Rule to validate PHP value record

Question

I have the following code:

$newprice = $ob->pennyauction == 1 ? $oldprice + 0.01 : $oldprice + $plusprice;

I need it to perform the following check, before displaying the value of $newprice.

The rule is to prevent the same value being written to DB, for example if in $oldprice you already have 0.02 and he tries to record the 0.02 again, the rule should add + 0.01.

He already does it there, but sometimes it happens to run at exactly the same time, then he inserts the same values, then enters this rule to validate it.

There’s something to implement there?

Answer 1

You can do this in two ways, with an execution queue, or with a file to lock the simultaneous execution, the idea is:

1 - While running, create a file . lock (can be any file extension, but we will use .lock)

2 - Run the actual script

3 - When finished remove the file

Example:

if (mkdir('/tmp/prevent.lock', 0700)) {
    funcaoDaRegra();
    rmdir('/tmp/prevent.lock');
} else {

    funcaoPreventiva();
}

function funcaoDaRegra() {
    //Faça aqui o que deve ser feito sem duplicar
    echo 'Aqui a função foi executada';
}

function funcaoPreventiva() {
    //De uma resposta ao usuário caso tenha sido prevenida a duplicação
    echo 'Aqui prevenimos a execução dupla';
}

NOTE: If you are using windows server, use mkdir with the third parameter:

mkdir('/tmp/prevent.lock', 0700,true)