PHP: Retrying a query a set number of times or until success

Question

I'm doing a query to the Alexa API which, for some unknown reason, will occasionally fail. When it does fail, I want to automatically retry the query, up to 10 times.

When it fails, the response returned by the API contains the substring AuthFailure.

What kind of loop can I do that will retry the query until either the response returned does not contain the substring AuthFailure or 10 retries have been attempted?

Answer 1

You could do this with a for loop.

for($i=0; $i < 10; $i++) {
    $return = (Alexa call here)
    if(!strstr($return,"AuthFailure")
        break;
}

Adjust 10 to whatever number you wish. Better yet, use a constant define()'ed elsewhere. This will run until the number of tries is exhausted or until the return value does not contain "AuthFailure".

Answer 2

I'd do something like this:

define('ALEXA_FAILED', 'AuthFailure');

$response = ALEXA_FAILED;
$tries = 0;

while ($tries <= 10 && stripos($response, ALEXA_FAILED) !== FALSE)
{
    $response = GetAlexaResponse();
    $tries++;
}

Answer 3

Personally I would wrap the call up in a function e.g.:

public function getAlexaResponse($aParam)
{
   //code that does the call
   return $response;
}

I would the extend that function with an additional param and call it recursively:

public function getAlexaResponse($aParam, $attempts = 10)
{
   //code that does the call
   if(!strstr($response,"AuthFailure") && ($attempt > 0)){
       $this->getAlexaResponse($aParam, --$attempts);
   }
   return $response;
}