudo ln -s /usr/local/jetty/bin/jetty.sh /etc/init.d/jetty

 # use this script to start/stop/restart the server
 $ /etc/init.d/jetty <start|stop|restart>

Contributing Hudson plugins

2009-09-03T09:51:00.000-07:00

Hudson is a Continuous Integration software that makes the developer's life easier. I don't believe it is better than CruiseControl, but at least, it is more friendly configurable.
It's plenty of plugins which add hudson tons of features. Most of then are well developed, documented and tested, but there are several ones which have a lack of features.

Lately I've been playing and installing hudson-jmeter plugin in order to monitor my Company's web servers. Even though this is a cool plugin, it is incomplete because it is only able to store and display statistics in the case of success builds.
But what I wanted was to have an easy way to monitor my services and a simple page where I can view the history of performance and availability.

Finally I've decided to modify the plugin, and I've added a new feature which sets a build as unstable or failure, based in the percentage of errors reported by jmeter. I've sent this patch to hudson guys. The patch also includes some fixes to the code.

Update: (Dec-2009), jmeter plugin v0.3.0 includes this feature, and I became a committer of Hudson.
Update: (May-2010), jmeter plugin doesn't exist any more, now it is called performance plugin because it handles jmeter and junit reports, and it it ready to add more parsers.

Ruby's open-uri fails when handling secure redirections

2009-09-02T02:22:00.000-07:00

I've realised that when the target server responds with a redirection to a https uri, ruby fails with the message:


(RuntimeError) redirection forbidden:
     http://hudson.gotdns.com/latest/hudson.war
  -> https://hudson.dev.java.net/files/documents/2402/142380/hudson.war
[...]/ruby/1.8/open-uri.rb:174:in `open_loop'
[...]/ruby/1.8/open-uri.rb:132:in `open_uri'

It's due to a paranoid check that rails do to avoid redirections to private stuff like 'file://'. But, this check uses a incomplete regular expression:


[...]
  unless OpenURI.redirectable?(uri, redirect)
    raise "redirection forbidden: #{uri} -> #{redirect}"
  end
[...]

def OpenURI.redirectable?(uri1, uri2) # :nodoc:
  # This test is intended to forbid a redirection from http://... to
  # file:///etc/passwd.
  # However this is ad hoc.  It should be extensible/configurable.
  uri1.scheme.downcase == uri2.scheme.downcase ||
  (/\A(?:http|ftp)\z/i =~ uri1.scheme && /\A(?:http|ftp)\z/i =~ uri2.scheme)
end

I've opened a ticket and sent a patch to the ruby core team reporting this issue.

But the questions are: is this check needed?, why don't check just the presence of file:// in the url?

Gwt's site publishes my article 'Exporting gwt libraries to Javascript'

2009-08-30T02:24:00.000-07:00

My article about exporting gwt libraries into javascript has been selected to be included in the google-web-toolkit's articles section.

Thanks to Sumit Chandel, the google's guy who has included the article in the site, and who I had the pleasure of knowing last Google Developer Day in Madrid.

Apache web server's code includes my patch for sticky sessions

2009-08-26T03:07:00.000-07:00

Months ago, I submitted a patch to apache's guys which fixed a bug related with the session tracking in apache installations using mod_balancer_proxy and serving java applications deployed in a tomcat cluster which is configured to use url sessions instead of the cookies ones.

You can see the ticket I opened here. And the applied patch here

Tutorial about producing JavaScript libraries using Gwt

2009-08-01T01:41:00.000-07:00

When I published a comment in javahispano.org about using gwt to produce javascript libraries, people asked me to write a tutorial explaining the process, because gwt-exporter was not documented at all.

Now, and based on the experience I have got exporting my Gwt projects (gwtchismes and gwtupload), I have written a detailed tutorial in English and Spanish.

Contributing GwtQuery

2009-08-01T01:06:00.000-07:00

GwtQuery is an awesome library, written by Ray Cromwell, which allows to do progressive javascript enhancement in Gwt.

Months ago I had to use it in a project, but those days gwtquery had a lack of the most useful jquery's methods, mainly due that it was just a prototype exhibited in the Google I/O 2008 .

Then, I decided to add all of the core methods present in jquery and I modified a considerable amount of code including effects, event handling, testing, etc. At the end I produced a patch with about 2500 lines which I sent to Ray, and he included in May 2009.

In the Google I/O 2009, Cromwell gave a conference speaking exclusively about gwtquery and he included me in his credits.

Now I'm planning to contribute this project more frequently.

Configure blogger to use code highlight syntax

2009-07-23T09:23:00.000-07:00

Despite the fact that Blogger doesn't support code coloring, you can do it putting javascript in your pages.

Modify your blog's template in order to use an external javascript library which parses the html document and does the work.

This is the configuration needed for using syntaxhighlighter.
Replace 'HOST' by 'http://syntaxhighlighter.googlecode.com/svn/trunk' to use the last version, or deploy these files in your own website.


<link href='HOST/Styles/SyntaxHighlighter.css' 
         rel='stylesheet' type='text/css'/>
<script src='HOST/Scripts/shCore.js' type='text/javascript'/>
<script src='HOST/Scripts/shBrushCss.js' type='text/javascript'/>
<script src='HOST/Scripts/shBrushJava.js' type='text/javascript'/>
<script src='HOST/Scripts/shBrushJScript.js' type='text/javascript'/>
<script src='HOST/Scripts/shBrushXml.js' type='text/javascript'/>
<script src='HOST/Scripts/shBrushPhp.js' type='text/javascript'/>
<script src='HOST/Scripts/shBrushRuby.js' type='text/javascript'/>
<script src='HOST/Scripts/shBrushCpp.js' type='text/javascript'/>
<script class='javascript'>
  dp.SyntaxHighlighter.ClipboardSwf = "HOST/Scripts/clipboard.swf";
  dp.SyntaxHighlighter.BloggerMode();
  dp.SyntaxHighlighter.HighlightAll("code");
</script>

Then, wrap your code using <pre> tags with the appropriate name and class attributes set, and take care replacing all '<' by '<' and '>' by '>'



<pre name="code" class="html">
[...]
</pre>

<pre name="code" class="javascript">
[...]
</pre>

Now a trick: if you don't want to lose these changes when you change your base template, add a HTML/Javascript widget without any description to your footer, and put there the javascript code.

open-uri in ruby doesn't support multiline headers

2009-07-21T02:57:00.000-07:00

Working with recipes in Automateit, I've released that the download() method fails when I try to download and install jetty from its repository server.
After some frustration, and some time tcpdumping and diving in the ruby sources, I realised that open-uri is raising an exception because the jetty mirror I'm using is sending a multi line header response. This is the server's response with the problematic header:


$ wget -S http://eclipse.ialto.org/jetty/7.0.0.M4/dist/jetty-distribution-7.0.0.M4.zip
HTTP/1.0 200 OK
Date: Tue, 21 Jul 2009 10:01:39 GMT
Server: Eclipse mirror service provided by <a style='font-weight: bold; color: [...]
 </a></div>

Length: 7735180 (7.4M) [application/zip]
Saving to: `jetty-distribution-7.0.0.M4.zip'

At the beginning I suspected that this was an illegal response, but it is not. RFC 2616 in the message headers specification says that 'values for headers can contain new lines if they begin with a space or tabulator character'.

As you can see in this piece of code, the problem is that ruby reads the response line by line, and checks whether each line is valid, even though it has to read blocks ending with a new-line and a non space character, and do the check.


file: net/http.rb 
lines: 2032-2040

def each_response_header(sock)
   while true
     line = sock.readuntil("\n", true).sub(/\s+\z/, '')
     break if line.empty?
     m = /\A([^:]+):\s*/.match(line) or
         puts HTTPBadResponse, 'wrong header line format'
     yield m[1], m.post_match if (m)
   end
 end

I've opened a bug with this problem in the ruby ticket system. Now it is time to know how long these tickets take to be fixed :-)

Slow alt-tab in Ubuntu 9.04 with intel graphic card

2009-07-20T01:09:00.000-07:00

After updating to Ubuntu 9.04, my laptop became so slow, specially the alt-tabing action in the gnome desktop.
Then, I started a little investigation trying to figure out what was going on, and I realised that most CPU time was spent by Xorg server. So, I suspected that something in the graphic acceleration was happening.
After some time googling, I read that intel graphics driver has been actively modified in order to introduce better acceleration and memory management code, these modifications has implied to remove the legacy acceleration code.
Unfortunately these new features are not enabled by default because of stability.
Enabling the new and faster acceleration method (UXA) my laptop increases the performance considerably and I've not released any problem.
So if you have an Intel integrated graphics chip, add this line to the Device section in your /etc/X11/xorg.conf file:


Section "Device"
[...]
   Option        "AccelMethod" "uxa"
EndSection

GWTUpload released

2009-07-18T23:44:00.000-07:00

I'm pleased to announce GWTUpload & JsUpload.

GWTUpload <http://code.google.com/p/gwtupload/> is a library for uploading files to web servers, showing a progress bar with real information about the process (file size, bytes transferred, etc). It uses AJAX requests to ask the web server for the upload progress. It has two components written in java, the server side with servlet and utility classes, and the gwt client side.

JsUpload is the client library but compiled and exported into javascript, so users that don't develop in java can use it directly in web pages. It provides a server program written in perl which can be installed in any web server as a cgi-bin script.

Pergola

2009-07-01T07:54:00.000-07:00

Today, I'm really angry because the builders that are making a pergola on my garden are doing everything wrong. I've published a blog relating this botched job. You can read more details in this page

Editing remote files with eclipse

2009-07-01T07:45:00.000-07:00

Exploring and editing remote filesystems from eclipse is nice and easy to use.

Add a new software update site: http://download.eclipse.org/dsdp/tm/updates/
Install RSE_Runtime from this repository
Add a new view to your workspace: Remote Systems
Add new servers to the view using the different options available: dstore, ssh, sftp, ftp, etc. I prefer to use ssh because it is available in all linuxes I manage.

Remove the awful Windows XP WGA screen in one minute

2009-05-12T13:43:00.000-07:00

Of course, I do not use windows at all, but a friend of me asked me to help him to remove the WGA (Windows Genuine Advantage) screen :-)

I typed these bunch of commands and the problem was fixed.


c:
cd windows\system32
ren WgaLogon.exe WgaLogon.exe_
ren WgaTray.exe WgaTray.exe_
Regsvr32 %Windir%\system32\LegitCheckControl.dll /u
shutdown -r -t 0

Use GWT to produce pure JavaScript libraries

2009-04-25T00:08:00.000-07:00

I've released my first release of JsChismes which is the result of compiling and exporting the code of the gwtchismes library in order to populate its classes and methods into native javascript. So the widgets can be used in html pages using pure javascript, and the goal is that the set of widgets can now be used directly in html pages without the need of knowing anything about gwt and java at all.

The main advantage of using this GWT to produce javascript libraries is that the developer can use the power of java tools (IDE, refactoring, namespaces, reuse, debug, testing, coverage, etc.) to develop his library/application without worrying about the well known javascript problems (versioning of files, obfuscate, optimize, browser compatibility, etc). Then non-java developers (ruby, php ..) and designers can use the library in their pages with a little effort.

This technique is easier since Ray Cromwell's gwt-export library makes it pretty simple.

Defective method in prototype: cumulativeOffSet

2009-04-08T23:31:00.000-07:00

Prototype is one of the most popular javasctipt libraries, nevertheless it has faulty methods.
Based on the documentation, cumulativeOffSet is supposed to return the real position of an element from the top left corner of the document, it works fine in most cases, but when a border is added to a parent element, the element is displaced to a new position which prototype is unable to consider. However, other javascript libraries like jQuery or Gwt returns the correct position.

I've opened a prototype ticket reporting this wrong behaviour, and I've submited a patch which fixes it:
cumulativeOffset patch

Example:

Normal nested div

$('div2').cumulativeOffset()[0] -> x

Adding a 10px border to the parent element, the nested div is moved 10px in the document

$('div2').cumulativeOffset()[0] -> x
This is wrong because the correct value is (x+10)

Automating system administration tasks

2008-11-19T07:50:00.000-08:00

I've been searching for tools to simplify system administration tasks that I've been doing using shell/perl scripts for years. I was looking for something allowing me to create receipts and to launch parallel processes over several machines at the same time without much effort.
I have found several tools that match my needs: Capistrano, Webistrano, Puppet, Zenworks, Cfengine, AutomateIt, Bcfg2, Landscape, Func, Smartfrog.

Eventually I've decided to use AutomateIt because:
- It uses a standard language: ruby.
- It's so easy to distribute/group your tasks into projects.
- There are drivers for most unix flavors
- There is no need to start any daemon. It uses ssh.
- It is ideal not only for administration tasks but also for compiling, testing and deployment ones

Visit AutomateIt site.

Move your projects from CVS to SVN

2008-10-17T08:29:00.000-07:00

If you want to migrate all your projects from CVS to SVN and maintain the same structure, just install cvs2svn and run it for each of your projects:


# SVN_DIR -> Folder where the svn is going to be
# CVS_DIR -> Folder with the cvs stuff
# Project -> Name of each project
# create the target directory if it doesn't exist
mkdir -p SVN_DIR
# run this command for each project
cvs2svn -s  SVN_DIR --existing-svnrepos CVS_DIR/Project  \
                    --trunk=Project/trunk \
                    --branches=Project/branches \
                    --tags=Projet/tags \
                    --encoding=utf-8

GWTChismes Collection for GWT 1.5

2008-10-14T15:02:00.000-07:00

I've released a new version of the gwtchismes library. GWTChismes is a collection of useful widgets for the Google web toolkit. The idea to create this collection comes because I wanted a simple library to put the widgets that I create for my GWT projects. Please take a look to the gwtchismes site for more information

LXP: linux with a XP look and feel

2007-12-09T14:36:00.000-08:00

LXP was my first project for the internet comunity.
It is a windows manager derived from icewm and other tools.
The result is a desktop identical to windows XP.
http://lxp.sf.net