(PHP) 用于查找特定 href 标记的正则表达式

Question

i have a html document with n "a href" tags with different target urls and different text between the tag.

For example:

<a href="http://www.example.com/d?12345abc" name="example"><span ....>lorem ipsum</span></a>
<a href="http://www.example.com/d/d?abc1234" name="example2"><span ....>example</span></a>
<a href="http://www.example.com/d.1234" name="example3">example3</a>
<a href="http://www.example.com/d/d.1234" name="example4"><img ...>test</img></a>
<a href="http://www.example.com/without_d/1234" name="example3">without a d as target url</a>

As you can see the target urls switch between "d?, d., d/d?, d/d." and between the "a tag" there could be any type of html which is allowed by w3c.

I need a Regex which gives me all links which has one of these combination in the target url: "d?, d., d/d?, d/d." and has "Lorem" or "test" between the "a tags" in any position including sub html tags.

My Regex so far:

href=[\"\']([^>]*?/[d]+[.|\?][^"]*?[\"\'][^>]*[/]?>.*?</a>)

I tried to include the lorem / test as followed:

href=[\"\']([^>]*?/[d]+[.|\?][^"]*?[\"\'][^>]*[/]?>(lorem|test)+</a>)

but this will only works if I put a ".*?" before and after the (lorem|test) and this would be to greedy.

If there is a easier way with SimpleXml or any other DOM parser, please let me know. Otherwise I would appreciate any help with the regex.

Thanks!

Answer 1

Here you go:

$html = array
(
    '<a href="http://www.example.com/d?12345abc" name="example"><span ....>lorem ipsum</span></a>',
    '<a href="http://www.example.com/d/d?abc1234" name="example2"><span ....>example</span></a>',
    '<a href="http://www.example.com/d.1234" name="example3">example3</a>',
    '<a href="http://www.example.com/d/d.1234" name="example4"><img ...>test</img></a>',
    '<a href="http://www.example.com/without_d/1234" name="example3">without a d as target url</a>',
);

$html = implode("\n", $html);
$result = array();
$anchors = phXML($html, '//a[contains(., "lorem") or contains(., "test")]');

foreach ($anchors as $anchor)
{
    if (preg_match('~d[.?]~', strval($anchor['href'])) > 0)
    {
        $result[] = strval($anchor['href']);
    }
}

echo '<pre>';
print_r($result);
echo '</pre>';

Output:

Array
(
    [0] => http://www.example.com/d?12345abc
    [1] => http://www.example.com/d/d.1234
)

The phXML() function is based on my DOMDocument / SimpleXML wrapper , and goes as follows:

function phXML($xml, $xpath = null)
{
    if (extension_loaded('libxml') === true)
    {
        libxml_use_internal_errors(true);

        if ((extension_loaded('dom') === true) && (extension_loaded('SimpleXML') === true))
        {
            if (is_string($xml) === true)
            {
                $dom = new DOMDocument();

                if (@$dom->loadHTML($xml) === true)
                {
                    return phXML(@simplexml_import_dom($dom), $xpath);
                }
            }

            else if ((is_object($xml) === true) && (strcmp('SimpleXMLElement', get_class($xml)) === 0))
            {
                if (isset($xpath) === true)
                {
                    $xml = $xml->xpath($xpath);
                }

                return $xml;
            }
        }
    }

    return false;
}

I'm too lazy not to use this function right now, but I'm sure you can get rid of it if you need to.

Answer 2

Here is a Regular Expression which works:

$search = '/<a\s[^>]*href=["\'](?:http:\/\/)?(?:[a-z0-9-]+(?:\.[a-z0-9-]+)*)\/(?:d\/)?d[?.].*?>.*?(?:lorem|test)+.*?<\/a>/i';
$matches = array();
preg_match_all($search, $html, $matches);

The only thing is it relies on there being a new-line character between each ` tag. Otherwise it will match something like:

<a href="http://www.example.com/d.1234" name="example3">example3</a><a href="http://www.example.com/d/d.1234" name="example4"><img ...>test</img></a>

Answer 3

Use an HTML parser. There are lots of reasons that Regex is absolutely not the solution for parsing HTML.

There's a good list of them here: Robust and Mature HTML Parser for PHP

Answer 4

Will print only first and fourth link because two conditions are met.

preg_match_all('#href="(.*?)"(.*?)>(.*?)</a>#is', $string, $matches);
$count = count($matches[0]);
unset($matches[0], $matches[2]);

for($i = 0; $i < $count; $i++){

    if(
        strpos($matches[1][$i], '/d') !== false 
        &&
        preg_match('#(lorem|test)#is', $matches[3][$i]) == true
    )
    {
        echo $matches[1][$i];    
    }

}