PHP determines if a remote picture or file or URL exists-180

I usually use curl to determine whether a remote picture or file exists:

/**
* @link http://www.phpddt.com
*/
function Url_exists ($url) {
$ch = Curl_init ();
curl_setopt ($ch, Curlopt_url, $url);
Do not download
curl_setopt ($ch, curlopt_nobody, 1);
Set timeout
curl_setopt ($ch, Curlopt_connecttimeout, 3);
curl_setopt ($ch, Curlopt_timeout, 3);
Curl_exec ($ch);
$http _code = Curl_getinfo ($ch, Curlinfo_http_code);
if ($http _code = = 200) {
return true;
}
return false;
}


There are, of course, many other ways, more or less limited and flawed, such as:
(1) using the fopen () function, it should be in the state of Allow_url_open open, otherwise it will be an error.

$url = ' Http://www.phpddt.com/img/qrcode_for_phpddt.JPG ';
if (@fopen ($url, ' R ')) {
echo ' file exists ';
} else {
Echo ' file does not exist ';
}


(2) Get_headers get the server response to an HTTP request sent by all headers, less efficient, you can test under.

$url = ' Http://www.phpddt.com/img/qrcode_for_phpddt.JPG ';

Stream_context_set_default (
Array
' http ' = = Array (
' Timeout ' = 1,
)
)
);

$headers = Get_headers ($url);

if (Preg_match ('/200/', $headers [0])) {
echo ' file exists ';
} else {
Echo ' file does not exist ';
}


(3) file_get_contents () function

$opts = Array (
' HTTP ' =>array (
' Timeout ' =>3,
)
);
$context = Stream_context_create ($opts);
$resource = @file_get_contents (' Http://www.phpddt.com/img/qrcode_for_phpddt.JPG ', false, $context);

if ($resource) {
echo ' file exists ';
} else {
Echo ' file does not exist ';
}

This article is from the "Yanzi" blog, make sure to keep this source http://daddysgirl.blog.51cto.com/1598612/1887742

PHP determines if a remote picture or file or URL exists-180