First impressions with Liferay

A couple of weekends ago I had my first experience customizing a Liferay site. I wrote a very simple theme to change the standard look & feel and I also wrote some portlets in several differente languages. The goal was to analyze which portlet technology was the best to suit our needs.

Writing the theme was not difficult at all. Liferay has an excellent SDK for writing plugins, which include themes. I didn’t start from scratch but used the great HTML5Goodness responsive theme. The main navigation menu was easy to do since there is a method to iterate over first level pages. However, when I tried to do the same with the footer menu I couldn’t find an easy and clean way to do it. I wanted to put standard links in the footer menu as the Terms of Use, the Privacy Policy and so on in the footer menu but I didn’t know how to organize this stuff in Liferay CMS so I could retrieve them back easily. I thought about using a portlet for the footer but I think that’s not the way to do it since that would affect the portlets layout for all the pages. So I added some variables in the XML that describes the theme and hardcoded the links there. At least I don’t have to change the theme code if we change any of those links.

About the portlets, we needed to write a portlet that pulls the content from an external service via REST calls and render it nicely using some kind of templates. These were the attempts I made and my conclusiĆ³ns:

  • Portlet written in Java: this was the obvious choice. The advantages was full access to Liferay API and easyness to integrate the portlet with the SDK stanrdard procedures. The disadvantages were, well, it has to be written in Java. We are far less productive in Java that with other languages. Just for making an HTTP request is quite involved. Hopefully Liferay has APIs for making this easier.
  • Portlet written in Javascript: This looked promising and was easy to setup, the problem was the importPackage and importClass functions were not available from the Rhino environment. This made Javascript just a toy language in Liferay since the language itself has no useful standard library and it needs to leverage the net or filesystem or any other calls to the runtime it runs on. This make javascript a very integrable language but also a very dependent language. If we can’t call Liferay API from Javascript and there are no network functions in the language itself we can’t use it for our purposes.
  • Portlet written in Python: Our last try was writting the portlet in Python. First we had to update the Jython jar that was included in Liferay since it was a little bit old. Then we added the jyson jar to the jython jar itself to have support for json parsing. We also used Liferay Network APIs since we couldn’t import urllib2 from Python. Finally we even managed to use the Python debugger (PDB) by running Tomcat in the foreground. (bin/catalina.sh run)

One important thing when writing portlets with a scripting language like Python or Javascript is that Liferay will concatenate all your modules into a single big file before running it in the scripting engine (jython or rhino, in our case). This is important to know when reading errors information where the line numbers is not always what we expect. In Python, we can avoid this behavior by changing the PYTHONPATH dinamically at runtime (at the beginning of our script) and then, importing our regular modules will work again.

5 Responses to “First impressions with Liferay”

  1. Wasim Shaikh says:

    Thanks! You liked my liferay theme.

    For more liferay discussion you can join Liferay Forum and
    Open FAQ for liferay

    http://faq.iloveliferay.com

    Thanks,
    Wasim

  2. Jonny says:

    Hi,

    Nice article. Just one question as full time Liferay (Portlet) Developer, why was writing a portlet in Java a disadvantage? Was this just personal opinion or something else?

    I’m just curious because I write all my portlets in Java, and find myself very productive. However I use it everyday, but I avoid some if its (and Liferay’s) nuances and boiler plate code with Libraries that I’ve written once to use each time.

    Thanks again for the article.

  3. Juan says:

    Hi Lorenzo! Regarding the footer, here’s a solution to that problem: http://www.liferay.com/es/web/bradley.wood/blog/-/blogs/7409196
    Read the discussion below the entry for further information.
    Regards!

  4. lgs says:

    @Jonny it’s more my personal opinion. There is nothing in Liferay that make writing portlets in Java less productive than in other languages, quite the opposite. The thing is that we come from the Python community and we found Java in general less productive.

    For example, the network code to make an HTTP GET request in Java is quite big but luckily, Liferay has nice APIs for making this easier.

    @Juan I think I saw that link but I don’t want to embed content in my theme, but to iterate over content pages and just put links to them. I guess I’m thinking against Liferay and the way to go is to put my foot content in a page and just embed that into the theme. It just didn’t look clean to me doing it that way.

  5. turbo says:

    How could you manage to debug with Python?
    I just cannot do it..and my biggest problem is, from my Python portlet i just cant import any Java classes from .jar files, from the portlets /lib. Only if i put the .jar’s in the tomcat’s /lib…
    It stops at the import statement :(

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