Merge "Add ss_active_users in SiteStats::isSane"

[mediawiki.git] / 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
         *    - postData            An array of key-value pairs or a url-encoded form data
         *    - proxy               The proxy to use.
         *                          Otherwise it will use $wgHTTPProxy (if set)
         *                          Otherwise it will use the environment variable "http_proxy" (if set)
         *    - noProxy             Don't use any proxy at all. Takes precedence over proxy value(s).
         *    - sslVerifyHost       (curl only) Verify hostname against certificate
         *    - sslVerifyCert       (curl only) Verify SSL certificate
         *    - caInfo              (curl only) Provide CA information
         *    - maxRedirects        Maximum number of redirects to follow (defaults to 5)
         *    - followRedirects     Whether to follow redirects (defaults to false).
         *                                  Note: this should only be used when the target URL is trusted,
         *                                  to avoid attacks on intranet services accessible by HTTP.
         *    - userAgent           A user agent, if you want to override the default
         *                          MediaWiki/$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';
                }

                $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;

                $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['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;
                $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;

                $context = stream_context_create( array( 'http' => $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;
        }
}