Twilio REST API unresponsive - php

Question

I have created a soft phone for use with Twilio, using Twilio.js (1.4) and the Twilio REST API.
On the connection callback, I have a need to fetch the childSid for a call. To accommodate this I created a route in my Laravel app to use the Calls list resource and get it into the browser using jQuery.get() on the connection callback.
For some reason the API does not respond at all if I don't first wait about 12 seconds after the initial connection. After using sleep(12) in my PHP function I can successfully read the calls and filter for the ParentSid with no issues.
Is there a reason the API will not respond if invoked too soon after a connection is made via Twilio.js? It seems to only do this when I'm using $client->calls>read(). I have no problem retrieving a parentCallSid from a call immediately using $client->calls($callSid)->fetch().
Here is the original code:
public function showChildCallSid(Request $request, Client $client) {
$callSid = $request->input('CallSid');
sleep(12); // only works after waiting about 12 seconds
$call = $client->calls->read(['ParentCallSid' => $callSid])[0];
return $call->sid;
}

Answer 1

I believe the issue was ultimately a problem with syntax. I revised to the code as shown below and it works very well now (only needing a 1-second pause usually):
public function showChildCallSid(Request $request, Client $client) {
$callSid = $request->input('CallSid');
$attempt = 1;
$maxAttempts = 15;
do {
$calls = $client->calls->read(['ParentCallSid' => $callSid]);
if (sizeof($calls) > 0) {
break;
}
sleep(1);
$attempt++;
} while ($attempt < $maxAttempts);
$childSid = $calls[0]->sid;
return $childSid;
}