// File to download
$remoteFile = 'http://www.yahoo.com/';

// Local file for saving
$localFile = "YahooHome.htm";

// Time to cache in hours
$cacheTime = 24;

// Connection time out
$connTimeout = 10;

if(file_exists($localFile) && (time() - ($cacheTime * 3600) < filemtime($localFile))){
     readfile($localFile);
}else{
     $url = parse_url($remoteFile);
     $host = $url['host'];
     $path = isset($url['path']) ? $url['path'] : '/';

     if (isset($url['query'])) {
          $path .= '?' . $url['query'];
     }

     $port = isset($url['port']) ? $url['port'] : '80';

     $fp = @fsockopen($host, '80', $errno, $errstr, $connTimeout );

     if(!$fp){
          // If connection failed, return the cached file
          if(file_exists($localFile)){
               readfile($localFile);
          }
     }else{
          // Header Info
          $header = "GET $path HTTP/1.0
";
          $header .= "Host: $host
";
          $header .= "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6
";
          $header .= "Accept: */*
";
          $header .= "Accept-Language: en-us,en;q=0.5
";
          $header .= "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
";
          $header .= "Keep-Alive: 300
";
          $header .= "Connection: keep-alive
";
          $header .= "Referer: http://$host

";

           $response = '';
          fputs($fp, $header);
          // Get the file content
          while($line = fread($fp, 4096)){
               $response .= $line;
          }
          fclose( $fp );

          // Remove Header Info
          $pos = strpos($response, "

");
          $response = substr($response, $pos + 4);
          echo $response;

          // Save the file content
          if(!file_exists($localFile)){
               // Create the file, if it doesn't exist already
               fopen($localFile, 'w');
          }
          if(is_writable($localFile)) {
               if($fp = fopen($localFile, 'w')){
                    fwrite($fp, $response);
                    fclose($fp);
               }
          }
     }
}

Remote File Saving

PHP