I recently have been working on a weather recording project and as part of this endeavour wanted to check that all of the variables I have posted to my API were set, it can be rather a lot of work to have to specify each if (!isset($_GET[])) parameter so I decided to use a function that can take any number of arguments using a ‘variadic’ function in PHP.

// Returns true if all variables are set, else returns false.
function getVariablesSet(string ...$getlinks) {
      foreach ( $getlinks as $link ) {
        if (!isset($_GET[$link]))
        {
            return false;
        }
    }
    return true;
}

Now, when I want to use a new api ‘command’, I can simply do the following,

$browser_response = new stdClass();
$browser_response->message = "Command not specified.";

if ($_GET['command'] == "new-temperature")
    {
        if (getVariablesSet("datetime","temperature","humidity"))
        {
            $browser_response->message = "All GET variables set.";
        }
        else
        {
            $browser_response->message = "All GET variables not set.";
        }
    }

echo json_encode($browser_response);

This way, so long as we have specified the command and the variables required we can enter the scope, otherwise, we can kick them out until their query is formatted correctly. Having lots of variables may become problematic so you may want to use POST or even break them out into subsections to give users a better understanding of their error. I should add this only works for PHP 5.6 and above.

In any capacity, Good Luck. Aidan.