I promised last time to show a simple way to render CRX content as PDF. The technique in question involves using a PDF form as the readymade container, into which form data is imported using XFDF. The latter is the XML version of Adobe's Forms Data Format, which in turn is a file format specifically designed to allow import and export of data to and from PDF forms.
The way it works is simple: Suppose you have a PDF form that you want to populate with data. You merely need to create a small data file (in XFDF format) and put it on the server. When a user requests the data file (which has a mimetype of "application/vnd.adobe.xfdf"), Acrobat Reader (or the Reader browser plug-in) detects the fact that form data will need to be imported into a form. The XFDF file itself contains a pointer to the actual form to be used. Reader fetches the form, then imports the form data into it, and renders the result as a PDF file containing the data. It all happens transparently to the user, and the user need only have Acrobat Reader (not a full copy of Acrobat Professional).
In the example I'm going to show below, we generate the XFDF file dynamically on the server, via a script called (what else?) xfdf.esp. We'll get to that in a minute.
The example we're going to talk about assumes that there is content in CRX (under a path of /content/films) that looks something like this:
This particular content node is named terminator_2. It lives under /content/films/ in my CRX repository.
Notice, in the above list, that there is a property (at the bottom) called sling:resourceType, set to a value of "films." This tells CRX to look under /apps/films for any scripts that might be necessary to render the content.
In previous blogs, I've shown how to write scripts that render this content as HTML, SVG, or CSV. Right now, what we need is an XFDF renderer. That turns out to be pretty easy to set up.
First, we need to create a PDF form to hold our data. In the Acrobat Professional forms editor, such a form looks like this:
