Apache crashes, probably because of this piece of php code. Can you have a look?

Question

I am working on the development of a web based application on codeigniter. I wrote this function to get the timezone data for any city or address.

function gettimezone($address)
    {
       $_url = 'http://api.local.yahoo.com/MapsService/V1/geocode';
        $_url .= sprintf('?appid=%s&location=%s',"phpclasses",rawurlencode($address));
        $_result = false;
        if($_result = file_get_contents($_url)) {
            preg_match('!<Latitude>(.*)</Latitude><Longitude>(.*)</Longitude>!U', $_result, $_match);
            $lng = $_match[2];
            $lat = $_match[1]; 
            $url = "http://ws.geonames.org/timezone?lat={$lat}&amp;lng={$lng}";
            $timedata = file_get_contents($url);
            $sxml = simplexml_load_string($timedata);
            return $sxml->timezone;
        } 
        else
            return false;
    }

I am working on Windows 7 and xampp 1.7 (php 5.2.8).
Is there any possible scenario where this piece of code would crash Apache? The application runs fine almost everytime, but I think running this piece of code when there is no internet connectivity or very poor internet connectivity (thereby no access to either of the webservices I have used) brings down the server. Something like this happened a few times and I think it was due to loss of internet connectivity but I am not sure what exactly is going on.

[ By the way, feel free to use this piece of code. Makes 2 web service calls so don't use to too often in your application. Consider storing the results in a database.]

Edit: This piece of code and my application works perfectly, almost every time. It just crashed Apache a couple of times a few days ago. And I think its this function is the culprit as this was one of the things that was added just before those crashes.

Edit 2: Here is a small snippet of my apache error log that doesn't look right. This is there in the log a few times, and I think(quite sure actually) it corresponds to the server crash. Apart from this, there are a few "file does not exist" errors, which won't crash the server

[Mon May 24 12:14:26 2010] [notice] Parent: child process exited with status 3221225477 -- Restarting.
[Mon May 24 12:15:29 2010] [warn] pid file c:/xampp/apache/logs/httpd.pid overwritten -- Unclean shutdown of previous Apache run?

Answer 1

Apart from absence of internet connectivity, it won't work if the allow_url_fopen is set to false from php.ini file and for this reason, file_get_contents function won't fetch data from a url.

Answer 2

Since there is no Error StackTarace or error log, I suspect the cause of the problem might be:

 $url = "http://ws.geonames.org/timezone?lat={$lat}&lng={$lng}";

Because you are trying to get somedata from another web service, so this might be the problem.

I would say, put a try/catch around that section like this:

try
{
    $url = "http://ws.geonames.org/timezone?lat={$lat}&lng={$lng}";
    $timedata = file_get_contents($url);
    $sxml = simplexml_load_string($timedata);
}
catch(Exception $e)
{
    // log this exception to file
}
return $sxml->timezone;

Like you said, it works most of the time. So leave it now and after a week or so, come back and see if the error log contains something interesting for you.