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Testing URL

nicey
nicey asked
on
433 Views
Last Modified: 2008-08-15
Hello.

I'm trying to test that a given URL is active on the Internet.

I'm using the following (before this though, i'm using Regular Expresssions to first check that the URL "looks" valid) :

--------------------------------------------------------------------------------
function testURL($url) {

  $urlArray = parse_url($url);
  if (isset($urlArray['query'])) {
   $urlArray['query'] = "?" . $urlArray['query'];
  } else {
   $urlArray['query'] = "";
  }

  $header = "GET " . $urlArray['scheme'] . "://" . $urlArray['path'] . $urlArray['query'] . " HTTP/1.0\r\n\r\n";

  $gotInfo = false;
  $found = false;
 
  if (($fp = @fsockopen($urlArray['host'], 80, $errno, $errstr, 5))) {
   if (fputs ($fp, $header)) {
    if (($snippet = fgets ($fp, 1024)) && ($snippet != "")) {
     $gotInfo = true;
    }
   }
   fclose($fp);
  }

  if ($gotInfo) {
   if ((stristr($snippet, '200 OK')) || (stristr($snippet, '302 Found')) || (stristr($snippet, '304 Not Modified'))) {
    $found = true;
   }
  }

  return $found;
 }
--------------------------------------------------------------------------------


And it seems ok, most of the time.

Only, some websites return Error 404 pages, even though the given URL is valid if you put it into a browser address bar.

Also, if a custom Error 404 is employed by a site, this function returns "true", as I assume that upon the server redirecting the target page sends our a 200 OK header?

Also, somtimes when you give it what is clearly a non existent domain, the function returns "true". Put the non-existent URL into a browser, and its shows "Page Cannot Be Displayed".

What way is there to test that a page is valid, without these problems?
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