如何在PHP中检查URL是否存在（而不是404）？
答案 0 :(得分：269)
下面：
$file = 'http://www.domain.com/somefile.jpg';
$file_headers = @get_headers($file);
if(!$file_headers || $file_headers[0] == 'HTTP/1.1 404 Not Found') {
$exists = false;
}
else {
$exists = true;
}
从上述帖子的here和right below开始，有一个curl解决方案：
function url_exists($url) {
if (!$fp = curl_init($url)) return false;
return true;
}
答案 1 :(得分：51)
当弄清楚php中是否存在url时，有几件事需要注意：
请记住，无论使用何种方法，等待回复都需要时间 所有代码可能（并且可能会）停止，直到您知道结果或请求已超时。
例如：如果网址无效或无法访问，则以下代码可能需要很长时间才能显示该网页：
<?php
$urls = getUrls(); // some function getting say 10 or more external links
foreach($urls as $k=>$url){
// this could potentially take 0-30 seconds each
// (more or less depending on connection, target site, timeout settings...)
if( ! isValidUrl($url) ){
unset($urls[$k]);
}
}
echo "yay all done! now show my site";
foreach($urls as $url){
echo "<a href=\"{$url}\">{$url}</a><br/>";
}
以下功能可能会有所帮助，您可能希望修改它们以满足您的需求：
function isValidUrl($url){
// first do some quick sanity checks:
if(!$url || !is_string($url)){
return false;
}
// quick check url is roughly a valid http request: ( http://blah/... )
if( ! preg_match('/^http(s)?:\/\/[a-z0-9-]+(\.[a-z0-9-]+)*(:[0-9]+)?(\/.*)?$/i', $url) ){
return false;
}
// the next bit could be slow:
if(getHttpResponseCode_using_curl($url) != 200){
// if(getHttpResponseCode_using_getheaders($url) != 200){ // use this one if you cant use curl
return false;
}
// all good!
return true;
}
function getHttpResponseCode_using_curl($url, $followredirects = true){
// returns int responsecode, or false (if url does not exist or connection timeout occurs)
// NOTE: could potentially take up to 0-30 seconds , blocking further code execution (more or less depending on connection, target site, and local timeout settings))
// if $followredirects == false: return the FIRST known httpcode (ignore redirects)
// if $followredirects == true : return the LAST known httpcode (when redirected)
if(! $url || ! is_string($url)){
return false;
}
$ch = @curl_init($url);
if($ch === false){
return false;
}
@curl_setopt($ch, CURLOPT_HEADER ,true); // we want headers
@curl_setopt($ch, CURLOPT_NOBODY ,true); // dont need body
@curl_setopt($ch, CURLOPT_RETURNTRANSFER ,true); // catch output (do NOT print!)
if($followredirects){
@curl_setopt($ch, CURLOPT_FOLLOWLOCATION ,true);
@curl_setopt($ch, CURLOPT_MAXREDIRS ,10); // fairly random number, but could prevent unwanted endless redirects with followlocation=true
}else{
@curl_setopt($ch, CURLOPT_FOLLOWLOCATION ,false);
}
// @curl_setopt($ch, CURLOPT_CONNECTTIMEOUT ,5); // fairly random number (seconds)... but could prevent waiting forever to get a result
// @curl_setopt($ch, CURLOPT_TIMEOUT ,6); // fairly random number (seconds)... but could prevent waiting forever to get a result
// @curl_setopt($ch, CURLOPT_USERAGENT ,"Mozilla/5.0 (Windows NT 6.0) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1"); // pretend we're a regular browser
@curl_exec($ch);
if(@curl_errno($ch)){ // should be 0
@curl_close($ch);
return false;
}
$code = @curl_getinfo($ch, CURLINFO_HTTP_CODE); // note: php.net documentation shows this returns a string, but really it returns an int
@curl_close($ch);
return $code;
}
function getHttpResponseCode_using_getheaders($url, $followredirects = true){
// returns string responsecode, or false if no responsecode found in headers (or url does not exist)
// NOTE: could potentially take up to 0-30 seconds , blocking further code execution (more or less depending on connection, target site, and local timeout settings))
// if $followredirects == false: return the FIRST known httpcode (ignore redirects)
// if $followredirects == true : return the LAST known httpcode (when redirected)
if(! $url || ! is_string($url)){
return false;
}
$headers = @get_headers($url);
if($headers && is_array($headers)){
if($followredirects){
// we want the the last errorcode, reverse array so we start at the end:
$headers = array_reverse($headers);
}
foreach($headers as $hline){
// search for things like "HTTP/1.1 200 OK" , "HTTP/1.0 200 OK" , "HTTP/1.1 301 PERMANENTLY MOVED" , "HTTP/1.1 400 Not Found" , etc.
// note that the exact syntax/version/output differs, so there is some string magic involved here
if(preg_match('/^HTTP\/\S+\s+([1-9][0-9][0-9])\s+.*/', $hline, $matches) ){// "HTTP/*** ### ***"
$code = $matches[1];
return $code;
}
}
// no HTTP/xxx found in headers:
return false;
}
// no headers :
return false;
}
答案 2 :(得分：44)
$headers = @get_headers($this->_value);
if(strpos($headers[0],'200')===false)return false;
因此，只要您联系某个网站并获得200以上的其他内容，就可以使用
答案 3 :(得分：15)
您无法在某些服务器中使用curl 你可以使用这段代码
<?php
$url = 'http://www.example.com';
$array = get_headers($url);
$string = $array[0];
if(strpos($string,"200"))
{
echo 'url exists';
}
else
{
echo 'url does not exist';
}
?>
答案 4 :(得分：7)
$url = 'http://google.com';
$not_url = 'stp://google.com';
if (@file_get_contents($url)): echo "Found '$url'!";
else: echo "Can't find '$url'.";
endif;
if (@file_get_contents($not_url)): echo "Found '$not_url!";
else: echo "Can't find '$not_url'.";
endif;
// Found 'http://google.com'!Can't find 'stp://google.com'.
答案 5 :(得分：7)
function URLIsValid($URL)
{
$exists = true;
$file_headers = @get_headers($URL);
$InvalidHeaders = array('404', '403', '500');
foreach($InvalidHeaders as $HeaderVal)
{
if(strstr($file_headers[0], $HeaderVal))
{
$exists = false;
break;
}
}
return $exists;
}
答案 6 :(得分：6)
我使用这个功能：
/**
* @param $url
* @param array $options
* @return string
* @throws Exception
*/
function checkURL($url, array $options = array()) {
if (empty($url)) {
throw new Exception('URL is empty');
}
// list of HTTP status codes
$httpStatusCodes = array(
100 => 'Continue',
101 => 'Switching Protocols',
102 => 'Processing',
200 => 'OK',
201 => 'Created',
202 => 'Accepted',
203 => 'Non-Authoritative Information',
204 => 'No Content',
205 => 'Reset Content',
206 => 'Partial Content',
207 => 'Multi-Status',
208 => 'Already Reported',
226 => 'IM Used',
300 => 'Multiple Choices',
301 => 'Moved Permanently',
302 => 'Found',
303 => 'See Other',
304 => 'Not Modified',
305 => 'Use Proxy',
306 => 'Switch Proxy',
307 => 'Temporary Redirect',
308 => 'Permanent Redirect',
400 => 'Bad Request',
401 => 'Unauthorized',
402 => 'Payment Required',
403 => 'Forbidden',
404 => 'Not Found',
405 => 'Method Not Allowed',
406 => 'Not Acceptable',
407 => 'Proxy Authentication Required',
408 => 'Request Timeout',
409 => 'Conflict',
410 => 'Gone',
411 => 'Length Required',
412 => 'Precondition Failed',
413 => 'Payload Too Large',
414 => 'Request-URI Too Long',
415 => 'Unsupported Media Type',
416 => 'Requested Range Not Satisfiable',
417 => 'Expectation Failed',
418 => 'I\'m a teapot',
422 => 'Unprocessable Entity',
423 => 'Locked',
424 => 'Failed Dependency',
425 => 'Unordered Collection',
426 => 'Upgrade Required',
428 => 'Precondition Required',
429 => 'Too Many Requests',
431 => 'Request Header Fields Too Large',
449 => 'Retry With',
450 => 'Blocked by Windows Parental Controls',
500 => 'Internal Server Error',
501 => 'Not Implemented',
502 => 'Bad Gateway',
503 => 'Service Unavailable',
504 => 'Gateway Timeout',
505 => 'HTTP Version Not Supported',
506 => 'Variant Also Negotiates',
507 => 'Insufficient Storage',
508 => 'Loop Detected',
509 => 'Bandwidth Limit Exceeded',
510 => 'Not Extended',
511 => 'Network Authentication Required',
599 => 'Network Connect Timeout Error'
);
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
if (isset($options['timeout'])) {
$timeout = (int) $options['timeout'];
curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
}
curl_exec($ch);
$returnedStatusCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
if (array_key_exists($returnedStatusCode, $httpStatusCodes)) {
return "URL: '{$url}' - Error code: {$returnedStatusCode} - Definition: {$httpStatusCodes[$returnedStatusCode]}";
} else {
return "'{$url}' does not exist";
}
}
答案 7 :(得分：4)
karim79的get_headers（）解决方案对我没有用，因为我在Pinterest中获得了疯狂的结果。
get_headers(): SSL operation failed with code 1. OpenSSL Error messages: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
Array
(
[url] => https://www.pinterest.com/jonathan_parl/
[exists] =>
)
get_headers(): Failed to enable crypto
Array
(
[url] => https://www.pinterest.com/jonathan_parl/
[exists] =>
)
get_headers(https://www.pinterest.com/jonathan_parl/): failed to open stream: operation failed
Array
(
[url] => https://www.pinterest.com/jonathan_parl/
[exists] =>
)
无论如何，这位开发人员证明cURL比get_headers（）更快：
http://php.net/manual/fr/function.get-headers.php#104723
由于很多人要求karim79修复cURL解决方案，这就是我今天建立的解决方案。
/**
* Send an HTTP request to a the $url and check the header posted back.
*
* @param $url String url to which we must send the request.
* @param $failCodeList Int array list of code for which the page is considered invalid.
*
* @return Boolean
*/
public static function isUrlExists($url, array $failCodeList = array(404)){
$exists = false;
if(!StringManager::stringStartWith($url, "http") and !StringManager::stringStartWith($url, "ftp")){
$url = "https://" . $url;
}
if (preg_match(RegularExpression::URL, $url)){
$handle = curl_init($url);
curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);
curl_setopt($handle, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($handle, CURLOPT_HEADER, true);
curl_setopt($handle, CURLOPT_NOBODY, true);
curl_setopt($handle, CURLOPT_USERAGENT, true);
$headers = curl_exec($handle);
curl_close($handle);
if (empty($failCodeList) or !is_array($failCodeList)){
$failCodeList = array(404);
}
if (!empty($headers)){
$exists = true;
$headers = explode(PHP_EOL, $headers);
foreach($failCodeList as $code){
if (is_numeric($code) and strpos($headers[0], strval($code)) !== false){
$exists = false;
break;
}
}
}
}
return $exists;
}
让我解释一下卷曲选项：
CURLOPT_RETURNTRANSFER ：返回一个字符串，而不是在屏幕上显示调用页面。
CURLOPT_SSL_VERIFYPEER ：cUrl不会结帐证书
CURLOPT_HEADER ：在字符串
中包含标题CURLOPT_NOBODY ：不要在字符串中包含正文
CURLOPT_USERAGENT ：某些网站需要正常运作（例如：https://plus.google.com）
附加说明：在此功能中，我使用Diego Perini的正则表达式在发送请求之前验证URL：
const URL = "%^(?:(?:https?|ftp)://)(?:\S+(?::\S*)?@|\d{1,3}(?:\.\d{1,3}){3}|(?:(?:[a-z\d\x{00a1}-\x{ffff}]+-?)*[a-z\d\x{00a1}-\x{ffff}]+)(?:\.(?:[a-z\d\x{00a1}-\x{ffff}]+-?)*[a-z\d\x{00a1}-\x{ffff}]+)*(?:\.[a-z\x{00a1}-\x{ffff}]{2,6}))(?::\d+)?(?:[^\s]*)?$%iu"; //@copyright Diego Perini
附加说明2 ：我会爆炸标题字符串和用户标题[0]，以确保只验证返回代码和消息（例如：200,404,405等）< / p>
附加说明3 ：有时仅验证代码404是不够的（参见单元测试），因此有一个可选的$ failCodeList参数来提供拒绝的所有代码列表。
当然，这是单元测试（包括所有流行的社交网络）合法化我的编码：
public function testIsUrlExists(){
//invalid
$this->assertFalse(ToolManager::isUrlExists("woot"));
$this->assertFalse(ToolManager::isUrlExists("https://www.facebook.com/jonathan.parentlevesque4545646456"));
$this->assertFalse(ToolManager::isUrlExists("https://plus.google.com/+JonathanParentL%C3%A9vesque890800"));
$this->assertFalse(ToolManager::isUrlExists("https://instagram.com/mariloubiz1232132/", array(404, 405)));
$this->assertFalse(ToolManager::isUrlExists("https://www.pinterest.com/jonathan_parl1231/"));
$this->assertFalse(ToolManager::isUrlExists("https://regex101.com/546465465456"));
$this->assertFalse(ToolManager::isUrlExists("https://twitter.com/arcadefire4566546"));
$this->assertFalse(ToolManager::isUrlExists("https://vimeo.com/**($%?%$", array(400, 405)));
$this->assertFalse(ToolManager::isUrlExists("https://www.youtube.com/user/Darkjo666456456456"));
//valid
$this->assertTrue(ToolManager::isUrlExists("www.google.ca"));
$this->assertTrue(ToolManager::isUrlExists("https://www.facebook.com/jonathan.parentlevesque"));
$this->assertTrue(ToolManager::isUrlExists("https://plus.google.com/+JonathanParentL%C3%A9vesque"));
$this->assertTrue(ToolManager::isUrlExists("https://instagram.com/mariloubiz/"));
$this->assertTrue(ToolManager::isUrlExists("https://www.facebook.com/jonathan.parentlevesque"));
$this->assertTrue(ToolManager::isUrlExists("https://www.pinterest.com/"));
$this->assertTrue(ToolManager::isUrlExists("https://regex101.com"));
$this->assertTrue(ToolManager::isUrlExists("https://twitter.com/arcadefire"));
$this->assertTrue(ToolManager::isUrlExists("https://vimeo.com/"));
$this->assertTrue(ToolManager::isUrlExists("https://www.youtube.com/user/Darkjo666"));
}
所有人都取得了巨大成功，
来自蒙特利尔的Jonathan Parent-Lévesque
答案 8 :(得分：3)
非常快：
function http_response($url){
$resURL = curl_init();
curl_setopt($resURL, CURLOPT_URL, $url);
curl_setopt($resURL, CURLOPT_BINARYTRANSFER, 1);
curl_setopt($resURL, CURLOPT_HEADERFUNCTION, 'curlHeaderCallback');
curl_setopt($resURL, CURLOPT_FAILONERROR, 1);
curl_exec ($resURL);
$intReturnCode = curl_getinfo($resURL, CURLINFO_HTTP_CODE);
curl_close ($resURL);
if ($intReturnCode != 200 && $intReturnCode != 302 && $intReturnCode != 304) { return 0; } else return 1;
}
echo 'google:';
echo http_response('http://www.google.com');
echo '/ ogogle:';
echo http_response('http://www.ogogle.com');
答案 9 :(得分：3)
检查网址是否在线或离线---
function get_http_response_code($theURL) {
$headers = @get_headers($theURL);
return substr($headers[0], 9, 3);
}
答案 10 :(得分：3)
以上所有解决方案+额外的糖。 （终极AIO解决方案）
/**
* Check that given URL is valid and exists.
* @param string $url URL to check
* @return bool TRUE when valid | FALSE anyway
*/
function urlExists ( $url ) {
// Remove all illegal characters from a url
$url = filter_var($url, FILTER_SANITIZE_URL);
// Validate URI
if (filter_var($url, FILTER_VALIDATE_URL) === FALSE
// check only for http/https schemes.
|| !in_array(strtolower(parse_url($url, PHP_URL_SCHEME)), ['http','https'], true )
) {
return false;
}
// Check that URL exists
$file_headers = @get_headers($url);
return !(!$file_headers || $file_headers[0] === 'HTTP/1.1 404 Not Found');
}
实施例：
var_dump ( urlExists('http://stackoverflow.com/') );
// Output: true;
答案 11 :(得分：2)
function urlIsOk($url)
{
$headers = @get_headers($url);
$httpStatus = intval(substr($headers[0], 9, 3));
if ($httpStatus<400)
{
return true;
}
return false;
}
答案 12 :(得分：1)
这是一个只读取源代码的第一个字节的解决方案...如果file_get_contents失败则返回false ...这也适用于像图像这样的远程文件。
function urlExists($url)
{
if (@file_get_contents($url,false,NULL,0,1))
{
return true;
}
return false;
}
答案 13 :(得分：0)
我进行了一些测试，以查看我网站上的链接是否有效-当第三方更改链接时提醒我。我的网站存在证书配置错误的问题，这意味着php的get_headers无法正常工作。
所以，我读到卷曲更快，因此决定试一试。然后我遇到了一个linkedin问题，给了我一个999错误，结果是一个用户代理问题。
我不在乎证书是否对该测试无效，并且我不在乎响应是否为重定向。
然后我想如果卷曲失败了，还是要使用get_headers。...
试试吧....
/**
* returns true/false if the $url is present.
*
* @param string $url assumes this is a valid url.
*
* @return bool
*/
private function url_exists (string $url): bool
{
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_NOBODY, TRUE); // this does a head request to make it faster.
curl_setopt($ch, CURLOPT_HEADER, TRUE); // just the headers
curl_setopt($ch, CURLOPT_SSL_VERIFYSTATUS, FALSE); // turn off that pesky ssl stuff - some sys admins can't get it right.
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
// set a real user agent to stop linkedin getting upset.
curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36');
curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
if (($http_code >= HTTP_OK && $http_code < HTTP_BAD_REQUEST) || $http_code === 999)
{
curl_close($ch);
return TRUE;
}
$error = curl_error($ch); // used for debugging.
curl_close($ch);
// just try the get_headers - it might work!
stream_context_set_default(array('http' => array('method' => 'HEAD')));
$file_headers = @get_headers($url);
if ($file_headers)
{
$response_code = substr($file_headers[0], 9, 3);
return $response_code >= 200 && $response_code < 400;
}
return FALSE;
}
答案 14 :(得分：0)
使用get_headers（）到目前为止最好和最简单的答案 最好检查字符串“ 200 ok”。比检查要好
$file_headers = @get_headers($file-path);
$file_headers[0];
因为有时阵列键号会有所不同。所以最好的办法是检查“ 200 ok”。任何启用的URL在get_headers（）响应中的任何位置都将显示“ 200 ok”。
function url_exist($url) {
$urlheaders = get_headers($url);
//print_r($urlheaders);
$urlmatches = preg_grep('/200 ok/i', $urlheaders);
if(!empty($urlmatches)){
return true;
}else{
return false;
}
}
现在检查该功能是对还是错
if(url_exist(php-url-variable-here)
URL exist
}else{
URL don't exist
}
答案 15 :(得分：0)
检查404标头时要考虑的一件事是站点不会立即生成404的情况。
许多站点会检查PHP / ASP（等等）源中是否存在页面，并将您转发到404页面。在那些情况下，标头基本上由生成的404的标头扩展。在这种情况下，404错误不是出现在标题的第一行，而是出现在第十行。
$array = get_headers($url);
$string = $array[0];
print_r($string) // would generate:
Array (
[0] => HTTP/1.0 301 Moved Permanently
[1] => Date: Fri, 09 Nov 2018 16:12:29 GMT
[2] => Server: Apache/2.4.34 (FreeBSD) LibreSSL/2.7.4 PHP/7.0.31
[3] => X-Powered-By: PHP/7.0.31
[4] => Set-Cookie: landing=%2Freed-diffuser-fig-pudding-50; path=/; HttpOnly
[5] => Location: /reed-diffuser-fig-pudding-50/
[6] => Content-Length: 0
[7] => Connection: close
[8] => Content-Type: text/html; charset=utf-8
[9] => HTTP/1.0 404 Not Found
[10] => Date: Fri, 09 Nov 2018 16:12:29 GMT
[11] => Server: Apache/2.4.34 (FreeBSD) LibreSSL/2.7.4 PHP/7.0.31
[12] => X-Powered-By: PHP/7.0.31
[13] => Set-Cookie: landing=%2Freed-diffuser-fig-pudding-50%2F; path=/; HttpOnly
[14] => Connection: close
[15] => Content-Type: text/html; charset=utf-8
)
答案 16 :(得分：0)
cURL可以返回HTTP代码，我认为不需要所有额外的代码吗？
function urlExists($url=NULL)
{
if($url == NULL) return false;
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_TIMEOUT, 5);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$data = curl_exec($ch);
$httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
if($httpcode>=200 && $httpcode<300){
return true;
} else {
return false;
}
}
答案 17 :(得分：0)
function url_exists($url) {
$headers = @get_headers($url);
return (strpos($headers[0],'200')===false)? false:true;
}
答案 18 :(得分：0)
get_headers()返回一个数组，其中包含服务器响应HTTP请求发送的标头。
$image_path = 'https://your-domain.com/assets/img/image.jpg';
$file_headers = @get_headers($image_path);
//Prints the response out in an array
//print_r($file_headers);
if($file_headers[0] == 'HTTP/1.1 404 Not Found'){
echo 'Failed because path does not exist.</br>';
}else{
echo 'It works. Your good to go!</br>';
}
答案 19 :(得分：0)
检查网址是否有效的其他方法可以是：
<?php
if (isValidURL("http://www.gimepix.com")) {
echo "URL is valid...";
} else {
echo "URL is not valid...";
}
function isValidURL($url) {
$file_headers = @get_headers($url);
if (strpos($file_headers[0], "200 OK") > 0) {
return true;
} else {
return false;
}
}
?>
答案 20 :(得分：0)
简单的方法是curl（也更快）
<?php
$mylinks="http://site.com/page.html";
$handlerr = curl_init($mylinks);
curl_setopt($handlerr, CURLOPT_RETURNTRANSFER, TRUE);
$resp = curl_exec($handlerr);
$ht = curl_getinfo($handlerr, CURLINFO_HTTP_CODE);
if ($ht == '404')
{ echo 'OK';}
else { echo 'NO';}
?>
答案 21 :(得分：-1)
有点旧的线程，但是.. 我这样做：
$file = 'http://www.google.com';
$file_headers = @get_headers($file);
if ($file_headers) {
$exists = true;
} else {
$exists = false;
}