AmiteshBharti's PHP Learning blog

Amitesh Bharti

PHP is the widely used open source language especially for developing web applications. Strings in PHP play very important role. In this tutorial, You will find about 20 handy and most used PHP functions.

1. addcslashes()

This string function returns a string also with backslashes before characters and characters are listed as parameter.

Syntax:

1	<?php addcslashes($str, characters); ?>

Example:

<?php
$mystr = "How are you.";
echo addcslashes($mystr, 'r');
?>

Output:

1	How a\re you.

2. convert_uudecode()

This string function decodes a string that is uuencoded (in simple words it decodes a string which is encrypted by some security methods).
Syntax:

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<?php
convert_uudecode($encrypted_string);
?>

Example:

<?php
$encrypted_string = "+2&]W($%R92!9;W4` `";

echo convert_uudecode($encrypted_string);
?>

Output:

1	How Are You

3. convert_uuencode()

This string function encodes a string.
Syntax:

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<?php
convert_uuencode($encrypted_string);
?>

Example:

<?php
$encrypted_string = "How Are You";

echo convert_uuencode($encrypted_string);
?>

Output:

1	+2&]W($%R92!9;W4` `

4. count_chars()

This string function returns how many times a character (ASCII) appears in a string depending on the modes we specified.
By default, mode is 0 that returns an array with Key (ASCII Value) and Value (Number of Occurrences.
Mode 1 returns an array with same functionality as Mode 2, but it only lists appearance of characters which are greater than zero.
Mode 2 returns occurrence which are equal to zero.
Mode 3 returns string with difference characters used.
Mode 4 generates string of all unused characters.
Syntax:

1	count_chars($str, mode);

Example:

<?php
$mystr = "Hello Dear, How are you";

print_r(count_chars($mystr, 0));
print_r(count_chars($mystr, 1));
print_r(count_chars($mystr, 2));

echo count_chars($mystr, 3);
echo count_chars($mystr, 4);

?>

5. echo()

This function helps to output more than one strings. Parameters in this function are optional.
Syntax:

1	echo(string)

6. explode()

explode() explodes or break a string into an array. We can easily understand the functionality of this function by the name “explode”. explode() has three parameters, first 2 are required and third is optional.
Syntax:

1	explode(string_separator, $str, limit);

Example:

<?php

$mystr = "Hello Dear, How are you";

print_r(explode(" ", $mystr));

?>

Output:

1	Array ( [0] => Hello [1] => Dear, [2] => How [3] => are [4] => you )

7. implode()

implode() is a reverse of explode(), means it joins an array into a sring. It has two parameters, first one is optional and second one is required.
Syntax:

1	imlode(string_separator, array);

Example:

<?php

$arr = array("Hello", "Dear", "How", "Are", "You");

echo implode(" ", $arr);

?>

Output:

1	Hello Dear How Are You

8. md5()

md5() function calculates Message-Digest Algorithm (md5) hash of a string. It has two parameters, first one is required and second one is optional which was included in PHP 5.0.
Syntax:

1	md5($str, raw);

Example:

<?php

$mystr = "How Are You";

echo md5($mystr);

?>

Output:

1	9e227bb366c119c7f27a7115f0136f42

9. str_replace()

If you want to replace some specified characters with other characters in PHP, str_replace() is the best choice. It has many rules like:

If we want to search a string in an array, it returns as an array.
Find and Replace is performed with each array element as we want to search a string in an array.
If we are finding an array and also replacing with it with an array, an empty string will be used as replace.
In case, replace is a string and find is an array, then it uses replace sting as find value.

Syntax:

1	str_replace(find, replace, string, count);

Example:

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<?php
echo str_replace("How", "Dear", "How Di");
?>

Output:

How Dear

10. str_split()

str_split() works like explode() in some manner, it is used for splitting a string into an array.
Syntax:

1	str_split($mystring, length);

Example:

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<?php
print_r(str_split("What"));
?>

Output:

Array
(
[0] => W
[1] => h
[2] => a
[3] => T
)

11. str_word_count()

This function is used for counting the words in a string.
Syntax:

1	str_word_count(string, return, char);

Example:

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<?php
echo str_word_count("What are you doing");
?>

Output:

12. strcmp()

This case-sensitive string function is used for comparing two strings. It returns “0″ if both strings are equal, “<0″ if first string is less than second string and “>0″ if first string is greater than second string.
Syntax:

1	strcmp(first string, second string);

Example:

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<?php
echo strcmp("What Are You Doing", "What I Should Do");
?>

Output:

-1

13. strlen()

strlen() calculates the length of string based on extra spaces and characters used in a string.
Syntax:

1	strlen($str);

Example:

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<?php
echo strlen("Oh, No!");
?>

Output:

14. strrpos()

strrpos() is used to find the position of the last occurrence string inside another string.
Syntax:

1	strrpos(strong, find, start)

Example:

<?php
echo strrpos("Where are you going?", "go");
?>
[code]

<strong>Output:</strong>

[code type="php"]14

15. strstr()

strstr() finds the first occurrence of a string in a string, if found it returns at the matching point else it returns 0.
Syntax:

strstr();

Example:

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<?php
echo strstr('Hi What', 'Hi');
?>

Output:

Hi What

16. strtolower()

This function converts a string to lowercase (It converts only letters from A-Z or a-z).
Syntax:

1	strtolower($str);

Example:

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<?php
echo strtolower("Now WhaT are");
?>

Output:

1	now what are

17. strtoupper()

This function converts a string to uppercase letters.
Syntax:

1	strtoupper($str)

Example:

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<?php
echo strtoupper("Yes");
?>

Output:

YES

18. substr()

This function split up a part from a string according to given criteria specified in the parameters.
Syntax:

1	substr($str, start, length)

Example:

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<?php
echo substr("Where I Can Find You", 7);
?>

Output:

1	Can Find You

19. trim()

This function erases predefined characters and whitespaces from every side of a string. Predefined characters are like: \0, \t, \n, \xob, \r etc.
Syntax:

1	trim($str, chars)

Example:

<?php
$mystr = "Hey dude, I'm going with you";
echo trim($mystr);
?>

20. wordwrap()

If you want to cut a string after it reaches to a specific length, wordwrap() is the best choice for achieving this.
Syntax:

1	wordwrap($str, width, break, cut)

Example:

<?php

$str = "Check the example: Supercalifragulistic";

echo wordwrap($str,9);
?>

Output:
Browser will display out like this

1	Check the example: Supercalifragulistic

But after checking the page source, output will be something like below:

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Check the
example:
Supercalifragulistic

Amitesh Bharti


<?php

Top Most important Php function 




1.  empty(); // return true false 


$p='val';



if(!empty($p)){ // if $p is not empty 


echo 'variable is not empty ';

} else {

 echo 'value is null';

}






2. unset();



use for unse session or variable values 


unset($a);




3. isset();



if(isset($a)){



echo 'value is set ';

} else {  

echo 'value is not set ';

}




4. trim()



use for removes the whitespaces from the left part of the string.


trim($a);




5. explode () ;




convert strin to array 


$str = "Rajeev Dhar dwivedi";
$array = explode(" ",$str);
print_r($array);


outPut :



Array ( [0] => Rajeev [1] => Dhar [2] => dwivedi )






6. implode();

convert array to string 



$array = array( 'Rajeev' ,'Dhar','Dwived') ;



echo implode(" ",$array);


Output : 
Rajeev Dhar Dwived





7. date() function 


this function use fot get date from system


echo date('Y-M-d');





8. time() 




this function use for get time from system in mili second 


echo time(); 




9. strip_tags();

use for remove html tags

example :
$tag="<b><p>rajeev</p></b>";

echo strip_tags($tag); // output : rajeev

Amitesh Bharti

Whenever you allow your users to submit text to your website, you need to be careful that you don't leave any security holes open for malicious users to exploit. If you are ever going to allow user submitted text to be visible by the public you should consider using the htmlentities function to prevent them from running html code and scripts that may be harmful to your visitors.

PHP - Converting HTML into Entities

The htmlentities function takes a string and returns the same string with HTML converted into HTML entities. For example, the string "<script>" would be converted to "<script>".
By converting the < and > into entities, it prevents the browser from using it as an HTML element and it prevents the code from running if you were to display some user's input on your website.
This may seem a little complicated, but if you think of the way a browser works, in separate stages, it becomes a little easier. Let's look at the way the function htmlentities changes the data at three different levels: in PHP, in raw HTML and in the web browser. The sample string is a bad script that will redirect visitors to the malicious user's own website.

PHP Code:

// An imaginary article submission from a bad user
//  it will redirect anyone to example.com if the code is run in a browser
$userInput = "I am going to hax0r your site, hahaha!
 <script type='text/javascript'>
 window.location = 'http://www.example.com/'
 </script>'";
 
//Lets make it safer before we use it
$userInputEntities = htmlentities($userInput);

//Now we can display it
echo $userInputEntities;

The HTML output of the above script would be as follows:

Safe Raw HTML Code:

I am going to hax0r your site, hahaha!
 &lt;script type='text/javascript'&gt;
 window.location = 'http://www.example.com/'
 &lt;/script&gt;'

If we had not used htmlentities to convert any HTML code into safe entities, this is what the raw HTML code would be and it would have redirect a visitor to example.com.

Dangerous Raw HTML Code:

I am going to hax0r your site, hahaha!
 <script type='text/javascript'>
 window.location = 'http://www.example.com/'
 </script>'

Those two HTML code examples are what you would see if you were to view source on the web page. However, if you were just viewing the output normally in your browser you would see the following.

Safe Display:

I am going to hax0r your site, hahaha! <script type='text/javascript'> window.location = 'http://www.example.com/' </script>'

Dangerous Display:

You'd see whatever spammer site that the malicious user had sent you to. Probably some herbal supplement site or weight loss pills would be displayed.

When Would You Use htmlentities?

Anytime you allow users to submit content to your website, that other visitors can see, you should consider removing the ability to let them use HTML. Although this will remove a lot of cool things that your users can do, like making heavily customized content, it will prevent your site from a lot of common attacks. With some custom coding you can just remove specific tags from running, but that is beyond the scope of this lesson.

Just remember, that when allowing users to submit content to your site you are also giving them access to your website. Be sure you take the proper precautions.

Amitesh Bharti

Object oriented programming (OOP) was first introduced in php4. Area for oop in php version 4 was not very vast. There were only few features available in php4. Major concept of the object oriented programming in PHP is introduced from version 5(we commonly known as php5). Also php community has plan to modify its object model structure in more better manner in php6(not released yet). But still in php5 object model is designed nicely. If you have good understanding of OOP then you can create very good architecture of your php application. You only need to know some of the basic principles of object oriented programming and how to implement that concept of oop in php. In whole series I will use abbreviation OOP for Object Oriented Programming.
This tutorial series is for both beginners and middle level programmer who want to learn advance concept of oop in php from basic . In this series we will explore all aspect of OOP in PHP from beginning. In every chapter we will covers some best practices. If you are completely beginner for oop please go through every topic of this tutorial series very carefully. If you have some knowledge about the concept of object oriented programming then you can directly go to section of your choice. In every section of tutorial you can download code used in example.

List of Topic/Chapter For OOP In PHP

Topics	Description
Basics of OOP in PHP	In this part of tutorial you will learn about the very basic concept of OOP in php. This part will cover topic like what is object and class. How to implement class and object in php. Also here we will show you the very basic example for class. If you are beginner for OOP in PHP please you may enjoy this part. This is essential for the beginner for OOP.
Class and Object in OOP	In this part of tutorial you will lean about the basic and advance concept of class and object. It will cover topic like what is class, what is object, how to use implement class and object. This chapter will be started from very basic concept of class and object and will describe upto depth level. This part will cover the best practice of class and object implementation.
Magic Function in PHP OOP	Although this is slightly different topic of tutorial but it is included here because some of the magic method is used in object oriented programming. This chapter will cover basic magic methods/function of php which is used in OOP.
Visibility In PHP(Public, Private and Protected)	In this part of tutorial you can learn about the access modifier of OOP in PHP. This part will have complete coverage of what is public, private and protected. Also this will describe how to use these access modifier and best practices.
Static Method and Property in OOP	In this part you will learn about static method and property of the class. In this section you will learn what are the static method and properties, how to use them.
Inheritance in PHP	In this part of tutorial, you will learn basics of inharitance in oop.
Abstract class and Interface PHP	In this part you will learn about interface and class class in php. Here you will learn about what is abstract classes and how and when you should use abstract class and basic concept of interface, How behavior of one class passes to another class
Overloading and Overriding	This part will cover the implementation of overloading and overriding of methods in php. Here you will learn about how to overload method of class and how to override method of class.
Object Cloning PHP	This part will cover how to clone object of your class. In this chapter you will learn about the implementation of object cloning in PHP.
Method Chaining PHP	In this part of tutorial we will explore about method chaining feature of object.

Basics of OOP in PHP

Object oriented programming is nothing but a technique to design your application. Application could be any type like it could be web based application, windows based application. OOP is a design concept. In object oriented programming, everything will be around the objects and class. By using OOP in php you can create modular web application. By using OOP in php we can perform any activity in the object model structure. There are many benefit of using oop over the parallel or procedural programming. Further in this part we will cover some basic of object and class and its implementation in php.

What is Object?

If you want to see theoretical definition of object described in the typical book of oop then following is the best definition of object is:

Any thing is the world is an object. Look around and you can find lots of object. Your laptop, pc, car every thing is an object. In this world every object has two thing properties and behaviors. Your car has property (color, brand name) and behavior(it can go forward and backward). If you are able to find properties and behaviors of real object. Then it will be very easy for you to work with Object Oriented Programming.

In real world different objects has different properties and behaviors. For example your television has property size, color, and has behavior turn on, turn off. If you observe carefully then you can find that every object has some property and behavior from other object. This phenomena is called inheritance. For example car object has property and behavior from engine object.
If you are able to understand what is object then good to go ahead. If not then please start visualizing properties and behavior of object around you. You will defiantly understand.
Object in programming is similar to real word object. Every programming object has some properties and behaviors. For example if you have object for interest calculator then it has property interest rate and capital and behavior simple interest calculation and compound interest calculation. Interest calculator has some property and method from calculator object like addition, multiplication etc.

What is Class ?

Class is something which defines your object. For example your class is Car. And your Honda car is object of car class. Like object explanation, here we will take an example of the real word and then we will move further in programming definition.

Blueprint of the object is class. Class represents all properties and behaviors of object. For example your car class will define that car should have color, number of door and your car which is an object will have color green and 2 doors. Your car is object of class car. Or in terms of programming we can say your car object is an instance of the car class. So structural representation (blueprint) of your object is class.

Now let us take an example of the programming. Your interest calculator object is instance of class interest calculator. Interest calculator class defines properties like capital rate, and behavior like simple interest calculation and compound interest calculation. Your interest calculator object has property rate as 3% and capital 300 USD. So you are describing your class definition of rate by giving rate value equals to 3% and capital 300USD in your interest calculator object. Now in your object when interest calculation behavior will be applied it will take your rate of interest and capital and provide you the result. Again your interest calculator class will inherit the definition of its property and behavior from calculator class.

Advantage of Object Oriented Programming

There are various advantage of using OOP over the procedural or parallel programming. Following are some of the basic advantages of using oop techniques.

Re-Usability of your code: If you will use OOP technique for creating your application then it will gives you a greater re-usability. For example, if you have created calculator class at one place then you can use the same calculator class in your application.
Easy to Maintain : Application develop using oop technique are easier to maintain than normal programming. Again let us take an example of your interest calculator class. Suppose your business need to change the calculation logic. They want to add some charges if your capital is less than 200 USD. Just think about your application is big and developed using normal programming techniques. So first you have to analyse that at how many places we have calculated interest, and then you will change. But just think of oop technique. You just need to change in your method of interest calculation at one place.
Good Level of Abstraction: Abstraction means making something hidden. By using oop technique you are abstracting your business logic from implementation. It will provide you greater ease. Again let us take and example of interest calculator. If you have created class for interest calculation and your team is going to use that class. Now you are only concern about how interest calculation will be performed, because you have created that. Your team member is always have understanding that if they will set rate and capital property and apply interest calculation method then it will return interest.
Molecularity: If are are creating separate class for your every problem then you are making it modular.So if someone need to change in the business logic part then he will always go to your business logic code part.

Now if you are clear with concept of class, object in oop and its advantages. Great!!! Its time to move over the implementation of oop in php.

Implementation of OOP in PHP

In this section we will discuss about some basic aspect of oop in php. For every basic aspect we have separate chapter in this tutorial. If you will say basic aspect of oop in php then it is all about classes, objects. For the further detail of oop topic like interface, object cloning etc then you can go to specific chapter of this tutorial. Refer table of contents for the complete list of chapter and its navigation. So let us discuss about basic concept of class, object inheritance here.
Class in PHP:
Class is a blueprint of any object in oop. So class is the first alphabet of oop. In php you can creation of class is very simple. You can create class using tag class. In class block you can define your properties as class variable and function as class behavior. So let us create a class for interest calculator and define its properties like rate, capital, duration and behavior like calculate interest.

class interestCalculator
 {
 var $rate;
 var $duration;
 var $capital;
 function calculateInterest()
 {
 return ($this->rate*$this->duration*$->capital)/100;
 }
 }

Above is a very simple and basic class to calculate interest. Let us explore all basic aspect of this class.
You can create class in php by using class keyword. here class interestCalculator{ } is class block. You can define all of your properties and methods(behavior of class, we will use method or function instead of behavior) of your class inside of your class block. All variable started with var keyword is property of your class. Commonalty we can say these are variable of class also. And the function are methods of this class. You can design your own class with your won variable and function.
Object in PHP:
As we have already discussed that object is an instance of any class. So we will take our interestCalculator class as an example. Creating object of the class is very easy in php. You can create object of class with the help of new keyword. Following is very basic example of creation of object of your class interest calculator:
$calculator = new interestCalculator()
In above declaration you are creating object of your class interestCalculator in variable $calculator. Now your variable $calculator is an object of class interestCalculator. Next step is to set property or variable of object calculator and perform calculation of interest.

$calculator = new InterestCalculator()
 $calculator->rate = 3;
 $calculator->duration =2;
 $calculator->capital = 300;
 echo $calculator->calculateInterest();

Here object of your class interestCalculator is your php variable $calculator. In next 3 lines of above code you are setting properties of class. You can access property of class with ->. So in above code rate property is set using $calculator->rate = 3;. Finally after setting all reaqired properties you have called method calculateInterest.
Hope you have clear understanding of oop in php. Download the basic code and run at your machine.
For Indepth Coverage on OOP theory your can further read on wikipedia:
http://en.wikipedia.org/wiki/Object-oriented_programming
original link :- http://www.techflirt.com/tutorials/oop-in-php/index.html#comments

Amitesh Bharti

You can include the content of a PHP file into another PHP file before the server executes it. There are two PHP functions which can be used to included one PHP file into another PHP file.

The include() Function
The require() Function

This is a strong point of PHP which helps in creating functions, headers, footers, or elements that can be reused on multiple pages. This will help developers to make it easy to change the layout of complete website with minimal effort. If there is any change required then instead of changing thousand of files just change included file.

The include() Function

The include() function takes all the text in a specified file and copies it into the file that uses the include function. If there is any problem in loading a file then the include() function generates a warning but the script will continue execution.

Assume you want to create a common menu for your website. Then create a file menu.php with the following content.

<a href="http://www.tutorialspoint.com/index.htm">Home</a> - 
<a href="http://www.tutorialspoint.com/ebxml">ebXML</a> - 
<a href="http://www.tutorialspoint.com/ajax">AJAX</a> - 
<a href="http://www.tutorialspoint.com/perl">PERL</a> <br />

Now create as many pages as you like and include this file to create header. For example now your test.php file can have following content.

<html>
<body>
<?php include("menu.php"); ?>
<p>This is an example to show how to include PHP file!</p>
</body>
</html>

This will produce following result

This is an example to show how to include PHP file. You can include mean.php file in as many as files you like!

The require() Function

The require() function takes all the text in a specified file and copies it into the file that uses the include function. If there is any problem in loading a file then the require() function generates a fatal error and halt the execution of the script.

So there is no difference in require() and include() except they handle error conditions. It is recommended to use the require() function instead of include(), because scripts should not continue executing if files are missing or misnamed.

You can try using above example with require() function and it will generate same result. But if you will try following two examples where file does not exist then you will get different results.

<html>
<body>
<?php include("xxmenu.php"); ?>
<p>This is an example to show how to include wrong PHP file!</p>
</body>
</html>

This will produce following result

This is an example to show how to include wrong PHP file!

Now lets try same example with require() function.

<html>
<body>
<?php require("xxmenu.php"); ?>
<p>This is an example to show how to include wrong PHP file!</p>
</body>
</html>

This time file execution halts and nothing is displayed.

NOTE: You may get plain warning messages or fatal error messages or nothing at all. This depends on your PHP Server configuration.

include vs. include_once vs. require vs. require_once - examples

include ('sponsor_links.php');
If the file sponsor_links is present in the current folder, it will be included ( way may want it to appear both - at the top and at the bottom).

include_once ('statistics.php');
If the file statistics.php is present, it means we want statistics for the page. Otherwise, we don't want statistics. Deleting statistics.php will not affect the main program.

require ('navigation.php');
We may want to include the navigational links both both at the top and the bottom at the page. If navigation.php is not present, the main program will stop running and an error message will be displayed.

require_once ('google_adsense_top.php');
Because a page has only one top, only one instance of google_adsense_top.php will be included. If google_adsense_top.php is not present, the main program will stop running and an error message will be displayed.

If you want more details about how each of include/require works, please reply to this post.

Amitesh Bharti

File handling in php

This chapter will explain following functions related to files:

Opening a file
Reading a file
Writing a file
Closing a file

Opening and Closing Files

The PHP fopen() function is used to open a file. It requires two arguments stating first the file name and then mode in which to operate.
Files modes can be specified as one of the six options in this table.

Mode	Purpose
r	Opens the file for reading only. Places the file pointer at the beginning of the file.
r+	Opens the file for reading and writing. Places the file pointer at the beginning of the file.
w	Opens the file for writing only. Places the file pointer at the beginning of the file. and truncates the file to zero length. If files does not exist then it attemts to create a file.
w+	Opens the file for reading and writing only. Places the file pointer at the beginning of the file. and truncates the file to zero length. If files does not exist then it attemts to create a file.
a	Opens the file for writing only. Places the file pointer at the end of the file. If files does not exist then it attemts to create a file.
a+	Opens the file for reading and writing only. Places the file pointer at the end of the file. If files does not exist then it attemts to create a file.

If an attempt to open a file fails then fopen returns a value of false otherwise it returns a file pointer which is used for further reading or writing to that file.
After making a changes to the opened file it is important to close it with the fclose() function. The fclose() function requires a file pointer as its argument and then returns true when the closure succeeds or false if it fails.

Reading a file

Once a file is opened using fopen() function it can be read with a function called fread(). This function requires two arguments. These must be the file pointer and the length of the file expressed in bytes.
The files's length can be found using the filesize() function which takes the file name as its argument and returns the size of the file expressed in bytes.
So here are the steps required to read a file with PHP.

Open a file using fopen() function.
Get the file's length using filesize() function.
Read the file's content using fread() function.
Close the file with fclose() function.

The following example assigns the content of a text file to a variable then displays those contents on the web page.

<html>
<head>
<title>Reading a file using PHP</title>
</head>
<body>

<?php
$filename = "/home/user/guest/tmp.txt";
$file = fopen( $filename, "r" );
if( $file == false )
{
   echo ( "Error in opening file" );
   exit();
}
$filesize = filesize( $filename );
$filetext = fread( $file, $filesize );

fclose( $file );

echo ( "File size : $filesize bytes" );
echo ( "<pre>$filetext</pre>" );
?>

</body>
</html>

Writing a file

A new file can be written or text can be appended to an existing file using the PHP fwrite() function. This function requires two arguments specifying a file pointer and the string of data that is to be written. Optionally a third integer argument can be included to specify the length of the data to write. If the third argument is included, writing would will stop after the specified length has been reached.
The following example creates a new text file then writes a short text heading insite it. After closing this file its existence is confirmed using file_exist() function which takes file name as an argument

<?php
$filename = "/home/user/guest/newfile.txt";
$file = fopen( $filename, "w" );
if( $file == false )
{
   echo ( "Error in opening new file" );
   exit();
}
fwrite( $file, "This is  a simple test\n" );
fclose( $file );
?>

<html>
<head>
<title>Writing a file using PHP</title>
</head>
<body>

<?php
if( file_exist( $filename ) )
{
   $filesize = filesize( $filename );
   $msg = "File  created with name $filename ";
   $msg .= "containing $filesize bytes";
   echo ($msg );
}
else
{
   echo ("File $filename does not exit" );
}
?>
</body>
</html>

We have covered all the function related to file input and out in PHP File System Function chapter.

Amitesh Bharti

There are two ways the browser client can send information to the web server.

The GET Method
The POST Method

Before the browser sends the information, it encodes it using a scheme called URL encoding. In this scheme, name/value pairs are joined with equal signs and different pairs are separated by the ampersand.

name1=value1&name2=value2&name3=value3

Spaces are removed and replaced with the + character and any other nonalphanumeric characters are replaced with a hexadecimal values. After the information is encoded it is sent to the server.

The GET Method

The GET method sends the encoded user information appended to the page request. The page and the encoded information are separated by the ? character.

http://www.test.com/index.htm?name1=value1&name2=value2

The GET method produces a long string that appears in your server logs, in the browser's Location: box.
The GET method is restricted to send upto 1024 characters only.
Never use GET method if you have password or other sensitive information to be sent to the server.
GET can't be used to send binary data, like images or word documents, to the server.
The data sent by GET method can be accessed using QUERY_STRING environment variable.
The PHP provides $_GET associative array to access all the sent information using GET method.

Try out following example by putting the source code in test.php script.

<?php
  if( $_GET["name"] || $_GET["age"] )
  {
     echo "Welcome ". $_GET['name']. "<br />";
     echo "You are ". $_GET['age']. " years old.";
     exit();
  }
?>
<html>
<body>
  <form action="<?php $_PHP_SELF ?>" method="GET">
  Name: <input type="text" name="name" />
  Age: <input type="text" name="age" />
  <input type="submit" />
  </form>
</body>
</html>

The POST Method

The POST method transfers information via HTTP headers. The information is encoded as described in case of GET method and put into a header called QUERY_STRING.

The POST method does not have any restriction on data size to be sent.
The POST method can be used to send ASCII as well as binary data.
The data sent by POST method goes through HTTP header so security depends on HTTP protocol. By using Secure HTTP you can make sure that your information is secure.
The PHP provides $_POST associative array to access all the sent information using GET method.

Try out following example by putting the source code in test.php script.

<?php
  if( $_POST["name"] || $_POST["age"] )
  {
     echo "Welcome ". $_POST['name']. "<br />";
     echo "You are ". $_POST['age']. " years old.";
     exit();
  }
?>
<html>
<body>
  <form action="<?php $_PHP_SELF ?>" method="POST">

  Name: <input type="text" name="name" />
  Age: <input type="text" name="age" />

  <input type="submit" />
  </form>
</body>
</html>

The $_REQUEST variable

The PHP $_REQUEST variable contains the contents of both $_GET, $_POST, and $_COOKIE. We will discuss $_COOKIE variable when we will explain about cookies.

The PHP $_REQUEST variable can be used to get the result from form data sent with both the GET and POST methods.

Try out following example by putting the source code in test.php script.

<?php
  if( $_REQUEST["name"] || $_REQUEST["age"] )
  {
     echo "Welcome ". $_REQUEST['name']. "<br />";
     echo "You are ". $_REQUEST['age']. " years old.";
     exit();
  }
?>
<html>
<body>
  <form action="<?php $_PHP_SELF ?>" method="POST">

  Name: <input type="text" name="name" />
  Age: <input type="text" name="age" />

  <input type="submit" />
  </form>
</body>
</html>

Here $_PHP_SELF variable contains the name of self script in which it is being called.

Wednesday, 7 August 2013

1. addcslashes()

2. convert_uudecode()

3. convert_uuencode()

4. count_chars()

5. echo()

6. explode()

7. implode()

8. md5()

9. str_replace()

10. str_split()

11. str_word_count()

12. strcmp()

13. strlen()

14. strrpos()

15. strstr()

16. strtolower()

17. strtoupper()

18. substr()

19. trim()

20. wordwrap()

Tuesday, 6 August 2013

Monday, 5 August 2013

PHP - Converting HTML into Entities

PHP Code:

Safe Raw HTML Code:

Dangerous Raw HTML Code:

Safe Display:

Dangerous Display:

When Would You Use htmlentities?

List of Topic/Chapter For OOP In PHP

Basics of OOP in PHP

What is Object?

What is Class ?

Advantage of Object Oriented Programming

Implementation of OOP in PHP

The include() Function

The require() Function

include vs. include_once vs. require vs. require_once - examples

Opening and Closing Files

Reading a file

Writing a file

The GET Method

The POST Method

The $_REQUEST variable