How to convert relative path to absolute path in php

php method to convert a relative path to an absolute path: This can be achieved through the preg_replace() function. The preg_replace() function can perform a regular expression search and replace. If the search target is a string array, this function returns an array.

#We can use the preg_replace() function to convert a relative path to an absolute path.

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Function introduction

preg_replace() function performs a regular expression search and replacement.

Function syntax

mixed preg_replace ( mixed $pattern , mixed $replacement , mixed $subject [, int $limit = -1 [, int &$count ]] )

Search for the part matching pattern in subject and replace it with replacement.

Parameter description:

• $pattern: The pattern to be searched, which can be a string or a string array.

• $replacement: String or array of strings used for replacement.

• $subject: The target string or string array to be searched and replaced.

• $limit: Optional, the maximum number of substitutions for each subject string per pattern. The default is -1 (no limit).

• $count: Optional, the number of times the replacement is performed.

Return value

If subject is an array, preg_replace() returns an array, otherwise it returns a string.

If a match is found, the replaced subject is returned, otherwise the unchanged subject is returned. If an error occurs, NULL is returned.

Code implementation:

//相对路径转化成绝对路径
<?
function relative_to_absolute($content, $feed_url) { 
preg_match(&#39;/(http|https|ftp):///&#39;, $feed_url, $protocol); 
$server_url = preg_replace("/(http|https|ftp|news):///", "", $feed_url);
//开源OSPhP.COM.CN
$server_url = preg_replace("//.*/", "", $server_url); 
    if ($server_url == &#39;&#39;) { 
        return $content; 
    } 
    if (isset($protocol[0])) {
//开源代码OSPhP.COm.CN
$new_content = preg_replace(&#39;/href="//&#39;, &#39;href="&#39;.$protocol[0].$server_url.&#39;/&#39;, $content); 
$new_content = preg_replace(&#39;/src="//&#39;, &#39;src="&#39;.$protocol[0].$server_url.&#39;/&#39;, $new_content);  //开源OSPhP.COM.CN
    } else { 
$new_content = $content; 
    } 
    return $new_content; 
} 
?>

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