11.8. Extracting Links from an HTML File
Problem
You need to extract the URLs that are specified inside an HTML document.
Solution
Use the pc_link_extractor( )
function shown in Example 11-2.
Example 11-2. pc_link_extractor( )
function pc_link_extractor($s) { $a = array(); if (preg_match_all('/<a\s+.*?href=[\"\']?([^\"\' >]*)[\"\']?[^>]*>(.*?)<\/a>/i', $s,$matches,PREG_SET_ORDER)) { foreach($matches as $match) { array_push($a,array($match[1],$match[2])); } } return $a; }
For example:
$links = pc_link_extractor($page);
Discussion
The pc_link_extractor( )
function returns an array. Each element
of that array is itself a two-element array. The first element is the
target of the link, and the second element is the text that is
linked. For example:
$links=<<<END Click <a href="http://www.oreilly.com">here</a> to visit a computer book publisher. Click <a href="http://www.sklar.com">over here</a> to visit a computer book author. END; $a = pc_link_extractor($links); print_r($a); Array ( [0] => Array ( [0] => http://www.oreilly.com [1] => here ) [1] => Array ( [0] => http://www.sklar.com [1] => over here ) )
The regular expression in pc_link_extractor( )
won’t work on all links, such as those that are
constructed with JavaScript or some hexadecimal escapes, but it
should function on the majority of reasonably well-formed HTML.
See Also
Recipe 13.8 for information on capturing text inside HTML tags;
documentation on preg_match_all( )
at
http://www.php.net/preg-match-all.
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