Re: Regex pattern for preg_match_all

Le 19/02/2011 0:23, Tommy Pham a écrit :

@Simon, Thanks for explaining about the [^href]. I need to read up more about greediness. I thought I understood it but guess not. @Peter, I tried your pattern but it didn't capture all of my new test cases. Also, it captures the single/double quotes in addition to the fragments inside the href. I couldn't figure out how to modify your pattern to exclude the ', ", and URL fragment from group 1 matches. Below is the new pattern with the new sample test cases that I got it to work. The new pattern failed only 1 of the non-compliant. $html =<<<HTML <a href=/sample/link>content</a> <a class=link href=/sample/link_extra_attribs title=sample link>content link_extra_attribs</a> <a href='/sample/link_single_quote'>content link_single_quote</a> <a class='link' href='/sample/link_single_quote_pre_attribs'>content link_single_quote_pre_attribs</a> <a class='link' href='/sample/link_single_quote_extra_attribs' title='sample link'>content link_single_quote_extra_attribs</a> <a class='link' href='/sample/link_single_quote_extra_attribs_frag#fragment' title='sample link'>content link_single_quote_extra_attribs_frag#fragment</a> <a class='link' href='/sample/link_single_quote_extra_attribs_query_frag?par=val#fragment' title='sample link'>content link_single_quote_extra_attribs_query_frag?par=val#fragment</a> <a href="/sample/link_double_quote">content link_double_quote</a> <a class="link" href="/sample/link_double_quote_pre_attribs">content link_double_quote_pre_attribs</a> <a class="link" href="/sample/link_double_quote_extra_attribs_frag#fragment" title="sample link">content link_double_quote_extra_attribs_frag#fragment</a> <a class="link" href="/sample/link_double_quote_extra_attribs_nested_tag" title="sample link"><img class="image" src="/images/content.jpg" alt="content" title="content"> link_double_quote_extra_attribs_nested_tag</a> <a href="#fragment">content fragment</a> <a class="link" href="#fragment" title="sample link">content fragment</a> <li class="small tab "><a class="y-mast-link images" href="http://images.search.yahoo.com/images" data-b="http://www.yahoo.com"><span class="tab-cover y-mast-bg-hide" style="padding-left:0em;padding-right:0em;">Images</span></a></li> <li class="small tab "><a class="y-mast-link video" href="http://video.search.yahoo.com/video" data-b="http://www.yahoo.com"><span class="tab-cover y-mast-bg-hide" style="padding-left:0em;padding-right:0em;">Video</span></a></li> <li class="small tab "><a class="y-mast-link local" href="http://local.yahoo.com/results" data-b="http://www.yahoo.com"><span class="tab-cover y-mast-bg-hide" style="padding-left:0em;padding-right:0em;">Local</span></a></li> <li class="small tab "><a class="y-mast-link shopping" href="http://shopping.yahoo.com/search" data-b="http://www.yahoo.com"><span class="tab-cover y-mast-bg-hide" style="padding-left:0em;padding-right:0em;">Shopping</span></a></li> <li class="small lasttab more-tab "><a class="y-mast-link more" href="http://tools.search.yahoo.com/about/forsearchers.html"><span class="tab-cover y-mast-bg-hide">More</span><span class="y-fp-pg-controls arrow"></span></a></li> HTML; $pattern = '%<a[\s]+[^>]*?href\s*=\s*["\']?([^"\'#>]*)["\']?\s?[^>]*>(.*?)</a>%ims'; preg_match_all($pattern, $html, $matches); Thanks for your time, Tommy

Hi Tommy, This is why you shouldn't mix regexes and HTML/XML, especially when you are not sure that you are working with valid/consistent html. A great/fun answer has been posted on StackOverflow about this at http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454 You could easily break any regular expressions solution by adding some valid comments, see example here : http://stackoverflow.com/questions/1357357/regexp-to-add-attribute-in-any-xml-tags/1357393#1357393 You really should consider using a XML parser instead for this kind of job. Here is a simple sample that matches your example : <?php $oTidy = new tidy(); $html = $oTidy->repairString($html,array("clean" => true, "drop-proprietary-attributes" => true)); unset($oTidy); $matches = get_links($html); function get_links($html) {

    // Create a new DOM Document to hold our webpage structure
    $xml = new DOMDocument();

    // Load the url's contents into the DOM
    $xml->loadHTML($html);

    // Empty array to hold all links to return
    $links = array();

    //Loop through each <a> tag in the dom and add it to the link array
    foreach($xml->getElementsByTagName('a') as $link) {
        $links[] = array('url' => $link->getAttribute('href'), 'text' => $link->nodeValue);
    }

    //Return the links
    return $links;

} ?> Regards, Yann