Latest News from Kevin Haverlock

New Version of the Web 2.0 Feature Pack for Websphere

Tue, 12 May 2009 14:12:36 EDT

This past Friday the Web 2.0 Feature Pack 1.0.0.2 version was made available. You can find it here:

Web 2.0 Feature Pack start page
OR
read more

New Version of the Web 2.0 Feature Pack for Websphere

Tue, 12 May 2009 14:12:36 EDT

This past Friday the Web 2.0 Feature Pack 1.0.0.2 version was made available. You can find it here:

Web 2.0 Feature Pack start page
OR
IBM's Fix Central

The 1.0.0.2 feature pack contains Dojo 1.3.1 and includes over a 1000 bug fixes over version Dojo 1.1, wider browser support, and performance enhancements. On the server side, Ajax proxy, JSON4J, RPCAdapter, and Web messaging have all seen improvements.

You can upgrade from 1.0 or 1.0.0.1 versions of the feature pack without adversely affecting your existing installation. Of course, if you want to pick up the latest changes into your applications, you'll need to rebuild.

Check it out.

Kevin Haverlock

This past Friday the Web 2.0 Feature Pack 1.0.0.2 version was made available. You can find it here: Web 2.0 Feature Pack start page OR IBM's Fix Central The 1.0.0.2 feature pack contains Dojo 1.3.1 and includes over a 1000 bug fixes over version Dojo... 0 0 1

Ajax Proxy for Web 2.0 Feature pack - quick look

Tue, 02 Dec 2008 15:59:37 EST

The security model of modern browsers dictate that XMLHttpRequests (Dojo.xhr style requests if using the Dojo Toolkit) must have the same domain in order to connect and exchange data. From a security perspective, that is a good thing and helps makeyour web application secure from outside influence. The problem is that it makes cross site mashup creation downright difficult.

There are a couple of options that have been proposed:

Flash: A proprietary solution that requires learning Adobe's programming model. Requires the deployment of a crossdomain.xmlfile.

JSONP: proposed by Bob Ippolito, JSONP is a script tag injection which passes the response from the server (normally JSON)into a user specified function.

Proxy: Using a service that marshals requests to the server. Since the Proxy is located on the same domain, the content appears to originate from the same server.

Lets look at the proxy option as a it relates to the Web 2.0 Feature Pack for WebSphere Application server. The Ajax proxy is a lightweight proxy application that is used by Ajax clients to issue out of domain requests. As an example, your web application may access various RSS sites outside of the your original domain to display current news information.

Under the covers the Ajax proxy uses Apache's HTTPClient to handle connecting to other servers and passing the results back to the Ajax client. On top of HTTPClient is code that provides a configuration interface that can be used to tailor the proxy. The customization include context mapping, white-listing, filtering based on cookies, mime-type, HTTP verbs (POST, GET, etc). The end result is a highly customizable Servlet proxy that can be embedded into your JEE application to provide proxy services. At the heart of the Ajax proxy is the proxy-config.xml configuration file. The configuration file is located in your WEB-INF/ directory of the Ajax Proxy WAR file.

The listing shows a basic proxy configuration that is used to access two services. In this case Yahoo's and CNN's RSS feeds. Lets walk through the configuration.

<?xml version="1.0" encoding="UTF-8"?><proxy:proxy-rules  xmlnssi="http://www.w3.org/2001/XMLSchema-instance"  xmlns:proxy="http://www.ibm.com/xmlns/prod/sw/ajax/proxy-config/1.0">	        <proxy:mapping contextpath="/rss/tech"          url="http://rss.news.yahoo.com" />        <proxy:mapping contextpath="/rss/cnn_world.rss" url="http://rss.cnn.com" />                <proxy:policy url="http://rss.news.yahoo.com/*" acf="none">         <proxy:actions>	    <proxy:method>GET</proxy:method>	</proxy:actions>      </proxy:policy>        <proxy:policy url="http://rss.cnn.com/*" acf="none">       <proxy:actions>	    <proxy:method>GET</proxy:method>	   </proxy:actions>      </proxy:policy>       

    <proxy:meta-data>         <proxy:name>maxconnectionsperhost</proxy:name>         <proxy:value>2</proxy:value>	</proxy:meta-data>	     <proxy:meta-data>         <proxy:name>maxtotalconnections</proxy:name>         <proxy:value>5</proxy:value>	</proxy:meta-data>

The <proxy:mapping> sets the contextpath for the URL of the service you are connecting too. As an example, ifyou are trying to access http://rss.news.yahoo.com/rss/tech from your site, then the contextpath would be /rss/tech and the matching URL would be http://rss.news.yahoo.com. When it comes time to access the service through the proxy, you would use the <servlet-mapping>

	<servlet-mapping>		<servlet-name>ProxyServlet</servlet-name>		<url-pattern>/proxy/*</url-pattern> 			</servlet-mapping>

combined with the context root mapping of mysite. As an example, if the Ajax proxy Servlet is accessed from http://localhost/mysite/proxy then the URL for Yahoo's news service would be http://localhost/mysite/proxy/rss/tech.

The <proxy:policy> defines a policy to be used against the URL. In the case of http://rss.news.yahoo.com, the <proxy:method> states thatonly a HTTP GET request is supported on the URL. Other requests, such as POST will be rejected by the Ajax proxy. In addition >proxy:method<, other rules can be applied such as preventing cookies, allowing only certain mime-types and http headers.

Additionally, performance tuning can also be done against the Ajax proxy. The parameters correspond to those that are available Apache's HTTPClient and can be used to fine tune the Ajax proxy. The <proxy:meta-data> contain optional parameters. The maxconnectionsperhost is a global value that specifies the maximum number of connections kept alive for any host or port combination and can be increased if your site access more than two remote sites for content. The maxtotalconnections is the maximum total of connections supported by the proxy. The default value is 5. The value you choose must be a high enough to support the number of simultaneous connections you might receive. In reality, the maximum connections will alsobe dependent on how WebSphere's Web container is configured.

There are additional parameters as well, including unsigned SSL certificate support, pass-through proxy support (in case the Ajax proxy needs to authenticate through a border firewall before accessing the network). Information and parameters are available with the documentation and can be found online through IBM's InfoCenter for the Web 2.0 Feature Pack.

Kevin Haverlock

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Ajax Proxy for Web 2.0 Feature pack - quick look

Tue, 02 Dec 2008 15:59:37 EST

One of the challenges of working in Ajax is dealing with the Asynchronous request and response. The scenario goes something like this: You create a widget that populates a table with information. The information returned fromthe server is in JSON format. The requests uses an XMLHttpRequest, or in the case of Dojo, a dojo.xhrGet(..) request. For whatever reason, the server fails to return you the data you expected. This may occur for a number of reasons:

The server fails and you get back a 500 error code.
The server does not recognize the request and issues some html instead of the JSON you were expecting
The Session times out, and you are redirected to a form login page to re-authenticate.

For whatever reason, you'll need to respond to the error condition.

Listed below is a roughed out framework of the error conditions an how you might respond within Dojo. The key is to use dojo.fromJSON(data) and parse the JSON response. The parse will fail if you receive HTML from a form login or an HTML error page fromthe server. If there is a problem, catch the exception and go from there. HTTP error condition codes can be caught by the error function. The ioArgs parameter provides additional attributesthat you can use to narrow down the problem.

Kevin Haverlock



<script>        var timer = null;        // Function that retrieves a JSON object and puts the information        // into the div with an id of 'json-content'. Notice how we're defining        // 'handleAs' to be of type 'text'. We we handle the parsing of the JSON        // data so that we can trap the exception if it occurs.        function getJson () {                        var d = dojo.xhrGet ({                                  url:      '/webseal/login',                                  handleAs: 'text',                                   load:     loadIntoNode,                                  error:    errorCondition                                               });        };

          function loadIntoNode(data, ioArgs){                          try{                console.log("Read JSON Data ... do something",data);						// read the JSON data that was returned by the service                 var jsonData = dojo.fromJson(data);

                console.log(jsonData.attribute);                console.log(jsonData.number);		                //do something with the JSON data that you read		//dojo.byId("json-content").innerHTML = data;

            }catch(e)            {                // respond with an error reading JSON.  As an example, if an HTML form login is returned, then dojo.fromJson                 // will throw an Exception.  Catch the exception and dispaly a login box. At this point, we are assuming the                 // error condition is because Dojo can't parse the JSON stream. You can fine tune the error condition by                 // looking at the e.message value		console.log("error reading json data ",e.message);                                // Do something on the error condition, display a login widget, or look at the ioArgs to further narrow                // the problem down.                           }

          function errorCondition(error,ioArgs){

           console.log("Status",ioArgs.xhr.status);                          // retrieve an error message for the HTTP response code.  As an example, if we get a 500 	    // (Server Error) then take an action.

            switch(ioArgs.xhr.status) {            case 404: //page not found error                      break;            case 500: // server side error                      break;            case 407: // proxy authentication                      break;            default: // default action            };

            console.log("HTTP Error code:",ioArgs.xhr.status);            console.log("Error Condition:",error.responseText);	    console.log("Error Message:  ",error.message);

            //dojo.byId("json-content").innerHTML = ioArgs.xhr.status;                                 };               </script>

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Using Google Web Toolkit with WebSphere Application Server

Fri, 10 Oct 2008 12:53:41 EDT

Using Google Web Toolkit with WebSphere Application Server

Fri, 10 Oct 2008 00:53:41 EDT

The other day I was asked about Google Web Toolkit (GWT) and developing JEE applications for WebSphere ApplicationServer. GWT is Google's toolkit that allows developers to create Ajax style architectures. What is unique about GWT isthat it provides a Java library for generating JavaScript. The developer writes Java classes, compiles, and executes the classfiles to create JavaScript. The JavaScript can then be packaged and rendered. They also have a set of server side classes which can act as RESTful serviceendpoints that your JavaScript generated code can connected too. There is a ton of information on GWT, so I won't go into detail. If your looking for a book,I enjoyed Ryan Dewsbury's Google Web Toolkit Applications.

So how can one approach GWT and WebSphere Applicaiton Server?

At the end of the day, you want a WAR file or EAR file that you can import as a Web application to WebSphere Application Server. While you can certainly use Eclipse/RAD to create a Dynamic Web Project and export the WAR alone with your GWT generated JavaScript, I've found using Ant much easier and automated. (As a side note, Eclipse is a natural development environment for GWT. GWT provides a command line tool to generate the necessary project files which can be imported into Eclipse).

I used the gwtcompile Ant task which compiles the Java GWT class files you created, executes the classes, then dumps theJavaScript output to a directory. From there, it's pretty straight forward to collect the generated output into a WAR file. I'll typically execute the build.xml directly inside Eclipse and take the WAR and publish it to WebSphere Application Server.

Kevin Haverlock The other day I was asked about Google Web Toolkit (GWT) and developing JEE applications for WebSphere ApplicationServer. GWT is Google's toolkit that allows developers to create Ajax style architectures. What is unique about GWT isthat it provides a Java... 0 0 2

Server Profiles - WebSphere

Tue, 17 Apr 2007 14:13:54 EDT

Server Profiles - WebSphere

Tue, 17 Apr 2007 14:13:54 EDT

I was asked the other day about Server Profiles in IBM's WebSphere Application Server product. For those that may not know, Profiles can be thought of as a specific server runtime environment operating within a separate instance of the JVM. Link to a fun article I wrote a while ago. Kevin I was asked the other day about Server Profiles in IBM's WebSphere Application Server product. For those that may not know, Profiles can be thought of as a specific server runtime environment operating within a separate instance of the JVM. Link to a fun ... 0 0 1

Early Programs - Ajax for IBM WebSphere Platform

Tue, 17 Apr 2007 14:04:39 EDT

Our team has made available an update to the Ajax for IBM WebSphere Platform as part of the Early Adapter program. The Early Adapter programallows users to get an early peek at technology that may be used within the WebSphere Application Server products. This release is based on the 0.4.2 Dojo Toolkit and addresses a number of fixes and improvements. Just as before, the toolkit includes a comet implementation for WebSphere 6.0 Platform Messaging and updates to the samples that were provided. The features are packaged for use in Eclipse 3.2.1 and include an offline version of the draft Dojo book. Distributions are also provided for non-Eclipse users. The documentation download includes explanations and pre-reqs for the various features. Worth a look. Our team has made available an update to the Ajax for IBM WebSphere Platform as part of the Early Adapter program. The Early Adapter programallows users to get an early peek at technology that may be used within the WebSphere Application Server products. ... 0 1 1

Early Programs - Ajax for IBM WebSphere Platform

Tue, 17 Apr 2007 14:04:39 EDT

Our team has made available an update to the Ajax for IBM WebSphere Platform as part of the Early Adapter program. The Early Adapter program

Dojo debugging and editors

Wed, 28 Feb 2007 15:35:06 EST

Most of the challenges in developing Ajax applications is dealing with the developmentlifecycle of creating applications for the various browsers. Despite the fact that Dojo attempts abstracts away the pecularities of the various browser platforms, there are stillgoing to be cases where it works on one browser and not the other. So here is a list of someof the tools that I use and feel free to add your own as well.

Firebug 1.0 for the Firefox browser.Where would we be without Firebug? Dojotoolkit.org thinks the same thing since they made a nicedonation to the Firebug project this January. Firebug is a Firefox plug-in that has a wealth offeatures for the weary Javascript developer: Inspect and edit HTML, CSS update and visalizationmetrics, monitor network activity, and of course debug features. I've only listed a few of thefeatures, but you should look at this amazing project.

http://blog.dojotoolkit.org/2007/01/02/thanks-firebug

I was pretty much resigned to the fact that I was going to have to use IE's MS Script Editor todo anything meaningful on IE, but then along came the IE Developer Toolbar which integrates intoIE 6 and IE 7. It's in Beta 3 right now so there are few problems, but it's a step in the right direction.

AptanaThe Aptana IDE is a free, open-source, cross-platform, JavaScript-focused developmentenvironment for building Ajax applications using the Eclipse IDE. It features code Assist on JavaScript, HTML, and CSS. There is also a Javascript debugger. It's valuable plugin if your doing any Javascript development in Eclipse.

Ajax Tools FrameworkIf your doing J2EE development and attempting to combine Ajax on the browser side, you mightalso consider the Ajax Tools Framework which was recently added as a sub project of Eclipse.org. The ATF can be used with a number of Ajax offerings, including Dojo, Zimbra, Rico, and others. The tool can also be used to create J2EE artifacts such as WAR files which embed a Javascript toolkit on the server side.

Dojo debugging and editors

Wed, 28 Feb 2007 15:35:06 EST

Contributing blogger - Kevin Haverlock

Tue, 27 Feb 2007 17:13:37 EST

Kevin Haverlock is a developer and architect with IBM's Software Group. Kevin is currently a member of the development team for the IBM WebSphere Application server where he works to create products and technology that can be utilized to help your business.

Contributing blogger - Kevin Haverlock

Tue, 27 Feb 2007 17:13:37 EST

Contributing blogger - Jared Jurkiewicz

Tue, 27 Feb 2007 17:12:41 EST

Contributing blogger - Jared Jurkiewicz

Tue, 27 Feb 2007 17:12:41 EST

Jared Jurkiewicz works for IBM's Software Group where he has been a developer on WebSphere Application Server for the past six years. During his tenure he has worked on many aspects of that product, but a significant portion was spent on porting the product to various platforms, such as Linux and other UNIX-like systems. He has also worked on many internal tools (some of which that were Web-based) that have successfully improved the productivity of the other WebSphere Application Server Developers. Jared graduated from the University of Missouri, Rolla, in 1999 with a Bachelors of Science in Computer Engineering. Outside of work, Jared primarily likes to spend his time with friends and family, work on various electronics projects, work on home improvement projects, and work on his cars.

Profiles for WebSphere Application Server 6.0

Wed, 23 Feb 2005 00:00:00 EST

The new IBM WebSphere Application Server (WAS) v6.0 software introduces the concept of Server Profiles. Profiles can be thought of as a specific server runtime environment operating within a separate instance of the JVM.