All posts by Pramod T P

PHP functions

A function is a group of statements that can be executed any time you want.

PHP has a number of predefine functions for you to use.

Below given are the different type of funtions available in PHP

register_globals

It can be considered as a flag that controls how you access form, server, and environment variables. By default this variable is set to Off, requiring you to use special arrays to access these variables. Its values are set in php.ini file .When the value is set to “on” , PHP will dynamically create global variable for many server variable as well as the query string parameters .

Its always better to set the value as “off”

Magic quotes

Magic quotes is a controversial feature of the PHP scripting language, which was introduced to help newcomers write functioning SQL commands without requiring manual escaping. It was later described and widely misinterpreted as help to prevent inexperienced developers from writing code which is vulnerable to SQL injection attacks. This feature is officially deprecated as of PHP 5.3.0, and removed in PHP 5.4 due to security concerns

Safe mode

Safe mode is a diagnostic mode of a computer operating system (OS). It can also refer to a mode of operation by application software. Safe mode is intended to fix most, if not all problems within an operating system. It is also widely used for removing Rogue security software.

The PHP safe mode is an attempt to solve the shared-server security problem. It is architecturally incorrect to try to solve this problem at the PHP level, but since the alternatives at the web server and OS levels aren’t very realistic, many people, especially ISP’s, use safe mode for now.

  • Limit the execution of shell commands
  • Limit access to system environment variables
  • Limit the paths from which PHP can include files using include or require

Simple XML

Simple XML is a variation of XML containing only elements. All attributes are converted into elements. Not having attributes or other xml elements such as the XML declaration / DTDs allows the use of simple and fast parsers. This format is also compatible with mainstream XML parsers.

PDO

The PHP Data Objects (PDO) extension defines a lightweight, consistent interface for accessing databases in PHP.

Features

  • Supports 12 different databases
  • Object Mapping
  • Supports prepared statements
  • Supports multiple statements
  • Object oriented interface
  • Named parameters
  • PDO has built-in support for Large Objects (LOBs).
  • When something goes wrong, PDO can throw an instance of its own exception class.
  • PDO does not emulate missing database features.
  • Placeholders within PDO prepared statements need not be named.

pcre

Perl Compatible Regular Expressions (PCRE) is a regular expression C library inspired by Perl’s external interface, written by Philip Hazel. PCRE’s syntax is much more powerful and flexible than either of the POSIX regular expression flavors and many classic regular expression libraries. The name is misleading, because PCRE is Perl-compatible only if you consider a subset of PCRE’s settings and a subset of Perl’s regular expression facilities.

The PCRE library is incorporated into a number of prominent open-source programs, such as the Apache HTTP Server and the PHP and R scripting languages; and can be incorporated in proprietary software too (BSD license). As of Perl 5.10, PCRE is also available as a replacement for Perl’s default regular expression engine through the re::engine::PCRE module.