How to simplify the process of verifying a certain value?

Question

For example, when I need to check some certain values, I create a "method", similar to that:

public function verificaString($campo)
{
    if (isset($_POST[$campo]) && (!empty($_POST[$campo]) && (is_string($_POST[$campo])))):
        (string)$var = filter_var(trim($_POST[$campo]), FILTER_SANITIZE_STRING);
        return $var;
    else:
        $var = 'Indisponível';
        return $var;
    endif;
}

Now thinking about this part more specifically:

if (isset($_POST[$campo]) && (!empty($_POST[$campo])

There is no way to simplify this process?

Every time I need to check if a variable is set and it has a value other than null, do I have to do just that? There’s no way to simplify this procedure?

Answer 1

Utilise isset and use !empty (in your case) is redundant as empty does exactly the opposite of isset (basically he is !isset($var);) with the addition of the variable negation command. That is:

empty($var); // true

is equal to:

!isset($var) || !$var; // true

The result of empty will be the same as !isset and negation (shown above). That is, you can add in your condition that is only !empty.

Already in your method, you can use Early Returns and remove the if/else of its method which will leave it with a better reading and a less cyclomatic complexity:

public function verificaString($campo)
{
    if (empty($_POST[$campo]) || !is_string($_POST[$campo]))
    {
        return 'Indisponível';
    }

    return filter_var(trim($_POST[$campo]), FILTER_SANITIZE_STRING);
}

Notice the inversion of the instruction if that is validating whether the value, in the superglobal $_POST, is empty or different from string. If true, it returns that it is unavailable.

Else is no longer needed as Return stops code execution. If the code does not fall into the if, the string can be sanitized.

Now, knowing if the method is useful or not (simplifying the existence of the method) is something I can’t say with so little code snippets.

Answer 2

I don’t know if this is exactly what you’re looking for but I’ll risk a cleaner and more beautiful way to check if your post variables are being passed:

Ex:

$nome = filter_input(INPUT_POST, 'nome', FILTER_SANITIZE_SPECIAL_CHARS);

Value of the requested variable in case of success, FALSE if the filter fails, or NULL if the variable_name parameter is an undefined variable. If the flag FILTER_NULL_ON_FAILURE is used, it returns FALSE if the variable is not defined and NULL if the filter fails.

For more information please follow the php manual, hugs and good studies boy!!!

Answer 3

Using the filter_input:

filter_input(INPUT_POST, $campo, FILTER_SANITIZE_STRING)

There’s a list of predefined constants for the filters.

You can then simplicate a little and reduce your function next to the operador ternário:

public function verificaString($campo)
{
    return trim(filter_input(INPUT_POST, $campo, FILTER_SANITIZE_STRING)) ?:  'Indisponível';
}