php curl check if url is reachable before query

Question

We're having problems with an api we are using.

Here is the code we're using (naming no names on the api front)

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'http://apiurl.com/whatever/api/we/call');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$ch_output = curl_exec($ch);
curl_close($ch);

This response times out, but not for ages. This is hideously slowing down our web app, and as such further code breaks because of the bad return value. This I can fix, however the response timeout I don't know how to fix. Is there any way to quickly see if a url is "responding" (e.g. something like ping in terminal) before trying to do a curl request?

Thank you.

But even if you ping it succesfully the second after that it might not respond. — Iznogood
– Iznogood, Commented Feb 17, 2012 at 20:20
Ping has nothing to do here. It can be that ping is present and site is unreachable and vice-versa. And besides - you cannot ping url - only hostnames. — Rok Kralj
– Rok Kralj, Commented Feb 17, 2012 at 20:26

Samar · Accepted Answer · 2012-02-17 20:20:26Z

3

Do you mean usingcurl_setopt($ch,CURLOPT_CONNECTTIMEOUT,NUMERIC_TIMEOUT_VALUE);to set the timeout?

answered Feb 17, 2012 at 20:20

Samar

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4 Comments

goat Over a year ago

Also see CURLOPT_TIMEOUT in case connection happens, but response stalls.

Thomas Clayson Over a year ago

I haven't used that flag so its at the default timeout, whatever that might be. What would be a reasonable timeout value for an api? At the moment the script takes a good minute or so to bother to bail... we really need to cut that down to instant really. What would you use? Is something like 400ms too short? Too long?

goat Over a year ago

You could give it a few seconds, and if it times out, cache that fact for a while. This way other scripts can just do a fast check using your local cache to see if the api was recently unusable. I think 400ms is short, because every so often a dns lookup needs to be performed, and those can easily take 400ms alone, but maybe you're ok with a once in a while false timeout.

Thomas Clayson Over a year ago

Thanks for the info chris. :) How would I know if it has timed out? Would it be if the response is blank?

PFY · Accepted Answer · 2012-02-17 20:21:23Z

2

Your best option would be to set the timeout on curl to a more acceptable level. There are several timeout options available for DNS lookup, connect timeout, transfer timeout, etc. More information is available here http://php.net/manual/en/function.curl-setopt.php

answered Feb 17, 2012 at 20:21

PFY

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