Author: saqibkhan

In PHP, the header() function is used to send an “Authentication Required” message to the client browser causing it to pop up a Username/Password input window. In fact header() allows you to send any raw HTTP header. The string parameter is passed to the header() function. For example It is used to figure out the…

PHP’s library of built-in function includes a category of functions that deal with invoking operating system utilities and external programs from within the PHP code. In this chapter, we shall discuss the PHP functions used to perform system calls. The system() Function The system() function is similar to the system() function in C that it…

PHP defines NULL as one of its special data types. It indicates that a certain variable has not been assigned a value any specific data type. It is a built-in constant in PHP and is used to indicate the intentional absence of any object or value. A variable can be explicitly assigned NULL or its…

Early versions of PHP included mcrypt extension, that provided encryption/decryption capabilities. Due to lack of maintenance, the mycrypt extension has been deprecated and removed from PHP 7.2 version onwards. PHP now includes OpenSSL library that has an extensive functionality to support encryption and decryption features. OpenSSL supports various encryption algorithms such as AES (Advanced Encryption…

The term “hashing” represents a technique of encrypting data (specially a text) to obtain a fixed-length value. PHP library includes a number of functions that can perform hashing on data by applying different hashing algorithms such as md5, SHA2, HMAC etc. The encrypted value obtained is called as the hash of the original key. Processing…

PHP’s two data types – resource and NULL – are classified as special types. An object of resource type refers to external resources like database connection, file streams etc. On the other hand, a NULL data type is a variable without any data assigned to it. In this chapter, we shall learn more about these types. Resource Type A PHP…

Prior to version 7, PHP parser used to report errors in response to various conditions. Each error used to be of a certain predefined type. PHP7 has changed the mechanism of error reporting. Instead of traditional error reporting, most errors are now reported by throwing error exceptions. The exception handling mechanism in PHP is similar…

Standard distributions of PHP have the JSON support enabled by default. The PHP extension implements the JavaScript Object Notation (JSON) data interchange format. The JSON extension in PHP parser handles the JSON data. JSON (JavaScript Object Notation) is a lightweight, text-based, language-independent data interchange format. JSON defines a small set of formatting rules for the…

It is important that the input data received in the form of client request is validated before processing in a PHP application. To perform input validation, the filter extension in PHP provides a number of filter functions, backed up by predefined filter constants and flags. The filter extension of PHP library also helps in sanitizing…

In the theory of software engineering, the term “Design patterns” generally refers to a reusable solution that can be used as a template for developing applications to address commonly occurring problems. You can consider the software design patterns as formalized best practices when developing software solutions. Most of the standard design patterns can be very…