One of my projects I was working on required PDFs to be concatenated/built on the fly from a stock set of 20 PDFs. Based on questionnaire answers, any 4 of the 20 + a core PDF would be concatenated together and provided for either email or download.

The first solution I saw was just to talk to a document creation service about painstaking create every single combination.  This wasn’t within budget.

After researching, I still did not have any solid solutions.  Apparently, because Adobe can charge so much for Acrobat, everyone thinks they can charge for PDF solutions. Don’t get me wrong there is a huge business need for PDF tools, but they all seem week and all look like a VB script. Trust me do a search for PDF concatenation and see what you get.

The solution I came up with was to use pdftk with PHP’s exec function. Since pdftk is a CLI solution, you have to be UBER careful using it with PHP’s exec with any kind of user input, as tampering could be devistating for your server.

The value in pdftk comes with the varity of platforms that are supported. So the solution will work with Windows, Linux, Mac OS X, FreeBSD, and Solaris.

Get ready for it, here’s the code.

$pdfMerge = exec("pdftk $execString cat output $fileName");

Basically, pdftk needs to be passed arguments like:

pdftk 1.pdf 2.pdf 3.pdf cat output 123.pdf

The $execString is the name of all the PDFs that need to be concatenated. I was creating this string with a foreach and used a similar method to generate the output filename.

I don’t know if this is the best solution for the job, but it’s the one that worked rather well for me.  I’d be interested to hear if any of you have better/smarter solutions.

Tags: concatenation, exec, pdf, pdftk, php, string

Technorati : View blog reactions
Posted at : April 23rd, 2009 - 12:36 pm
Filed under : Programming
Navigate : Previous post /