Rasmus Lerdorf on security, hormones and PHP

PHP inventor Rasmus Lerdorf spoke yesterday at the Future of Web Apps conference in London. It was the highlight of the conference: at once funny, insightful, techie and thought-provoking.

“I had no intention of writing a language”, he told us. “I hate programming with a passion. It’s boring. It’s tedious. It’s hard. I love solving problems. You endure the pain to get to the end destination.”

In case there are any non-geeks reading, I should explain that PHP is the most popular server-side programming language on the Web. This blog is driven by a PHP application called WordPress. PHP is also free, and one of the big successes of open source.

Lerdorf related the history of PHP, which originally stood for “Personal Home Page tools”. They were little scripts he wrote for his own home page, “my own little hack to reuse the C code I had written”. He then shared his work with friends. He showed us some code samples. Here is PHP in 1994:

<!--getenv HTTP_USER_AGENT--> 
<!--ifsubstr $exec_result Mozilla--> 
Hey, you are using Netscape!<p> 
<!--endif-->

By 1995 PHP looked more like what we would recognize at PHP. By 2007 it has sprouted all sorts of modern object-oriented features and Lerdorf noted that while he understood the importance of these, it has somewhat moved away from its original intent as a quick and dirty tool.

Lerdorf made PHP a completely open source project in 1997. He was fed up with maintaining scripts for other people and realised that he could not do it alone. “No one person can possibly learn 20 different database APIs”. So he contacted all the people who had made suggestions to him, gave them access to PHP’s source on CVS (a source code management system), and relinquished control.

This was the lead-in to some reflections on why people bother to contribute to open source software. Lerdorf gives 4 reasons:

  1. Self-interest
  2. Self-expression
  3. Hormones
  4. Improve the world

The last of these is, in his view, the least important. But why hormones? His theory is that open source is one way geeks get human interaction, despite preferring keyboards and screens to going out and meeting people. It follows that factors like recognition (within their circle) and a sense of ownership are critical to successful open source projects, or even to any form of user-generated content. “You have to think about how people feel about themselves”, says Lerdorf. In fact, his comments chimed nicely with what Kevn Rose said about Digg.

Performance and security

Next, Lerdorf addressed the two major hurdles facing web applications. He is a strong believer in performance as a feature. “Unless you can make it work, there’s no point.” He dived into a couple of profiling tools to make his point, showing how to identify bottlenecks in PHP applications.

Security on the web is awful – I fully take the blame

Then security. “Security on the web today is awful. I know a lot of people blame PHP for that … I fully take the blame for some of it, but not all of it.”

What could he have done? Well, PHP does not spoonfeed security; Microsoft’s ASP.NET is actually better in that respect (my comment, not his). It could be more secure by design. On the other hand, as Lerdorf notes, “there was no such thing as cross-site scripting in 1995″. He gave us a great explanation of how cross-site scripting works; it is not the easiest thing to explain. PHP 5.2 has a new filter function for making user-input safe.

How to be safe on the web? “You can never click on a link. Sorry. Unless you understand everything in that link, and some of them are huge. You can never be sure that it is safe….most people are really easy to trick.”

Finally, Lerdorf gave us a few general comments on future directions, the possibilities opened up by geocoding in Flickr, for example. He says don’t make new portals, “We have enough portals out there.” Use the APIs published by major sites, and finally – make it fast.

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3 comments to Rasmus Lerdorf on security, hormones and PHP

  • Clyde Davies

    What was it that motivated you to write and publish the HTMLEditor, as a matter of interest?

  • Tim

    > What was it that motivated you to write and publish the HTMLEditor

    It was because I needed an HTML editor for a .NET app. It was based on a sample by Lutz Roeder – he posted the code to Usenet – so it struck me that it should stay as open source; and there was no reason not to do so.

    I certainly learned a lot about COM interop and about MSHTML – enough to be embarassed about the mistakes I made in the first code I posted.

    Tim

  • Clyde Davies

    And very impressive it is, too.

    I first got involved in this OS malarky as a result of rashly promising to an online community (the BBC’s h2g2) that I’d sort out a long standing issue of theirs: the lack of a WYSIWYG editor. The initial motivation was probably recognition. After all, the site was set up by Douglas Adams and I suppose anybody who could have delivered a knockout tool would probably have got to meet the great man at some point.

    Several years down the line and Douglas Adams is no longer with us and I still haven’t written it. Also, all the initial offers of help dried up when I said I was going to use MSHTML as the primary component. I have since learned that another, clandestine but very significant motivation for writing open source software is that it is *not* written by Microsoft, regardless of whether it’s ultimately of any use.

    I probably sound very cynical about OS, but I’ve learned a lot about MSHTML and C++/CLI, now. It’s been an interesting journey, at the very least.