Question

Given the redundancy, is there a better way to do this? If so, what would it look like?

Note the first $method argument, which is passed as a function name within the $api class, and must not be passed as an argument to the API function. Every argument thereafter might not exist.

function jsonRequest( $method )
{
    $api = new JsonRpcClient( 'https://api.example.com' );
    switch ( func_num_args() ) {
        case 2:
            $result = $api->$method( 'AccountRef', 'APIKey', func_get_arg( 1 ) );
        break; case 3:
            $result = $api->$method( 'AccountRef', 'APIKey', func_get_arg( 1 ), func_get_arg( 2 ) );
        break; case 4:
            $result = $api->$method( 'AccountRef', 'APIKey', func_get_arg( 1 ), func_get_arg( 2 ), func_get_arg( 3 ) );
        break; case 5:
            $result = $api->$method( 'AccountRef', 'APIKey', func_get_arg( 1 ), func_get_arg( 2 ), func_get_arg( 3 ), func_get_arg( 4 ) );
        break;
    }
    return json_decode( $result );
}

Answer 1

You should use call_user_func_array:

$data = array_merge(array('AccountRef', 'APIKey'), func_get_args());

call_user_func_array(array($api, $method), $data);

Source: http://php.net/manual/en/function.call-user-func-array.php