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[ fetch any user input html tag from html document live url using php regular expression ]

I want to fetch any meta, title, script, link tag that is available on HTML page, this is the program i write (not correct but will give idea for experts).

<?php
function get_tag($tag_name, $url)
{
    $content = file_get_contents($url);

    // this is not correct : regular expression please //
    preg_match_all($tag_name, $content, $matches);

    return $matches;
}

print_r(get_tag('title', 'http://stackoverflow.com'));

?>

Output should come something like this :

Array
(
    [0] => title
    [1] => Stack Overflow
)

Thanks!!

Answer 1


Before using regex for parsing HTML, you want to read the first answer from this question.

Try with DOMDocument, like this:

<?

function get_tags($tags, $url) {

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

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

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

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

    //Return the links
    return $tags_found;
}

print_r(get_tags('title', 'http://stackoverflow.com'));

?>

Answer 2


function get_tags($tag, $url) {
//allow for improperly formatted html
libxml_use_internal_errors(true);
// Instantiate DOMDocument Class to parse html DOM
$xml = new DOMDocument();

// Load the file into the DOMDocument object
$xml->loadHTMLFile($url);

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

//Loop through all tags of the given type and store details in the array
foreach($xml->getElementsByTagName($tag) as $tag_found) {
      if ($tag_found->tagName == "meta")
      {
        $tags[] = array("meta_name" => $tag_found->getAttribute("name"), "meta_value" => $tag_found->getAttribute("content"));
      }
      else {
    $tags[] = array('tag' => $tag_found->tagName, 'text' => $tag_found->nodeValue);
     }
}

//Return the links
return $tags;
}

This answer will actually give you the name of the tag as your first array value rather than "array" and will also stop the warning.

Answer 3


Since these tags cannot be nested, parsing is not necessary.

#<(meta|title|script|link)(?: .*?)?(?:/>|>(.*?)<(?:/\1)>)#is

If you are using this with your function, you will have to write $tag_name instead "meta|title|script|link".