Example of a request and response object with cUrl

myrequest.php

<?php
/*
 * @link http://codepad.viper-7.com/OtahKC
 * @link http://stackoverflow.com/q/8632366/367456
 */

/**
 * curl based request class that fullfils my needs
 */
class MyRequest
{
	const GET = 1;
	const POST = 2;

	private $url;
	private $method;
	private $postFields = array();
	private $cookieFile = 'cookies.txt';
	private $returnHeaders = FALSE;
	
	public function __construct($url, $method = self::GET)
	{
		$this->setURL($url);
		$this->setMethod($method);
	}
	public function setURL($url)
	{
		if (!parse_url($url, PHP_URL_SCHEME))
			throw new InvalidArgumentException(sprintf("Not a valid URL: %s.", $url));
		$this->url = $url;
	}
	/**
	 * set request method
	 * 
	 * @param int $method
	 * @throws InvalidArgumentException
	 * @return MyRequest (chaining)
	 */
	public function setMethod($method)
	{
		if (! in_array($method, array(self::GET, self::POST)))
			throw new InvalidArgumentException(sprintf('Invalid method %d.', $method));

		$this->method = $method;
		return $this;
	}
	/**
	 * set post fields, will automatically set method to POST.
	 * 
	 * @param array|string $postFields, empty array or string will result in clearing fields
	 * @throws InvalidArgumentException
	 * @return MyRequest (chaining)
	 */
	public function setPostFields($postFields)
	{
		if (is_string($postFields))
			parse_str($postFields, $postFields);

		if (!is_array($postFields))
			throw new InvalidArgumentException('Post-Fields must be either string or array.');

		$this->postFields = $postFields ? $postFields + $this->postFields : array();
		$this->method = self::POST;
		
		return $this;
	}
	public function returnHeaders($bool)
	{
		$this->returnHeaders = (bool) $bool;
		return $this;
	}
	public function execute()
	{
		$curlHandle = curl_init($this->url);
		if (!$curlHandle)
			throw new RuntimeException(sprintf('Unable to initialize for %s.', $this->url));

		// my request uses always cookies because I know it needs them:
		curl_setopt($curlHandle, CURLOPT_COOKIEJAR, $this->cookieFile);
		curl_setopt($curlHandle, CURLOPT_COOKIEFILE, $this->cookieFile);

		// return headers in the output?
		if ($this->returnHeaders)
		{
			curl_setopt($curlHandle, CURLOPT_HEADER, TRUE);
		}

		// my request should ignore some SSL errors because I know the site I request does
		// not handle them properly (which is bad style):
		curl_setopt($curlHandle, CURLOPT_SSL_VERIFYPEER, FALSE);

		// my request 

		if ($this->method === self::POST)
		{
			curl_setopt($curlHandle, CURLOPT_POST, 1);                       // Use POST (not GET)
			curl_setopt($curlHandle, CURLOPT_POSTFIELDS, $this->postFields); // Insert headers
		}
		
		curl_setopt($curlHandle, CURLOPT_RETURNTRANSFER, 1);
		$buffer = curl_exec($curlHandle); // Get the results

		if ($errorNo = curl_errno($curlHandle))
		{
			$error = curl_error($curlHandle);
			curl_close($curlHandle);
			throw new RuntimeException(sprintf('Request failed: (%d) %s.', $errorNo, $error));
		}

		curl_close($curlHandle);

		return $buffer;
	}
	public function __toString()
	{
		return $this->execute();
	}
}

class MyResponse
{
	/**
	 * @var string
	 */
	private $buffer;
	/**
	 * @var string
	 */
	private $headers;
	/**
	 * @var DOMDocument
	 */
	private $doc;
	public function __construct($buffer)
	{
		if (is_object($buffer))
		{
			$buffer = (string) $buffer;
		}
		if (!is_string($buffer))
		{
			throw new InvalidArgumentException(sprintf('Response takes a string, %s given.', gettype($buffer)));
		}
		$this->buffer = $buffer;
	}
	public function getDOMDocument()
	{
		if (!$this->doc)
		{
			$doc = new DOMDocument();
			$setting = libxml_use_internal_errors(TRUE);
			$result = $doc->loadHTML($this->buffer);
			libxml_use_internal_errors($setting);
			if (!$result)
			{
				throw new RuntimeException('Failed to parse HTML.');
			}
			$this->doc = $doc;
		}
		return $this->doc;
	}
	/**
	 * run xpath expression on response buffer
	 * 
	 * @param string $expression
	 * @return array|SimpleXMLElement array if there are multiple matches, otherwise the single SimpleXMLElement
	 */
	public function xpath($expression)
	{
		$result = simplexml_import_dom($this->getDOMDocument())->xpath($expression);
		if (count($result) === 1)
		{
			list($result) = $result;
		}
		return $result;
	}
	/**
	 * take out headers from buffer
	 */
	public function splitHeaders()
	{
		list($this->headers, $this->buffer) = explode("\r\n\r\n", $this->buffer, 2) + array('', '');
		return $this;
	}
	public function getHeaders()
	{
		return $this->headers;
	}
	public function __toString()
	{
		return $this->buffer;
	}
}

# simple get request
$request = new MyRequest('http://hakre.wordpress.com/');
$response = new MyResponse($request);

foreach($response->xpath('//div[@id="container"]//div[contains(normalize-space(@class), " post ")]') as $node)
{
	if (!$node->h2->a) continue;
	echo $node->h2->a, "\n<", $node->h2->a['href'] ,">\n\n"; 
}

# simple post request
$request = new MyRequest('https://example.wordpress.com/wp-login.php');
$postFields = array(
	'log' => 'username', 
	'pwd' => 'password',
);
$request->setPostFields($postFields);
$response = new MyResponse($request->returnHeaders(1)->execute());
echo (string) $response; # output to view headers