Sessions, Cookies, and Error Handling

Note: The reference notes did not contain material on this topic. The following answer is based on standard PHP web development curriculum as taught in BSc CSIT. --- A cookie is a small piece of data stored on the client's browser by the server. It is used ...

A cookie is a small piece of data that a server sends to the user's web browser. The browser stores it and sends it back with subsequent requests to the same server. Cookies are commonly used to: - Remember user login information - Track user sessions - Sto...

HTTP Authentication is a built-in mechanism provided by the HTTP protocol that allows a web server to challenge a client (browser) for credentials (username and password) before granting access to a protected resource. It is defined in the HTTP specificatio...

An error handler is a user-defined function that is called automatically whenever a PHP error occurs. Instead of displaying the default PHP error messages, a custom error handler allows the programmer to control how errors are handled, such as logging them,...

A running PHP script reports trouble in two different ways, and the two words in this question name the two halves of the response to it. An error handler decides what happens at the moment something goes wrong, while an error log is the permanent written r...

An error handler is a function of your own that PHP calls whenever it raises a diagnostic, in place of printing its built in message. Instead of a raw grey line of text in the middle of a page, the handler receives the details as arguments and can format th...

These three terms describe three different responses to the same event, a PHP script running into something it cannot do. Error handling is what the program does about it, error reporting is how much PHP announces about it, and error suppression is the deli...

A session is a way to store information (in variables) to be used across multiple pages of a website. Unlike cookies, session data is stored on the server side. Each user gets a unique session ID which is used to identify and retrieve their session data. No...

HTTP has no memory, so two requests from the same visitor look unrelated to the server. A session gives them a thread: PHP generates a session id, sends it to the browser in a cookie, and keeps a matching store on the server. The $SESSION array is that stor...

These three directives in php.ini control what a PHP script says when something goes wrong and which request data the engine hands it in the first place. The first is an error visibility setting; the other two decide which superglobals get filled and in wha...

These two settings sit on opposite sides of the same question: how much should a PHP script say when something goes wrong. Error reporting decides which classes of problem PHP announces at all, and error suppression silences the announcement for one express...

Exception handling lets a script deal with a runtime failure at the place that knows what to do about it, instead of letting the failure end the request. The code that might fail goes inside try, throw raises an object describing the failure, one or more ca...

HTTP is stateless: each request stands alone and the server has no memory of the one before it. A session supplies that memory. When a session starts, PHP generates a long random session id, sends it to the browser in a cookie, and keeps a matching store on...