Conversion of text within delimeters to valid url - php

Question

I have to convert an old website to a CMS and one of the challenges I have is at present there are over 900 folders that contain up to 9 text files in each folder. I need to combine the up to 9 text files into one and then use that file as the import into the CMS.
The file concatenation and import are working perfectly.
The challenge that I have is parsing some of the text in the text file.
The text file contains a url in the form of
Some text [http://xxxxx.com|About something] some more text
I am converting this with this code
if (substr ($line1, 0, 7) !=="Replace") {
$pattern = '/\\[/';
$pattern2 = '/\\]/';
$pattern3 = '/\\|/';
$replacement = '<a href="';
$replacement3 = '">';
$replacement2='</a><br>';
$subject = $line1;
$i=preg_replace($pattern, $replacement, $subject, -1 );
$i=preg_replace($pattern3, $replacement3, $i, -1 );
$i=preg_replace($pattern2, $replacement2, $i, -1 );
$line .= '<div class="'.$folders[$x].'">'.$i.'</div>' ;
}
It may not be the most efficient code but it works and as this is a one off exercise execution time etc is not an issue.
Now to the problem that I cannot seem to code around. Some of the urls in the text files are in this format
Some text [http://xxxx.com] some more text
The pattern matching that I have above finds pattern and pattern2 but as there is no pattern3 the url is malformed in the output.
Regular expressions are not my forte is there a way to modify what I have above or is there another way to get the correctly formatted url in my output or will I need to parse the output a second time looking for the malformed url and correct it before writing it to the output file?

Answer 1

You can use preg_replace_callback() to achieve this:
Find any string of the format [...]
Try to split them by the delimiter | using explode()
If the split array contains two pieces, then it means the [...] string contains two pieces: the link href and the link anchor text
If not, then it means the the [...] string contains only the link href part
Format and return the link
Code:
$input = <<<EOD
Some text [http://xxxxx.com|About something] some more text
Some text [http://xxxx.com] some more text
EOD;
$output = preg_replace_callback('#\[([^\]]+)\]#', function($m)
{
$parts = explode('|', $m[1]);
if (count($parts) == 2)
{
return sprintf('%s', $parts[0], $parts[1]);
}
else
{
return sprintf('%1$s', $m[1]);
}
}, $input);
echo $output;
Output:
Some text About something some more text
Some text http://xxxx.com some more text
Live demo