If you’re coding in PHP and checking variables to see if they have a strlen() == 0, or isset() or a variety of other possibilities, you might consider using empty() instead. It’s quite versatile and is nice because it doesn’t trigger any warnings or notices if you use it on a variable which hasn’t been set yet. Here are some examples to show you what it will match against:
<?php
$zero_string = '0';
$zero_int = 0;
$false = false;
$empty_string = '';
$array = array();
$obj = new stdClass();
echo empty( $zero_string ) ? "'0' = empty\n" : '';
echo empty( $zero_int ) ? "0 = empty\n" : '';
echo empty( $false ) ? "false = empty\n" : '';
echo empty( $empty_string ) ? "'' = empty\n" : '';
echo empty( $array ) ? "array() = empty\n" : '';
echo empty( $obj ) ? "stdClass() = empty\n" : '';
echo empty( $foo ) ? "foo is empty (and the variable was never set)\n" : '';
Over the weekend, I attended microformatsDevCamp here in San Francisco. It was a chance for a bunch of people who are interested in microformats to get together and hack on some projects that used microformats to Do Cool Things. I ended up being the instigator of one of the projects we worked on, because I had a concrete “system” in mind that would leverage microformats to meet a real need.
The project was to create a web service that would scrape URLs and pull out any content marked up in hCard content (e.g. my contact page) and would then load that content into an LDAP directory. The reason for this is that most Address Book/Contact applications can plug into an LDAP directory to populate their details, so this would provide a direct pipe between client-side contact storage and web-based, decentralized information. The web service would periodically check the URLs it knew about for updates and update LDAP appropriately. If people update their hCard-based information, the LDAP directory would automatically pick up that change and update itself. I’ve talked about this idea before.
Building (or even tinkering with) this system required that we learned about LDAP, and as it turned out, none of us knew much more than the very basic concepts involved with LDAP, so we had a lot of learning to do. I’m putting together a list of LDAP basics that I’ll publish once they’re straightened out a bit. In the meantime, a specifically big thank you to Tantek for organizing ufDevCamp, to Stephen Weber for working with me on the LDAP/code side of things (and showing me how to get started on github.com, and to Mark Ng for setting up an OpenLDAP server for us to play with, and for helping figure out some of the configuration options etc required to get it all working.
Oh, and there’s some code over here if you’re interested, and we made a page on the microformats wiki with some info on our progress.
