Interview by Darcy Thomas: July 30, 2009

Maarten Balliauw is a MVP ASP.NET and is a .NET Software Engineer at RealDolmen.  His interests are mainly in web applications development in ASP.NET (C#) or PHP.  In this interview he discusses his experiences working with PHPExcel and Open XML.

What is the coolest implementation of Open XML you have completed?   If the answer is Office, then list the 2nd coolest.
 Of course, PHPExcel.  It shows clearly that Open XML is not bound to one environment and that PHP on Linux, Unix, Mac, and Windows can perfectly work with Open XML documents.
  
Where do you go to seek help on Open XML development?
 The ECMA and ISO documents (part 4, the “fat” part…), and of course using PackageExplorer (on CodePlex) to see how Excel does the thing I want to implement.
  
Did you do development of the old office binary file formats?  Discuss differences and whether it was easier working with Open XML?
 I had a look at the binary library for Excel but found the code to be a bit of a mess and difficult to work with.  I have found working with Open XML more effortless to work with. We are very fortunate to have another developer who is working with the Excel binary library and integrating it into PHPExcel.
  
What do you do when you are not building software?
Right now I am working on some renovations to our house. You could say that in my spare time I am still developing; not software but physical development.  Development using my hands instead of my computer.
 
Why did you choose spreadsheetML?
It wasn’t so much of a choice it was something that just happened. I started wanting to create an Open XML spreadsheet using PHP.  I blogged about it.  It was not much more than a hello world, but people started requesting features and asking for the source code. PHPExcel evolved out of that.
 
There are other PHP tools that can be used when working with Excel files, what makes your one different?
We have a spreadsheet engine, which allows you to create a spreadsheet, perform calculations. By plugging in file format providers we can now easily use the same API to create Open XML, binary format, PDF, HTML, CSV etc.
 

We have been doing a lot of work with ASP.Net too.  Have you thought about porting any of your functionality to ASP.Net?
Where I work, we do a lot with ASP.Net. I have been thinking about porting PHPExcel, but then I realised that a week only has 7 days at the moment - it would require more days!
 
Have you ever thought of porting any of your functionally from PHPExcel to work on asp.net?
Luckily there are other projects on CodePlex which provide Open XML functionally on ASP.Net.
 
Have you tried running PHPExcel in the Windows Azure Cloud?
No, I haven’t tried using PHPExcel on the Azure Cloud. I cannot see a reason why it would not work.  PHPExcel is a proper library.  It’s just a collection of PHP code, therefore it should be possible to use it on the Microsoft Azure Cloud.
 
You went to the document interoperability workshop in London – what are some things you can tell us about that?  What were some of the stand out sessions for you?
The stand out session for me was the panel on digital signing.  There was a lot of discussion surrounding the different laws and requirements from various countries representatives.  I found it all very interesting.
 
PHP PowerPoint is a new project of yours, what have you got planned for that in the future?
Big plan is to also attract other developers to this project and implement all features required by our users.  The same plan as with PHPExcel: let it grow based on community feedback.