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PHP

PHP: Hypertext Preprocessor.

version - PHP 5.6.16

PHP is a server side scripting language that is embedded in HTML. It is used to manage dynamic content, databases, session tracking, even build entire e-commerce sites.

Usage

hello world

	<html>
   	   <head>
	      <title>Hello World</title>
	   </head>
	   <body>

	      <?php echo "Hello, World!";?>

	   </body>
	</html>

PHP Markup tags

	<?php PHP code goes here?>
	
	<?	php code goes here ?>

	<script	language="php"> PHP code goes here</script>

PHP Configuration file (PHP.INI)

The PHP configuration file, php.ini, is the final and most immediate way to affect PHP's functionality. The php.ini file is read each time PHP is initialized.

PHP is case sensitive

Syntax

Canonical PHP tags

	<?php...?>

Short-open tags

	<?...?>

Note - this tag we need to enable from php.ini file.

Comment

	<?
   	# This is a comment, and
   	# This is the second line of the comment
   	
   	// This is a comment too. Each style comments only
   	print "An example with single line comments";
   ?>

Variable

	 $msg = "john";
    print "Welcome $msg";

Variable Type

Simple Data type

Integer

$int_var = 12345;

Double

$many = 2.2888800;

Boolean TRUE or FALSE
NULL

	$var = NULL;

String

Constant

	<?php
		define("MINSIZE", 50);
		
		echo MINSIZE;
		echo constant("MINSIZE"); // same thing as the previous line
	?>

Array

<?php
         /* First method to create array. */
         $numbers = array( 1, 2, 3, 4, 5);
         
         foreach( $numbers as $value )
         {
            echo "Value is $value <br />";
         }
         
         /* Second method to create array. */
         $numbers[0] = "one";
         $numbers[1] = "two";
         $numbers[2] = "three";
         $numbers[3] = "four";
         $numbers[4] = "five";
         
         foreach( $numbers as $value )
         {
            echo "Value is $value <br />";
         }
      ?>

Key value array

<?php
         /* First method to associate create array. */
         $salaries = array("mohammad" => 2000, "qadir" => 1000, "zara" => 500);
  		
		 $salaries['mohammad'] = "high";       
?>

GET POST

 	# Get - http://www.test.com/index.htm?name1=value1&name2=value2
	 # Get value
	 $name = $_GET["name"];
	 
	 
	 
	 # Get post value
	 $name = $_POST["name"]

$_REQUEST variable

$_REQUEST variable contains the contents of both $_GET, $_POST, and $_COOKIE.

<?php
   if( $_REQUEST["name"] || $_REQUEST["age"] )
   {
      echo "Welcome ". $_REQUEST['name']. "<br />";
      echo "You are ". $_REQUEST['age']. " years old.";
      exit();
   }
?>

include() function

The include() function takes all the text in a specified file and copies it into the file that uses the include function.

<?php
	<?php include("menu.php"); ?>
?>

require() function

So there is no difference in require() and include() except require() function generates a fatal error and halt the execution of the script if there is any problem.

PHP Function

<?php
         /* Defining a PHP Function */
         function writeMessage($num1)
         {
            echo "You are really a nice person, Have a nice time!";
         }
         
         /* Calling a PHP Function */
         writeMessage(123);
		 
		 
		 #passing argument by reference
		 function test(&$num)
		 {
			 $num += 5
	     }
		 $n =5;
		 test($n);
		 
		 
		 # setting default value to function
		 function test2( $num = NULL)
		 {
		 }
		 
		 
		 # Dynamic function call
		 
		 $fun_holder = "test2";
		 $fun_holder();
		 	 
		 
      ?>

Session

A session creates a file in a temporary directory on the server where registered session variables and their values are stored. The location of the temporary file is determined by a setting in the php.ini file called session.save_path.

<?php
   session_start();
   	
	   $_SESSSION['counter'] = "some value";
	   
  ?>