how can i get data from mediwiki - php

Question

Hi I am using following api to get the data from mediawiki. When I copy this url and paste it into a browser, an xml response appears.
http://en.wikipedia.org/w/api.php?action=query&prop=revisions&titles=API|Main_Page&rvprop=timestamp|user|comment|content
but when I try to do with curl it gives me the error "Scripts should use an informative User-Agent string with contact information, or they may be IP-blocked without notice. ".
I am using following code for this. Can any one trace my error?
$url='http://en.wikipedia.org/w/api.php?action=query&prop=revisions&titles=API|Main_Page&rvprop=timestamp|user|comment|content';
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
//curl_setopt($curl, CURLOPT_TIMEOUT, 1);
$objResponse = curl_exec($curl);
curl_close($curl);
echo $objResponse;die;

Answer 1

this will work to bypass there referrer user agent checks:
<?php
function getwiki($url="", $referer="", $userAgent="") {
if($url==""||$referer==""||$userAgent=="") { return false;};
$headers[] = 'Accept: image/gif, image/x-bitmap, image/jpeg, image/pjpeg';
$headers[] = 'Connection: Keep-Alive';
$headers[] = 'Content-type: application/x-www-form-urlencoded;charset=UTF-8';
$user_agent = $userAgent;
$process = curl_init($url);
curl_setopt($process, CURLOPT_HTTPHEADER, $headers);
curl_setopt($process, CURLOPT_HEADER, 0);
curl_setopt($process, CURLOPT_USERAGENT, $user_agent);
curl_setopt($process, CURLOPT_REFERER, $referer);
curl_setopt($process, CURLOPT_TIMEOUT, 30);
curl_setopt($process, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($process, CURLOPT_FOLLOWLOCATION, 1);
$return = curl_exec($process);
curl_close($process);
return $return;
}
//edited to include Adam Backstrom's sound advice
echo getwiki('http://en.wikipedia.org/w/api.php?action=query&prop=revisions&titles=API|Main_Page&rvprop=timestamp|user|comment|content', 'http://en.wikipedia.org/', 'Mozilla/5.0 (compatible; YourCoolBot/1.0; +http://yoursite.com/botinfo)');
?>

Answer 2

From the MediaWiki API:Quick start guide:
Pass a User-Agent header that properly identifies your client: don't use the default User-Agent from your client library, but use a custom one including the name of your client and the version number, something like MyCuteBot/0.1.
On Wikimedia wikis, failing to supply a User-Agent header or supplying an empty or generic one will cause the request to fail with an HTTP 403 error. See meta:User-Agent policy. Other MediaWiki wikis may have similar policies.
From meta:User-Agent policy:
If you run a bot, please send a User-Agent header identifying the bot and supplying some way of contacting you, e.g.: User-Agent: MyCoolTool (+http://example.com/MyCoolToolPage/)