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
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: