Parse Web Pages with PHP Simple HTML DOM Parser

// Pull in PHP Simple HTML DOM Parser
include("simplehtmldom/simple_html_dom.php");

// Settings on top
$sitesToCheck = array(
          // id is the page ID for selector
          array("url" => "http://www.arsenal.com/first-team/players", "selector" => "#squad"),
          array("url" => "http://www.liverpoolfc.tv/news", "selector" => "ul[style='height:400px;']")
        );
$savePath = "cachedPages/";
$emailContent = "";

// For every page to check...
foreach($sitesToCheck as $site) {
  $url = $site["url"];

  // Calculate the cachedPage name, set oldContent = "";
  $fileName = md5($url);
  $oldContent = "";

  // Get the URL's current page content
  $html = file_get_html($url);

  // Find content by querying with a selector, just like a selector engine!
  foreach($html->find($site["selector"]) as $element) {
    $currentContent = $element->plaintext;;
  }

  // If a cached file exists
  if(file_exists($savePath.$fileName)) {
    // Retrieve the old content
    $oldContent = file_get_contents($savePath.$fileName);
  }

  // If different, notify!
  if($oldContent && $currentContent != $oldContent) {
    // Here's where we can do a whoooooooooooooole lotta stuff
    // We could tweet to an address
    // We can send a simple email
    // We can text ourselves

    // Build simple email content
    $emailContent = "David, the following page has changed!nn".$url."nn";
  }

  // Save new content
  file_put_contents($savePath.$fileName,$currentContent);
}

// Send the email if there's content!
if($emailContent) {
  // Sendmail!
  mail("david@davidwalsh.name","Sites Have Changed!",$emailContent,"From: alerts@davidwalsh.name","rn");
  // Debug
  echo $emailContent;
}