Forum OpenACS Development: Re: Moving to XHTML

I'm not sure what the templating system has to do with XHTML? Template engines should output whatever is asked of them. One failure of acs-templating is adding whitespace in place of removed tags, but otherwise can't it output XHTML right now? Maybe you mean that templates need to look like valid XHTML?

How do html editors fit into OpenACS development? Will future work require their use?

The thing I don't understand about XHTML is how it fits into the needs of a site which allows users to provide dynamic content. Users would never be able to put in anything which wasn't perfect. That means a very smart input filter, and I can't see how the filter would be able to distinguish errors from intentional user input.

But maybe there is a good reason for using XHTML. What is it?

Are there any pages on OpenACS which could be delivered as application/xhtml+xml? If not, are there any pages which are close? Has anyone tried to convert them to see what they look like?

My guess is that you would have to rewrite every page and proc which doesn't know about XHTML, and you would never be able to have a template that had any HTML tags in it, or every page would need to pass through a smart output filter with the same problems as the input filter. Then you have to deal with javascript and css differences, not just quoting the code, but the scripts themselves would need change.

I still think the fastest way to explore this is to find another site/toolkit which takes dynamic input and see how they handle the issues.

Okay, so you are not going to be serving it as application/xhtml+xml, but as plain ol' text/html.

But I did notice that the static home page at w3.org is treated by Firefox as application/xhtml+xml even though a meta tag and the server headers indicate text/html.

I guess there isn't going to be an option of which to use in OpenACS, the home page here is already not HTML 4.01 transitional, using /> to close empty tags.

My version of Mozilla Firefox gets the w3 home page with a meta tag 'http-equiv="Content-Type" content="text/html; charset=utf-8"'. It is hard to see, smashed up against the head tag. However, I think you must be correct: the page it is being sent as application/xhtml+xml, when I use wget, it is text/html. Moving the identical file to my server and sending it, Firefox detects it as text/html, the only difference must be the server headers.

So how to solve the problem of being able to serve both. Simply making an additional template for each page wouldn't work. Some markup is produced in the tcl pages, in procs, and some is in the data. Somehow all these sources which make up the page which gets sent to the user have to be in sync.

My own method is to try to separate data, code and templating, roughly model-view-controller, but markup is difficult to handle generally. One idea is to have a data model which resembles RDF and to be able to apply templating to tiny chunks of code to create markup. As long as the two remain separate and allow for switching out the template, many different opportunities for reuse will open up. The RDF type model would allow the possibility of browsing the elements which were used to create a web page. (A simple html browser, or something using more complex, but either could operate on such a page just by using a different template. That is, the editor/browser would use the same technology on an expanded scale.) The RDF type linking between objects provides the semantic hints needed to pull this off.