Create random code by loading the PHP page

Question

I’m creating a system for a real estate company, I need to create a random code for each insertion.

Examples are: C for home = C5241a4d / T for land = T77d4a1r

I want to play this code in an input, to create the folder that will receive the files, among other things.

I believe to be something like the example below:

    <?
$num = rand(1, 10);
  echo "O número gerado foi: " . $num;
?>

I would like instructions.

Answer 1

I would not do this in any way, there are no guarantees of "integrity", names can be repeated mixing files, folders that will be empty can be created and stay there without link with the bank, other problems can occur like this (depending on the system).

You can solve everything based on the ID of the item in the database table, when you create a table in a reasonable format, usually in most types of database you have the ID column, which is usually AUTO_INCREMENT, ie using this id will already solve the problem.

So when registering the property, take the ID, for example at the time of registering the property you use Insert, then right after use LAST_INSERT_ID, something like:

INSERT INTO imoveis (categoria, descricao) VALUES ('casa', 'foo bar baz');
SELECT LAST_INSERT_ID();

Then you can create a folder name based on this ID.

Of course, since you are using the PHP API so you could do everything yourself, you can create a function just to generate the ID-based folder:

function GerarPasta($categoria, $id, $target) {
    $prefixo = strtoupper($categoria{0}); // Gera C (casa), T (terreno), A (apartamento)

    $path = $prefixo . str_pad($id, 10, '0', STR_PAD_LEFT);

    if (!is_dir($path)) mkdir($path, 0755);
}

The use would be:

GerarPasta(<categoria>, <id do banco do imovel>, <pasta aonde vai criar as pastas>);

In this function I did not generate strings with url format youtube, but rather based only on ID, so properties with ids like 1, 2, 3, 4 and 100 will generate:

GerarPasta('casa', 1, '/foo/bar/');        // Gera pasta: /foo/bar/C0001
GerarPasta('terreno', 2, '/foo/bar/');     // Gera pasta: /foo/bar/T0002
GerarPasta('apartamento', 3, '/foo/bar/'); // Gera pasta: /foo/bar/A0003
GerarPasta('casa', 4, '/foo/bar/');        // Gera pasta: /foo/bar/C0004
GerarPasta('casa', 100, '/foo/bar/');      // Gera pasta: /foo/bar/C0100

Which I believe already suits your case well, but if you really want a string scheme I think you should use the function like this:

function GerarPasta($categoria, $id, $target) {
    $prefixo = $categoria{0}; // Gera C (casa), T (terreno), A (apartamento)

    //Usando L gera em 32bit combinado com o "repetidor *"
    $packb64 = base64_encode(pack('L*', $id));

    //Remove qualquer caractere diferente de A-Z e 0-9
    $foldername = preg_replace('#[^\da-z]#i', '', $packb64);

    $path = $prefixo . $foldername;

    if (!is_dir($path)) mkdir($path, 0755);
}

Note: I haven’t tested the function, I don’t know if she can conflict

Examples generate something like:

GerarPasta('casa', 1, '/foo/bar/');        // Gera pasta: /foo/bar/CAQAAAA
GerarPasta('casa', 2, '/foo/bar/');        // Gera pasta: /foo/bar/CAGAAAA
GerarPasta('casa', 3, '/foo/bar/');        // Gera pasta: /foo/bar/CAWAAAA
GerarPasta('casa', 1000, '/foo/bar/');     // Gera pasta: /foo/bar/C6AMAAA
GerarPasta('casa', 1000000, '/foo/bar/');  // Gera pasta: /foo/bar/CQEIPAA
GerarPasta('casa', 10000000, '/foo/bar/'); // Gera pasta: /foo/bar/CGJAYAA

---

Example of use:

I don’t know how you did the code, but if you used preparedstatment it must be something similar to this:

if (isset($_POST['categoria'], $_POST['descricao'])) {

    $categoria = $_POST['categoria'];
    $descricao = $_POST['descricao'];

    if (!$connection->prepare('INSERT INTO imoveis (categoria, descricao) VALUES (?, ?)')) {
       if ($prepared->bind_param('ss', $categoria, $descricao)) {
            if ($prepared->execute()) {
                 //Aqui pega a ID
                 $id_inserido = mysqli_insert_id($link);

                 GerarPasta($categoria, $id_inserido, '/home/user/public_html/'); //Cria a pasta
            } else {
                echo 'Falha ao executar a query';
            }
       } else {
            echo 'Falha nos parametros passados';
       }

       $prepared->close();
    } else {
         echo 'Falha no prepare';
    }
}

Answer 2

I’ll give an opinion:

I want to play this code in an input, to create the folder that will receive the files, among other things.

Really? You will really trust information coming from the customer (understand "browser").

It’s not a good idea to use a value from input to create a folder based on a value from that input.

But objectively answering the question: You can generate unique values through some PHP functions like uniqid.

   $valor = uniquid()

You can pass in the first parameter a value to be the prefix of the generated code, and in the second parameter to "leave more unique still", if necessary.

If you want to put that in an input, just do something like:

<input type="hidden" value="<?= uniquid() ?>" name="codigo_aleatorio">

But with sincerity, distrusting for the end that will be used, I would not advise.

If you want to have a unique code to create a folder after form submission, use a session value, or generate it at the time of upload, or anything else, except rely on what comes from the client to do this, for safety reasons.