Adobe XFDF

Adobe Xml Forms Data Format is an xml format that allows you to fill PDF forms.  I used this in my D&D character generator to allow for easy creation of a printable character sheet in PDF form.

I started with an editable PDF form.  Each field in an editable form has a name of some sort, and if you have access to Adobe LiveCycle Designer, you can view the fields as XML.  All you have to do is open the editable PDF in LiveCycle Designer and click View->XML Source.  This will give you a long XML list detailing all the fields in your form.

UPDATE 2008-11-13: I got an email from someone recently who was creating his editable form using LiveCycle Designer.  It turns out that if you use LiveCycle Designer to build your form, it won't work with XFDF.  If you want to use XFDF, you have to create the form using Acrobat.  LiveCycle Designer forms require that you use XDP (which I have never used).  You can read a bit more about the incompatibilities here.

To specify the values to go into an editable PDF, you create an XFDF file.  The basic format is this:

<?xml version="1.0" encoding="UTF-8"?>

<xfdf xmlns="http://ns.adobe.com/xfdf/" xml:space="preserve">

<f href="http://www.lukerymarz.com/files/CharacterSheet.pdf"/>

<fields>

  <field name="name">

    <value>null</value>

  </field>

  <field name="level">

    <value>1</value>

  </field>

  <field name="class">

    <value>Warlock</value>

  </field>

  <field name="race">

    <value>Tiefling</value>

  </field>

   ...

   ...

   ...

</fields>

</xfdf>

You put this in a text file with an xfdf extension and when you open it, it will reference the pdf in the <f> field and fill in the specified fields.  

So how do you get from the XML LiveCycle Designer gives you to the actual xfdf data.  Well, I didn't want to type a bunch of repetitive lines for each field in the form, so I wrote a little tool to take the LiveCycle xml and spit out ActionScript.  My tool opens the LiveCycle XML, parses each field, and provides a listing with the field type.  It then converts each field to ActionScript code that will append to a string in a my output function.  All I did then was copy the ActionScript code, fill in the specific piece of data for each field (for example, currentCharacter.name for the "name" field), and the output was done.  

There are two caveats I ran into, and the first has to do with spaces.  For each field, the name of that field in the LiveCycle XML has an underscore where a space is.  In the XFDF XML you generate, those underscores need to be replaced with an actual space, otherwise your field won't get filled in.  

The second caveat has to do with arrays.  For example, a part of the ActionScript code my tool generated looks like this:

xfdf += '<field name="class_feature.0"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.1"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.2"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.3"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.4"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.5"><value>' + Database.Data.currentCharacter. + '</value></field>';

xfdf += '<field name="class_feature.6"><value>' + Database.Data.currentCharacter. + '</value></field>';

This is an array of class features.  You'd think you could just go through the list, creating:

  <field name="class feature.0">

    <value>sample feature 1</value>

  </field>

  <field name="class feature.1">

    <value>sample feature 2</value>

  </field>

But that is incorrect.  Since this is an array, you have to represent it as one in the xfdf.  The actual output would look like this:

  <field name="class feature">

    <field name="0">

      <value>Eldritch Blast:</value>

    </field>

    <field name="1">

      <value>Edlritch Pact: Choose Fey Pact, Infernal Pact, or Star Pact.</value>

    </field>

    <field name="2">

      <value>Prime Shot: If you are closest to your target, +1 to attack rolls</value>

    </field>

  </field>

And that's it.  If you reference a pdf on a website, you can send only the xfdf to your user, and as long as they have access to your website, when they open the xfdf, Adobe will take care of the rest.  Pretty neat, once you get past the catches.