Test Website Up/Down

[The Little Guy]

what would be the best way to test a websites up/downtime?

 

I have a program that pings a website every 5 minutes, would that be a good way to test if the site is up or down, or would it be better to do a cURL request to the domain?

 

OR... is there an even better way to test if a domain is up or down?

 

Thanks!

[ManiacDan]

Ping only tells you if there's a working OS at the other end of the line.

 

cURL only tells you if the web server is serving SOMETHING, not necessarily the page itself.

 

You need to combine curl with grep (or preg or whatever) and ensure that the page CONTENTS are coming through.  If I wanted to check if PHPF were up, I would check for the phrase "Page Created In" because that only shows up in the footer and only on successful page load.

[The Little Guy]

I don't think you need to do regexp, I'm sure this would work:

 

<?php
$domains = array("http://asdfasdfaassafaf.com", "http://google.com", "123.123.123.123");
foreach($domains as $domain){
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $domain);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_exec($ch);
$info = curl_getinfo($ch);
curl_close($ch);
if($info['http_code'] == 0)
	echo "Page not served from $domain";
else
	echo "$domain Responded: ".$info['http_code'];
echo "<br>";
}
?>

[Philip]

That could return a 403, 404, 500, etc. return code which means your user doesn't have access to the page. That could be because of the page IS a 404 page or whatever, but it could also mean that you have an error with the server setup.

 

At the least, you should be checking a normal page (non-404 nor authorization required) for a HTTP 200 code. Dan's solution is more robust in making sure your page actually outputs something worthwhile (although if you have dynamic pages you'd have to select something more general like <html)

[The Little Guy]

That could return a 403, 404, 500, etc. return code which means your user doesn't have access to the page. That could be because of the page IS a 404 page or whatever, but it could also mean that you have an error with the server setup.

 

At the least, you should be checking a normal page (non-404 nor authorization required) for a HTTP 200 code. Dan's solution is more robust in making sure your page actually outputs something worthwhile (although if you have dynamic pages you'd have to select something more general like <html)

 

But the web service still responded, which is all I am really after. I don't really care if a page works or not, but whether or not the web service is working.

[ManiacDan]

But if the web service returns a 503 with every request, is that "working?"  That's the question.  What constitutes a "working" website? 

 

If you just want to know if the server is turned on, use ping.

 

If you just want to know if apache is running, use curl with no check.

 

If you just want to know if PHP is working, use curl with preg to pull specific items off a known good page.

 

If you just want to know if the whole end-to-end website is working, perform activity on the site (creating content, changing menu options) and check their results with multiple sequential calls from cURL or some other page-fetching tech.

 

-Dan

[The Little Guy]

For the service I am providing, I think what I posted would be fine. As I am not providing a service to check if you page renders correctly, but if it responds to requests that come into the server.

 

But I still don't know, but.. I do believe that sending a cURL request to the server is the best way to check if a website is up/down, and sending pings to test if a server is up/down. Is there a better way to check, maybe something like http://canyouseeme.org and test port 80?

[scootstah]

There may be times a website doesn't run on port 80, so that wouldn't be 100% accurate.

[ManiacDan]

There isn't much more to say to this, I already gave the whole list.  If you don't think "is port 80 responding" is enough of an indication of "up," then...go down the list.

 

When I wrote the monitoring for softlayer, those were the levels we offered: Ping, tcp connection, tcp response, parsed string response.  (plus a lot more for non-web servers, but that's the web stack)

[Adam]

.. Or if you really want to have a fun day, you can get into automated regression testing.