Sam’s Greenstone Blog 27/5/2011

sjm84. Thursday, June 2nd, 2011.

At the end of last week we discovered the that - unlike the current skin - the new skin did not correctly allow for custom user templates for things like browsing classifiers and search results. We were originally unsure why it was not working but we tracked it down to XSL template priorities. For those of you who are unaware, Greenstone 3 makes heavy use of XML to produce the information necessary to serve pages to the end-user. This XML is then transformed into an actual web page by performing several XSL transformations. XSL (Extensible Stylesheet Language) is basically made up of a set of rules (templates) that say what to do when you encounter a given piece of XML. For example there might be template that means: when you see a documentNode in the XML, replace it with a book icon (HTML tag) followed by a link (HTML tag) to the page for that document. These rules are stored in various files in the web/interfaces/{interface name} folder. To support format statements like what Greenstone 2 has we also allow users to write format statements in the collectionConfig.xml file and these are added to the other templates used to transform the page. So what happens when a user wants to overwrite a pre-existing template (like the one I mentioned before)? Well, we deliberately give the user’s template a higher priority than the default one, so it will do that transformation instead. We found that the default templates in the new skin had deliberately been designed to be more important that the user’s templates, mean that they weren’t showing up at all. So this has now been changed to be more user-template friendly.

Next week I will be adding the finishing touches to the new skin (mostly organising it so that it is easy to modify) and assuming that we can clear up the remaining tickets then I predict I will be spending time testing Greenstone 3 to make sure they are ready for release.

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