userAgentDefault = self::UA_BROWSER;
$this->referer = self::REF_GOOGLE;
// set the request method
if (in_array($method, array(1,2,4))) {
$this->method = $method;
} else {
if (class_exists('HttpRequestPool')) {
$this->method = self::METHOD_REQUEST_POOL;
} elseif (function_exists('curl_multi_init')) {
$this->method = self::METHOD_CURL_MULTI;
} else {
$this->method = self::METHOD_FILE_GET_CONTENTS;
}
}
if ($this->method == self::METHOD_CURL_MULTI) {
require_once(dirname(__FILE__).'/RollingCurl.php');
}
// create cookie jar
$this->cookieJar = new CookieJar();
// set request options (redirect must be 0)
$this->requestOptions = array(
'timeout' => 15,
'redirect' => 0 // we handle redirects manually so we can rewrite the new hashbang URLs that are creeping up over the web
// TODO: test onprogress?
);
if (is_array($requestOptions)) {
$this->requestOptions = array_merge($this->requestOptions, $requestOptions);
}
$this->httpContext = array(
'http' => array(
'ignore_errors' => true,
'timeout' => $this->requestOptions['timeout'],
'max_redirects' => $this->requestOptions['redirect'],
'header' => "Accept: */*\r\n"
)
);
}
protected function debug($msg) {
if ($this->debug) {
$mem = round(memory_get_usage()/1024, 2);
$memPeak = round(memory_get_peak_usage()/1024, 2);
echo '* ',$msg;
if ($this->debugVerbose) echo ' - mem used: ',$mem," (peak: $memPeak)";
echo "\n";
ob_flush();
flush();
}
}
protected function getUserAgent($url, $asArray=false) {
$host = @parse_url($url, PHP_URL_HOST);
if (strtolower(substr($host, 0, 4)) == 'www.') {
$host = substr($host, 4);
}
if ($host) {
$try = array($host);
$split = explode('.', $host);
if (count($split) > 1) {
array_shift($split);
$try[] = '.'.implode('.', $split);
}
foreach ($try as $h) {
if (isset($this->userAgentMap[$h])) {
$ua = $this->userAgentMap[$h];
break;
}
}
}
if (!isset($ua)) $ua = $this->userAgentDefault;
if ($asArray) {
return array('User-Agent' => $ua);
} else {
return 'User-Agent: '.$ua;
}
}
public function rewriteHashbangFragment($url) {
// return $url if there's no '#!'
if (strpos($url, '#!') === false) return $url;
// split $url and rewrite
// TODO: is SimplePie_IRI included?
$iri = new SimplePie_IRI($url);
$fragment = substr($iri->fragment, 1); // strip '!'
$iri->fragment = null;
if (isset($iri->query)) {
parse_str($iri->query, $query);
} else {
$query = array();
}
$query['_escaped_fragment_'] = (string)$fragment;
$iri->query = str_replace('%2F', '/', http_build_query($query)); // needed for some sites
return $iri->get_iri();
}
public function getUglyURL($url, $html) {
if ($html == '') return false;
$found = false;
foreach ($this->ajaxTriggers as $string) {
if (stripos($html, $string)) {
$found = true;
break;
}
}
if (!$found) return false;
$iri = new SimplePie_IRI($url);
if (isset($iri->query)) {
parse_str($iri->query, $query);
} else {
$query = array();
}
$query['_escaped_fragment_'] = '';
$iri->query = str_replace('%2F', '/', http_build_query($query)); // needed for some sites
return $iri->get_iri();
}
public function removeFragment($url) {
$pos = strpos($url, '#');
if ($pos === false) {
return $url;
} else {
return substr($url, 0, $pos);
}
}
public function rewriteUrls($url) {
foreach ($this->rewriteUrls as $find => $action) {
if (strpos($url, $find) !== false) {
if (is_array($action)) {
return strtr($url, $action);
}
}
}
return $url;
}
public function enableDebug($bool=true) {
$this->debug = (bool)$bool;
}
public function minimiseMemoryUse($bool = true) {
$this->minimiseMemoryUse = $bool;
}
public function setMaxParallelRequests($max) {
$this->maxParallelRequests = $max;
}
public function validateUrl($url) {
$url = filter_var($url, FILTER_SANITIZE_URL);
$test = filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED);
// deal with bug http://bugs.php.net/51192 (present in PHP 5.2.13 and PHP 5.3.2)
if ($test === false) {
$test = filter_var(strtr($url, '-', '_'), FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED);
}
if ($test !== false && $test !== null && preg_match('!^https?://!', $url)) {
return $url;
} else {
return false;
}
}
public function fetchAll(array $urls) {
$this->fetchAllOnce($urls, $isRedirect=false);
$redirects = 0;
while (!empty($this->redirectQueue) && ++$redirects <= $this->maxRedirects) {
$this->debug("Following redirects #$redirects...");
$this->fetchAllOnce($this->redirectQueue, $isRedirect=true);
}
}
// fetch all URLs without following redirects
public function fetchAllOnce(array $urls, $isRedirect=false) {
if (!$isRedirect) $urls = array_unique($urls);
if (empty($urls)) return;
//////////////////////////////////////////////////////
// parallel (HttpRequestPool)
if ($this->method == self::METHOD_REQUEST_POOL) {
$this->debug('Starting parallel fetch (HttpRequestPool)');
try {
while (count($urls) > 0) {
$this->debug('Processing set of '.min($this->maxParallelRequests, count($urls)));
$subset = array_splice($urls, 0, $this->maxParallelRequests);
$pool = new HttpRequestPool();
foreach ($subset as $orig => $url) {
if (!$isRedirect) $orig = $url;
unset($this->redirectQueue[$orig]);
$this->debug("...$url");
if (!$isRedirect && isset($this->requests[$url])) {
$this->debug("......in memory");
/*
} elseif ($this->isCached($url)) {
$this->debug("......is cached");
if (!$this->minimiseMemoryUse) {
$this->requests[$url] = $this->getCached($url);
}
*/
} else {
$this->debug("......adding to pool");
$req_url = $this->rewriteUrls($url);
$req_url = ($this->rewriteHashbangFragment) ? $this->rewriteHashbangFragment($req_url) : $req_url;
$req_url = $this->removeFragment($req_url);
if (!empty($this->headerOnlyTypes) && !isset($this->requests[$orig]['wrongGuess']) && $this->possibleUnsupportedType($req_url)) {
$_meth = HttpRequest::METH_HEAD;
} else {
$_meth = HttpRequest::METH_GET;
unset($this->requests[$orig]['wrongGuess']);
}
$httpRequest = new HttpRequest($req_url, $_meth, $this->requestOptions);
// send cookies, if we have any
if ($cookies = $this->cookieJar->getMatchingCookies($req_url)) {
$this->debug("......sending cookies: $cookies");
$httpRequest->addHeaders(array('Cookie' => $cookies));
}
//$httpRequest->addHeaders(array('User-Agent' => $this->userAgent));
$httpRequest->addHeaders($this->getUserAgent($req_url, true));
// add referer for picky sites
$httpRequest->addheaders(array('Referer' => $this->referer));
$this->requests[$orig] = array('headers'=>null, 'body'=>null, 'httpRequest'=>$httpRequest);
$this->requests[$orig]['original_url'] = $orig;
$pool->attach($httpRequest);
}
}
// did we get anything into the pool?
if (count($pool) > 0) {
$this->debug('Sending request...');
try {
$pool->send();
} catch (HttpRequestPoolException $e) {
// do nothing
}
$this->debug('Received responses');
foreach($subset as $orig => $url) {
if (!$isRedirect) $orig = $url;
$request = $this->requests[$orig]['httpRequest'];
//$this->requests[$orig]['headers'] = $this->headersToString($request->getResponseHeader());
// getResponseHeader() doesn't return status line, so, for consistency...
$this->requests[$orig]['headers'] = substr($request->getRawResponseMessage(), 0, $request->getResponseInfo('header_size'));
// check content type
// TODO: use getResponseHeader('content-type') or getResponseInfo()
if ($this->headerOnlyType($this->requests[$orig]['headers'])) {
$this->requests[$orig]['body'] = '';
$_header_only_type = true;
$this->debug('Header only type returned');
} else {
$this->requests[$orig]['body'] = $request->getResponseBody();
$_header_only_type = false;
}
$this->requests[$orig]['effective_url'] = $request->getResponseInfo('effective_url');
$this->requests[$orig]['status_code'] = $status_code = $request->getResponseCode();
// is redirect?
if ((in_array($status_code, array(300, 301, 302, 303, 307)) || $status_code > 307 && $status_code < 400) && $request->getResponseHeader('location')) {
$redirectURL = $request->getResponseHeader('location');
if (!preg_match('!^https?://!i', $redirectURL)) {
$redirectURL = SimplePie_Misc::absolutize_url($redirectURL, $url);
}
if ($this->validateURL($redirectURL)) {
$this->debug('Redirect detected. Valid URL: '.$redirectURL);
// store any cookies
$cookies = $request->getResponseHeader('set-cookie');
if ($cookies && !is_array($cookies)) $cookies = array($cookies);
if ($cookies) $this->cookieJar->storeCookies($url, $cookies);
$this->redirectQueue[$orig] = $redirectURL;
} else {
$this->debug('Redirect detected. Invalid URL: '.$redirectURL);
}
} elseif (!$_header_only_type && $request->getMethod() === HttpRequest::METH_HEAD) {
// the response content-type did not match our 'header only' types,
// but we'd issues a HEAD request because we assumed it would. So
// let's queue a proper GET request for this item...
$this->debug('Wrong guess at content-type, queing GET request');
$this->requests[$orig]['wrongGuess'] = true;
$this->redirectQueue[$orig] = $this->requests[$orig]['effective_url'];
} elseif (strpos($this->requests[$orig]['effective_url'], '_escaped_fragment_') === false) {
// check for
// for AJAX sites, e.g. Blogger with its dynamic views templates.
// Based on Google's spec: https://developers.google.com/webmasters/ajax-crawling/docs/specification
if (isset($this->requests[$orig]['body'])) {
$redirectURL = $this->getUglyURL($this->requests[$orig]['effective_url'], substr($this->requests[$orig]['body'], 0, 4000));
if ($redirectURL) {
$this->debug('AJAX trigger (meta name="fragment" content="!") found. Queueing '.$redirectURL);
$this->redirectQueue[$orig] = $redirectURL;
}
}
}
//die($url.' -multi- '.$request->getResponseInfo('effective_url'));
$pool->detach($request);
unset($this->requests[$orig]['httpRequest'], $request);
/*
if ($this->minimiseMemoryUse) {
if ($this->cache($url)) {
unset($this->requests[$url]);
}
}
*/
}
}
}
} catch (HttpException $e) {
$this->debug($e);
return false;
}
}
//////////////////////////////////////////////////////////
// parallel (curl_multi_*)
elseif ($this->method == self::METHOD_CURL_MULTI) {
$this->debug('Starting parallel fetch (curl_multi_*)');
while (count($urls) > 0) {
$this->debug('Processing set of '.min($this->maxParallelRequests, count($urls)));
$subset = array_splice($urls, 0, $this->maxParallelRequests);
$pool = new RollingCurl(array($this, 'handleCurlResponse'));
$pool->window_size = count($subset);
foreach ($subset as $orig => $url) {
if (!$isRedirect) $orig = $url;
unset($this->redirectQueue[$orig]);
$this->debug("...$url");
if (!$isRedirect && isset($this->requests[$url])) {
$this->debug("......in memory");
/*
} elseif ($this->isCached($url)) {
$this->debug("......is cached");
if (!$this->minimiseMemoryUse) {
$this->requests[$url] = $this->getCached($url);
}
*/
} else {
$this->debug("......adding to pool");
$req_url = $this->rewriteUrls($url);
$req_url = ($this->rewriteHashbangFragment) ? $this->rewriteHashbangFragment($req_url) : $req_url;
$req_url = $this->removeFragment($req_url);
if (!empty($this->headerOnlyTypes) && !isset($this->requests[$orig]['wrongGuess']) && $this->possibleUnsupportedType($req_url)) {
$_meth = 'HEAD';
} else {
$_meth = 'GET';
unset($this->requests[$orig]['wrongGuess']);
}
$headers = array();
//$headers[] = 'User-Agent: '.$this->userAgent;
$headers[] = $this->getUserAgent($req_url);
// add referer for picky sites
$headers[] = 'Referer: '.$this->referer;
// send cookies, if we have any
if ($cookies = $this->cookieJar->getMatchingCookies($req_url)) {
$this->debug("......sending cookies: $cookies");
$headers[] = 'Cookie: '.$cookies;
}
$httpRequest = new RollingCurlRequest($req_url, $_meth, null, $headers, array(
CURLOPT_CONNECTTIMEOUT => $this->requestOptions['timeout'],
CURLOPT_TIMEOUT => $this->requestOptions['timeout']
));
$httpRequest->set_original_url($orig);
$this->requests[$orig] = array('headers'=>null, 'body'=>null, 'httpRequest'=>$httpRequest);
$this->requests[$orig]['original_url'] = $orig; // TODO: is this needed anymore?
$pool->add($httpRequest);
}
}
// did we get anything into the pool?
if (count($pool) > 0) {
$this->debug('Sending request...');
$pool->execute(); // this will call handleCurlResponse() and populate $this->requests[$orig]
$this->debug('Received responses');
foreach($subset as $orig => $url) {
if (!$isRedirect) $orig = $url;
// $this->requests[$orig]['headers']
// $this->requests[$orig]['body']
// $this->requests[$orig]['effective_url']
// check content type
if ($this->headerOnlyType($this->requests[$orig]['headers'])) {
$this->requests[$orig]['body'] = '';
$_header_only_type = true;
$this->debug('Header only type returned');
} else {
$_header_only_type = false;
}
$status_code = $this->requests[$orig]['status_code'];
if ((in_array($status_code, array(300, 301, 302, 303, 307)) || $status_code > 307 && $status_code < 400) && isset($this->requests[$orig]['location'])) {
$redirectURL = $this->requests[$orig]['location'];
if (!preg_match('!^https?://!i', $redirectURL)) {
$redirectURL = SimplePie_Misc::absolutize_url($redirectURL, $url);
}
if ($this->validateURL($redirectURL)) {
$this->debug('Redirect detected. Valid URL: '.$redirectURL);
// store any cookies
$cookies = $this->cookieJar->extractCookies($this->requests[$orig]['headers']);
if (!empty($cookies)) $this->cookieJar->storeCookies($url, $cookies);
$this->redirectQueue[$orig] = $redirectURL;
} else {
$this->debug('Redirect detected. Invalid URL: '.$redirectURL);
}
} elseif (!$_header_only_type && $this->requests[$orig]['method'] == 'HEAD') {
// the response content-type did not match our 'header only' types,
// but we'd issues a HEAD request because we assumed it would. So
// let's queue a proper GET request for this item...
$this->debug('Wrong guess at content-type, queing GET request');
$this->requests[$orig]['wrongGuess'] = true;
$this->redirectQueue[$orig] = $this->requests[$orig]['effective_url'];
} elseif (strpos($this->requests[$orig]['effective_url'], '_escaped_fragment_') === false) {
// check for
// for AJAX sites, e.g. Blogger with its dynamic views templates.
// Based on Google's spec: https://developers.google.com/webmasters/ajax-crawling/docs/specification
if (isset($this->requests[$orig]['body'])) {
$redirectURL = $this->getUglyURL($this->requests[$orig]['effective_url'], substr($this->requests[$orig]['body'], 0, 4000));
if ($redirectURL) {
$this->debug('AJAX trigger (meta name="fragment" content="!") found. Queueing '.$redirectURL);
$this->redirectQueue[$orig] = $redirectURL;
}
}
}
// die($url.' -multi- '.$request->getResponseInfo('effective_url'));
unset($this->requests[$orig]['httpRequest'], $this->requests[$orig]['method']);
}
}
}
}
//////////////////////////////////////////////////////
// sequential (file_get_contents)
else {
$this->debug('Starting sequential fetch (file_get_contents)');
$this->debug('Processing set of '.count($urls));
foreach ($urls as $orig => $url) {
if (!$isRedirect) $orig = $url;
unset($this->redirectQueue[$orig]);
$this->debug("...$url");
if (!$isRedirect && isset($this->requests[$url])) {
$this->debug("......in memory");
/*
} elseif ($this->isCached($url)) {
$this->debug("......is cached");
if (!$this->minimiseMemoryUse) {
$this->requests[$url] = $this->getCached($url);
}
*/
} else {
$this->debug("Sending request for $url");
$this->requests[$orig]['original_url'] = $orig;
$req_url = $this->rewriteUrls($url);
$req_url = ($this->rewriteHashbangFragment) ? $this->rewriteHashbangFragment($req_url) : $req_url;
$req_url = $this->removeFragment($req_url);
// send cookies, if we have any
$httpContext = $this->httpContext;
$httpContext['http']['header'] .= $this->getUserAgent($req_url)."\r\n";
// add referer for picky sites
$httpContext['http']['header'] .= 'Referer: '.$this->referer."\r\n";
if ($cookies = $this->cookieJar->getMatchingCookies($req_url)) {
$this->debug("......sending cookies: $cookies");
$httpContext['http']['header'] .= 'Cookie: '.$cookies."\r\n";
}
if (false !== ($html = @file_get_contents($req_url, false, stream_context_create($httpContext)))) {
$this->debug('Received response');
// get status code
if (!isset($http_response_header[0]) || !preg_match('!^HTTP/\d+\.\d+\s+(\d+)!', trim($http_response_header[0]), $match)) {
$this->debug('Error: no status code found');
// TODO: handle error - no status code
} else {
$this->requests[$orig]['headers'] = $this->headersToString($http_response_header, false);
// check content type
if ($this->headerOnlyType($this->requests[$orig]['headers'])) {
$this->requests[$orig]['body'] = '';
} else {
$this->requests[$orig]['body'] = $html;
}
$this->requests[$orig]['effective_url'] = $req_url;
$this->requests[$orig]['status_code'] = $status_code = (int)$match[1];
unset($match);
// handle redirect
if (preg_match('/^Location:(.*?)$/mi', $this->requests[$orig]['headers'], $match)) {
$this->requests[$orig]['location'] = trim($match[1]);
}
if ((in_array($status_code, array(300, 301, 302, 303, 307)) || $status_code > 307 && $status_code < 400) && isset($this->requests[$orig]['location'])) {
$redirectURL = $this->requests[$orig]['location'];
if (!preg_match('!^https?://!i', $redirectURL)) {
$redirectURL = SimplePie_Misc::absolutize_url($redirectURL, $url);
}
if ($this->validateURL($redirectURL)) {
$this->debug('Redirect detected. Valid URL: '.$redirectURL);
// store any cookies
$cookies = $this->cookieJar->extractCookies($this->requests[$orig]['headers']);
if (!empty($cookies)) $this->cookieJar->storeCookies($url, $cookies);
$this->redirectQueue[$orig] = $redirectURL;
} else {
$this->debug('Redirect detected. Invalid URL: '.$redirectURL);
}
} elseif (strpos($this->requests[$orig]['effective_url'], '_escaped_fragment_') === false) {
// check for
// for AJAX sites, e.g. Blogger with its dynamic views templates.
// Based on Google's spec: https://developers.google.com/webmasters/ajax-crawling/docs/specification
if (isset($this->requests[$orig]['body'])) {
$redirectURL = $this->getUglyURL($this->requests[$orig]['effective_url'], substr($this->requests[$orig]['body'], 0, 4000));
if ($redirectURL) {
$this->debug('AJAX trigger (meta name="fragment" content="!") found. Queueing '.$redirectURL);
$this->redirectQueue[$orig] = $redirectURL;
}
}
}
}
} else {
$this->debug('Error retrieving URL');
//print_r($req_url);
//print_r($http_response_header);
//print_r($html);
// TODO: handle error - failed to retrieve URL
}
}
}
}
}
public function handleCurlResponse($response, $info, $request) {
$orig = $request->url_original;
$this->requests[$orig]['headers'] = substr($response, 0, $info['header_size']);
$this->requests[$orig]['body'] = substr($response, $info['header_size']);
$this->requests[$orig]['method'] = $request->method;
$this->requests[$orig]['effective_url'] = $info['url'];
$this->requests[$orig]['status_code'] = (int)$info['http_code'];
if (preg_match('/^Location:(.*?)$/mi', $this->requests[$orig]['headers'], $match)) {
$this->requests[$orig]['location'] = trim($match[1]);
}
}
protected function headersToString(array $headers, $associative=true) {
if (!$associative) {
return implode("\n", $headers);
} else {
$str = '';
foreach ($headers as $key => $val) {
if (is_array($val)) {
foreach ($val as $v) $str .= "$key: $v\n";
} else {
$str .= "$key: $val\n";
}
}
return rtrim($str);
}
}
public function get($url, $remove=false, $gzdecode=true) {
$url = "$url";
if (isset($this->requests[$url]) && isset($this->requests[$url]['body'])) {
$this->debug("URL already fetched - in memory ($url, effective: {$this->requests[$url]['effective_url']})");
$response = $this->requests[$url];
/*
} elseif ($this->isCached($url)) {
$this->debug("URL already fetched - in disk cache ($url)");
$response = $this->getCached($url);
$this->requests[$url] = $response;
*/
} else {
$this->debug("Fetching URL ($url)");
$this->fetchAll(array($url));
if (isset($this->requests[$url]) && isset($this->requests[$url]['body'])) {
$response = $this->requests[$url];
} else {
$this->debug("Request failed");
$response = false;
}
}
/*
if ($this->minimiseMemoryUse && $response) {
$this->cache($url);
unset($this->requests[$url]);
}
*/
if ($remove && $response) unset($this->requests[$url]);
if ($gzdecode && stripos($response['headers'], 'Content-Encoding: gzip')) {
if ($html = gzdecode($response['body'])) {
$response['body'] = $html;
}
}
return $response;
}
public function parallelSupport() {
return class_exists('HttpRequestPool') || function_exists('curl_multi_init');
}
private function headerOnlyType($headers) {
if (preg_match('!^Content-Type:\s*(([a-z-]+)/([^;\r\n ]+))!im', $headers, $match)) {
// look for full mime type (e.g. image/jpeg) or just type (e.g. image)
$match[1] = strtolower(trim($match[1]));
$match[2] = strtolower(trim($match[2]));
foreach (array($match[1], $match[2]) as $mime) {
if (in_array($mime, $this->headerOnlyTypes)) return true;
}
}
return false;
}
private function possibleUnsupportedType($url) {
$path = @parse_url($url, PHP_URL_PATH);
if ($path && strpos($path, '.') !== false) {
$ext = strtolower(trim(pathinfo($path, PATHINFO_EXTENSION)));
return in_array($ext, $this->headerOnlyClues);
}
return false;
}
}
// gzdecode from http://www.php.net/manual/en/function.gzdecode.php#82930
if (!function_exists('gzdecode')) {
function gzdecode($data,&$filename='',&$error='',$maxlength=null)
{
$len = strlen($data);
if ($len < 18 || strcmp(substr($data,0,2),"\x1f\x8b")) {
$error = "Not in GZIP format.";
return null; // Not GZIP format (See RFC 1952)
}
$method = ord(substr($data,2,1)); // Compression method
$flags = ord(substr($data,3,1)); // Flags
if ($flags & 31 != $flags) {
$error = "Reserved bits not allowed.";
return null;
}
// NOTE: $mtime may be negative (PHP integer limitations)
$mtime = unpack("V", substr($data,4,4));
$mtime = $mtime[1];
$xfl = substr($data,8,1);
$os = substr($data,8,1);
$headerlen = 10;
$extralen = 0;
$extra = "";
if ($flags & 4) {
// 2-byte length prefixed EXTRA data in header
if ($len - $headerlen - 2 < 8) {
return false; // invalid
}
$extralen = unpack("v",substr($data,8,2));
$extralen = $extralen[1];
if ($len - $headerlen - 2 - $extralen < 8) {
return false; // invalid
}
$extra = substr($data,10,$extralen);
$headerlen += 2 + $extralen;
}
$filenamelen = 0;
$filename = "";
if ($flags & 8) {
// C-style string
if ($len - $headerlen - 1 < 8) {
return false; // invalid
}
$filenamelen = strpos(substr($data,$headerlen),chr(0));
if ($filenamelen === false || $len - $headerlen - $filenamelen - 1 < 8) {
return false; // invalid
}
$filename = substr($data,$headerlen,$filenamelen);
$headerlen += $filenamelen + 1;
}
$commentlen = 0;
$comment = "";
if ($flags & 16) {
// C-style string COMMENT data in header
if ($len - $headerlen - 1 < 8) {
return false; // invalid
}
$commentlen = strpos(substr($data,$headerlen),chr(0));
if ($commentlen === false || $len - $headerlen - $commentlen - 1 < 8) {
return false; // Invalid header format
}
$comment = substr($data,$headerlen,$commentlen);
$headerlen += $commentlen + 1;
}
$headercrc = "";
if ($flags & 2) {
// 2-bytes (lowest order) of CRC32 on header present
if ($len - $headerlen - 2 < 8) {
return false; // invalid
}
$calccrc = crc32(substr($data,0,$headerlen)) & 0xffff;
$headercrc = unpack("v", substr($data,$headerlen,2));
$headercrc = $headercrc[1];
if ($headercrc != $calccrc) {
$error = "Header checksum failed.";
return false; // Bad header CRC
}
$headerlen += 2;
}
// GZIP FOOTER
$datacrc = unpack("V",substr($data,-8,4));
$datacrc = sprintf('%u',$datacrc[1] & 0xFFFFFFFF);
$isize = unpack("V",substr($data,-4));
$isize = $isize[1];
// decompression:
$bodylen = $len-$headerlen-8;
if ($bodylen < 1) {
// IMPLEMENTATION BUG!
return null;
}
$body = substr($data,$headerlen,$bodylen);
$data = "";
if ($bodylen > 0) {
switch ($method) {
case 8:
// Currently the only supported compression method:
$data = gzinflate($body,$maxlength);
break;
default:
$error = "Unknown compression method.";
return false;
}
} // zero-byte body content is allowed
// Verifiy CRC32
$crc = sprintf("%u",crc32($data));
$crcOK = $crc == $datacrc;
$lenOK = $isize == strlen($data);
if (!$lenOK || !$crcOK) {
$error = ( $lenOK ? '' : 'Length check FAILED. ') . ( $crcOK ? '' : 'Checksum FAILED.');
return false;
}
return $data;
}
}
?>