Skipping the Learning Curve - Page 2

Generating PDF document on-the-fly from within your Perl scripts does pose several challenges. The first challenge is acquiring familiarity with the PDF specification. Several Perl modules are available which can create a PDF binary stream, but each of these modules does require some degree of understanding as to how PDF documents are structured. Martin Hosken's Text::PDF and Fabien Tassin's PDF::Create are two good examples -- both modules could be used flexibly by someone with an understanding of PDF, although even despite that learning curve, possess their limitations (such as PDF::Create's inability to include images in the PDF document).

A more fully rounded solution can be found in PDFLib, a commercial package for generating on-the-fly PDF which includes a Perl interface. For commercial use, though, this product does come with a price tag, at least $500 at that, and although sophisticated, the library still possesses a learning curve beyond our current aspirations.

The simple fact is, we don't feel like learning the PDF specification. Sure, it might be valuable, as would becoming an ASE certified auto mechanic for the next time the car makes that funny noise -- but there's only so much time to do what you need to do!

The Kindness of Strangers: HTMLDOC

Fortunately, the folks at Easy Software Products have already learned the PDF specification and written a tool that is nearly perfect for our needs: HTMLDOC, released freely under the GPL or GNU General Public License. In fact, HTMLDOC is a full-blooded HTML conversion tool with a graphical interface that can convert web pages to either Postscript or PDF format. Wisely, though, the Easy Software angels built in a command-line interface with capabilities that let us integrate the functionality of HTMLDOC into our Perl scripts, making for a nearly seamless PDF-generating back-end.

You will need to obtain HTMLDOC to implement our simple solution to generated PDF from Perl scripts. Fortunately, binaries of HTMLDOC are available for a wide variety of platforms, including Linux, Solaris, and Windows. For the most part, the installation instructions are simple and straightforward, as illuminated at the Easy Software documentation page. However, we did find two points worth noting in our own installation of the .tar.gz distribution of HTMLDOC on a RedHat 6.1 Linux system:

1. The htmldoc-1.version-platform.tar.gz archive does not create its own subfolder, so you might want to create a subfolder for the installation and move the archive into there before decompressing it.
   
   
2. When installing HTMLDOC on a remote host via a telnet connection, the setup routine failed because it wants to be in a graphical X environment. However, we were able to install the binary by launching the htmldoc.install script also located among the installation files; e.g.
   
   prompt> cd htmldoc-install
   prompt> ./htmldoc.install

You can test the HTMLDOC installation with a simple commandline call:

prompt> echo "test" | htmldoc --webpage -t pdf -

A successful test will yield several lines of garbled-looking output, which itself is not important, except to prove that the program is running and producing output.

The Perl You Need to Know Part 16: A Simple Approach to PDF - Page 1
The Perl You Need to Know
HTML Becomes PDF - Page 3