handling a GET error properly

I have a website that takes two primary get strings:

PHP MVC error handling, view display and user permissions

I am building a moderation panel from scratch in a MVC approach and a lot of questions cropped up during development. I would like to hear from others how they handle these situations.

Returning status code where one of many errors could have occured

I’m developing a PHP login component which includes functions to manipulate the User object, such as $User->changePassword(string $old, string $new)
What I need some advice with is how to return a status, as the function can either succeed (no further information needs to be given) or fail (and the calling code needs to know why, for example incorrect password, database problem etc.)

Custom error handling

I’m trying to figure out the best way to handle custom errors in my application.

Error checking in actor-based paradigm

I have an existing Scala application that I am trying to refactor in order to use Akka. One of the problems I have is how to manage error-checking in actor-based applications.

How safe are hidden AJAX requests that fake performance?

What is a hidden AJAX request? I’ve noticed an increase in the usage of hidden AJAX requests designed to make a user’s action appear to happen immediately. I’ll refer to this type of AJAX request as non-blocking. It’s an AJAX request made without the user being aware it’s happening, it’s performed in the background and […]

How should my web application handle common errors such as incorrect password, session timeout, etc.?

How should my web application handle common errors such as incorrect password, session timeout, etc.?

How can I ensure a method is called only once when using a API?

In general, if I am using an API whose methods have side-effects that I only want to occur once, how can I guarantee that my own application only calls them once even if an error occurs before it can register a response?

Are error codes wrong in SQL queries too?

I have an SQL query which does several things at once¹: it does multiple checks and then, if the checks pass, updates some data. Without entering in the domain-specific details, here’s an imaginary example:

Why is 0 false?

Why does 0 evaluate to false and any other integer value to true is most programming languages?