Using $this when not in object context static function

Question

This is my static function to generate a random string:

    public static function generateCode($salt)
    {
        $this->generate = substr(hash('sha512', $salt), 0, 15);
        return $this->generate;
    }

And that's how I use it:

            $this->insert->execute(array(
            ":username" => $username,
            "generated_code" => self::generateCode($email)
            ));

I have declared the property:

    protected $generate;

Getting this error:

Fatal error: Using $this when not in object context in C:\xampp\htdocs\drip\class\users.class.php on line 154

Line 154:

        $this->generate = substr(hash('sha512', $salt), 0, 15);

What's wrong with this? Why is it giving me that error?

Answer 1

Static methods do not belong to the instance of an object, $this relates to the instance...

In this instance I don't think you need anything other than to simply return the result of the hash (candidate for a lambda expression maybe?)

public static function generateCode($salt)
{
    return substr(hash('sha512', $salt), 0, 15);
}

Answer 2

A static function means it is 'bound' to the class, not each instance (object). Call it like this:

  ClassName::generateCode($email);

Also, you cannot use object members in static functions. Make your $generate member also static, and refer to it as:

  ClassName::$generate 

Answer 3

Inside your function you should use self instead of $this because the function is declared static.

Declare your member $generate as static, else it would not work.