Skip to main content

The Paradox between Functionality and Extensibility

(Stupid blogger/writeley. Blog publish still not working.)

Apoorv's post reminded me of the extensibility requirements of a WCMS. While his approach seems to be a more pragmatic find-requirements-and-select-best-solution, I prefer the generic but extensible solutions (probably because I'm a developer/programmer at heart). Apoorv also differentiates between customization and extension, but I find it hard to draw a clear line between these two. Here's some lines on extensibility from my thesis:

The final and most important requirement of the WCMS stems from a single principle. It is impossible to predefine all requirements for a WCMS. Each year new concepts, ideas and methods are introduced to the World Wide Web, and web-sites must change the way they deliver content, content managers must change the way they produce content, and developers must change the WCMS to allow the requisite changes.


We propose that extensibility is the most important requirement of WCMS, because they have no definite set of requirements. A WCMS is an abstract information system, and users will not properly realize potential functionality before the WCMS has been put to use. The requirements are indefinite, and more functionality will be demanded as time goes by, and this is why extensibility is such a crucial requirement.


[On our old proprietary CMS]

Whenever there is a new requirement and the customer is willing to pay, the functionality is sown into the existing code-base of the project.


I suggest that the improvements of functionality reduces the extensibility of the product. More code makes it harder to read and use existing code, and every decision made in the certain case of one customer makes the module unusable in the eyes of another customer. For example, the customer had a very specific requirement that each web-shop product be editable by its distributor or producer. To make this work in our CMS, the products were simply divided by distributor, and correct access privileges were granted to one distributor user for her products, respectively. For another customer, the distributor-product scheme could be completely useless, and the entire web-shop would have to be re-factored for such a purpose.


The question becomes whether the case be any different with an open source system. One point was that the we avoided changing the CMS source directly, as any changes made here would be overwritten (or have to be dealt with) on rolling out the next version of the CMS. As a result the extension was entirely made outside the core source in its own module.


The restriction of extensibility can be avoided by having a central architecture which is unnecessary to change. Such an architecture would have to be generic to adopt to possible use-cases (like the web-shop for instance), and we hope that has been achieved in the JCR. The content nodes are flexible enough to be changed into web-shop products, and the developers are confident that they would withstand other WCMS extending transformations as well.


...

Here's some example extensions from our customers (removed this from the thesis):

Web-shop

An organization selling membership-articles used their website for displaying product information on their merchandise. At one point, they decide it would be better if merchandise can be bought directly off the site and require a webshop functionality built into their WCMS.

Web service

The Norwegian Association of Allergic People daily update their website with the most recent pollen-forecast. They realize their members would like historic information and require the page to connect to a repository of pollen-numbers, where queries can produce graphs of pollen levels.

Integrating external services

A trading company see the need to feed various stock quotes on to their front page automatically. A service reading information from another site needs to be set up and connected to the WCMS.

Extranet

A news-company comes up with a new category of news which should be displayed for paying-customers only. Customers gain access to this privileged part of the WCMS by entering a personal user name and password on the site.

Integrating local services

A news company decides that its web page should also display information from a data sheet (which is being constantly updated) directly onto their site. The WCMS needs a data sheet reading service which flushes its content onto a web page at regular intervals.


These are just some example applications that can be implemented outside the WCMS, but sooner or later they need to interconnect in some way or the other, and the system will have to be modified to allow this connection.

Comments

Popular posts from this blog

Open source CMS evaluations

I have now seen three more or less serious open source CMS reviews. First guy to hit the field was Matt Raible ( 1 2 3 4 ), ending up with Drupal , Joomla , Magnolia , OpenCms and MeshCMS being runner-ups. Then there is OpenAdvantage that tries out a handful ( Drupal , Exponent CMS , Lenya , Mambo , and Silva ), including Plone which they use for their own site (funny/annoying that the entire site has no RSS-feeds, nor is it possible to comment on the articles), following Matt's approach by exluding many CMS that seem not to fit the criteria. It is somewhat strange that OpenAdvantage cuts away Magnolia because it "Requires J2EE server; difficult to install and configure; more of a framework than CMS", and proceed to include Apache Lenya in the full evaluation. Magnolia does not require a J2EE server. It runs on Tomcat just like Lenya does (maybe it's an idea to bundle Magnolia with Jetty to make it seem more lightweight). I'm still sure that OpenAdvant

Encrypting and Decrypting with Spring

I was recently working with protecting some sensitive data in a typical Java application with a database underneath. We convert the data on its way out of the application using Spring Security Crypto Utilities . It "was decided" that we'd be doing AES with a key-length of 256 , and this just happens to be the kind of encryption Spring crypto does out of the box. Sweet! The big aber is that whatever JRE is running the application has to be patched with Oracle's JCE  in order to do 256 bits. It's a fascinating story , the short version being that U.S. companies are restricted from exporting various encryption algorithms to certain countries, and some countries are restricted from importing them. Once I had patched my JRE with the JCE, I found it fascinating how straight forward it was to encrypt and decrypt using the Spring Encryptors. So just for fun at the weekend, I threw together a little desktop app that will encrypt and decrypt stuff for the given password

What I've Learned After a Month of Podcasting

So, it's been about a month since I launched   GitMinutes , and wow, it's been a fun ride. I have gotten a lot of feedback, and a lot more downloads/listeners than I had expected! Judging the numbers is hard, but a generous estimate is that somewhere around 2000-3000 have listened to the podcast, and about 500-1000 regularly download. Considering that only a percentage of my target audience actively listen to podcasts, these are some pretty good numbers. I've heard that 10% of the general population in the western world regularly listen to podcasts (probably a bit higher percentage among Git users), so I like to think I've reached a big chunk of the Git pros out there. GitMinutes has gathered 110 followers on Twitter, and 63, erm.. circlers on Google+, and it has received 117 +'es! And it's been flattr'ed twice :) Here are some of the things I learned during this last month: Conceptually.. Starting my own sandbox podcast for trying out everythin

The academical approach

Oops, seems I to published this post prematurely by hitting some Blogger keyboard shortcut. I've been sitting for some minutes trying to figure out how to approach the JavaZone talk mentioned in my previous blog-post. Note that I have already submitted an abstract to the comittee, and that I won't publish the abstract here in the blog. Now of course the abstract is pretty detailed on what the talk is going to be about, but I've still got some elbow room on how to "implement" the talk. I will use this blog as a tool to get my aim right on how to present the talk, what examples to include, what the slides should look like, and how to make it most straightforward and understandable for the audience. Now in lack of having done any presentations at a larger conference before, I'm gonna dig into what I learned at the University, which wasn't very much, but they did teach me how to write a research paper, a skill which I will adapt into creating my talk: The one

Git Stash Blooper (Could not restore untracked files from stash)

The other day I accidentally did a git stash -a , which means it stashes *everything*, including ignored output files (target, build, classes, etc). Ooooops.. What I meant to do was git stash -u , meaning stash modifications plus untracked new files. Anyhows, I ended up with a big fat stash I couldn't get back out. Each time I tried, I got something like this: .../target/temp/dozer.jar already exists, no checkout .../target/temp/core.jar already exists, no checkout .../target/temp/joda-time.jar already exists, no checkout .../target/foo.war already exists, no checkout Could not restore untracked files from stash No matter how I tried checking out different revisions (like the one where I actually made the stash), or using --force, I got the same error. Now these were one of those "keep cool for a second, there's a git way to fix this"situation. I figured: A stash is basically a commit. If we look at my recent commits using   git log --graph --