How do I use CRM_Utils_Request::retrieve when the POSTed field is an array?

Question

In the snippet below, I build api calls by looping through each student, and then each event within that. However, the field data is coming straight from the request with no server-side validation. Is it possible to use the Request class for array variables? If so, how would I implement it in my code below? What's the proper syntax?

  foreach ($_POST['student_details'] AS $student_record){

    $student_details = array(
          'sequential'  => 1,
          'debug' => 1,
          'contact_type' => 'Individual',
          'contact_sub_type' => 'Student',
          'first_name'  =>  $student_record['student_first_name'],
          'last_name'   => $student_record['student_last_name'],
          'gender_id'   =>  $student_record['gender_id'],
          'birth_date'  => $student_record['birth_date'],
          'custom_8'   => $student_record['shirt_size'],
          'custom_9'   => $student_record['allergies'],
          'api.Relationship.create' => array (
                  'sequential' => 1,
                  'contact_id_a' => '$value.id',
                  'contact_id_b' => $parent_id,
                  'relationship_type_id' => 1,
                  'is_permission_a_b' => 0,
                  'is_permission_b_a' => 1,
                ),
          );

    $student_event_list = [];

    foreach($student_record['event_id'] AS $student_event) {
      $student_event_list[] = array(
                    'sequential' => 1,
                    'event_id' => $student_event,
                    'contact_id' => '$value.id',
                    'status_id' => "Pending from pay later",
                    'role_id' => "Attendee",
                    'register_date' => date("m/d/Y g:i a"),
                    'is_pay_later' => 1,
                    'fee_level' => "Single",
                    );
    }

    $student_details['api.Participant.create'] = $student_event_list;


    try {
        $student_api_result = civicrm_api3('Contact', 'create', $student_details);
    }
    catch (CiviCRM_API3_Exception $e) {
          $errorMessage = $e->getMessage();
          $errorCode = $e->getErrorCode();
          $errorData = $e->getExtraParams();
      return $errorMessage . ' (Code ' . $errorCode . ')';
        }

  }

Answer 1

I suspect u will need to use

CRM_Utils_Type::validate (which is what CRM_Utils_Request::retrieve actually calls for validation) directly

lobo