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Showing posts with label PHP. Show all posts
Showing posts with label PHP. Show all posts

Friday, 2 June 2023

How to send emails to your users from your website using Brevo (SendInBlue) API in PHP?

Below PHP code demonstrates how to send emails from your website using Brevo (SendInBlue) API in PHP. You should have API key handy before using this code. Please put entire code in try catch block.

//Set endpoint and api key

$endpoint = 'https://api.brevo.com/v3/smtp/email';

$api_key = 'YOUR_API_KEY';

//Request payload

$data = array(

    'sender' => array(

        'name' => 'Sender Alex',

        'email' => 'senderalex@example.com'

    ),

    'to' => array(

        array(

            'email' => 'testmail@example.com',

            'name' => 'John Doe'

        )

    ),

    'subject' => 'Hello world',

    'htmlContent' => '<html><head></head><body><p>Hello,</p><p>This is my first transactional email sent from Brevo.</p></body></html>'

);

//Set cURL options

$options = array(

    CURLOPT_URL => $endpoint,

    CURLOPT_POST => true,

    CURLOPT_POSTFIELDS => json_encode($data),

    CURLOPT_RETURNTRANSFER => true,

    CURLOPT_HTTPHEADER => array(

        'accept: application/json',

        'api-key: ' . $api_key,

        'content-type: application/json'

    )

);

//Initialize cURL session

$curl = curl_init();

//Set cURL options

curl_setopt_array($curl, $options);

//Execute the request

$response = curl_exec($curl);

//Check for errors

if ($response === false) {

    echo 'Error: ' . curl_error($curl);

} else {

    //Process the response

    $response_data = json_decode($response, true);

    if (isset($response_data['message'])) {

        echo 'Email sent successfully!';

    } else {

        echo 'Email sending failed. Error: ' . $response_data['error'];

    }

}

//Close cURL session

curl_close($curl);

Friday, 4 April 2014

How to pass a Javascript Array to PHP file using AJAX and JSON?

How to pass a Javascript Array to PHP file using AJAX and JSON?

I have an array in javascript and I need to pass this array to a PHP by using AJAX call to that PHP file. I will get this array in PHP file and assign this javascript array to PHP array. Then I will find out the count of that PHP array elements and return it back to the javascript. I will convert JS array in JSON format by JSON.stringify. This is a very simple example on how to pass javascript array to PHP asynchronously. You can perform a lot of operations on this array which you have passed to PHP file but for simplicity I am just returning its count. Let's have a look at the following code snippet.

Javascript Array

var myJSArray = new Array("Saab","Volvo","BMW");

ProcessAJAXRequest() function wil pass JS array to PHP file using AJAX request and will show count of array elements returned by PHP file.

function ProcessAJAXRequest()
{
    $.ajax
    ({
        type: "POST",
        url: "myphpfile.php",
        data: {"myJSArray" : JSON.stringify(myJSArray)},
        success: function (data) 
        {
            alert(data); //count of array elements
        }
    });
}

myphpfile.php

<?php 
    $myPHPArray = json_decode($_POST["myJSArray"]);
    echo count($myPHPArray);
 ?>

Saturday, 30 November 2013

PHP Basic Interview Questions and Answers for Web Developers - Part 1

PHP Basic Interview Questions and Answers for Web Developers - Part 1

In this article on PHP Interview Questions, I have compiled a list of very basic and fundamental PHP interview questions and answers for web developers. Every PHP web developer should know these basic questions of PHP. So, if you are preparing for any interview in PHP development, you should go through the following list of PHP basic interview questions. There PHP questions are based on very simple PHP concepts like basic introduction to PHP, Sessions and Cookies in PHP, Input / Output in PHP, Error Management in PHP, MySQL database connectivity in PHP, SQL Injection in PHP, Encryption and Decryption in PHP, Sending Emails in PHP, datatypes in PHP and many more. Lets have a look...

1. What is PHP?

PHP is a server side scripting object oriented language commonly used for web applications. 

2. What is the use of "echo" in php?

It is used to print a data in the webpage.

Example: 

<?php echo 'Hi'; ?>

The above code print the text in the webpage

3. How to include a file to a php page?

We can include a file using "include()" or "require()" function with file path as its parameter.

4. What's the difference between include and require?

If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

5. What is difference between require_once(), require() and include()?

require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page). So, require_once() is recommended to use when you want to include a file where you have a lot of functions for example. This way you make sure you don't include the file more times and you will not get the "function re-declared" error.

6. Differences between GET and POST methods?

We can send 1024 bytes using GET method but POST method can transfer large amount of data and POST is the secure method than GET method .

7. How to declare an array in php?

Eg : var $arr = array('apple', 'grape', 'lemon');

8. What is the use of 'print' in php?

This is not actually a real function, It is a language construct. So you can use without parentheses with its argument list.

Example:

print('PHP Interview Questions'); 
print 'PHP Interview Questions';

9. What is use of in_array() function in php?

in_array used to checks if a value exists in an array

10. What is use of count() function in php?

count() is used to count all elements in an array, or something in an object

11. What is the difference between Session and Cookie?

The main difference between sessions and cookies is that sessions are stored on the server, and cookies are stored on the user’s computers in the text file format. Cookies can not hold multiple variables, but Session can hold multiple variables. We can set expiry for a cookie while the session only remains active as long as the browser is open. Users do not have access to the data you stored in Session because it is stored in the server. Session is mainly used for login/logout purpose while cookies using for user activity tracking

12. How to set cookies in PHP?

Setcookie("sample", "ram", time()+3600);

13. How to retrieve a Cookie Value?

eg : echo $_COOKIE["user"];

14. How to create a session? How to set a value in session ? How to remove data from a session?

Create session : session_start();
Set value into session : $_SESSION['USER_ID']=1;
Remove data from a session : unset($_SESSION['USER_ID'];

15. What types of loops exist in php?

for,while,do while and foreach 

16. How to create a mysql connection?

mysql_connect(servername,username,password);

17. How to select a database?

mysql_select_db($db_name);

18. How to execute an sql query? How to fetch its result ?

$my_qry = mysql_query("SELECT * FROM `users` WHERE `u_id`='1'; "); 
$result = mysql_fetch_array($my_qry);
echo $result['First_name'];

19. Write a program using while loop

$my_qry = mysql_query("SELECT * FROM `users` WHERE `u_id`='1'; "); 
while($result = mysql_fetch_array($my_qry))
{
   echo $result['First_name'.]."<br/>";
}

20. How we can retrieve the data in the result set of MySQL using PHP?

1. mysql_fetch_row
2. mysql_fetch_array
3. mysql_fetch_object
4. mysql_fetch_assoc

21. What is the use of explode() function?

Syntax : array explode ( string $delimiter , string $string [, int $limit ] ); 

This function breaks a string into an array. Each of the array elements is a substring of string formed by splitting it on boundaries formed by the string delimiter.

22. What is the difference between explode() and split() functions?

Split function splits string into array by regular expression. Explode splits a string into array by string.

23. What is the use of mysql_real_escape_string() function?

It is used to escapes special characters in a string for use in an SQL statement

24. Write down the code for save an uploaded file in php.

if ($_FILES["file"]["error"] == 0)
{
       move_uploaded_file($_FILES["file"]["tmp_name"],
      "upload/" . $_FILES["file"]["name"]);
      echo "Stored in: " . "upload/" . $_FILES["file"]["name"]; 
}

25. How to create a text file in 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 );

26. How to strip whitespace (or other characters) from the beginning and end of a string?

The trim() function removes whitespaces or other predefined characters from both sides of a string.

27. What is the use of header() function in php?

The header() function sends a raw HTTP header to a client browser.Remember that this function must be called before sending the actual out put.For example, You do not print any HTML element before using this function.

28. How to redirect a page in php?

The following code can be used for it, header("Location:index.php");

29. How stop the execution of a php script?

exit() function is used to stop the execution of a page

30. How to set a page as a home page in a php based site?

index.php is the default name of the home page in php based sites

31. How to find the length of a string?

strlen() function used to find the length of a string

32. What is the use of rand() in php?

It is used to generate random numbers.If called without the arguments it returns a pseudo-random integer between 0 and getrandmax(). If you want a random number between 6 and 12 (inclusive), for example, use rand(6, 12).This function does not generate cryptographically safe values, and should not be used for cryptographic uses. If you want a cryptographically secure value, consider using openssl_random_pseudo_bytes() instead.

33. What is the use of isset() in php?

This function is used to determine if a variable is set and is not NULL

34. What is the difference between mysql_fetch_array() and mysql_fetch_assoc()?

mysql_fetch_assoc function Fetch a result row as an associative array, While mysql_fetch_array() fetches an associative array, a numeric array, or both

35. What is mean by an associative array?

Associative arrays are arrays that use string keys is called associative arrays.

36. What is the importance of "method" attribute in a html form?

"method" attribute determines how to send the form-data into the server.There are two methods, get and post. The default method is get.This sends the form information by appending it on the URL.Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.

37. What is the importance of "action" attribute in a html form?

The action attribute determines where to send the form-data in the form submission.

38. What is the use of "enctype" attribute in a html form?

The enctype attribute determines how the form-data should be encoded when submitting it to the server. We need to set enctype as "multipart/form-data" when we are using a form for uploading files

39. How to create an array of a group of items inside an HTML form?

We can create input fields with same name for "name" attribute with squire bracket at the end of the name of the name attribute, It passes data as an array to PHP. 

For instance :

<input name="MyArray[]" />  <input name="MyArray[]" />  <input name="MyArray[]" />  <input name="MyArray[]" />

40. Define Object-Oriented Methodology.

Object orientation is a software/Web development methodology that is based on the modeling a real world system.An object is the core concept involved in the object orientation. An object is the copy of the real world enity.An object oriented model is a collection of objects and its inter-relationships

41. How do you define a constant?

Using define() directive, like define ("MYCONSTANT",150)

42. How send email using php?

To send email using PHP, you use the mail() function.This mail() function accepts 5 parameters as follows (the last 2 are optional). You need webserver, you can't send email from localhost. eg : mail($to,$subject,$message,$headers);

43. How to find current date and time?

The date() function provides you with a means of retrieving the current date and time, applying the format integer parameters indicated in your script to the timestamp provided or the current local time if no timestamp is given. In simplified terms, passing a time parameter is optional - if you don't, the current timestamp will be used.

44. Difference between mysql_connect and mysql_pconnect?

There is a good page in the php manual on the subject, in short mysql_pconnect() makes a persistent connection to the database which means a SQL link that do not close when the execution of your script ends. mysql_connect()provides only for the databasenewconnection while using mysql_pconnect , the function would first try to find a (persistent) link that's already open with the same host, username and password. If one is found, an identifier for it will be returned instead of opening a new connection... the connection to the SQL server will not be closed when the execution of the script ends. Instead, the link will remain open for future use.

45. What is the use of "ksort" in php?

It is used for sort an array by key in reverse order.

46. What is the difference between $var and $$var?

They are both variables. But $var is a variable with a fixed name. $$var is a variable who's name is stored in $var. For example, if $var contains "message", $$var is the same as $message.

47. What are the encryption techniques in PHP?

MD5: PHP implements the MD5 hash algorithm using the md5 function.

eg : $encrypted_text = md5 ($msg);

mcrypt_encrypt: string mcrypt_encrypt ( string $cipher , string $key , string $data , string $mode [, string $iv ] ); 

Encrypts plaintext with given parameters

48. What is the use of the function htmlentities?

htmlentities Convert all applicable characters to HTML entities This function is identical to htmlspecialchars() in all ways, except with htmlentities(), all characters which have HTML character entity equivalents are translated into these entities.

49. How to delete a file from the system?

Unlink() deletes the given file from the file system.

50. How to get the value of current session id?

session_id() function returns the session id for the current session.

51. What are the differences between mysql_fetch_array(), mysql_fetch_object(), mysql_fetch_row()?

Mysql_fetch_array Fetch a result row as an associative array, a numeric array, or both.
mysql_fetch_object ( resource result ) Returns an object with properties that correspond to the fetched row and moves the internal data pointer ahead. Returns an object with properties that correspond to the fetched row, or FALSE if there are no more rows
mysql_fetch_row() fetches one row of data from the result associated with the specified result identifier. The row is returned as an array. Each result column is stored in an array offset, starting at offset 0.

52. What are the different types of errors in PHP?

Here are three basic types of runtime errors in PHP:

1. Notices: These are trivial, non-critical errors that PHP encounters while executing a script - for example, accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all - although you can change this default behavior.

2. Warnings: These are more serious errors - for example, attempting to include() a file which does not exist. By default, these errors are displayed to the user, but they do not result in script termination.

3. Fatal errors: These are critical errors - for example, instantiating an object of a non-existent class, or calling a non-existent function. These errors cause the immediate termination of the script, and PHP's default behavior is to display them to the user when they take place.

53. What is SQL Injection?

SQL injection is a malicious code injection technique.It exploiting SQL vulnerabilities in Web applications

54. What is x+ mode in fopen() used for?

Read/Write. Creates a new file. Returns FALSE and an error if file already exists

55. How to find the position of the first occurrence of a substring in a string?

strpos() is used to find the position of the first occurrence of a substring in a string

56. What is PEAR?

PEAR is a framework and distribution system for reusable PHP components.The project seeks to provide a structured library of code, maintain a system for distributing code and for managing code packages, and promote a standard coding style.PEAR is broken into three classes: PEAR Core Components, PEAR Packages, and PECL Packages. The Core Components include the base classes of PEAR and PEAR_Error, along with database, HTTP, logging, and e-mailing functions. The PEAR Packages include functionality providing for authentication, networking, and file system features, as well as tools for working with XML and HTML templates.

57. Distinguish between urlencode and urldecode?

This method is best when encode a string to used in a query part of a url. it returns a string in which all non-alphanumeric characters except -_. have replece with a percentege(%) sign . the urldecode->Decodes url to encode string as any %and other symbole are decode by the use of the urldecode() function.

I will come up with more PHP interview questions and answers in second part of this post.

Saturday, 23 November 2013

How to secure jQuery AJAX calls in PHP from hackers?

How to secure jQuery AJAX calls in PHP from hackers?

If you are making jQuery AJAX calls in your PHP website, please ensure that those jQuery AJAX calls are secure from website hackers. Your code should not be vulnerable to hackers. Below are some methods and steps which need to be taken to secure your jQuery AJAX calls to PHP files. I am writing this post because I had written a simple post "How to call PHP function from JavaScript function? Always use AJAX." without mentioning any security code. I got following comment on that post:

"Your code is very vulnerable. You're not filtering the $_POST variable at all. This opens yourself to HTML injection. A hacker could pwn your web site very quickly if you used this code. Careless examples like yours is exactly why so many web sites are hacked."

That's why this is my small attempt to make your jQuery AJAX calls secure. 

1. Use $_SERVER['HTTP_X_REQUESTED_WITH']

This is a basic check to see if the request is an Ajax request or not?

if(!empty($_SERVER['HTTP_X_REQUESTED_WITH']) &&       strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') 
{
    //Request identified as ajax request
}

However you should never base your security on this check. It will eliminate direct accesses to the page if that is what you need.

2. Use $_SERVER['HTTP_REFERER']

if(@isset($_SERVER['HTTP_REFERER']) && $_SERVER['HTTP_REFERER']=="http://yourdomain/ajaxurl")
{
 //Request identified as ajax request
}

But not all browsers set it. So don't properly rely on it but yes, to some extent it can secure your webpage.

Nobody can AJAX your site from other domain, but always can connect and drieclty send http request, for example by cURL.

JavaScript running on another domain cannot access any page on your domain because this is a violation of the Same-Origin Policy. The attacker would need to exploit an XSS vulnerability in order to pull this off. In short you don't need to worry about this specific attack, just the same old attacks that affect every web application.

3. Generate Access Tokens

$token = md5(rand(1000,9999)); //you can use any encryption
$_SESSION['token'] = $token; //store it as session variable

You can create some token in cookies, that will be also seen from jquery request, but that solution can also be hacked.

4. Always check $_POST variables in your PHP file whether those are set or not? Whether there is valid value in $_POST or not before executing the actual PHP code.

Basic code snippet for securing your jQuery AJAX calls in PHP

Step-1 : Generate Token System For All Web-Service:

Generating Token :

<?php
  session_start();
  $token = md5(rand(1000,9999)); //you can use any encryption
  $_SESSION['token'] = $token; //store it as session variable
?>

Step-2 : Use it while sending ajax call:

var form_data = 
{
  data: $("#data").val(), //your data being sent with ajax
  token:'<?php echo $token; ?>', //used token here.
  is_ajax: 1
};

$.ajax({
  type: "POST",
  url: 'yourajax_url_here',
  data: form_data,
  success: function(response)
  {
    //do further
  }
});

Step-3 : NOW, Let's secure ajax handler PHP file with,

session_start(); 
if($_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest') 
{
  //Request identified as ajax request

  if(@isset($_SERVER['HTTP_REFERER']) &&    $_SERVER['HTTP_REFERER']=="http://yourdomain/ajaxurl")
  {
   //HTTP_REFERER verification
    if($_POST['token'] == $_SESSION['token']) {
      //do your ajax task
      //don't forget to use sql injection prevention here.
    }
    else
   {
      header('Location: http://yourdomain.com');
    }
  }
  else 
  {
    header('Location: http://yourdomain.com');
  }
}
else 
{
  header('Location: http://yourdomain.com');
}

Wednesday, 20 November 2013

How to call PHP function from JavaScript function? Always use AJAX.

How to call PHP function from JavaScript function? Always use AJAX.

Recently, I was developing a web application in PHP. I get into the need of calling my PHP function from my Javascript function. This is the common thing when you are developing a web application in PHP and have to call a PHP code from Javascript to refresh only a certain portion of your web page with server results. Always use AJAX to achieve this functionality. Using AJAX you can call server side code / functions (your PHP code) from client side (Javascript). Below is the PHP and Javascript code snippet to illustrate this concept. 

This is very simple example on how to call server side functions of PHP from client browsers (Javascript)? In following example, I have a PHP file named myscript.php which has function named myfunction(). This function uses two $_POST variables and just echoes them. I have mydiv HTML div anywhere on my webpage which I want to refresh with the result which is returned from my PHP script. In my Javascript code, I am using AJAX to call my PHP script with parameters and POST method. The result which is getting returned, I am showing that in mydiv HTML div. 

Have a look at this very simple PHP AJAX example:

PHP code

<?php

myfunction();

function myfunction()
{
$myvar = $_POST['q']." how are you?";
$myvar2 = $_POST['z'];
echo $myvar."\n".$myvar2;
}
?>

HTML code

<div id="mydiv"></div>

Javascript code

var data =" hello world";
var data2=" hello all";
function run()
{
$.ajax(
{
                   url: 'myscript.php',
                data: {'q': data,'z':data2},
                   type: 'post',
                   success: function(output) 
                {
                          //alert(output);
                          document.getElementById("mydiv").innerHTML += output; //add output to div  
                }
}
          );
}

Friday, 18 October 2013

How to use setInterval and clearInterval jQuery methods in PHP?

How to use setInterval and clearInterval jQuery methods in PHP?

I will explain usage of setInterval and clearInterval jQuery methods with the help of simple example in PHP. Suppose there is a PHP array in which there are 3 elements. I want to display all of them one by one at regular intervals and stop when all the three array elements have been displayed. I will use setInterval and clearInterval jQuery methods here to implement it.

Here is my index.php file

<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script type="text/javascript">
var count = 0;
$(document).ready(function(){
var auto_refresh = setInterval(function (){
    $('#mydiv').load('myphpfile.php', {count: count}, function () {
        count = count + 1;
        //after three attempts it won't call php file.
        if (count > 2) {
            clearInterval(auto_refresh);
        }
    }).fadeIn("slow");
    }, 1000); 
});
</script>
</head>
<body>
<div id="mydiv"> </div>
</body>
</html>

Here is my myphpfile.php file

<?php
$questions=array(
                 "Array Item 0",
                 "Array Item 1",
                 "Array Item 2");

if (isset($_REQUEST["count"])) 
{
    echo $questions[intval($_REQUEST["count"])];
}
?>

Thursday, 17 October 2013

How to generate Random Numbers at Regular Intervals in PHP?

How to generate Random Numbers at Regular Intervals in PHP? 

Following is the simple PHP tutorial to demonstrate how to generate random numbers at regular intervals in PHP? I will use jquery setInterval() method for calling PHP file (which generates random numbers) at regular intervals say after every second in my example. I will use PHP rand() function to generate random numbers in PHP. I am using google CDN for jquery libraray. So here is the simple example in PHP to generate random numbers at regular intervals.

index.php file

<!DOCTYPE html>
<html lang="en">

<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>

<script type="text/javascript">
$(document).ready(function(){
var auto_refresh_random_numbers = setInterval(
function ()
{
$('#load_random_numbers').load('generate_random_numbers.php').fadeIn("slow");
}, 1000); // refresh random numbers after every 1000 milliseconds
});
</script>

</head>

<body>
<div id="load_random_numbers"> </div>
</body>

</html>

generate_random_numbers.php file

<?php
echo rand();
?>

So, that's all. Above PHP code snippet is very easy to understand by everyone. So, I don't think there is need of any explanation.

Friday, 22 February 2013

How to Redirect URLs using Apache .htaccess File in PHP?

How to Redirect URLs using Apache .htaccess File in PHP?

In this apache .htaccess tutorial, we will learn how to redirect urls in PHP using .htaccess file?

.htacces is a configuration file in apache. The .htaccess file is a small text document that generally sits in the same location as your index.php or index.htm pages. It gives you the ability to interact with Apache on an individual domain-to-domain and directory-to-directory basis.

You can place the htaccess file anywhere where you'd like to control the flow of visitors. So for instance you can protect directories and redirect the traffic visiting those pages. This page will show you how to use the .htaccess file to redirect your visitors in different ways.

You can use .htaccess to redirect users to a different URL. The most basic .htaccess looks for any request for a specific page and if it finds that request, it forwards it to a new page you have specified. The syntax is:

redirect accessed-file URL-to-go-to

There are 3 parts;

(1) the Redirect command,
(2) the location of the file/directory you want redirected, and
(3) the full URL of the location you want that request sent to.

These parts are separated by a single space and should be on one line.
 
Contents of .htaccess file

1. 301 (Permanent) Redirect:

301 redirect is the most efficient and Search Engine Friendly method for webpage redirection. It's not that hard to implement and it should preserve your search engine rankings for that particular page. If you have to change file names or move pages around, it's the safest option. The code "301" is interpreted as "moved permanently".

Point an entire site to a different URL on a permanent basis. This is the most common type of redirect and is useful in most situations. In this example, we are redirecting to the "mt-example.com" domain:

# This allows you to redirect your entire website to any other domain
Redirect 301 / http://mywebsite.com/

2. 302 (Temporary) Redirect: Point an entire site to a different temporary URL. This is useful for SEO purposes when you have a temporary landing page and plan to switch back to your main landing page at a later date:

# This allows you to redirect your entire website to any other domain
Redirect 302 /
http://mywebsite.com/

3. Redirect index.html to a specific subfolder:

# This allows you to redirect index.html to a specific subfolder
Redirect /index.html
http://mywebsite.com/newdirectory/

4. Redirect an old file to a new file path:

# Redirect old file path to new file path
Redirect /olddirectory/oldfile.html
http://mywebsite.com/newdirectory/newfile.html

5. Redirect to a specific index page:

# Provide Specific Index Page (Set the default handler)
DirectoryIndex index.html

Precautions to use before using .htaccess file:

1. Even the slightest syntax error (like a missing space) can result in your content not displaying correctly or at all.

2. Since .htaccess is a hidden system file, please make sure your FTP client is configured to show hidden files. This is usually an option in the program's preferences/options.

3. Create an empty text file using a text editor such as notepad, and save it as htaccess.txt. The reason you should save the file as htaccess.txt is because many operating systems and FTP applications are unable to read or view .htaccess files by default. Once uploaded to the server you can rename the file to .htaccess.

Monday, 11 February 2013

PHP Form Validation Script: PHP GET and POST Methods

PHP Form Validation Script: PHP GET and POST Methods

Form validation in PHP is very easy. Whenever you submit any form in PHP, you must validate the input data before storing that in database. Basic validations which you can put on your input data might be trimming the input form data, stripping the slashes from form data, handling special html characters and various functional things depending upon the need of your PHP application. Below is the PHP Form Validation Script using POST method.

HTML Page

<form action="validateForm.php" method="post">
Name: <input type="text" name="name">
Email: <input type="text" name="email">
<input type="submit">
</form>

PHP Script to Validate Form

<?php
$name = validateData($_POST['name']);
$email = validateData($_POST['email']);
?>

function validateData($data)
{
    $data = trim($data);
    $data = stripslashes($data);
    $data = htmlspecialchars($data);
    return $data;
}

Now lets discuss PHP Get and POST methods in detail:

PHP GET Method

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


PHP Script to illustrate GET Method

<form action="index.php" method="get">
Name: <input type="text" name="name">
<input type="submit">
</form>

When the user clicks the "Submit" button, the URL sent to the server will look like this:


The index.php file can now use the $_GET variable to collect php form data (the names of the form fields will automatically be the keys in the $_GET array):

Hello <?php echo $_GET["name"]; ?>

The PHP provides $_GET associative array to access all the sent information using PHP GET method.

Limitations of PHP GET Method:

1. When using method="get" in HTML forms, all variable names and values are displayed in the URL. So, PHP GET method should not be used when sending passwords or other sensitive information.

2. The PHP GET method is not suitable for very large variable values. It should not be used with values exceeding 1024 characters.

3. PHP GET method can't be used to send binary data, like images or word documents, to the server.

Advantages of PHP GET Method:

1. Because the variables are displayed in the URL, it is possible to bookmark the page.

PHP Post Method

The POST method transfers information via HTTP headers. The information is put into a header called QUERY_STRING.

PHP Script to illustrate POST Method

<form action="index.php" method="post">
Name: <input type="text" name="name">
<input type="submit">
</form>

When the user clicks the "Submit" button, the URL sent to the server will look like this:


The index.php file can now use the $_POST variable to collect form data (the names of the form fields will automatically be the keys in the $_POST array):

Hello <?php echo $_POST["name"]; ?>

Advantages of PHP POST Method

1. No limit to send data. There is an 8 MB max size for the POST method, by default (can be changed by setting the post_max_size in the php.ini file).

2. Variables are not visible in URL. So one can easily send passwords and critical information using POST method.

3. You can even post binary data using PHP Post Method.

Limitation of PHP POST Method

1. You cannot bookmark a specific page unlike GET method.

Saturday, 9 February 2013

Online PHP Programming Tutorial: Learn Basics of PHP Scripting With Simple PHP Code and Examples (Part 1)

Online PHP Programming Tutorial: Learn Basics of PHP Scripting With Simple PHP Code and Examples (Part 1)

Introduction to PHP: PHP stands for Hypertext Preprocessor. PHP is a server scripting language and is used for creating dynamic web pages. PHP is an open source scripting language. We will discuss some similarities and differences between PHP and ASP.NET later in this tutorial.

Learning PHP Programming

Learning PHP programming and development is very easy. PHP has very simple syntax. In this online PHP tutorial, we will learn PHP step by step by simple PHP examples using short and simple PHP scripts and codes. Lets start learning PHP scripting now:

1. Simple PHP Code Snippet

<?php
echo "Lets learn PHP Programming!";
?>

Some basic things to note in PHP scripting:

1. A PHP script starts with <?php and ends with ?>.
2. Each code line in PHP must end with a semicolon.
3. PHP files have a default file extension of ".php".
4. In PHP, there are two basic statements to output text in the browser: echo and print.

2. Comments in PHP Programming

<?php
//PHP Single Line Comments
/*
PHP
Multi Line Comments
*/
?>

3. Rules for PHP Variables

1. PHP variable starts with the $ sign, followed by the name of the variable
2. PHP variable name must begin with a letter or the underscore character
3. PHP variable name only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
4. PHP variable name should not contain spaces
5. PHP variable names are case sensitive ($y and $Y are two different variables)
6. PHP has no command for declaring a variable
7. PHP variables can be local, global and static
8. PHP string variable is used to store and manipulate text. When you assign a text value to a variable, remember to put single or double quotes around the value.

PHP Variables Example

<?php
$x=5;
$y=6;
$z=$x+$y;
echo $z;
?>

4. PHP is a Loosely Typed Language

You don't have to declare data type the variable in PHP. PHP automatically converts the variable to the correct data type, depending on its value. In a strongly typed programming language, we will have to declare datatype of the variable before using it.

Consider the following simple PHP example:

$txt="PHP is a loosely typed language";
$x=5;

After the execution of the statements above, the variable txt will hold the value Hello world!, and the variable x will hold the value 5. When you assign a text value to a variable, put quotes around the value.

5. Types of Array in PHP

In PHP, there are three types of arrays:

Indexed arrays - Arrays with numeric index
Associative arrays - Arrays with named keys - Associative arrays are arrays that use named keys that you assign to them.
Multidimensional arrays - Arrays containing one or more arrays

Similarity and Differences between PHP and ASP.NET

PHP is a strong competitor of Microsoft ASP.NET. PHP goes ahead of ASP.NET in some case like:

1. PHP runs on different platforms likeWindows, Linux, Unix, Mac OS X, etc. ASP.NET on the other hand, only runs fine on Windows.


2. PHP is compatible with both Apache, IIS while ASP.NET has compatibility only with IIS. You can configure ASP.NET to run on Apache, but that is cumbersome.

3. PHP is open source and free. No license required for using PHP for commercial purposes.
 
Similarity between ASP.NET and PHP

1. Both ASP.NET and PHP are used for dynamic webpage development.


2. Both ASP.NET and PHP are easy to learn and understand.

3. Both ASP.NET and PHP have support for a wide range of databases.

4. Both ASP.NET and PHP have large online developer forums to support web development. For example, you will find a large community of ASP.NET and PHP developers on StackOverflow.com.

About the Author

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I am currently messing up with neural networks in deep learning. I am learning Python, TensorFlow and Keras.

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