blocks|key|1326232|text|这里：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326233|$file+=+'http://www.example.com/somefile.jpg';
$file_headers+=+@get_headers($file);
if(!$file_headers+%7C%7C+$file_headers[0]+==+'HTTP/1.1+404+Not+Found')+{
++++$exists+=+false;
}
else+{
++++$exists+=+true;
}|code-block|syntax|javascript|1326234|在上面的帖子中，来自here和right+below，有一个curl解决方案：|offset|length|1326235|function+url_exists($url)+{
++++return+curl_init($url)+!==+false;
}|1326236|entityMap|0|LINK|mutability|MUTABLE|url|http://www.php.net/manual/en/function.file-exists.php#75064|1|http://www.php.net/manual/en/function.file-exists.php#74469|2|http://php.net/manual/en/book.curl.php^0|0|0|A|4|0|F|B|1|U|4|2|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|10|8|@]|9|@$I|11|J|12|1|13]|$I|14|J|15|1|16]|$I|17|J|18|1|19]]|A|$]]|$1|K|3|L|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]|U|$5|P|Q|R|A|$S|V]]|W|$5|P|Q|R|A|$S|X]]]]

Here:
<pre><code>$file = 'http://www.example.com/somefile.jpg';
$file_headers = @get_headers($file);
if(!$file_headers || $file_headers[0] == 'HTTP/1.1 404 Not Found') {
 $exists = false;
}
else {
 $exists = true;
}
</code></pre>
From <a href="http://www.php.net/manual/en/function.file-exists.php#75064" rel="noreferrer">here</a> and <a href="http://www.php.net/manual/en/function.file-exists.php#74469" rel="noreferrer">right below</a> the above post, there's a <a href="http://php.net/manual/en/book.curl.php" rel="noreferrer">curl</a> solution:
<pre><code>function url_exists($url) {
 return curl_init($url) !== false;
}
</code></pre>

blocks|key|1326282|text|$headers+=+@get_headers($this->_value);
if(strpos($headers[0],'200')===false)return+false;|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1326283|所以，任何时候你联系一个网站，得到比200ok更多的东西，它都会工作。|unstyled|1326284|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>$headers = @get_headers($this-&gt;_value);
if(strpos($headers[0],'200')===false)return false;
</code></pre>

so anytime you contact a website and get something else than 200 ok it will work

blocks|key|1326439|text|你不能在某些服务器上使用curl，你可以使用下面的代码|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326440|<?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';
++}
?>|code-block|syntax|javascript|1326441|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

you cannot use curl in certain servers
u can use this code

<pre><code>&lt;?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';
 }
?&gt;
</code></pre>

blocks|key|1326453|text|我使用这个函数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326454|/**
+*+@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";
++++}
}|code-block|syntax|javascript|1326455|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I use this function:

<pre><code>/**
 * @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 =&gt; 'Continue',
 101 =&gt; 'Switching Protocols',
 102 =&gt; 'Processing',
 200 =&gt; 'OK',
 201 =&gt; 'Created',
 202 =&gt; 'Accepted',
 203 =&gt; 'Non-Authoritative Information',
 204 =&gt; 'No Content',
 205 =&gt; 'Reset Content',
 206 =&gt; 'Partial Content',
 207 =&gt; 'Multi-Status',
 208 =&gt; 'Already Reported',
 226 =&gt; 'IM Used',
 300 =&gt; 'Multiple Choices',
 301 =&gt; 'Moved Permanently',
 302 =&gt; 'Found',
 303 =&gt; 'See Other',
 304 =&gt; 'Not Modified',
 305 =&gt; 'Use Proxy',
 306 =&gt; 'Switch Proxy',
 307 =&gt; 'Temporary Redirect',
 308 =&gt; 'Permanent Redirect',
 400 =&gt; 'Bad Request',
 401 =&gt; 'Unauthorized',
 402 =&gt; 'Payment Required',
 403 =&gt; 'Forbidden',
 404 =&gt; 'Not Found',
 405 =&gt; 'Method Not Allowed',
 406 =&gt; 'Not Acceptable',
 407 =&gt; 'Proxy Authentication Required',
 408 =&gt; 'Request Timeout',
 409 =&gt; 'Conflict',
 410 =&gt; 'Gone',
 411 =&gt; 'Length Required',
 412 =&gt; 'Precondition Failed',
 413 =&gt; 'Payload Too Large',
 414 =&gt; 'Request-URI Too Long',
 415 =&gt; 'Unsupported Media Type',
 416 =&gt; 'Requested Range Not Satisfiable',
 417 =&gt; 'Expectation Failed',
 418 =&gt; 'I\'m a teapot',
 422 =&gt; 'Unprocessable Entity',
 423 =&gt; 'Locked',
 424 =&gt; 'Failed Dependency',
 425 =&gt; 'Unordered Collection',
 426 =&gt; 'Upgrade Required',
 428 =&gt; 'Precondition Required',
 429 =&gt; 'Too Many Requests',
 431 =&gt; 'Request Header Fields Too Large',
 449 =&gt; 'Retry With',
 450 =&gt; 'Blocked by Windows Parental Controls',
 500 =&gt; 'Internal Server Error',
 501 =&gt; 'Not Implemented',
 502 =&gt; 'Bad Gateway',
 503 =&gt; 'Service Unavailable',
 504 =&gt; 'Gateway Timeout',
 505 =&gt; 'HTTP Version Not Supported',
 506 =&gt; 'Variant Also Negotiates',
 507 =&gt; 'Insufficient Storage',
 508 =&gt; 'Loop Detected',
 509 =&gt; 'Bandwidth Limit Exceeded',
 510 =&gt; 'Not Extended',
 511 =&gt; 'Network Authentication Required',
 599 =&gt; '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";
 }
}
</code></pre>

blocks|key|1111172|text|$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'.|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1111173|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>$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'.
</code></pre>

blocks|key|1326359|text|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;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1326360|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>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;
}
</code></pre>

blocks|key|1326450|text|function+urlIsOk($url)
{
++++$headers+=+@get_headers($url);
++++$httpStatus+=+intval(substr($headers[0],+9,+3));
++++if+($httpStatus<400)
++++{
++++++++return+true;
++++}
++++return+false;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1326451|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>function urlIsOk($url)
{
 $headers = @get_headers($url);
 $httpStatus = intval(substr($headers[0], 9, 3));
 if ($httpStatus&lt;400)
 {
 return true;
 }
 return false;
}
</code></pre>

blocks|key|1111161|text|相当快：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1111162|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');|code-block|syntax|javascript|1111163|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

pretty fast:

<pre><code>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 &amp;&amp; $intReturnCode != 302 &amp;&amp; $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');
</code></pre>

blocks|key|1111444|text|检查url是在线还是离线|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1111445|function+get_http_response_code($theURL)+{
++++$headers+=+@get_headers($theURL);
++++return+substr($headers[0],+9,+3);
}|code-block|syntax|javascript|1111446|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

to check if url is online or offline ---

<pre><code>function get_http_response_code($theURL) {
 $headers = @get_headers($theURL);
 return substr($headers[0], 9, 3);
}
</code></pre>

blocks|key|1111510|text|function+url_exists($url)+{
++++$headers+=+@get_headers($url);
++++return+(strpos($headers[0],'200')===false)?+false:true;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1111511|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>function url_exists($url) {
 $headers = @get_headers($url);
 return (strpos($headers[0],'200')===false)? false:true;
}
</code></pre>

blocks|key|1326795|text|我运行一些测试来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。我在一个网站上遇到了一个问题，该网站的证书配置不佳，这意味着php的get_headers无法工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326796|所以，我读到curl更快，并决定试一试。然后，我在linkedin上遇到了一个问题，它给了我一个999错误，结果是一个用户代理问题。|1326797|我不关心证书对于这个测试是否有效，我也不关心响应是否是重定向的。|1326798|然后我想，如果curl失败了，无论如何也要使用get_headers……|1326799|试一试……|1326800|/**
+*+returns+true/false+if+the+$url+is+valid.
+*
+*+@param+string+$url+assumes+this+is+a+valid+url.
+*
+*+@return+bool
+*/
private+function+urlExists(string+$url):+bool
{
++++$ch+=+curl_init($url);
++++curl_setopt($ch,+CURLOPT_URL,+$url);
++++curl_setopt($ch,+CURLOPT_RETURNTRANSFER,+true);+++++//+do+not+output+response+in+stdout
++++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+(($http_code+>=+200+&&+$http_code+<+400)+%7C%7C+$http_code+===+999)+{
++++++++curl_close($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(
++++++++['http'+=>+['method'+=>+'HEAD']]
++++);
++++$file_headers+=+@get_headers($url);

++++if+($file_headers+!==+false)+{
++++++++$response_code+=+substr($file_headers[0],+9,+3);
++++++++return+$response_code+>=+200+&&+$response_code+<+400;
++++}

++++return+false;
}|code-block|syntax|javascript|1326801|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|S|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|T|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|U|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|V|8|@]|9|@]|A|$M|N]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I run some tests to see if links on my site are valid - alerts me to when third parties change their links. I was having an issue with a site that had a poorly configured certificate that meant that php's get_headers didn't work.
SO, I read that curl was faster and decided to give that a go. then i had an issue with linkedin which gave me a 999 error, which turned out to be a user agent issue.
I didn't care if the certificate was not valid for this test, and i didn't care if the response was a re-direct.
Then I figured use get_headers anyway if curl was failing....
Give it a go....
<pre class="lang-php prettyprint-override"><code>/**
 * returns true/false if the $url is valid.
 *
 * @param string $url assumes this is a valid url.
 *
 * @return bool
 */
private function urlExists(string $url): bool
{
 $ch = curl_init($url);
 curl_setopt($ch, CURLOPT_URL, $url);
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); // do not output response in stdout
 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 &gt;= 200 &amp;&amp; $http_code &lt; 400) || $http_code === 999) {
 curl_close($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(
 ['http' =&gt; ['method' =&gt; 'HEAD']]
 );
 $file_headers = @get_headers($url);

 if ($file_headers !== false) {
 $response_code = substr($file_headers[0], 9, 3);
 return $response_code &gt;= 200 &amp;&amp; $response_code &lt; 400;
 }

 return false;
}
</code></pre>

blocks|key|1111387|text|这是一个只读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+...这也适用于远程文件，如图像。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1111388|+function+urlExists($url)
{
++++if+(@file_get_contents($url,false,NULL,0,1))
++++{
++++++++return+true;
++++}
++++return+false;
}|code-block|syntax|javascript|1111389|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is a solution that reads only the first byte of source code... returning false if the file_get_contents fails... This will also work for remote files like images.

<pre><code> function urlExists($url)
{
 if (@file_get_contents($url,false,NULL,0,1))
 {
 return true;
 }
 return false;
}
</code></pre>

blocks|key|1326496|text|检查URL是否有效的其他方法可以是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326497|<?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;
++++++}
++}
?>|code-block|syntax|javascript|1326498|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Other way to check if a URL is valid or not can be:

<pre><code>&lt;?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") &gt; 0) {
 return true;
 } else {
 return false;
 }
 }
?&gt;
</code></pre>

blocks|key|1326744|text|当您检查404的标头时，需要考虑的一件事是站点不会立即生成404。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326745|很多网站都会检查PHP/ASP+(等)源代码中是否存在页面，然后将您转到404页面。在这些情况下，报头基本上由所生成的404的报头扩展。在这些情况下，404错误不是在标题的第一行，而是第十行。|1326746|$array+=+get_headers($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=%252Freed-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=%252Freed-diffuser-fig-pudding-50%252F;+path=/;+HttpOnly+
[14]+=>+Connection:+close+
[15]+=>+Content-Type:+text/html;+charset=utf-8+
)+|code-block|syntax|javascript|1326747|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

One thing to take into consideration when you check the header for a 404 is the case where a site does not generate a 404 immediately. 

A lot of sites check whether a page exists or not in the PHP/ASP (et cetera) source and forward you to a 404 page. In those cases the header is basically extended by the header of the 404 that is generated. In those cases the 404 error not in the first line of the header, but the tenth.

<pre><code>$array = get_headers($url);
$string = $array[0];
print_r($string) // would generate:

Array ( 
[0] =&gt; HTTP/1.0 301 Moved Permanently 
[1] =&gt; Date: Fri, 09 Nov 2018 16:12:29 GMT 
[2] =&gt; Server: Apache/2.4.34 (FreeBSD) LibreSSL/2.7.4 PHP/7.0.31 
[3] =&gt; X-Powered-By: PHP/7.0.31 
[4] =&gt; Set-Cookie: landing=%2Freed-diffuser-fig-pudding-50; path=/; HttpOnly 
[5] =&gt; Location: /reed-diffuser-fig-pudding-50/ 
[6] =&gt; Content-Length: 0 
[7] =&gt; Connection: close 
[8] =&gt; Content-Type: text/html; charset=utf-8 
[9] =&gt; HTTP/1.0 404 Not Found 
[10] =&gt; Date: Fri, 09 Nov 2018 16:12:29 GMT 
[11] =&gt; Server: Apache/2.4.34 (FreeBSD) LibreSSL/2.7.4 PHP/7.0.31 
[12] =&gt; X-Powered-By: PHP/7.0.31 
[13] =&gt; Set-Cookie: landing=%2Freed-diffuser-fig-pudding-50%2F; path=/; HttpOnly 
[14] =&gt; Connection: close 
[15] =&gt; Content-Type: text/html; charset=utf-8 
) 
</code></pre>

blocks|key|1326390|text|简单的方法是卷曲(也更快)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1326391|<?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';}

?>|code-block|syntax|javascript|1326392|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

the simple way is curl (and FASTER too)

<pre><code>&lt;?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';}

?&gt;
</code></pre>

blocks|key|1111496|text|get_headers()返回一个数组，其中包含服务器在响应HTTP请求时发送的标头。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1111497|$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.';
}else{
+++echo+'It+works.+Your+good+to+go!';
}|code-block|syntax|javascript|1111498|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/function.get-headers.php^0|0|D|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

<a href="http://php.net/manual/en/function.get-headers.php" rel="nofollow noreferrer">get_headers()</a> returns an array with the headers sent by the server in response to a HTTP request. 

<pre><code>$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.&lt;/br&gt;';
}else{
 echo 'It works. Your good to go!&lt;/br&gt;';
}
</code></pre>

blocks|key|1111717|text|到目前为止，使用get_headers()最好、最简单的答案是检查字符串“200ok”。这比检查好多了|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1111718|$file_headers+=+@get_headers($file-path);
$file_headers[0];|code-block|syntax|javascript|1111719|因为有时数组密钥号会变化。所以最好的方法是检查“200ok”。任何打开的网址在get_headers()响应中的任何地方都会有“200ok”。|1111720|function+url_exist($url)+{
++++++++$urlheaders+=+get_headers($url);
++++++++//print_r($urlheaders);
++++++++$urlmatches++=+preg_grep('/200+ok/i',+$urlheaders);
+++++++++if(!empty($urlmatches)){
+++++++++++return+true;
+++++++++}else{
+++++++++++return+false;
+++++++++}
}|1111721|现在检查函数是否为真或假|1111722|if(url_exist(php-url-variable-here)
++URL+exist
}else{
++URL+don't+exist
}|1111723|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

The best and simplest answer so far using get_headers()
The best thing to check for string &quot;200 ok&quot;. its far better than to check
<pre><code>$file_headers = @get_headers($file-path);
$file_headers[0];
</code></pre>
because sometime the array key numbers varies. so best thing is to check for &quot;200 ok&quot;. Any URL which is up will have &quot;200 ok&quot; anywhere in get_headers() response.
<pre><code>function url_exist($url) {
 $urlheaders = get_headers($url);
 //print_r($urlheaders);
 $urlmatches = preg_grep('/200 ok/i', $urlheaders);
 if(!empty($urlmatches)){
 return true;
 }else{
 return false;
 }
}
</code></pre>
now check the function if true or false
<pre><code>if(url_exist(php-url-variable-here)
 URL exist
}else{
 URL don't exist
}
</code></pre>

blocks|key|1111672|text|有点老套了，但是..我这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1111673|$file+=+'http://www.google.com';
$file_headers+=+@get_headers($file);
if+($file_headers)+{
++++$exists+=+true;
}+else+{
++++$exists+=+false;
}|code-block|syntax|javascript|1111674|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

kind of an old thread, but..
i do this:

<pre><code>$file = 'http://www.google.com';
$file_headers = @get_headers($file);
if ($file_headers) {
 $exists = true;
} else {
 $exists = false;
}
</code></pre>

问如何通过PHP检查URL是否存在？
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问如何通过PHP检查URL是否存在？EN

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问如何通过PHP检查URL是否存在？
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