Accessing CKAN data from PHP

I've been working on a couple of open data projects recently - which has been very rewarding.

A couple of people have asked for some code so I've knocked up a quick version of the sort of thing I've been working on.

This code requires PHP 5.1 for the JSON functions but doesn't need any extra libraries (pecl_http can give better error messages but is a bit of a pain to install).

The Notes field in packages returns output in Markdown format - you can convert this to HTMl with a parser available at http://michelf.com/projects/php-markdown [1]

This isn't production code so please test before using.

<?php
class Ckan {
    private  $url = 'http://www.ckan.net/';
    private $errors = array(
                              '400'  =>   'Bad Request',
                              '403'  =>   'Not Authorized',
                              '404'  =>   'Not Found',
                              '500'  =>   'Internal Server Error', 
    );
    
    public function __construct($url=null){
        if ($url){
            $this->url=$url;
        }
    }
    
    private function transfer($url){

        $ch = curl_init($this->url . $url);


        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_HEADER, 0);
        curl_setopt($ch, CURLOPT_TIMEOUT, 30);
        $result = curl_exec($ch);
        $info = curl_getinfo($ch);
        curl_close($ch);
        if ($info['http_code'] != 200){
            throw new CkanException($this->error_codes["$info[http_code]"]);
        }
        if (!$result){
            throw new CkanException("No Result");
        }
        return json_decode($result);
    }

    public function search($keyword){
        $results = $this->transfer('api/search/package/?all_fields=1&q=' . urlencode($keyword));
        if (!$results->count){
            throw new CkanException("Search Error");
        }
        return $results;
    }

    public function getPackage($package){
        $package = $this->transfer('api/rest/package/' . urlencode($package));
        if (!$package->name){
            throw new CkanException("Package Load Error");
        }
        return $package;
    }


    public function getPackageList(){
        $list =  $this->transfer('api/rest/package/');
        if (!is_array($list)){
            throw new CkanException("Package List Error");
        }
        return $list;
    }

    public function getGroup($group){
        $group = $this->transfer('api/rest/group/' . urlencode($group) );
        if (!$group->name){
            throw new CkanException("Group Error");
        }
        return $group;
    }

    public function getGroupList(){
        $groupList = $this->transfer('api/rest/group/');
        if (!is_array($groupList)){
            throw new CkanException("Group List Error");
        }
        return $groupList;
    }
}

class CkanException extends Exception{}
?>

Test with

<?php
require_once("ckan.php");

$ckan = new Ckan();


$data = $ckan->getPackage('edmonton-data');

print_r($data);
?>

I'm keeping this file and a Drupal module that uses it on Github at:

http://github.com/practicalweb/drupal-ckan [2]