DIWE - Advanced PHP Concepts

Diploma in Web Engineering
Module VII: Advanced PHP
Concepts
Rasan Samarasinghe
ESOFT Computer Studies (pvt) Ltd.
No 68/1, Main Street, Pallegama, Embilipitiya.

Contents
1. Arrays
2. Indexed Arrays
3. Associative Arrays
4. Multidimensional arrays
5. Array Functions
6. PHP Objects and Classes
7. Creating an Object
8. Properties of Objects
9. Object Methods
10. Constructors
11. Inheritance
12. Method overriding
13. PHP Strings
14. printf() Function
15. String Functions
16. PHP Date/Time Functions
17. time() Function
18. getdate() Function
19. date() Function
20. mktime() function
21. checkdate() function
22. PHP Form Handling
23. Collecting form data with PHP
24. GET vs POST
25. Data validation against malicious code
26. Required fields validation
27. Validating an E-mail address
28. PHP mail() Function
29. Using header() function to redirect user
30. File Upload
31. Processing the uploaded file
32. Check if File Already Exists
33. Limit File Size
34. Limit File Type
35. Check if image file is an actual image
36. Uploading File
37. Cookies
38. Sessions

Arrays
10 30 20 50 15 35
0 1 2 3 4 5
Size = 6
Element Index No
An array can hold many values under a
single name. you can access the values by
referring an index.
A single dimensional array

Arrays
In PHP, there are three types of arrays
• Indexed arrays
• Associative arrays
• Multidimensional arrays

Indexed Arrays
The index can be assigned automatically starts from 0
$fruits = array(“apple”, “mango”, “grapes”);
or the index can be assigned manually
$fruits[0] = “apple”;
$fruits[1] = “mango”;
$fruits[2] = “grapes”;

Loop Through an Indexed Array
$fruits = array(“apple”, “mango”, “grapes”);
$length = count($fruits);
for($i = 0; $i <= $length-1; $i++) {
echo $fruits[$i];
echo "<br>";
}

Associative Arrays
Associative arrays use named keys that you assign to
them
$age = array(“Roshan”=>23, “Nuwan”=>24,
“Kamal”=>20);
Or
$age = array();
$age[“Roshan”] = 23;
$age[“Nuwan”] = 24;
$age[“Kamal”] = 20;

Loop Through an Associative Array
$age = array(“Roshan”=>23, “Nuwan”=>24,
“Kamal”=>20);
foreach($age as $x=>$x_value) {
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}

Multidimensional arrays
• A multidimensional array is an array containing
one or more arrays.
• A two-dimensional array is an array of arrays
• A three-dimensional array is an array of arrays of
arrays

Two dimensional Arrays
Name Age City
Roshan 23 Colombo
Nuwan 24 Kandy
Kamal 20 Galle
Ruwan 21 Matara
Two dimensional array is forming a grid of data.

Creating a Two dimensional Array
$students = array
(
array(“Roshan”, 23, “Colombo”),
array(“Nuwan”, 24, “Kandy”),
array(“Kamal”, 20, “Galle”),
array(“Ruwan”, 21, “Matara”)
);

Accessing a 2D Array Elements
Syntax:
Array name[row index][column index];
Ex:
$age = $students[ 0 ][ 1 ];

Array Functions
Function Description Example
count() Counts the number of elements in the
array
$n = count($ArrayName)
sizeof() Counts the number of elements in the
array
$n = sizeof($ArrayName)
each() Return the current element key and
value, and move the internal pointer
forward
each($ArrayName)
reset() Rewinds the pointer to the beginning
of the array
reset($ArrayName)
list() Assign variables as if they were an
array
list($a, $b, $c) = $ArrayName
array_push() Adds one or more elements to the
end of the array
array_push($ArrayName, “element1”,
“element2”, “element3”)
array_pop() Removes and returns the last element
of an array
$last_element = array_pop($ArrayName)

Array Functions
Function Description Example
array_unshift() Adds one or more elements to
the beginning of an array
array_unshift($ArrayName, “element1”,
“element2”, “element3”)
array_shift() Removes and returns the first
element of an array
$first_element = array_shift($ArrayName)
array_merge() Combines two or more arrays $NewArray = array_merge($array1, $array2)
array_keys() Returns an array containing all
the keys of an array
$KeysArray = array_keys($ArrayName)
array_values() Returns an array containing all
the values of an array
$ValuesArray = array_values($ArrayName)
shuffle() Randomize the elements of an
array
shuffle($ArrayName)

PHP Objects and Classes
• An object is a theoretical box of thing consists
from properties and functions.
• An object can be constructed by using a template
structure called Class.

Creating an Object
class Class_name {
// code will go here
}
$object_name = new Class_name();

Properties of Objects
Variables declared within a class are called
properties
class Car {
var $color = “Red”;
var $model = “Toyota”;
var $VID = “GV - 5432”;
}

Accessing object properties
$MyCar = new Car();
echo “Car color” . $MyCar -> color . “<br/>”;
echo “Car model” . $MyCar -> model . “<br/>”;
echo “Car VID” . $MyCar -> VID . “<br/>”;

Changing object properties
$MyCar = new Car();
$MyCar -> color = “White”;
$MyCar -> model = “Honda”;
$MyCar -> VID = “GC 4565”;

Object Methods
A method is a group of statements performing a
specific task.
class Car {
var $color = “Red”;
var $model = “Toyota”;
var $VID = “GV - 5432”;
function start() {
echo “Car started”;
}
}

Object Methods
A call to an object function executes statements of
the function.
$MyCar = new Car();
$MyCar -> start();

Accessing object properties within a method
class Car {
var $color;
function setColor($color) {
$this -> color = $color;
}
function start() {
echo $this -> color . “ color car started”;
}
}

Constructors
A constructor is a function within a class given the same name as
the class.
It invokes automatically when new instance of the class is created.
class Student {
var $name;
function Student($name) {
$this -> name = $name;
}
}
$st = new Student(“Roshan”);

Inheritance
In inheritance, one class inherits the functionality from
it’s parent class.
class super_class {
// code goes here
}
class sub_class extends super_class {
// code goes here
}

Method overriding
class Person {
var $name;
function sayHello(){
echo “My name is “ . $this -> name;
}
}
class Customer extends Person {
function sayHello(){
echo “I will not tell you my name”;
}
}

PHP Strings
A string is a sequence of characters, like:
"Hello world!"
‘Even single quotes are works fine but $variable
values and special characters like n t are not
working here’

printf() Function
The printf() function outputs a formatted string and
returns the length of the outputted string.
$number = 20;
$str = “Sri Lanka”;
printf(“There are %u million people live in %s.”,
$number, $str);

Type specifiers in printf()
Specifier Description
%b Binary number
%c The character according to the ASCII value
%d Signed decimal number (negative, zero or positive)
%e Scientific notation using a lowercase (e.g. 1.2e+2)
%E Scientific notation using a uppercase (e.g. 1.2E+2)
%u Unsigned decimal number (equal to or greater than zero)
%f Floating-point number
%o Octal number
%s String
%x Hexadecimal number (lowercase letters)
%X Hexadecimal number (uppercase letters)
[0-9] Specifies the minimum width held of to the variable value. Example: %10s
' Specifies what to use as padding. Example: %'x20s
.[0-9] Specifies the number of decimal digits or maximum string length. Example: %.2d

String Functions
Function Description
sprintf() Writes a formatted string to a variable and returns it
strlen() Returns the length of a string
strstr() Find the first occurrence of a string, and return the rest of the string
strpos() Returns the position of the first occurrence of a string inside another string
substr() Returns a part of a string
strtok() Splits a string into smaller strings
trim() Removes whitespace or other characters from both sides of a string
ltrim() Removes whitespace or other characters from the left side of a string
rtrim() Removes whitespace or other characters from the right side of a string
strip_tags() Strips HTML and PHP tags from a string
substr_replace() Replaces a part of a string with another string
str_replace() Replaces all instances of a string with another string
strtoupper() Converts a string to uppercase letters
strtolower() Converts a string to lowercase letters
ucwords() Converts the first character of each word in a string to uppercase
ucfirst() Converts the first character of a string to uppercase
wordwrap() Wraps a string to a given number of characters
nl2br() Inserts HTML line breaks in front of each newline in a string
explode() Breaks a string into an array

PHP Date/Time Functions
• The date/time functions allow you to get the date
and time from the server where your PHP script
runs.
• You can use the date/time functions to format the
date and time in several ways.

time() Function
Returns the current time in the number of seconds
since the Unix Epoch (January 1 1970 00:00:00
GMT)
$t=time();
echo $t . "<br/>";

getdate() Function
Returns an associative array with date/time
information of a timestamp or the current local
date/time.
Syntax:
getdate(timestamp);

Elements contained in the returned array by gettdate()
Key Description
[‘seconds’] Seconds past the minutes
[‘minutes’] Minutes past the hour
[‘hours’] Hours of the day
[‘mday’] Day of the month
[‘wday’] Day of the week
[‘mon’] Month of the year
[‘year’] Year
[‘yday’] Day of the year
[‘weekday’] Name of the weekday
[‘month’] Name of the month
[‘0’] seconds since Unix Epoch

date() Function
Format a local date and time and return the formatted
date strings
Syntax:
date(format, timestamp);
// Prints the day
echo date("l") . "<br/>";
// Prints the day, date, month, year, time, AM or PM
echo date("l jS of F Y h:i:s A");

Format codes for use with date()
Format Description
d The day of the month (from 01 to 31)
D A textual representation of a day (three letters)
j The day of the month without leading zeros (1 to 31)
l A full textual representation of a day
S The English ordinal suffix for the day of the month
z The day of the year (from 0 through 365)
F A full textual representation of a month (January through December)
m A numeric representation of a month (from 01 to 12)
M A short textual representation of a month (three letters)
n A numeric representation of a month, without leading zeros (1 to 12)
L Whether it's a leap year (1 if it is a leap year, 0 otherwise)
Y A four digit representation of a year
y A two digit representation of a year

Format codes for use with date()
Format Description
a Lowercase am or pm
A Uppercase AM or PM
g 12-hour format of an hour (1 to 12)
G 24-hour format of an hour (0 to 23)
h 12-hour format of an hour (01 to 12)
H 24-hour format of an hour (00 to 23)
i Minutes with leading zeros (00 to 59)
s Seconds, with leading zeros (00 to 59)
u Microseconds (added in PHP 5.2.2)
r The RFC 2822 formatted date (e.g. Fri, 12 Apr 2013 12:01:05 +0200)
U The seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)
Z Timezone offset in seconds. The offset for timezones west of UTC is
negative (-43200 to 50400)

mktime() function
Returns the Unix timestamp for a date.
Syntax:
mktime(hour,minute,second,month,day,year,is_dst);
// Prints: October 3, 1975 was a Friday
echo "Oct 3, 1975 was a " . date("l",
mktime(0,0,0,10,3,1975));

checkdate() function
Used to validate a Gregorian date.
Syntax:
checkdate(month, day, year);
var_dump(checkdate(2,29,2003));
var_dump(checkdate(2,29,2004));

PHP Form Handling
The PHP superglobals $_GET and $_POST are used
to collect form-data.

A Simple HTML Form
<form action="welcome.php" method="post">
Name: <input type="text" name=“txtname”><br>
E-mail: <input type="text" name=“txtemail”><br>
<input type="submit">
</form>
When the user fills out the form above and clicks
the submit button, the form data is sent to a PHP
file named "welcome.php". The form data is sent
with the HTTP POST method.

Collecting form data with PHP
The "welcome.php" looks like this:
<body>
Welcome <?php echo $_POST[“txtname”]; ?><br>
Your email address is: <?php echo
$_POST[“txtemail”]; ?>
</body>

A Form with a hidden field
<form action="welcome.php" method="post"
name="myForm">
Name: <input name="txtName" type="text" />
<input name="txtHidden" type="hidden"
value="This is the hidden value" />
<input name="" type="submit" />
</form>

Collecting hidden field data with PHP
Welcome <?php echo $_POST["txtName"]; ?><br>
Your hidden field value was: <?php echo
$_POST["txtHidden"]; ?>

Form including multiple select elements
<form name="myForm" action="details.php" method="post">
Company: <br /><select name="companies[]" multiple="multiple">
<option value="microsoft">Microsoft</option>
<option value="google">Google</option>
<option value="oracle">Oracle</option>
</select>
Products:
<input type="checkbox" name="products[]" value="tab" />Tab
<input type="checkbox" name="products[]" value="mobile"
/>Mobile
<input type="checkbox" name="products[]" value="pc" />PC
<input type="submit" />
</form>

Collecting select field form data with PHP
<?php
foreach($_POST["companies"] as $val){
echo $val . "<br/>";
}
foreach($_POST["products"] as $val){
echo $val . "<br/>";
}
?>

GET vs POST
• Both GET and POST create an array. This array holds
key/value pairs.
• Both GET and POST are treated as $_GET and $_POST.
These are superglobals, which means that they are always
accessible, regardless of scope.
• $_GET is an array of variables passed via the URL
parameters.
• $_POST is an array of variables passed via the HTTP POST
method.

GET vs POST
When to use GET?
• Information sent from a form with the GET
method is visible to everyone.
• GET also has limits on the amount of information
to send about 2000 characters.
• Because the variables are displayed in the URL, it
is possible to bookmark the page.
• GET may be used for sending non-sensitive data.

GET vs POST
When to use POST?
• Information sent from a form with the POST
method is invisible to others.
• POST method has no limits on the amount of
information to send.
• Because the variables are not displayed in the
URL, it is not possible to bookmark the page.
• POST may be used for sending sensitive data.

Data validation against malicious code
<?php
function validate_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
$name = $email = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$name = validate_input($_POST["name"]);
$email = validate_input($_POST["email"]);
}
?>

Required fields validation
<?php
$nameErr = $emailErr = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Name is required";
} else {
$name = validate_input($_POST["name"]);
}
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
}
}
?>

Display the error messages in form
<form action="welcome.php" method="post">
Name: <input type="text" name="name">*
<?php echo $nameErr; ?><br/>
E-mail: <input type="text" name="email">*
<?php echo $emailErr; ?><br/>
<input type="submit">
</form>

Validating an E-mail address
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email format";
}

PHP mail() Function
The mail() function allows you to send emails
directly from a script.
Syntax:
mail(to, subject, message, headers, parameters);

PHP mail() Function
Parameter Description
to Required. Specifies the receiver / receivers of the email
subject
Required. Specifies the subject of the email. Note: This
parameter cannot contain any newline characters
message
Required. Defines the message to be sent. Each line should be
separated with a LF (n). Lines should not exceed 70
characters.
headers
Optional. Specifies additional headers, like From, Cc, and Bcc.
The additional headers should be separated with a CRLF (rn).
parameters
Optional. Specifies an additional parameter to the sendmail
program

PHP mail() Example
<?php
// the message
$msg = "First line of textnSecond line of text";
// use wordwrap() if lines are longer than 70 characters
$msg = wordwrap($msg, 70);
// send email
mail("someone@example.com","My subject",$msg);
?>

PHP mail() Example
<?php
$to = "somebody@example.com";
$subject = "My subject";
$txt = "Hello world!";
$headers = "From: webmaster@example.com" .
"rn" .
"CC: somebodyelse@example.com";
mail($to, $subject, $txt, $headers);
?>

Using header() function to redirect user
The header() function sends a raw HTTP header to a
client.
Syntax:
header(“Location: URL”);
Note: The header statement can only be used
before any other output is sent.

header() function example
<?php
header(“Location: http://company.com”);
?>
<html>
<head><title>testing header</title></head>
<body>
</body>
</html>

File Upload
Using a form to upload the file
<form action="upload.php" method="post"
enctype="multipart/form-data" name="myForm">
File: <input name="user_file" type="file" />
<input name="" type="submit" value="Upload File"
/>
</form>

Points regarding the form
• Make sure that the form uses method="post"
• The form also needs the following attribute:
enctype="multipart/form-data". It specifies which
content-type to use when submitting the form
• The form above sends data to a file called
"upload.php"

Processing the uploaded file
Information about the uploaded file is stored in the
PHP built-in array called $_FILES
$_FILES[‘fieldname’][‘name’] // file name
$_FILES[‘fieldname’][‘type’] // file type
$_FILES[‘fieldname’][‘tmp_name’] // temp file path
$_FILES[‘fieldname’][‘size’] // file size

Processing the uploaded file
The processing program must move the uploaded file
from the temporary location to a permanent location.
Syntax:
move_uploaded_file(path/tempfilename,
path/permfilename);
Ex:
move_uploaded_file($_FILES['user_file']['tmp_name'],"
uploads/" . $_FILES['user_file']['name']);

Check if File Already Exists
$target_file = "uploads/" .
basename($_FILES["user_file"]["name"]);
if (file_exists($target_file)) {
echo "Sorry, file already exists.";
$uploadOk = false;
}

Limit File Size
if ($_FILES["fileToUpload"]["size"] > 500000) {
echo "Sorry, your file is too large.";
$uploadOk = false;
}

Limit File Type
$imageFileType =
pathinfo($_FILES['user_file']['name'],
PATHINFO_EXTENSION);
if($imageFileType != "jpg" && $imageFileType !=
"png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
echo "Sorry, only JPG, JPEG, PNG & GIF files are
allowed.";
$uploadOk = false;
}

Check if image file is an actual image
$check =
getimagesize($_FILES["fileToUpload"]["tmp_name"]
);
if($check === false) {
echo "File is not an image.";
$uploadOk = false;
}

Uploading File
if (!$uploadOk) {
echo "Sorry, your file was not uploaded.";
} else {
if
(move_uploaded_file($_FILES["fileToUpload"]["tmp_name
"], $target_file)) {
echo "The file has been uploaded.";
} else {
echo "Sorry, there was an error uploading your file.";
}
}

Cookies
• A cookie is often used to identify a user.
• A cookie is a small file that the server embeds on
the user's computer.
• Each time the same computer requests a page
with a browser, it will send the cookie too.

Create Cookies
A cookie is created with the setcookie() function.
Syntax:
setcookie(name, value, expire, path, domain,
secure, httponly);

Create Cookies
$cookie_name = "user";
$cookie_value = “Roshan”;
setcookie($cookie_name, $cookie_value, time() +
(86400 * 30), "/"); // 86400 = 1 day

Retrieve a Cookie
if(!isset($_COOKIE[$cookie_name])) {
echo "Cookie named '" . $cookie_name . "' is not
set!";
} else {
echo "Cookie '" . $cookie_name . "' is set!<br>";
echo "Value is: " . $_COOKIE[$cookie_name];
}

Modify a Cookie Value
To modify a cookie, just set the cookie again using
the setcookie() function
$cookie_value = “Ruwan Perera”;
setcookie($cookie_name, $cookie_value, time() +
(86400 * 30), "/");

Delete a Cookie
setcookie("user", "", time() – 3600, "/");

Check if Cookies are Enabled
First, try to create a test cookie with the setcookie()
function, then count the $_COOKIE array variable
setcookie("test_cookie", "test", time() + 3600, '/');
if(count($_COOKIE) > 0) {
echo "Cookies are enabled.";
} else {
echo "Cookies are disabled.";
}

Sessions
• A session is a way to store information (in
variables) to be used across multiple pages.
• Unlike a cookie, the information is not stored on
the users computer.

Start a PHP Session
A session is started with the session_start() function.
The session_start() function must be the very first thing
in your document. Before any HTML tags.
<?php
session_start();
?>
<!DOCTYPE html>
<html>
</html>

Set session variables
$_SESSION["favcolor"] = "green";
$_SESSION["favanimal"] = "cat";
echo "Session variables are set.";

Get PHP Session Variable Values
echo "Favorite color is " . $_SESSION["favcolor"] .
"<br>";
echo "Favorite animal is " . $_SESSION["favanimal"];

Modify a PHP Session Variable
To change a session variable, just overwrite it
$_SESSION["favcolor"] = "yellow";

Destroy a PHP Session
// remove all session variables
session_unset();
// destroy the session
session_destroy();

The End
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DIWE - Advanced PHP Concepts

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