so – you say you want to detect which mobile devices hit your site? – in the past, this has been a bit of an issue, but lately – with really nice projects available out there such as WURFL or DeviceAtlas, you are able to concentrate harder on other issues, instead of having to write a complete library of your own.

so for this, i’ve decided on DeviceAtlas.  just head on over to DeviceAtlas and open a developers account – you will get a one year developer’s license to play around to see how cool it is.

after registering – click on the downloads link – then go to the php example and download the source files.  after de-tar-and-un-zipping the file, just extract the contents.  at the moment all we are really interested in, is the Mobi/Mtld/DA directory and its contents – also create a json directory and drop the Sample.json file inside.

dump everything into a web directory somewhere.

create a deviceatlas.php file in the working directory root and put the following inside.

//includes the DeviceAtlas API

include 'Mobi/Mtld/DA/Api.php';//fetch the previously populated apc cache instance into a variable

$tree = apc_fetch('tree');

//Get the properties from a variable containing a JSON tree loaded from cache

$properties = Mobi_Mtld_DA_Api::getProperties($tree, $_SERVER['HTTP_USER_AGENT']);

//Output the phone properties for your viewing pleasure

print_r($properties);

‘hhmmm, that’s it?’, you might ask, and if you were clever you would have noticed something strange in the code above.

yip, that is pretty much it – but you also need caching.  the apc_fetch(‘tree’) command in the code above actually fetches the json file already dumped into a ‘tree’ cache instance in PHP APC (Alternative PHP Cache).

why PHP APC, you may also ask.  well, besides using the overstated memcached (you might want to read this), there are some methods to the madness.  with PHP APC, the cache is shared on a server.  it might not be accessible from other servers, but this is not really a con in my mind.

if you wish to scale your application later one and add another server, there is going to be some issues, you might say – but there will also be issues if you have millions of users hit one central instance of DeviceAtlas.  so, having one instance of DeviceAtlas per server might not be too much of an issue.  also when it comes to updating the json file, you might want to consider the single point of failure issue of just having one server.

so have a couple of servers, and just write some scripts to update the single instances of DeviceAtlas, rather than updating one, already busy server which still needs a cache update.

but, back to business.

first you have to install PHP APC.  i found this handy guide on the net, which helped me install it on my debian system and integrate it with apache and php5 – there is also a guide at the bottom for fedora based machines, so don’t fret my linux loving friends

you can create a php script to run the following – which should cache your DeviceAtlas tree into PHP APC.

//ads the sample json data from DeviceAtlas

apc_add('tree', Mobi_Mtld_DA_Api::getTreeFromFile("json/Sample.json"));

from the first code example, the output might look something like this (depending on your phone)

Array
(
[wmv] => 0
[vendor] => Nokia
[mobileDevice] => 1
[memoryLimitMarkup] => 357000
[memoryLimitDownload] => 61440
[midiMonophonic] => 1
[midiPolyphonic] => 1
[mpeg4] => 1
[3gpp] => 1
[drmOmaForwardLock] => 1
[drmOmaCombinedDelivery] => 1
[drmOmaSeparateDelivery] => 1
[markup.xhtmlMp10] => 1
[markup.xhtmlBasic10] => 1
[image.Jpg] => 1
[image.Png] => 1
[amr] => 1
[mp3] => 1
[aac] => 1
[h263Type0InVideo] => 1
[gprs] => 1
[edge] => 1
[image.Gif87] => 1
[uriSchemeTel] => 0
[qcelp] => 0
[hsdpa] => 0
[amrInVideo] => 1
[3gpp2] => 0
[displayColorDepth] => 18
[model] => N70
[https] => 1
[image.Gif89a] => 0
[umts] => 0
[displayWidth] => 176
[displayHeight] => 208
[markup.xhtmlMp11] => 0
[markup.xhtmlMp12] => 0
[csd] => 0
[hscsd] => 0
[id] => 204255
[_matched] => NokiaN70
[_unmatched] => -1/5.0609.2.0.1 Series60/2.8 Profile/MIDP-2.0 Configuration/CLDC-1.1 UP.Link/6.3.1.13.0
)

you can view the attribute explanations here

now you can use the phone’s specific properties to your advantage.  you also might want to look at the user agent switcher add-on for firefox for testing purposes.

that’s it.  now every once in a while you can just update the json file, delete the current cache (http://www.php.net/manual/en/function.apc-delete.php) and bob’s your device detecting, apc caching uncle.