How can I check if a URL exists via PHP?

Here:

$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;
}

From here and right below the above post, there's a curl solution:

function url_exists($url) {
    return curl_init($url) !== false;
}

$headers = @get_headers($this->_value);
if(strpos($headers[0],'200')===false)return false;

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

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....

/**
 * 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) || $http_code === 999) {
        curl_close($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;
}

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

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.

 function urlExists($url)
{
    if (@file_get_contents($url,false,NULL,0,1))
    {
        return true;
    }
    return false;
}

cURL can return HTTP code I don’t think all that extra code is necessary?

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;
        }
    }

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.

$array = get_headers($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 
) 

The best and simplest answer so far using get_headers() The best thing to check for string "200 ok". its far better than to check

$file_headers = @get_headers($file-path);
$file_headers[0];

because sometime the array key numbers varies. so best thing is to check for "200 ok". Any URL which is up will have "200 ok" anywhere in get_headers() response.

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;
         }
}

now check the function if true or false

if(url_exist(php-url-variable-here)
  URL exist
}else{
  URL don't exist
}

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

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