WURFL (Wireless Universal Resource
File) is an XML file that contains the information needed to
identify a wide range of mobile devices. On its own, it doesn’t do anything.
But if you use one of the many available libraries for it, you can create
web apps that can figure out what kind of device has connected to your
app.For example, wurfl-php (http://sourceforge.net/projects/wurfl/files/WURFL%20PHP/)
lets you detect which operating system a remote device is running from
within a PHP script.
Note:
To use WURFL and wurfl-php, you’ll need to be
running your web app on a hosting provider that supports PHP. You’ll also
need to understand how to install files and PHP libraries onto your
server. In this appendix, I show you how to do this using the Unix or Mac
OS X command line. If you are uncomfortable with any of this, but are
comfortable working with PHP, contact your hosting provider’s support
department and ask if they’d be willing to install WURFL and wurfl-php on
the server you use. If you’re using a shared server, it would give your
hosting provider a competitive advantage to offer this feature to all
their customers.
1. Installation
First, download wurfl-php and unzip it
somewhere on your server (in general, it’s best to not put libraries in
your public web folder, so I’m putting it into the
src~/src with the location you want to install it to and replace
wurfl-php-1.1.tar.gz with the name of the file you actually
downloaded: directory in my home directory). Replace
$ mkdir ~/src
$ cd ~/src
$ tar xvfz ~/Downloads/wurfl-php-1.1.tar.gz
Next, download the latest WURFL file (http://sourceforge.net/projects/wurfl/files/WURFL/), copy
it into the wurfl-php folder, and gunzip it (see the wurfl-php
documentation for tips on using this file in its compressed state).
Replace ~/src/wurfl-php-1.1/ with the full path to the
directory that was created in the previous step when you extracted the wurfl-php
distribution, and replace ~/Downloads/wurfl-latest.xml.gz with the path to
the WURFL distribution that you downloaded:
$ cd ~/src/wurfl-php-1.1/
$ cp ~/Downloads/wurfl-latest.xml.gz .
$ gunzip wurfl-latest.xml.gz
Finally, download the desktop web browser patch
so WURFL doesn’t encounter errors when someone visits your page from a
desktop browser:
$ curl -O http://wurfl.sourceforge.net/web_browsers_patch.xml
2. Configuration
Create the following wurfl-config file
(wurfl-config.xml) in
~/src/wurfl-php-1.1/ (or the directory you created
when you extracted wurfl-php):
<?xml version="1.0" encoding="UTF-8"?>
<wurfl-config>
<wurfl>
<main-file>wurfl-latest.xml</main-file>
<patches>
<patch>web_browsers_patch.xml</patch>
</patches>
</wurfl>
<persistence>
<provider>file</provider>
<params>dir=./cache</params>
</persistence>
</wurfl-config>
Create a cache directory and make sure it’s
writable by whichever user runs PHP scripts. If your web server is
configured to run your PHP scripts under your user credentials, this step
should not be necessary. As with previous examples, replace
~/src/wurfl-php-1.1/ with the location you created earlier.
Replace _www with the username that your PHP scripts run
under (you will need superuser credentials to run this command):
$ mkdir ~/src/wurfl-php-1.1/cache
$ sudo chown _www ~/src/wurfl-php-1.1/cache
Note:
If in doubt, contact your hosting provider’s
tech support and explain you want the cache directory to be writable by
your PHP scripts.
3. Testing wurfl-php
Now, in your web directory (such as
Sites or public_html), create
the following PHP file (name it something like
wurfl-test.php). The first time you visit it from
your Android device (or any other browser), it will take a long time as it
builds the initial cache. After that it should be zippy. Figure 1 shows how this should appear in your browser. You
can now modify this PHP code to suit your needs:
<html>
<head>
<meta name="viewport" content="user-scalable=no, width=device-width" />
<title>WURFL Test</title>
<?php
define("WURFL_DIR", "/Users/bjepson/src/wurfl-php-1.1/WURFL/");
define("RESOURCES_DIR", "/Users/bjepson/src/wurfl-php-1.1/");
require_once WURFL_DIR . 'Application.php';
$wurflConfigFile = RESOURCES_DIR . 'wurfl-config.xml';
$wurflConfig = new WURFL_Configuration_XmlConfig($wurflConfigFile);
$wurflManagerFactory = new WURFL_WURFLManagerFactory($wurflConfig);
$wurflManager = $wurflManagerFactory->create();
$wurflInfo = $wurflManager->getWURFLInfo();
$requestingDevice = $wurflManager->getDeviceForHttpRequest($_SERVER);
$is_android = FALSE;
if ($requestingDevice->getCapability("device_os") == "Android") {
$is_android = TRUE;
}
?>
</head>
<body>
<?php
if ($is_android) {
echo "I spy an Android phone.";
}
?>
<ul>
<?php
foreach ($requestingDevice->getAllCapabilities() as $key => $value) {
echo "<li>$key = $value";
}
?>
</ul>
</body>
</html>
Note:
I couldn’t use ~, so I had
to put in the full path to the WURFL stuff; replace
/Users/NAME/src/wurfl-php-1.1/ with the full path to the
wurfl-php directory you created earlier.
