How to debug an issue happening only when a (google) bot requests a page?

Question

My application is throwing a Zend_Locale_Exception when called from googlebot where ZF sends the following error message:

Autodetection of Locale has been failed!

The problem is probably because the default locale isn't set, but how can I debug this?

Since google bot isn't real time I need to actually forge the HTTP Request the bot is making, but how can I find out how this request is being made?

Trying to send the Accept-Language header with curl wouldn't reproduce the error:

   $ch = curl_init();
   curl_setopt($ch, CURLOPT_URL, 'http://www.mysite.com.br/');
   curl_setopt($ch, CURLOPT_HEADER, true);
   curl_setopt($ch, CURLOPT_HTTPHEADER, array('Accept-Language'));
   echo $data = curl_exec($ch);
   curl_close($ch);

EDIT:

to clarify even further:

• I Know the issue is probably the lack of a default locale, but I NEED to debug this
• Changing the user agent of my browser doesn't work, it only changes the UA string, the Locale is still sent from my browser

Answer 1

There is a "Fetch as Googlebot" feature in Google Webmaster Tools. You might be able to use this to trigger the bot hitting your site. You could even temporarily add a phpinfo() page to your site and use the feature to hit that, which will list all the headers in the response that it shows you.