Performs a cURL-Request to check, if a website exists / is online
Technique #1
<?php
if (isDomainAvailible('https://css-tricks.com'))
{
echo "Up and running!";
}
else
{
echo "Woops, nothing found there.";
}
//returns true, if domain is availible, false if not
function isDomainAvailible($domain)
{
//check, if a valid url is provided
if(!filter_var($domain, FILTER_VALIDATE_URL))
{
return false;
}
//initialize curl
$curlInit = curl_init($domain);
curl_setopt($curlInit,CURLOPT_CONNECTTIMEOUT,10);
curl_setopt($curlInit,CURLOPT_HEADER,true);
curl_setopt($curlInit,CURLOPT_NOBODY,true);
curl_setopt($curlInit,CURLOPT_RETURNTRANSFER,true);
//get answer
$response = curl_exec($curlInit);
curl_close($curlInit);
if ($response) return true;
return false;
}
?>
Technique #2
<?php
function Visit($url){
$agent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";$ch=curl_init();
curl_setopt ($ch, CURLOPT_URL,$url );
curl_setopt($ch, CURLOPT_USERAGENT, $agent);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch,CURLOPT_VERBOSE,false);
curl_setopt($ch, CURLOPT_TIMEOUT, 5);
curl_setopt($ch,CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch,CURLOPT_SSLVERSION,3);
curl_setopt($ch,CURLOPT_SSL_VERIFYHOST, FALSE);
$page=curl_exec($ch);
//echo curl_error($ch);
$httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
if($httpcode>=200 && $httpcode<300) return true;
else return false;
}
if (Visit("http://www.google.com"))
echo "Website OK"."n";
else
echo "Website DOWN";
?>
Technique #3
<?php
ini_set("default_socket_timeout","05");
set_time_limit(5);
$f=fopen("https://css-tricks.com","r");
$r=fread($f,1000);
fclose($f);
if(strlen($r)>1) {
echo("<span class='online'>Online</span>");
}
else {
echo("<span class='offline'>Offline</span>");
}
?>
In technique #2 it should probably read
... && $httpcode<400) return true;
instead of
... && $httpcode<300) return true;
Otherwise a redirect would be regarded as “server down”.
Hello NetHawk.
I tested and you are totally right. $httpcode<300 always returns server down.
Anyway, I made a little modification so I can test several sites, but sometimes, sites appear down randomly, what could be wrong if you can help me? I tried to do this for a cron job.
CODE:
=200 && $httpcode”.$sitio.””;
else
echo “DOWN->”.$sitio.””;
}
?>
It seems like code was cutted… Anyway, the only modification I made, was put urls in an array, then test one by one in a foreach loop.
Here is an alternative for this method : http://www.softwaregeneration.org/downforeveryoneorjustme
how to use it ?????????
what is the method
Copy code from example #2 into a text file. Give it the extension .php. Move the file to your webserver and call the url that points to the file. If you have a PHP enabled server (most are) the code will check if Google is up (probably always).
You can take it from there, but you will need some basic PHP knowledge.
Which technique is better to use? advantages? disadvantages?
#1 checks if the url is valid, that’s a great plus, if the urls are entered by a user and don’t come out of a database or from a list with urls known to be valid.
#2 on the other hand submits a user agent string. Without it, some server will answer the request with a error 403 (forbidden) or 405 (method not allowed).
Conclusion: I suggest #2 but with the filter test of #1.
Actually, Chris should say something about this, because he is running aremysitesup.com, a service that probably uses this technique (see button in the footer of this page – great service, highly recommended).
We actually use Ruby and some methods that are far more complex =). But the principal is the same.
Thanks! I’m wondering if http://www.checksite.us uses the same method?
Also, what is the purpose of the agent?
Checksite.us is probably based on a similar mechanism, although it’s not clear what language is used.
The UserAgent is a string sent by any browser to identify itself. At least, that was the intention. Nowadays many browser lie about the details. However, as long as a UserAgent is sent, the web server usually sees a request as legitimate. Also robots, e.g. Google have UserAgent strings to identify them.
If no UserAgent string is sent, some web server don’t let you access the site for whatever reason (they probably don’t like the idea that some tool or other server accesses their pages directly).
You can see the UserAgent string of your browser (among other information) on this page:
http://browser.delucamarketing.ch/
They use php and I think code is similar to the example but with some changes, http is not needed in their form and it is needed in the example on this website however it’s easy to add a function that is able to strip or add http:// or other parts eg if you do not want to allow subdomains to be checked like alexa.com is replacing parts of url’s..
checksite.us has an index.php file so it is using php, 99% sure: http://www.checksite.us/index.php?url=www.awesomehosting.nl I have scripts to display information about websites and to extract information send by their server…
Thank you for sharing!
none of these techniques really seem to work…everytime i check something like http://www.adfsfdasffsfasfsf.com it always comes back as 200…does anyone know of a way to find out if a website is unavailable like *cough* *cough* godaddy *cough* *cough*
It is a simple whois look up. You need to create a socket connection on port 43. It is just getting PHP to connect to the exact same whois server terminal uses when you do a whois lookup.
It is a simple whois look up. You need to create a socket connection on port 43. It is just getting PHP to connect to the exact same whois server terminal uses when you do a whois lookup.
Sorry for some reason it is not showing the code, you can find a good tut at http://www.phptoys.com/e107_plugins/content/content.php?content.38 which details how to build one.
There’s another solution that uses sockets:
http://neo22s.com/check-if-url-exists-and-is-online-php/
Hi Chris,
Any idea, how can I check if a bunch of URLS are valid. For example. I need to run a check on 1000 twitter profiles and I need to know if they are active or invalid URLS. I want to be able to paste the entire list of twitter urls and check if they are valid pages.
Nice,
But is there any API from who.is to check it? I think using web services will help the cause more effectively. Say as I did in getting the alexa ranking,
http://tutology.net/category/how-php/get-alexa-rank-php-and-alexa-api
Great concepts
Seems to me that these scripts wouldn’t actually work if there was a redirect. So “facebook.com” and “www.facebook.com” might return different results even if the site was up.
No?
Anyone know how “downforeveryoneorjustme.com” does it? That script seems to work every time, redirects or not…
Those codes are not bulletproof. I tried different domains at isitdownrightnow.com and the script fails on some domains. ask.com is such an example.
http://www.downforeveryoneorjustme.com/ask.com
However it works at Doj.me.. Not sure what method they are using…
http://doj.me/?url=ask.com
Hello,
Thanks for the tuts. But, one question though. How do you make sure that it is not your internet connection that has disconnected?
Thanks a lot.
You wouldn’t have even been able to connect to the server to run the script if this was the case : )
Hello
None of these scripts work for me!
I am trying to get the script to tell me if my server is online. I have no domain, so I’m using the IP (and somtimes a port).
When i have entered the IP to my server, it says it’s online.
Also; when I am shutting down the server, it still says it’s online…
How can I fix this? Any ideas?
– Mystic
That’s a good technique and a very similar technique is posted here : http://geeks-wiki.blogspot.com/2012/10/how-to-check-if-url-is-up.html , i think this technique is similar yet effective.
Best,
Patrick
Thank’s
it’s very use full trick #2
it’s solve my issue check 500 URL at one time
So hard :D Thanks
I have this situation where the url redirects to another url which is dead. How can I check for this kind of errors?
I started using technique 1 and some links were not reported correctly so I added technique 2 and the combination seems to be working fine:
“Availible” is not a word.
It’s a word
Grammar Police, this is a false arrest! “Availible” is not a grammatical error, so you have no jurisdiction.
Typo Police, at ease; Spelling Police, arrest that offender, pronto!
Given script are very useful, I was looking such script to check site is live or not, But few more things if you can add, Some sites are up but parked, any way to check that, sites are properly hosted on server not parked
hmm.. none of the methods above work for me ? aka
1. and 2. method return always true and 3rd throws errors like a baws
EDIT: 2. Method works but it’s inverted for me (ture -> DOWN, false -> UP) … don’t ask me why
Hi guys..
I thonk, just use this one..
http://www.phpservermonitor.org/
This can only tell you if server is up or down
But can not really tell if website is down suspended, 500 error and so on
I see a lot of people having problems here.
Be sure that if you use example two, that you see NetHawk’s comment about making 200<=$httpcode<400.
Also, it’s good practice to declare functions with the first letter being lowercase.
Much love for CSS Tricks over here.
Curtis
See I have a form which has website to be taken. We have to check if the website is valid or not. Where should I embed the codes? That is, in the #1, the url has to be manually entered. But I need it to be done automatically. How am is supposed to do it ?
I tested and you are totally right.but i had doubt. this scripts used for one domain. but, i need to know 50 domain is working or not at a ti me.
pls reply
Hi,
Firstly, thanks for the scripts. They are very useful.
I have used your script #1 on a site recently to check a known JSON source was available and if not switch to a backup. I haven’t changed the 300 response to 400, as mentioned above, as both sites are known and controlled by me so are not redirected.
The problem I had the other day was that an AWS server hung. What I found was that because this script uses CURLOPT_CONNECTTIMEOUT the connection was made then the script just stayed open waiting for a response. As the site had more and more pages open, it filled up PHP memory and the site eventually went down. As soon as I switched the AWS server off, the script handled the response as it should.
After this I have been looking for a fix to the hanging server issue. I have a test page based on your script #2 (for some reason #1 won’t work on that site). I have just added the middle line below: –
$agent = “Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)”;$ch=curl_init();
curl_setopt($curlInit,CURLOPT_CONNECTTIMEOUT_MS,500);
curl_setopt ($ch, CURLOPT_URL,$url );
Is using $curlInit correct in with the $ch lines?
With script #1, could I add the
curl_setopt($ch, CURLOPT_TIMEOUT_MS, 2000);
or should I make that: –
curl_setopt($curlInit, CURLOPT_TIMEOUT_MS, 2000);
Lastly, I can easily test the server being down by switching it off in the EC2 console, but do you know how I can test what happens if the server is hung? Is there a “well hung” server that I can try and connect to anywhere for testing purposes?
Sorry, so many questions, and so little knowledge on my part!
you can use online alternative method >>>>https://downforeveryoneorjust.me/ to check