PHP & Last.fm/Audioscrobbler’s API

Like many others out there, I’ve chosen to display the album covers of my most recently listened to songs in my blog’s sidebar. It was with this expressed intention in mind that I set up a Last.fm account to start tracking my listening habits.

Present Solution

Right now I’m successfully displaying this information using Dirk’s Last.fm widget which nicely piggybacks Automatic’s Sidebar Widget. Although temporary, I’ve been very happy with this setup and I encourage anyone out there using Wordpress as a blogging platform to consider this plugin combination.

That being said, this seems like the perfect opportunity to introduce myself to API offerings from Last.fm.

Inspired in large part by J Wynia’s article on this same subject; I’ll stick to his approach and more or less follow his example to create the skeletal page he introduced about a month ago.

What’s in the Data?

The data available with the Last.fm API is currently accessible in four formats: Plain text, XML, XSPF and RSS.

XML is available for every displayed data offering while the other three are more sporadically available; because of that, we’ll stick to XML in our examples.

Before working with the data, you need to take a look at it of course. To do that, simply append “?wsdl” to the end of the XML URL (e.g., http://ws.audioscrobbler.com/1.0/user/jrob00/topalbums.xml?wsdl) and your browser (I’m using Firefox) should nicely spit out something similar to this screenshot.

Feeding PHP

Let’s take a look at a simple script to get this data into PHP. First assign the URL…

<?php
$user = "jrob00"; //Your Last.FM username
$url = "http://ws.audioscrobbler.com/";
$url .="1.0/user/$user/topalbums.xml";

We then need to get that XML data into something PHP can work with natively.

PHP5 users can use one simple line to put the XML data into a simpleXML object.

//PHP5
$xml = simplexml_load_file("$url");

PHP4 users however are forced to use any number of far less elegant options. If you’re planning on using PHP4 for any real amount of XML parsing it might be worth your while to look for a solid backport of simpleXML. Otherwise, I would suggest trying the minixml library which is somewhat similar to simpleXML.

Let’s take a look at the same code this time using PHP4 and minixml.

//PHP4
$curl = curl_init();
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_CONNECTTIMEOUT, 5);
curl_setopt($curl, CURLOPT_URL, $url);
$xml = curl_exec($curl);
curl_close($curl);

include_once("minixml.inc.php");
$minixml = new MiniXMLDoc();
$minixml->fromString($xml);
$array = $minixml->toArray();

This accomplishes basically the same thing as the single line of PHP5 code. The major difference noteworthy to our example is that the PHP4 result is stored in an array and not an object.

Looping & Displaying the Data

In keeping true to the inspiration for this article, let’s use Wynia’s simple three column table to display our data.

print "<table align='center' width='10%' border='1'>";
$columns=3;
$i=0;

When setting up the loop to access our data we’ll need to use different snippets for PHP4 & PHP5 because of the class vs object handling.

PHP5 users:

//PHP5
foreach($xml->album as $album)
{
	$i++;
	$artist = $album->artist;
	$album_name = $album->name;
	$album_url = $album->url;
	$album_image = $album->image->medium;

PHP4 users:

//PHP4
foreach ($array["topalbums"]["album"] as $album)
{
	$i++;
	$artist = $album["artist"]["_content"];
	$album_name = $album["name"];
	$album_url = $album["url"];
	$album_image = $album["image"]["medium"];

Fortunately at this point, we can close both loops and end our script with the same code for both versions of PHP.

	if($i==0)
		print "<tr>";

	print "
	<td align='center' valign='top'>
	  <img src='$album_image'><br>
          <a href='$album_url'>$artist - $album_name</a>
	</td>
	";

	if($i==$columns)
	{
		$i=0;
		print "</tr>";
	}
}
print "</table>";

Additional Resources

• See it in action
• Source Code
• Last.fm API