PHP determines whether the url can be opened

Solution to using PHP to determine whether the url can be opened:

1. Use the file_get_contents function, but the disadvantage is that if the url cannot be accessed, There will be a problem of terminating the program

2. Use curl to return, and then determine whether it is executed correctly

3. Use the get_headers function to check whether there is 200

## based on the HTTP return value #get_headers needs to be supported

1. php_openssl support Check phpinfo to see if it is enabled

2.allow_url_fopen=on Modify php.ini and run it using remote open

Function introduction:

array get_headers ( string $url [, int $format ] )

get_headers() returns an array containing the headers sent by the server in response to an HTTP request. If it fails, it returns FALSE and issues an E_WARNING level error message. If the optional format parameter is set to 1, get_headers() will parse the corresponding information and set the array keys. For example:

Example:

<?php
$url = "http://cn.php.net/images/php.gif";
$array = get_headers($url,1);
if(preg_match(&#39;/200/&#39;,$array[0])){
    echo "<pre/>";
    print_r($array);
}else{
    echo "无效url资源！";
}

Result:

Advantages and Disadvantages:

Requires allow_url_fopen=on, which is somewhat similar to the file_get_contents function usage conditions, but the return value is relatively small, you can Use function_exists to determine whether the method can be used.

Recommended tutorial:

PHP video tutorial

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