Category Archives: programming

Most popular is recaptcha by google
Honeypot technique – include a hidden field, if it is filled, then it is a robot
A simple random questions. E.g. is fire hot or cold , five – 3 is ___
http://nomorecaptchas.com/ (with price)
https://visualcaptcha.net/ (no longer developed but they claim it still work)
Algorithm
1. after 5 failed attempt, lockout IP for 15 minutes
2. if 5 times lockout, lockout IP for 24 hours
3. if 3 times lockout, blacklist IP permanently (option for sys admin to clear)
More alternatives

Cronjob timer

This is a useful generator for crontab command line

You can set for every minute/hour, set by time range etc.

crontab.guru

Below are scenarios that may cause duplicates

Solutions

Post-redirect-get (PRG) – on wikipedia
One easy way is to have injected a hidden parameter with a random hash/number (e.g called token). Upon submission you’ll have to check that the token you expect (which you’ll have probably stored in the http session) is being sent together with the other POST parameters. On valid submission you’ll remove/invalidate this token. That way when a POST comes which a non recognised token then it’s most probably a duplicate or out of date request. source
To check whether the data submitted exist in the database. This is the most tedious part to do and you need to have a unique data for this. i.e. the data must be unique in the table or create a unique data for this purpose sent together with other data.
Add a one-time token to your forms and save it to the $_SESSION-variable. Then if it is used (form is submitted), remove it from the session (or create a new token). If the form is then sent again, the two tokens don’t match and you have a duplicate entry (you can ignore the second for example). source

I’ve been using laravel for years already. Now I need to move to Laravel and I need strong reasons why I should.

Here I compiled some

Laravel is truly OOP
The ORM (eloquent) in Laravel is really powerful
Can tune the speed with cache and queue
Artisan command that really help doing job faster – e.g. creating controllers, models, run migration (database) etc.
Migration that acts like database version control for the development team
RESTful resource controllers
Many available packages developed by other programmers that can be used
More support, community, references. e.g. laracasts.com, laravel.io
Powerful routes
Class autoloading?

And below are the articles you may wan to read that are also my reference to the above points.

Some useful laravel packages

Sometimes we construct an array in a loop and end up with an empty element at the end (or beginning) of the array.

It will look something like elem1,elem2,elem3,

To remove empty element from an array, can simply use array_filter function

Be careful, by removing empty it includes false, null, ” etc.