path: root/includes/HttpFunctions.php

<?php
/**
 * Various HTTP related functions.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup HTTP
 */

/**
 * @defgroup HTTP HTTP
 */

/**
 * Various HTTP related functions
 * @ingroup HTTP
 */
class Http {
	static $httpEngine = false;

	/**
	 * Perform an HTTP request
	 *
	 * @param string $method HTTP method. Usually GET/POST
	 * @param string $url full URL to act on. If protocol-relative, will be expanded to an http:// URL
	 * @param array $options options to pass to MWHttpRequest object.
	 *	Possible keys for the array:
	 *    - timeout             Timeout length in seconds
	 *    - connectTimeout      Timeout for connection, in seconds (curl only)
	 *    - postData            An array of key-value pairs or a url-encoded form data
	 *    - proxy               The proxy to use.
	 *                          Otherwise it will use $wgHTTPProxy (if set)
	 *                          Otherwise it will use the environment variable "http_proxy" (if set)
	 *    - noProxy             Don't use any proxy at all. Takes precedence over proxy value(s).
	 *    - sslVerifyHost       Verify hostname against certificate
	 *    - sslVerifyCert       Verify SSL certificate
	 *    - caInfo              Provide CA information
	 *    - maxRedirects        Maximum number of redirects to follow (defaults to 5)
	 *    - followRedirects     Whether to follow redirects (defaults to false).
	 *		                    Note: this should only be used when the target URL is trusted,
	 *		                    to avoid attacks on intranet services accessible by HTTP.
	 *    - userAgent           A user agent, if you want to override the default
	 *                          MediaWiki/$wgVersion
	 * @return Mixed: (bool)false on failure or a string on success
	 */
	public static function request( $method, $url, $options = array() ) {
		wfDebug( "HTTP: $method: $url\n" );
		wfProfileIn( __METHOD__ . "-$method" );

		$options['method'] = strtoupper( $method );

		if ( !isset( $options['timeout'] ) ) {
			$options['timeout'] = 'default';
		}
		if ( !isset( $options['connectTimeout'] ) ) {
			$options['connectTimeout'] = 'default';
		}

		$req = MWHttpRequest::factory( $url, $options );
		$status = $req->execute();

		$content = false;
		if ( $status->isOK() ) {
			$content = $req->getContent();
		}
		wfProfileOut( __METHOD__ . "-$method" );
		return $content;
	}

	/**
	 * Simple wrapper for Http::request( 'GET' )
	 * @see Http::request()
	 *
	 * @param $url
	 * @param $timeout string
	 * @param $options array
	 * @return string
	 */
	public static function get( $url, $timeout = 'default', $options = array() ) {
		$options['timeout'] = $timeout;
		return Http::request( 'GET', $url, $options );
	}

	/**
	 * Simple wrapper for Http::request( 'POST' )
	 * @see Http::request()
	 *
	 * @param $url
	 * @param $options array
	 * @return string
	 */
	public static function post( $url, $options = array() ) {
		return Http::request( 'POST', $url, $options );
	}

	/**
	 * Check if the URL can be served by localhost
	 *
	 * @param string $url full url to check
	 * @return Boolean
	 */
	public static function isLocalURL( $url ) {
		global $wgCommandLineMode, $wgConf;

		if ( $wgCommandLineMode ) {
			return false;
		}

		// Extract host part
		$matches = array();
		if ( preg_match( '!^http://([\w.-]+)[/:].*$!', $url, $matches ) ) {
			$host = $matches[1];
			// Split up dotwise
			$domainParts = explode( '.', $host );
			// Check if this domain or any superdomain is listed in $wgConf as a local virtual host
			$domainParts = array_reverse( $domainParts );

			$domain = '';
			for ( $i = 0; $i < count( $domainParts ); $i++ ) {
				$domainPart = $domainParts[$i];
				if ( $i == 0 ) {
					$domain = $domainPart;
				} else {
					$domain = $domainPart . '.' . $domain;
				}

				if ( $wgConf->isLocalVHost( $domain ) ) {
					return true;
				}
			}
		}

		return false;
	}

	/**
	 * A standard user-agent we can use for external requests.
	 * @return String
	 */
	public static function userAgent() {
		global $wgVersion;
		return "MediaWiki/$wgVersion";
	}

	/**
	 * Checks that the given URI is a valid one. Hardcoding the
	 * protocols, because we only want protocols that both cURL
	 * and php support.
	 *
	 * file:// should not be allowed here for security purpose (r67684)
	 *
	 * @todo FIXME this is wildly inaccurate and fails to actually check most stuff
	 *
	 * @param $uri Mixed: URI to check for validity
	 * @return Boolean
	 */
	public static function isValidURI( $uri ) {
		return preg_match(
			'/^https?:\/\/[^\/\s]\S*$/D',
			$uri
		);
	}
}

/**
 * This wrapper class will call out to curl (if available) or fallback
 * to regular PHP if necessary for handling internal HTTP requests.
 *
 * Renamed from HttpRequest to MWHttpRequest to avoid conflict with
 * PHP's HTTP extension.
 */
class MWHttpRequest {
	const SUPPORTS_FILE_POSTS = false;

	protected $content;
	protected $timeout = 'default';
	protected $headersOnly = null;
	protected $postData = null;
	protected $proxy = null;
	protected $noProxy = false;
	protected $sslVerifyHost = true;
	protected $sslVerifyCert = true;
	protected $caInfo = null;
	protected $method = "GET";
	protected $reqHeaders = array();
	protected $url;
	protected $parsedUrl;
	protected $callback;
	protected $maxRedirects = 5;
	protected $followRedirects = false;

	/**
	 * @var  CookieJar
	 */
	protected $cookieJar;

	protected $headerList = array();
	protected $respVersion = "0.9";
	protected $respStatus = "200 Ok";
	protected $respHeaders = array();

	public $status;

	/**
	 * @param string $url url to use. If protocol-relative, will be expanded to an http:// URL
	 * @param array $options (optional) extra params to pass (see Http::request())
	 */
	protected function __construct( $url, $options = array() ) {
		global $wgHTTPTimeout, $wgHTTPConnectTimeout;

		$this->url = wfExpandUrl( $url, PROTO_HTTP );
		$this->parsedUrl = wfParseUrl( $this->url );

		if ( !$this->parsedUrl || !Http::isValidURI( $this->url ) ) {
			$this->status = Status::newFatal( 'http-invalid-url' );
		} else {
			$this->status = Status::newGood( 100 ); // continue
		}

		if ( isset( $options['timeout'] ) && $options['timeout'] != 'default' ) {
			$this->timeout = $options['timeout'];
		} else {
			$this->timeout = $wgHTTPTimeout;
		}
		if ( isset( $options['connectTimeout'] ) && $options['connectTimeout'] != 'default' ) {
			$this->connectTimeout = $options['connectTimeout'];
		} else {
			$this->connectTimeout = $wgHTTPConnectTimeout;
		}
		if ( isset( $options['userAgent'] ) ) {
			$this->setUserAgent( $options['userAgent'] );
		}

		$members = array( "postData", "proxy", "noProxy", "sslVerifyHost", "caInfo",
				"method", "followRedirects", "maxRedirects", "sslVerifyCert", "callback" );

		foreach ( $members as $o ) {
			if ( isset( $options[$o] ) ) {
				// ensure that MWHttpRequest::method is always
				// uppercased. Bug 36137
				if ( $o == 'method' ) {
					$options[$o] = strtoupper( $options[$o] );
				}
				$this->$o = $options[$o];
			}
		}

		if ( $this->noProxy ) {
			$this->proxy = ''; // noProxy takes precedence
		}
	}

	/**
	 * Simple function to test if we can make any sort of requests at all, using
	 * cURL or fopen()
	 * @return bool
	 */
	public static function canMakeRequests() {
		return function_exists( 'curl_init' ) || wfIniGetBool( 'allow_url_fopen' );
	}

	/**
	 * Generate a new request object
	 * @param string $url url to use
	 * @param array $options (optional) extra params to pass (see Http::request())
	 * @throws MWException
	 * @return CurlHttpRequest|PhpHttpRequest
	 * @see MWHttpRequest::__construct
	 */
	public static function factory( $url, $options = null ) {
		if ( !Http::$httpEngine ) {
			Http::$httpEngine = function_exists( 'curl_init' ) ? 'curl' : 'php';
		} elseif ( Http::$httpEngine == 'curl' && !function_exists( 'curl_init' ) ) {
			throw new MWException( __METHOD__ . ': curl (http://php.net/curl) is not installed, but' .
				' Http::$httpEngine is set to "curl"' );
		}

		switch ( Http::$httpEngine ) {
			case 'curl':
				return new CurlHttpRequest( $url, $options );
			case 'php':
				if ( !wfIniGetBool( 'allow_url_fopen' ) ) {
					throw new MWException( __METHOD__ . ': allow_url_fopen needs to be enabled for pure PHP' .
						' http requests to work. If possible, curl should be used instead. See http://php.net/curl.' );
				}
				return new PhpHttpRequest( $url, $options );
			default:
				throw new MWException( __METHOD__ . ': The setting of Http::$httpEngine is not valid.' );
		}
	}

	/**
	 * Get the body, or content, of the response to the request
	 *
	 * @return String
	 */
	public function getContent() {
		return $this->content;
	}

	/**
	 * Set the parameters of the request
	 *
	 * @param $args Array
	 * @todo overload the args param
	 */
	public function setData( $args ) {
		$this->postData = $args;
	}

	/**
	 * Take care of setting up the proxy (do nothing if "noProxy" is set)
	 *
	 * @return void
	 */
	public function proxySetup() {
		global $wgHTTPProxy;

		// If there is an explicit proxy set and proxies are not disabled, then use it
		if ( $this->proxy && !$this->noProxy ) {
			return;
		}

		// Otherwise, fallback to $wgHTTPProxy/http_proxy (when set) if this is not a machine
		// local URL and proxies are not disabled
		if ( Http::isLocalURL( $this->url ) || $this->noProxy ) {
			$this->proxy = '';
		} elseif ( $wgHTTPProxy ) {
			$this->proxy = $wgHTTPProxy;
		} elseif ( getenv( "http_proxy" ) ) {
			$this->proxy = getenv( "http_proxy" );
		}
	}

	/**
	 * Set the referrer header
	 */
	public function setReferer( $url ) {
		$this->setHeader( 'Referer', $url );
	}

	/**
	 * Set the user agent
	 * @param $UA string
	 */
	public function setUserAgent( $UA ) {
		$this->setHeader( 'User-Agent', $UA );
	}

	/**
	 * Set an arbitrary header
	 * @param $name
	 * @param $value
	 */
	public function setHeader( $name, $value ) {
		// I feel like I should normalize the case here...
		$this->reqHeaders[$name] = $value;
	}

	/**
	 * Get an array of the headers
	 * @return array
	 */
	public function getHeaderList() {
		$list = array();

		if ( $this->cookieJar ) {
			$this->reqHeaders['Cookie'] =
				$this->cookieJar->serializeToHttpRequest(
					$this->parsedUrl['path'],
					$this->parsedUrl['host']
				);
		}

		foreach ( $this->reqHeaders as $name => $value ) {
			$list[] = "$name: $value";
		}

		return $list;
	}

	/**
	 * Set a read callback to accept data read from the HTTP request.
	 * By default, data is appended to an internal buffer which can be
	 * retrieved through $req->getContent().
	 *
	 * To handle data as it comes in -- especially for large files that
	 * would not fit in memory -- you can instead set your own callback,
	 * in the form function($resource, $buffer) where the first parameter
	 * is the low-level resource being read (implementation specific),
	 * and the second parameter is the data buffer.
	 *
	 * You MUST return the number of bytes handled in the buffer; if fewer
	 * bytes are reported handled than were passed to you, the HTTP fetch
	 * will be aborted.
	 *
	 * @param $callback Callback
	 * @throws MWException
	 */
	public function setCallback( $callback ) {
		if ( !is_callable( $callback ) ) {
			throw new MWException( 'Invalid MwHttpRequest callback' );
		}
		$this->callback = $callback;
	}

	/**
	 * A generic callback to read the body of the response from a remote
	 * server.
	 *
	 * @param $fh handle
	 * @param $content String
	 * @return int
	 */
	public function read( $fh, $content ) {
		$this->content .= $content;
		return strlen( $content );
	}

	/**
	 * Take care of whatever is necessary to perform the URI request.
	 *
	 * @return Status
	 */
	public function execute() {
		global $wgTitle;

		wfProfileIn( __METHOD__ );

		$this->content = "";

		if ( strtoupper( $this->method ) == "HEAD" ) {
			$this->headersOnly = true;
		}

		if ( is_object( $wgTitle ) && !isset( $this->reqHeaders['Referer'] ) ) {
			$this->setReferer( wfExpandUrl( $wgTitle->getFullURL(), PROTO_CURRENT ) );
		}

		$this->proxySetup(); // set up any proxy as needed

		if ( !$this->callback ) {
			$this->setCallback( array( $this, 'read' ) );
		}

		if ( !isset( $this->reqHeaders['User-Agent'] ) ) {
			$this->setUserAgent( Http::userAgent() );
		}

		wfProfileOut( __METHOD__ );
	}

	/**
	 * Parses the headers, including the HTTP status code and any
	 * Set-Cookie headers.  This function expects the headers to be
	 * found in an array in the member variable headerList.
	 */
	protected function parseHeader() {
		wfProfileIn( __METHOD__ );

		$lastname = "";

		foreach ( $this->headerList as $header ) {
			if ( preg_match( "#^HTTP/([0-9.]+) (.*)#", $header, $match ) ) {
				$this->respVersion = $match[1];
				$this->respStatus = $match[2];
			} elseif ( preg_match( "#^[ \t]#", $header ) ) {
				$last = count( $this->respHeaders[$lastname] ) - 1;
				$this->respHeaders[$lastname][$last] .= "\r\n$header";
			} elseif ( preg_match( "#^([^:]*):[\t ]*(.*)#", $header, $match ) ) {
				$this->respHeaders[strtolower( $match[1] )][] = $match[2];
				$lastname = strtolower( $match[1] );
			}
		}

		$this->parseCookies();

		wfProfileOut( __METHOD__ );
	}

	/**
	 * Sets HTTPRequest status member to a fatal value with the error
	 * message if the returned integer value of the status code was
	 * not successful (< 300) or a redirect (>=300 and < 400).  (see
	 * RFC2616, section 10,
	 * http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html for a
	 * list of status codes.)
	 */
	protected function setStatus() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		if ( (int)$this->respStatus > 399 ) {
			list( $code, $message ) = explode( " ", $this->respStatus, 2 );
			$this->status->fatal( "http-bad-status", $code, $message );
		}
	}

	/**
	 * Get the integer value of the HTTP status code (e.g. 200 for "200 Ok")
	 * (see RFC2616, section 10, http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
	 * for a list of status codes.)
	 *
	 * @return Integer
	 */
	public function getStatus() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		return (int)$this->respStatus;
	}

	/**
	 * Returns true if the last status code was a redirect.
	 *
	 * @return Boolean
	 */
	public function isRedirect() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		$status = (int)$this->respStatus;

		if ( $status >= 300 && $status <= 303 ) {
			return true;
		}

		return false;
	}

	/**
	 * Returns an associative array of response headers after the
	 * request has been executed.  Because some headers
	 * (e.g. Set-Cookie) can appear more than once the, each value of
	 * the associative array is an array of the values given.
	 *
	 * @return Array
	 */
	public function getResponseHeaders() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		return $this->respHeaders;
	}

	/**
	 * Returns the value of the given response header.
	 *
	 * @param $header String
	 * @return String
	 */
	public function getResponseHeader( $header ) {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		if ( isset( $this->respHeaders[strtolower( $header )] ) ) {
			$v = $this->respHeaders[strtolower( $header )];
			return $v[count( $v ) - 1];
		}

		return null;
	}

	/**
	 * Tells the MWHttpRequest object to use this pre-loaded CookieJar.
	 *
	 * @param $jar CookieJar
	 */
	public function setCookieJar( $jar ) {
		$this->cookieJar = $jar;
	}

	/**
	 * Returns the cookie jar in use.
	 *
	 * @return CookieJar
	 */
	public function getCookieJar() {
		if ( !$this->respHeaders ) {
			$this->parseHeader();
		}

		return $this->cookieJar;
	}

	/**
	 * Sets a cookie. Used before a request to set up any individual
	 * cookies. Used internally after a request to parse the
	 * Set-Cookie headers.
	 * @see Cookie::set
	 * @param $name
	 * @param $value null
	 * @param $attr null
	 */
	public function setCookie( $name, $value = null, $attr = null ) {
		if ( !$this->cookieJar ) {
			$this->cookieJar = new CookieJar;
		}

		$this->cookieJar->setCookie( $name, $value, $attr );
	}

	/**
	 * Parse the cookies in the response headers and store them in the cookie jar.
	 */
	protected function parseCookies() {
		wfProfileIn( __METHOD__ );

		if ( !$this->cookieJar ) {
			$this->cookieJar = new CookieJar;
		}

		if ( isset( $this->respHeaders['set-cookie'] ) ) {
			$url = parse_url( $this->getFinalUrl() );
			foreach ( $this->respHeaders['set-cookie'] as $cookie ) {
				$this->cookieJar->parseCookieResponseHeader( $cookie, $url['host'] );
			}
		}

		wfProfileOut( __METHOD__ );
	}

	/**
	 * Returns the final URL after all redirections.
	 *
	 * Relative values of the "Location" header are incorrect as stated in RFC, however they do happen and modern browsers support them.
	 * This function loops backwards through all locations in order to build the proper absolute URI - Marooned at wikia-inc.com
	 *
	 * Note that the multiple Location: headers are an artifact of CURL -- they
	 * shouldn't actually get returned this way. Rewrite this when bug 29232 is
	 * taken care of (high-level redirect handling rewrite).
	 *
	 * @return string
	 */
	public function getFinalUrl() {
		$headers = $this->getResponseHeaders();

		//return full url (fix for incorrect but handled relative location)
		if ( isset( $headers['location'] ) ) {
			$locations = $headers['location'];
			$domain = '';
			$foundRelativeURI = false;
			$countLocations = count( $locations );

			for ( $i = $countLocations - 1; $i >= 0; $i-- ) {
				$url = parse_url( $locations[$i] );

				if ( isset( $url['host'] ) ) {
					$domain = $url['scheme'] . '://' . $url['host'];
					break; //found correct URI (with host)
				} else {
					$foundRelativeURI = true;
				}
			}

			if ( $foundRelativeURI ) {
				if ( $domain ) {
					return $domain . $locations[$countLocations - 1];
				} else {
					$url = parse_url( $this->url );
					if ( isset( $url['host'] ) ) {
						return $url['scheme'] . '://' . $url['host'] . $locations[$countLocations - 1];
					}
				}
			} else {
				return $locations[$countLocations - 1];
			}
		}

		return $this->url;
	}

	/**
	 * Returns true if the backend can follow redirects. Overridden by the
	 * child classes.
	 * @return bool
	 */
	public function canFollowRedirects() {
		return true;
	}
}

/**
 * MWHttpRequest implemented using internal curl compiled into PHP
 */
class CurlHttpRequest extends MWHttpRequest {
	const SUPPORTS_FILE_POSTS = true;

	protected $curlOptions = array();
	protected $headerText = "";

	/**
	 * @param $fh
	 * @param $content
	 * @return int
	 */
	protected function readHeader( $fh, $content ) {
		$this->headerText .= $content;
		return strlen( $content );
	}

	public function execute() {
		wfProfileIn( __METHOD__ );

		parent::execute();

		if ( !$this->status->isOK() ) {
			wfProfileOut( __METHOD__ );
			return $this->status;
		}

		$this->curlOptions[CURLOPT_PROXY] = $this->proxy;
		$this->curlOptions[CURLOPT_TIMEOUT] = $this->timeout;

		// Only supported in curl >= 7.16.2
		if ( defined( 'CURLOPT_CONNECTTIMEOUT_MS' ) ) {
			$this->curlOptions[CURLOPT_CONNECTTIMEOUT_MS] = $this->connectTimeout * 1000;
		}

		$this->curlOptions[CURLOPT_HTTP_VERSION] = CURL_HTTP_VERSION_1_0;
		$this->curlOptions[CURLOPT_WRITEFUNCTION] = $this->callback;
		$this->curlOptions[CURLOPT_HEADERFUNCTION] = array( $this, "readHeader" );
		$this->curlOptions[CURLOPT_MAXREDIRS] = $this->maxRedirects;
		$this->curlOptions[CURLOPT_ENCODING] = ""; # Enable compression

		/* not sure these two are actually necessary */
		if ( isset( $this->reqHeaders['Referer'] ) ) {
			$this->curlOptions[CURLOPT_REFERER] = $this->reqHeaders['Referer'];
		}
		$this->curlOptions[CURLOPT_USERAGENT] = $this->reqHeaders['User-Agent'];

		$this->curlOptions[CURLOPT_SSL_VERIFYHOST] = $this->sslVerifyHost ? 2 : 0;
		$this->curlOptions[CURLOPT_SSL_VERIFYPEER] = $this->sslVerifyCert;

		if ( $this->caInfo ) {
			$this->curlOptions[CURLOPT_CAINFO] = $this->caInfo;
		}

		if ( $this->headersOnly ) {
			$this->curlOptions[CURLOPT_NOBODY] = true;
			$this->curlOptions[CURLOPT_HEADER] = true;
		} elseif ( $this->method == 'POST' ) {
			$this->curlOptions[CURLOPT_POST] = true;
			$this->curlOptions[CURLOPT_POSTFIELDS] = $this->postData;
			// Suppress 'Expect: 100-continue' header, as some servers
			// will reject it with a 417 and Curl won't auto retry
			// with HTTP 1.0 fallback
			$this->reqHeaders['Expect'] = '';
		} else {
			$this->curlOptions[CURLOPT_CUSTOMREQUEST] = $this->method;
		}

		$this->curlOptions[CURLOPT_HTTPHEADER] = $this->getHeaderList();

		$curlHandle = curl_init( $this->url );

		if ( !curl_setopt_array( $curlHandle, $this->curlOptions ) ) {
			wfProfileOut( __METHOD__ );
			throw new MWException( "Error setting curl options." );
		}

		if ( $this->followRedirects && $this->canFollowRedirects() ) {
			wfSuppressWarnings();
			if ( ! curl_setopt( $curlHandle, CURLOPT_FOLLOWLOCATION, true ) ) {
				wfDebug( __METHOD__ . ": Couldn't set CURLOPT_FOLLOWLOCATION. " .
					"Probably safe_mode or open_basedir is set.\n" );
				// Continue the processing. If it were in curl_setopt_array,
				// processing would have halted on its entry
			}
			wfRestoreWarnings();
		}

		$curlRes = curl_exec( $curlHandle );
		if ( curl_errno( $curlHandle ) == CURLE_OPERATION_TIMEOUTED ) {
			$this->status->fatal( 'http-timed-out', $this->url );
		} elseif ( $curlRes === false ) {
			$this->status->fatal( 'http-curl-error', curl_error( $curlHandle ) );
		} else {
			$this->headerList = explode( "\r\n", $this->headerText );
		}

		curl_close( $curlHandle );

		$this->parseHeader();
		$this->setStatus();

		wfProfileOut( __METHOD__ );

		return $this->status;
	}

	/**
	 * @return bool
	 */
	public function canFollowRedirects() {
		if ( strval( ini_get( 'open_basedir' ) ) !== '' || wfIniGetBool( 'safe_mode' ) ) {
			wfDebug( "Cannot follow redirects in safe mode\n" );
			return false;
		}

		if ( !defined( 'CURLOPT_REDIR_PROTOCOLS' ) ) {
			wfDebug( "Cannot follow redirects with libcurl < 7.19.4 due to CVE-2009-0037\n" );
			return false;
		}

		return true;
	}
}

class PhpHttpRequest extends MWHttpRequest {

	/**
	 * @param $url string
	 * @return string
	 */
	protected function urlToTcp( $url ) {
		$parsedUrl = parse_url( $url );

		return 'tcp://' . $parsedUrl['host'] . ':' . $parsedUrl['port'];
	}

	public function execute() {
		wfProfileIn( __METHOD__ );

		parent::execute();

		if ( is_array( $this->postData ) ) {
			$this->postData = wfArrayToCgi( $this->postData );
		}

		if ( $this->parsedUrl['scheme'] != 'http' &&
			 $this->parsedUrl['scheme'] != 'https' ) {
			$this->status->fatal( 'http-invalid-scheme', $this->parsedUrl['scheme'] );
		}

		$this->reqHeaders['Accept'] = "*/*";
		if ( $this->method == 'POST' ) {
			// Required for HTTP 1.0 POSTs
			$this->reqHeaders['Content-Length'] = strlen( $this->postData );
			if ( !isset( $this->reqHeaders['Content-Type'] ) ) {
				$this->reqHeaders['Content-Type'] = "application/x-www-form-urlencoded";
			}
		}

		$options = array();
		if ( $this->proxy ) {
			$options['proxy'] = $this->urlToTCP( $this->proxy );
			$options['request_fulluri'] = true;
		}

		if ( !$this->followRedirects ) {
			$options['max_redirects'] = 0;
		} else {
			$options['max_redirects'] = $this->maxRedirects;
		}

		$options['method'] = $this->method;
		$options['header'] = implode( "\r\n", $this->getHeaderList() );
		// Note that at some future point we may want to support
		// HTTP/1.1, but we'd have to write support for chunking
		// in version of PHP < 5.3.1
		$options['protocol_version'] = "1.0";

		// This is how we tell PHP we want to deal with 404s (for example) ourselves.
		// Only works on 5.2.10+
		$options['ignore_errors'] = true;

		if ( $this->postData ) {
			$options['content'] = $this->postData;
		}

		$options['timeout'] = $this->timeout;

		if ( $this->sslVerifyHost ) {
			$options['CN_match'] = $this->parsedUrl['host'];
		}
		if ( $this->sslVerifyCert ) {
			$options['verify_peer'] = true;
		}

		if ( is_dir( $this->caInfo ) ) {
			$options['capath'] = $this->caInfo;
		} elseif ( is_file( $this->caInfo ) ) {
			$options['cafile'] = $this->caInfo;
		} elseif ( $this->caInfo ) {
			throw new MWException( "Invalid CA info passed: {$this->caInfo}" );
		}

		$scheme = $this->parsedUrl['scheme'];
		$context = stream_context_create( array( "$scheme" => $options ) );

		$this->headerList = array();
		$reqCount = 0;
		$url = $this->url;

		$result = array();

		do {
			$reqCount++;
			wfSuppressWarnings();
			$fh = fopen( $url, "r", false, $context );
			wfRestoreWarnings();

			if ( !$fh ) {
				break;
			}

			$result = stream_get_meta_data( $fh );
			$this->headerList = $result['wrapper_data'];
			$this->parseHeader();

			if ( !$this->followRedirects ) {
				break;
			}

			# Handle manual redirection
			if ( !$this->isRedirect() || $reqCount > $this->maxRedirects ) {
				break;
			}
			# Check security of URL
			$url = $this->getResponseHeader( "Location" );

			if ( !Http::isValidURI( $url ) ) {
				wfDebug( __METHOD__ . ": insecure redirection\n" );
				break;
			}
		} while ( true );

		$this->setStatus();

		if ( $fh === false ) {
			$this->status->fatal( 'http-request-error' );
			wfProfileOut( __METHOD__ );
			return $this->status;
		}

		if ( $result['timed_out'] ) {
			$this->status->fatal( 'http-timed-out', $this->url );
			wfProfileOut( __METHOD__ );
			return $this->status;
		}

		// If everything went OK, or we received some error code
		// get the response body content.
		if ( $this->status->isOK() || (int)$this->respStatus >= 300 ) {
			while ( !feof( $fh ) ) {
				$buf = fread( $fh, 8192 );

				if ( $buf === false ) {
					$this->status->fatal( 'http-read-error' );
					break;
				}

				if ( strlen( $buf ) ) {
					call_user_func( $this->callback, $fh, $buf );
				}
			}
		}
		fclose( $fh );

		wfProfileOut( __METHOD__ );

		return $this->status;
	}
}