<?php
/*
 * Gallery - a web based photo album viewer and editor
 * Copyright (C) 2000-2008 Bharat Mediratta
 *
 * 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.
 */

/**
 * A collection of useful web-page post/get related utilities
 * @package GalleryCore
 * @subpackage Helpers
 * @author Bharat Mediratta <bharat@menalto.com>
 * @version $Revision: 17580 $
 * @static
 */
class WebHelper_simple {

    /**
     * @see GalleryCoreApi::fetchWebFile
     *
     * @todo We should probably be checking the data we get back against the HTTP Content-Length
     *       header to verify that we got all the data we expected.
     *
     */
    function fetchWebFile($url, $outputFile, $extraHeaders=array(), $postDataArray=array(),
	    $depth=0) {
	global $gallery;

	/* Convert illegal characters */
	$url = str_replace(' ', '%20', $url);

	/* Don't redirect too far */
	if ($depth > 5) {
	    $gallery->debug('Too many levels of HTTP redirection!');
	    return array(false, null, null, null);
	}

	$urlComponents = WebHelper_simple::_parseUrlForFsockopen($url);
	$platform =& $gallery->getPlatform();
	$fd = @$platform->fsockopen(
		$urlComponents['fsockhost'], $urlComponents['port'], $errno, $errstr, 5);
	if (empty($fd)) {
	    $gallery->debug("Error $errno: '$errstr' retrieving $url");
	    return array(false, null, null, null);
	}

	$requestMethod = 'GET';
	$postDataRaw = '';
	if (!empty($postDataArray)) {
	    $requestMethod = 'POST';
	    $postDataRaw = WebHelper_simple::_encodePostData($postDataArray, $extraHeaders);
	}

	$headerLines = array('Host: ' . $urlComponents['host']);
	foreach ($extraHeaders as $headerKey => $headerValue) {
	    $headerLines[] = "$headerKey: $headerValue";
	}

	$ok = $platform->fwrite($fd, sprintf("%s %s HTTP/1.0\r\n%s\r\n\r\n%s",
					     $requestMethod,
					     $urlComponents['uri'],
					     implode("\r\n", $headerLines),
					     $postDataRaw));
	if (!$ok) {
	    /* Zero bytes written or false was returned */
	    $gallery->debug(
		"fwrite call failed in fetchWebFile($url)" . ($ok === false ? ' - false' : ''));
	    return array(false, null, null, null);
	}
	$platform->fflush($fd);

	/*
	 * Read the response code. fgets stops after newlines.
	 * The first line contains only the status code (200, 404, etc.).
	 */
	$headers = array();
	$response = trim($platform->fgets($fd, 4096));
	if (empty($response)) {
	    $gallery->debug('Empty http response code, maybe timeout');
	    return array(false, null, null, null);
	}

	/* Read the headers. */
	while (!$platform->feof($fd)) {
	    $line = trim($platform->fgets($fd, 4096));
	    if (empty($line)) {
		break;
	    }

	    /* Normalize the line endings */
	    $line = str_replace("\r", '', $line);

	    list ($key, $value) = explode(':', $line, 2);
	    if (isset($headers[$key])) {
		if (!is_array($headers[$key])) {
		    $headers[$key] = array($headers[$key]);
		}
		$headers[$key][] = trim($value);
	    } else {
		$headers[$key] = trim($value);
	    }
	}

	if (isset($headers['Location'])) {
	    $redirectUrl = WebHelper_simple::_parseLocation($headers['Location'], $urlComponents);

	    /* Returning output directly from fetchWebFile() confuses the CodeAudit */
	    $result = WebHelper_simple::fetchWebFile($redirectUrl, $outputFile, $extraHeaders,
		$postDataArray, $depth+1);
	    return array($result[0], $result[1], $result[2], $result[3]);
	}

	$success = false;
	$ofd = $platform->fopen($outputFile, 'wb');
	if ($ofd) {
	    /* Read the body */
	    $failed = false;
	    while (!$platform->feof($fd) && !$failed) {
		$buf = $platform->fread($fd, 4096);
		if ($platform->fwrite($ofd, $buf) != strlen($buf)) {
		    $failed = true;
		    break;
		}
	    }
	    $platform->fclose($ofd);
	    if (!$failed) {
		$success = true;
	    }
	}
	$platform->fclose($fd);

	/* if the HTTP response code did not begin with a 2 this request was not successful */
	if (!preg_match("/^HTTP\/\d+\.\d+\s2\d{2}/", $response)) {
	    $success = false;
	}

	return array($success, $response, $headers, $url);
    }

    /**
     * @see GalleryCoreApi::fetchWebPage
     */
    function fetchWebPage($url, $extraHeaders=array(), $depth=0) {
	global $gallery;

	/* Don't redirect too far */
	if ($depth > 5) {
	    $gallery->debug('Too many levels of HTTP redirection!');
	    return array(false, null, null, null, null);
	}

	/* Convert illegal characters */
	$url = str_replace(' ', '%20', $url);

	/* Unescape ampersands, since if the URL comes from form input it will be escaped */
	$url = str_replace('&amp;', '&', $url);

	/* Read the web page into a buffer */
	list ($responseStatus, $responseHeaders, $responseBody) =
	    WebHelper_simple::requestWebPage($url, 'GET', $extraHeaders);

	if (isset($responseHeaders['Location'])) {
	    $redirectUrl =
		WebHelper_simple::_parseLocation($responseHeaders['Location'], parse_url($url));

	    /* Returning output directly from fetchWebPage confuses the CodeAudit */
	    $result = WebHelper_simple::fetchWebPage($redirectUrl, $extraHeaders, $depth + 1);
	    return array($result[0], $result[1], $result[2], $result[3], $result[4]);
	}

	/* If the HTTP response code did not begin with 2 this request was not successful */
	$success = preg_match("/^HTTP\/\d+\.\d+\s2\d{2}/", $responseStatus);

	return array($success, $responseBody, $responseStatus, $responseHeaders, $url);
    }

    /**
     * @see GalleryCoreApi::postToWebPage
     */
    function postToWebPage($url, $postDataArray, $extraHeaders=array()) {
	$postDataRaw = WebHelper_simple::_encodePostData($postDataArray, $extraHeaders);

	/* Read the web page into a buffer */
	list ($responseStatus, $responseHeaders, $responseBody) =
	    WebHelper_simple::requestWebPage($url, 'POST', $extraHeaders, $postDataRaw);

	return array($responseBody, $responseStatus, $responseHeaders);
    }

    /**
     * Encode the post data.  For each key/value pair, urlencode both the key and the value and then
     * concatenate together.  As per the specification, each key/value pair is separated with an
     * ampersand (&)
     * @param array $postDataArray the key/value post data
     * @param array $extraHeaders extra headers to pass to the server
     * @return string the encoded post data
     */
    function _encodePostData($postDataArray, &$extraHeaders) {
	$postDataRaw = '';
	foreach ($postDataArray as $key => $value) {
	    if (!empty($postDataRaw)) {
		$postDataRaw .= '&';
	    }
	    $postDataRaw .= urlencode($key) . '=' . urlencode($value);
	}

	$extraHeaders['Content-Type'] = 'application/x-www-form-urlencoded';
	$extraHeaders['Content-Length'] = strlen($postDataRaw);

	return $postDataRaw;
    }

    /**
     * @see GalleryCoreApi::requestWebPage
     */
    function requestWebPage($url, $requestMethod='GET', $requestHeaders=array(), $requestBody='') {
	global $gallery;
	$platform =& $gallery->getPlatform();

	/* Convert illegal characters */
	$url = str_replace(' ', '%20', $url);

	$urlComponents = WebHelper_simple::_parseUrlForFsockopen($url);
	$handle = @$platform->fsockopen(
	    $urlComponents['fsockhost'], $urlComponents['port'], $errno, $errstr, 5);
	if (empty($handle)) {
	    $gallery->debug("Error $errno: '$errstr' requesting $url");
	    return array(null, null, null);
	}

	$headerLines = array('Host: ' . $urlComponents['host']);
	foreach ($requestHeaders as $key => $value) {
	    $headerLines[] = $key . ': ' . $value;
	}

	$success = $platform->fwrite($handle, sprintf("%s %s HTTP/1.0\r\n%s\r\n\r\n%s",
						      $requestMethod,
						      $urlComponents['uri'],
						      implode("\r\n", $headerLines),
						      $requestBody));
	if (!$success) {
	    /* Zero bytes written or false was returned */
	    $gallery->debug(
		"fwrite failed in requestWebPage($url)" . ($success === false ? ' - false' : ''));
	    return array(null, null, null);
	}
	$platform->fflush($handle);

	/*
	 * Read the status line.  fgets stops after newlines.  The first line is the protocol
	 * version followed by a numeric status code and its associated textual phrase.
	 */
	$responseStatus = trim($platform->fgets($handle, 4096));
	if (empty($responseStatus)) {
	    $gallery->debug('Empty http response code, maybe timeout');
	    return array(null, null, null);
	}

	/* Read the headers */
	$responseHeaders = array();
	while (!$platform->feof($handle)) {
	    $line = trim($platform->fgets($handle, 4096));
	    if (empty($line)) {
		break;
	    }

	    /* Normalize the line endings */
	    $line = str_replace("\r", '', $line);

	    list ($key, $value) = explode(':', $line, 2);
	    if (isset($responseHeaders[$key])) {
		if (!is_array($responseHeaders[$key])) {
		    $responseHeaders[$key] = array($responseHeaders[$key]);
		}
		$responseHeaders[$key][] = trim($value);
	    } else {
		$responseHeaders[$key] = trim($value);
	    }
	}

	/* Read the body */
	$responseBody = '';
	while (!$platform->feof($handle)) {
	    $responseBody .= $platform->fread($handle, 4096);
	}
	$platform->fclose($handle);

	return array($responseStatus, $responseHeaders, $responseBody);
    }

    /**
     * Prepare for fsockopen call.
     * @param string $url
     * @return array url components
     * @access private
     */
    function _parseUrlForFsockopen($url) {
	$urlComponents = parse_url($url);
	if (GalleryUtilities::strToLower($urlComponents['scheme']) == 'https') {
	    $urlComponents['fsockhost'] = 'ssl://' . $urlComponents['host'];
	    $defaultPort = 443;
	} else {
	    $urlComponents['fsockhost'] = $urlComponents['host'];
	    $defaultPort = 80;
	}
	if (empty($urlComponents['port'])) {
	    $urlComponents['port'] = $defaultPort;
	}
	if (empty($urlComponents['path'])) {
	    $urlComponents['path'] = '/';
	}
	$uri = $urlComponents['path']
	    . (empty($urlComponents['query']) ? '' : '?' . $urlComponents['query']);
	/* Unescape ampersands, since if the url comes from form input it will be escaped */
	$urlComponents['uri'] = str_replace('&amp;', '&', $uri);
	return $urlComponents;
    }

    /**
     * Prepare to follow redirect URL.
     * @param string $location
     * @param array $fromComponents context we're redirecting from
     * @param string redirect URL
     */
    function _parseLocation($location, $fromComponents) {
	if (is_array($location)) {
	    /* If odd http response has multiple Location headers just pick the first */
	    $location = array_shift($location);
	}

	/* The redirect url is supposed to be absolute, but not everybody plays by the rules */
	$components = parse_url($location);
	foreach (array('scheme', 'host') as $key) {
	    if (empty($components[$key])) {
		$components[$key] = $fromComponents[$key];
		if ($key == 'host' && empty($components['port'])
			&& !empty($fromComponents['port'])) {
		    $components['port'] = $fromComponents['port'];
		}
	    }
	}

	$port = empty($components['port']) ? '' : ':' . $components['port'];
	$query = empty($components['query']) ? '' : '?' . $components['query'];

	return sprintf('%s://%s%s%s%s',
		$components['scheme'], $components['host'], $port, $components['path'], $query);
    }
}
?>