How can I retrieve the favicon of a website?

I want to list featured websites on my website and I thought it would be cool to honor and use their favicon. How do I get it from the domain for an arbitrary URL in either JSP or XSLT? I can fire off PHP or javascript, but XSLT is the preferred methodology.

To get the favicon of a website, you need to load the index HTML of each featured website and check for either of the following:

HTML:

<link rel="icon" type="image/vnd.microsoft.icon" href="http://example.com/image.ico">
<link rel="icon" type="image/png" href="http://example.com/image.png">
<link rel="icon" type="image/gif" href="http://example.com/image.gif">

XHTML:

<link rel="icon" type="image/vnd.microsoft.icon" href="/somepath/image.ico" />
<link rel="icon" type="image/png" href="/somepath/image.png" />
<link rel="icon" type="image/gif" href="/somepath/image.gif" />

Internet Explorer may use a slightly different format:

<link rel="SHORTCUT ICON" href="http://www.example.com/myicon.ico" />

Also note that since most web browsers do not require the HTML link to retrieve a favicon, you should also check for favicon.ico in the website's document root, if none of the above link references are found.

With PHP, it is easy to get the HTML contents of a web page by using file_get_contents($url):

$url = 'http://www.exmaple.com';
$output = file_get_contents($url);

you could also simply do this

http://s2.googleusercontent.com/s2/favicons?domain_url=http://domain.com

Here is my attempt at it. It uses various strategies to work around the many possible cases :

<?
/*
  nws-favicon : Get site's favicon using various strategies

  This script is part of NWS
  https://github.com/xaccrocheur/nws/

*/


function CheckImageExists($imgUrl) {
    if (@GetImageSize($imgUrl)) {
        return true;
    } else {
        return false;
    };
};

function getFavicon ($url) {

$fallback_favicon = "/var/www/favicon.ico";    
// $fallback_favicon = "http://stackoverflow.com/favicon.ico";


    $dom = new DOMDocument();
    @$dom->loadHTML($url);
    $links = $dom->getElementsByTagName('link');
    $l = $links->length;
    $favicon = "/favicon.ico";
    for( $i=0; $i<$l; $i++) {
        $item = $links->item($i);
        if( strcasecmp($item->getAttribute("rel"),"shortcut icon") === 0) {
            $favicon = $item->getAttribute("href");
            break;
        }
    }

    $u = parse_url($url);

    $subs = explode( '.', $u['host']);
    $domain = $subs[count($subs) -2].'.'.$subs[count($subs) -1];

    $file = "http://".$domain."/favicon.ico";
    $file_headers = @get_headers($file);

    if($file_headers[0] == 'HTTP/1.1 404 Not Found' || $file_headers[0] == 'HTTP/1.1 404 NOT FOUND' || $file_headers[0] == 'HTTP/1.1 301 Moved Permanently') {

        $fileContent = @file_get_contents("http://".$domain);

        $dom = @DOMDocument::loadHTML($fileContent);
        $xpath = new DOMXpath($dom);

        $elements = $xpath->query("head/link//@href");

        $hrefs = array();

        foreach ($elements as $link) {
            $hrefs[] = $link->value;
        }

        $found_favicon = array();
        foreach ( $hrefs as $key => $value ) {
            if( substr_count($value, 'favicon.ico') > 0 ) {
                $found_favicon[] = $value;
                $icon_key = $key;
            }
        }

        $found_http = array();
        foreach ( $found_favicon as $key => $value ) {
            if( substr_count($value, 'http') > 0 ) {
                $found_http[] = $value;
                $favicon = $hrefs[$icon_key];
                $method = "xpath";
            } else {
                $favicon = $domain.$hrefs[$icon_key];
                if (substr($favicon, 0, 4) != 'http') {
                    $favicon = 'http://' . $favicon;
                    $method = "xpath+http";
                }
            }
        }

        if (isset($favicon)) {
            if (!CheckImageExists($favicon)) {
                $favicon = $fallback_favicon;
                $method = "fallback";
            }
        } else {
            $favicon = $fallback_favicon;
            $method = "fallback";
        }

    } else {
        $favicon = $file;
        $method = "classic";

        if (!CheckImageExists($file)) {
            $favicon = $fallback_favicon;
            $method = "fallback";
        }

    }
    return $favicon;
}

?>

For Firefox you could use https://addons.mozilla.org/en-US/firefox/addon/httpfox/. Load a website then press F10 > ... > "open HttpFox in own Window" then look for "image/x-icon"; in the column to the right is the URL.

Open the page source code (right click View page source) find the below mentioned line, click the images/favicon.png link.

<link rel="icon" href="images/favicon.png" type="image/png" sizes="16x16">

user11302523

Using IE, bookmark the site
Drag the shortcut from your bookmarks menu onto your desktop
Open the resulting .URL using a (real) text editor
There will be a line in the file for IconFile, which will point to the favicon file on the web server
Browse to the file... viola!

来源：https://stackoverflow.com/questions/1990475/how-can-i-retrieve-the-favicon-of-a-website

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web

favicon