In the context of blacklisting websites, what considerations should be made when deciding to block entire domains versus specific subpages?

When deciding whether to block entire domains or specific subpages, it is important to consider the potential impact on legitimate content and user experience. Blocking entire domains may be more effective at preventing access to harmful content, but it could also inadvertently block access to other useful resources hosted on the same domain. On the other hand, blocking specific subpages allows for more targeted filtering but may require more maintenance to keep up with new harmful content.

// Example of blocking entire domain
$blocked_domains = array("example.com", "malicious.com");
if (in_array(parse_url($url, PHP_URL_HOST), $blocked_domains)) {
    // Block access to the entire domain
    header("HTTP/1.1 403 Forbidden");
    exit;
}

// Example of blocking specific subpages
$blocked_subpages = array("example.com/badpage", "malicious.com/evilpage");
if (in_array($url, $blocked_subpages)) {
    // Block access to the specific subpage
    header("HTTP/1.1 403 Forbidden");
    exit;
}