Getting title and meta tags from external website

<?php
// Assuming the above tags are at www.example.com
$tags = get_meta_tags('http://www.example.com/');

// Notice how the keys are all lowercase now, and
// how . was replaced by _ in the key.
echo $tags['author'];       // name
echo $tags['keywords'];     // php documentation
echo $tags['description'];  // a php manual
echo $tags['geo_position']; // 49.33;-86.59
?>

get_meta_tags will help you with all but the title. To get the title just use a regex.

$url = 'http://some.url.com';
preg_match("/<title>(.+)<\/title>/siU", file_get_contents($url), $matches);
$title = $matches[1];

Hope that helps.

Shouldnt we be using OG?

The chosen answer is good but doesn't work when a site is redirected (very common!), and doesn't return OG tags, which are the new industry standard. Here's a little function which is a bit more usable in 2018. It tries to get OG tags and falls back to meta tags if it cant them:

function getSiteOG( $url, $specificTags=0 ){
    $doc = new DOMDocument();
    @$doc->loadHTML(file_get_contents($url));
    $res['title'] = $doc->getElementsByTagName('title')->item(0)->nodeValue;

    foreach ($doc->getElementsByTagName('meta') as $m){
        $tag = $m->getAttribute('name') ?: $m->getAttribute('property');
        if(in_array($tag,['description','keywords']) || strpos($tag,'og:')===0) $res[str_replace('og:','',$tag)] = $m->getAttribute('content');
    }
    return $specificTags? array_intersect_key( $res, array_flip($specificTags) ) : $res;
}

How to use it:

/////////////
//SAMPLE USAGE:
print_r(getSiteOG("http://www.stackoverflow.com")); //note the incorrect url

/////////////
//OUTPUT:
Array
(
    [title] => Stack Overflow - Where Developers Learn, Share, & Build Careers
    [description] => Stack Overflow is the largest, most trusted online community for developers to learn, shareâ âtheir programming âknowledge, and build their careers.
    [type] => website
    [url] => https://stackoverflow.com/
    [site_name] => Stack Overflow
    [image] => https://cdn.sstatic.net/Sites/stackoverflow/img/apple-touch-icon@2.png?v=73d79a89bded
)

A simple function to understand how to retrieve og:tags, title and description, adapt this for yourself

function read_og_tags_as_json($url){


    $ch = curl_init();

    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);

    $HTML_DOCUMENT = curl_exec($ch);
    curl_close($ch);

    $doc = new DOMDocument();
    $doc->loadHTML($HTML_DOCUMENT);

    // fecth <title>
    $res['title'] = $doc->getElementsByTagName('title')->item(0)->nodeValue;

    // fetch og:tags
    foreach( $doc->getElementsByTagName('meta') as $m ){

          // if had property
          if( $m->getAttribute('property') ){

              $prop = $m->getAttribute('property');

              // here search only og:tags
              if( preg_match("/og:/i", $prop) ){

                  // get results on an array -> nice for templating
                  $res['og_tags'][] =
                  array( 'property' => $m->getAttribute('property'),
                          'content' => $m->getAttribute('content') );
              }

          }
          // end if had property

          // fetch <meta name="description" ... >
          if( $m->getAttribute('name') == 'description' ){

            $res['description'] = $m->getAttribute('content');

          }


    }
    // end foreach

    // render JSON
    echo json_encode($res, JSON_PRETTY_PRINT |
    JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);

}

Return for this page (may have more infos) :

{
    "title": "php - Getting title and meta tags from external website - Stack Overflow",
    "og_tags": [
        {
            "property": "og:type",
            "content": "website"
        },
        {
            "property": "og:url",
            "content": "https://stackoverflow.com/questions/3711357/getting-title-and-meta-tags-from-external-website"
        },
        {
            "property": "og:site_name",
            "content": "Stack Overflow"
        },
        {
            "property": "og:image",
            "content": "https://cdn.sstatic.net/Sites/stackoverflow/Img/apple-touch-icon@2.png?v=73d79a89bded"
        },
        {
            "property": "og:title",
            "content": "Getting title and meta tags from external website"
        },
        {
            "property": "og:description",
            "content": "I want to try figure out how to get the\n\n<title>A common title</title>\n<meta name=\"keywords\" content=\"Keywords blabla\" />\n<meta name=\"description\" content=\"This is the descript..."
        }
    ]
}

My solution (adapted from parts of cronoklee's & shamittomar's posts) so I can call it from anywhere and get a JSON return. Can be easily parsed into any content.

<?php
header('Content-type: application/json; charset=UTF-8');

if (!empty($_GET['url']))
{
    file_get_contents_curl($_GET['url']);
}
else
{
    echo "No Valid URL Provided.";
}


function file_get_contents_curl($url)
{
    $ch = curl_init();

    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);

    $data = curl_exec($ch);
    curl_close($ch);

    echo json_encode(getSiteOG($data), JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
}

function getSiteOG( $OGdata){
    $doc = new DOMDocument();
    @$doc->loadHTML($OGdata);
    $res['title'] = $doc->getElementsByTagName('title')->item(0)->nodeValue;

    foreach ($doc->getElementsByTagName('meta') as $m){
        $tag = $m->getAttribute('name') ?: $m->getAttribute('property');
        if(in_array($tag,['description','keywords']) || strpos($tag,'og:')===0) $res[str_replace('og:','',$tag)] = utf8_decode($m->getAttribute('content'));

    }

    return $res;
}
?>

I've got this working a different way and thought I'd share it. Less code than others and found it here. I've added a few things to make it load the page meta that you are on instead of a certain page. I wanted this to copy the default page title and description into the og tags automatically.

For some reason though, whatever way (different scripts) I tried, the page loads super slow online but instant on wamp. Not sure why so I'm probably going with a switch case since the site is not huge.

<?php
$url = 'http://sitename.com'.$_SERVER['REQUEST_URI'];
$fp = fopen($url, 'r');

$content = "";

while(!feof($fp)) {
    $buffer = trim(fgets($fp, 4096));
    $content .= $buffer;
}

$start = '<title>';
$end = '<\/title>';

preg_match("/$start(.*)$end/s", $content, $match);
$title = $match[1];

$metatagarray = get_meta_tags($url);
$description = $metatagarray["description"];

echo "<div><strong>Title:</strong> $title</div>";
echo "<div><strong>Description:</strong> $description</div>";
?>

and in the HTML header

<meta property="og:title" content="<?php echo $title; ?>" />
<meta property="og:description" content="<?php echo $description; ?>" />

Improved answer from @shamittomar above to get the meta tags (or the specified one from html source)

Can be improved further... the difference from php's default get_meta_tags is that it works even when there is unicode string

function getMetaTags($html, $name = null)
{
    $doc = new DOMDocument();
    try {
        @$doc->loadHTML($html);
    } catch (Exception $e) {

    }

    $metas = $doc->getElementsByTagName('meta');

    $data = [];
    for ($i = 0; $i < $metas->length; $i++)
    {
        $meta = $metas->item($i);

        if (!empty($meta->getAttribute('name'))) {
            // will ignore repeating meta tags !!
            $data[$meta->getAttribute('name')] = $meta->getAttribute('content');
        }
    }

    if (!empty($name)) {
        return !empty($data[$name]) ? $data[$name] : false;
    }

    return $data;
}