Welcome!

Microservices Expo Authors: Elizabeth White, Anders Wallgren, Derek Weeks, Jason Bloomberg, SmartBear Blog

Related Topics: Agile Computing

Agile Computing: Article

Is Web 2.0 Possible with Existing Open Source Technologies?

AJAX Pushed

If you Google "AJAX Web 2.0" you'll get over eight million hits, but what technologies will you find in that mix that can truly deliver on the promises of Web 2.0 today? While there's no single definition of Web 2.0, at its heart lays the Internet acting as a platform for social networks, where information can be created and shared in a community of interest. Rich Internet Applications (RIAs) relate to Web 2.0 concepts only in that they enhance the platform by providing a more effective user interface. AJAX relates to Web 2.0 only in that it provides a lightweight approach for developing RIAs that execute through a single ubiquitous interface, the Web browser.

An examination of the interaction models for existing social networking platforms like wikis and blogs reveals that they lack the instantaneous nature of true human interaction. This is an artifact of the synchronous Web model that must be overcome when we consider next-generation platforms envisioned in the Web 2.0 spectrum. Internet-based chat is the most basic example of the near-instantaneous interaction that Web 2.0 demands, but even delivering these basic capabilities in a scalable, lightweight, browser-based mechanism is beyond the scope of most AJAX technologies. In fact, if you sift through those eight million Google hits, you'll find only a handful of open source technologies that address the problems associated with pushing content asynchronously to the user through standard browser mechanisms. We'll provide an overview of those technologies later, but first some basics.

The Basics of Web-based Push
Industry has not standardized on a mechanism or a name for asynchronous data push to the browser. In the AJAX realm the technique goes by a variety of names including AJAX Push, Comet, and Reverse AJAX, but regardless of what you call it, the various approaches share a common characteristic. The only lightweight communication mechanism available to the browser is the HTTP protocol, but HTTP only facilitates standard request/response communication initiated from the browser to the server. To deliver responses asynchronously, it's necessary to invert the HTTP protocol by holding an open request at the server, and fulfilling that request when an update is available. The differences between standard AJAX request processing and the inverted mechanism required for push are illustrated in Figure 1.

To support asynchronous push we need to hold a browser connection open in anticipation of a server-based event that will result in presentation changes in the browser. Intuition suggests that there are issues with this approach and in this case intuition serves us well, since we face connection-related problems at both the browser and the server.

Browser Connection Limit
One of the main difficulties faced by asynchronous Web techniques is caused by the typical browser "two-connection limit." To reduce server load, the HTTP specification recommends that user agents establish at most two connections per server, but asynchronous techniques consume one of these connections as a notification channel. Considering the case where multiple browser windows are open to the same Web page, if each window attempts to establish its own connection, we quickly saturate the available connections. To work within these limitations, a single connection must be shared, but the scripting environments of distinct browser windows are isolated for security reasons, making it difficult to coordinate a shared connection. One technique that can be applied is to make use of a shared HTTP cookie, which is associated with all HTTP interaction with a given server. The cookie is shared across windows and, by manipulation through JavaScript, can be used for cross-window communication.

The problem is amplified in portal environments because legacy portal engines don't support the necessary asynchronous communication path. For push to work in multiple portlets it's not only necessary to share the browser connection, but a single shared server connection is required to marshal asynchronous responses. If portlets are deployed from multiple WARs, there's an additional complication in that the sharing mechanism must coordinate between multiple Web applications and will require some IPC mechanism to do so.

More Stories By Ted Goddard

Ted Goddard is the senior architect of the ICEfaces AJAX framework. Following a Ph.D. in mathematics, he proceeded with postdoctoral research in component and Web-based collaborative technologies. He currently participates in the JavaServer Faces and Servlet expert groups.

More Stories By Steve Maryka

Stephen Maryka is CTO at ICEsoft Technologies Inc., and leads the ICEfaces open source project. He has been involved in Java-based AJAX techniques since 2003 - a time before the term "AJAX" was even coined. Prior to joining ICEsoft, Steve was co-founder of AudeSi Technologies where he served as VP of Technology and led Java product development for Internet appliances. After AudeSi was acquired by Wind River Systems in 2000, he served as a principle technologist there until joining ICEsoft.

Comments (2) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
radixweb 08/13/08 09:21:00 AM EDT

Hey, Great Post.. Thanks for this..

MiamiWebDesigner 08/02/08 09:34:25 AM EDT

Web 2.0 Is Like Pornography

Like so many tech articles posted since Tim O'Reilly coined the term in 2004, this one references "Web 2.0" as if it were something tangible--or at least a concept with clear, concise definition. It is not. In 2006, Web founder Sir Tim Berners-Lee sagely observed that "nobody knows what it means":

http://tinyurl.com/y6ewzy

In 2007, Michael Wesch put together this video that supposedly "explains what Web 2.0 really is about":

http://tinyurl.com/6pdz2q

It is a cool video. But the message is all about XML and how it can be used to separate form and content. There was no mention of CSS and XHTML, but no matter. I was writing XML parsers in the '90s, and XHTML/CSS web design pre-dates "Web 2.0" as well. No cigar, Professor Wesch.

And now in 2008, the most honest thing we can say is that "Web 2.0" means whatever the techno-marketeer (ab)using it wants it to mean. Otherwise, why would intelligent people like Isaac O'Bannon still be writing articles asking "What is Web 2.0?":

http://tinyurl.com/5solok

And, why would McKinsey's just-released best-of-breed report entitled "Building the Web 2.0 Enterprise" ...

http://tinyurl.com/6sxls7

... include no attempt at defining the term other than to list the "Web 2.0 Tools" that comprise or enable it? And even there, the chief ingredient is identified only as "Web Services", adding more mystery to the mix as one ethereal term is offered up to explain another.

As originated in an Onstartups.com website design posting...

http://tinyurl.com/576sgs

... "Web 2.0" is like pornography: Nobody has defined it, but you know it when you see it.

Bruce Arnold, Web Designer, Miami Florida
http://www.PervasivePersuasion.com

@MicroservicesExpo Stories
SYS-CON Events announced today that DatacenterDynamics has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY. DatacenterDynamics is a brand of DCD Group, a global B2B media and publishing company that develops products to help senior professionals in the world's most ICT dependent organizations make risk-based infrastructure and capacity decisions.
With DevOps becoming more well-known and established practice in nearly every industry that delivers software, it is important to continually reassess its efficacy. This week’s top 10 includes a discussion on how the quick uptake of DevOps adoption in the enterprise has posed some serious challenges. Additionally, organizations who have taken the DevOps plunge must find ways to find, hire and keep their DevOps talent in order to keep the machine running smoothly.
Call it DevOps or not, if you are concerned about releasing more code faster and at a higher quality, the resulting software delivery chain and process will look and smell like DevOps. But for existing development teams, no matter what the velocity objective is, getting from here to there is not something that can be done without a plan. Moving your release cadence from months to weeks is not just about learning Agile practices and getting some automation tools. It involves people, tooling and ...
Between the mockups and specs produced by analysts, and resulting applications built by developers, there exists a gulf where projects fail, costs spiral, and applications disappoint. Methodologies like Agile attempt to address this with intensified communication, with partial success but many limitations. In his session at 18th Cloud Expo, Charles Kendrick, CTO & Chief Architect at Isomorphic Software, will present a revolutionary model enabled by new technologies. Learn how business and devel...
The notion of customer journeys, of course, are central to the digital marketer’s playbook. Clearly, enterprises should focus their digital efforts on such journeys, as they represent customer interactions over time. But making customer journeys the centerpiece of the enterprise architecture, however, leaves more questions than answers. The challenge arises when EAs consider the context of the customer journey in the overall architecture as well as the architectural elements that make up each...
APIs have taken the world by storm in recent years. The use of APIs has gone beyond just traditional "software" companies, to companies and organizations across industries using APIs to share information and power their applications. For some organizations, APIs are the biggest revenue drivers. For example, Salesforce generates nearly 50% of annual revenue through APIs. In other cases, APIs can increase a business's footprint and initiate collaboration. Netflix, for example, reported over 5 bi...
As the software delivery industry continues to evolve and mature, the challenge of managing the growing list of the tools and processes becomes more daunting every day. Today, Application Lifecycle Management (ALM) platforms are proving most valuable by providing the governance, management and coordination for every stage of development, deployment and release. Recently, I spoke with Madison Moore at SD Times about the changing market and where ALM is headed.
If there is anything we have learned by now, is that every business paves their own unique path for releasing software- every pipeline, implementation and practices are a bit different, and DevOps comes in all shapes and sizes. Software delivery practices are often comprised of set of several complementing (or even competing) methodologies – such as leveraging Agile, DevOps and even a mix of ITIL, to create the combination that’s most suitable for your organization and that maximize your busines...
These days I mostly make my living as a consultant. Consultants in general are probably not the best loved group in the world. It is common to think of consultants wafting-in to your organization, telling you things that you already know and advising you to “change your culture”, whatever that means. Subsequently they depart, no-doubt with a fat fee, and leave you as you were before with the same problems and no progress made.
Struggling to keep up with increasing application demand? Learn how Platform as a Service (PaaS) can streamline application development processes and make resource management easy.
In the rush to compete in the digital age, a successful digital transformation is essential, but many organizations are setting themselves up for failure. There’s a common misconception that the process is just about technology, but it’s not. It’s about your business. It shouldn’t be treated as an isolated IT project; it should be driven by business needs with the committed involvement of a range of stakeholders.
New Relic, Inc. has announced a set of new features across the New Relic Software Analytics Cloud that offer IT operations teams increased visibility, and the ability to diagnose and resolve performance problems quickly. The new features further IT operations teams’ ability to leverage data and analytics, as well as drive collaboration and a common, shared understanding between teams. Software teams are under pressure to resolve performance issues quickly and improve availability, as the comple...
The goal of any tech business worth its salt is to provide the best product or service to its clients in the most efficient and cost-effective way possible. This is just as true in the development of software products as it is in other product design services. Microservices, an app architecture style that leans mostly on independent, self-contained programs, are quickly becoming the new norm, so to speak. With this change comes a declining reliance on older SOAs like COBRA, a push toward more s...
Join IBM June 8 at 18th Cloud Expo at the Javits Center in New York City, NY, and learn how to innovate like a startup and scale for the enterprise. You need to deliver quality applications faster and cheaper, attract and retain customers with an engaging experience across devices, and seamlessly integrate your enterprise systems. And you can't take 12 months to do it.
This is not a small hotel event. It is also not a big vendor party where politicians and entertainers are more important than real content. This is Cloud Expo, the world's longest-running conference and exhibition focused on Cloud Computing and all that it entails. If you want serious presentations and valuable insight about Cloud Computing for three straight days, then register now for Cloud Expo.
The proper isolation of resources is essential for multi-tenant environments. The traditional approach to isolate resources is, however, rather heavyweight. In his session at 18th Cloud Expo, Igor Drobiazko, co-founder of elastic.io, will draw upon their own experience with operating a Docker container-based infrastructure on a large scale and present a lightweight solution for resource isolation using microservices. He will also discuss the implementation of microservices in data and applicat...
Digital means customer preferences and behavior are driving enterprise technology decisions to be sure, but let’s not forget our employees. After all, when we say customer, we mean customer writ large, including partners, supply chain participants, and yes, those salaried denizens whose daily labor forms the cornerstone of the enterprise. While your customers bask in the warm rays of your digital efforts, are your employees toiling away in the dark recesses of your enterprise, pecking data into...
SYS-CON Events announced today that Stratoscale, the software company developing the next generation data center operating system, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Stratoscale is revolutionizing the data center with a zero-to-cloud-in-minutes solution. With Stratoscale’s hardware-agnostic, Software Defined Data Center (SDDC) solution to store everything, run anything and scale everywhere...
SYS-CON Events announced today that Men & Mice, the leading global provider of DNS, DHCP and IP address management overlay solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. The Men & Mice Suite overlay solution is already known for its powerful application in heterogeneous operating environments, enabling enterprises to scale without fuss. Building on a solid range of diverse platform support,...
You deployed your app with the Bluemix PaaS and it's gaining some serious traction, so it's time to make some tweaks. Did you design your application in a way that it can scale in the cloud? Were you even thinking about the cloud when you built the app? If not, chances are your app is going to break. Check out this webcast to learn various techniques for designing applications that will scale successfully in Bluemix, for the confidence you need to take your apps to the next level and beyond.