Captcha
API reference
If it is necessary that you permit the unauthenticated user to POST to the store, you might need to block automated scripts. In Topincs you can achieve this with minimal effort by using the function captcha.
Compared to other methods, the Topincs CAPTCHA is easier to solve for a literate user that is familiar with some basic concepts taught in elementary school. It is not impossible to circumvent the mechanism, but requires some effort by the attacker.
API reference
The implementation in a POST service is straight forward. Just put the captcha call in the very beginning of the service. To protect a form place the call in a BEFORE SAVE trigger. If you do not want your authenticated users to be bothered by the CAPTCHA, use the user function.
Conditional CAPTCHA
if (user()->name === null) {
captcha();
}