Kumpulan beberapa syntac pada PHP

PHP Data Types

Variables can store data of different types, and different data types can do different things.

PHP supports the following data types:

• String
• Integer
• Float (floating point numbers - also called double)
• Boolean
• Array
• Object
• NULL
• Resource

PHP String Functions

Example

<?php

echo strlen("Hello world!"); // outputs 12  /Get The Length of a String

?>

<?php

echo str_word_count("Hello world!"); // outputs 2 Count The Number of Words in a String

?>

Reverse a String

Example

<?php

echo strrev("Hello world!"); // outputs !dlrow olleH

?>

Search For a Specific Text Within a String

Example

<?php

echo strpos("Hello world!", "world"); // outputs 6

?>

Replace Text Within a String

Example

<?php

echo str_replace("world", "Dolly", "Hello world!"); // outputs Hello Dolly!

?>

PHP Operators

Operators are used to perform operations on variables and values.

PHP divides the operators in the following groups:

• Arithmetic operators
• Assignment operators
• Comparison operators
• Increment/Decrement operators
• Logical operators
• String operators
• Array operators

PHP Arithmetic Operators

Example

<?php

$x = 10;  

$y = 6;

echo $x + $y;

?>

PHP Assignment Operators

Example

<?php

$x = 10;  

echo $x;

?>

PHP Conditional Statements

Very often when you write code, you want to perform different actions for different conditions. You can use conditional statements in your code to do this.

In PHP we have the following conditional statements:

• if statement - executes some code if one condition is true
• if...else statement - executes some code if a condition is true and another code if that condition is false
• if...elseif....else statement - executes different codes for more than two conditions
• switch statement - selects one of many blocks of code to be executed

PHP - The if Statement

Example

<?php

$t = date("H");

if ($t < "20") {

echo "Have a good day!";

}

?>

PHP - The if...else Statement

Example

<?php

$t = date("H");

if ($t < "20") {

   echo "Have a good day!";

} else {

echo "Have a good night!";

}

?>

PHP - The if...elseif....else Statement

Example

<?php

$t = date("H");

if ($t < "10") {

echo "Have a good morning!";

} elseif ($t < "20") {

echo "Have a good day!";

} else {

echo "Have a good night!";

}

?>

The PHP switch Statement

Example

<?php

$favcolor = "red";

switch ($favcolor) {

case "red":

    echo "Your favorite color is red!";

       break;

   case "blue":

   echo "Your favorite color is blue!";

       break;

   case "green":

   echo "Your favorite color is green!";

       break;

   default:

   echo "Your favorite color is neither red, blue, nor green!";

}

?>

PHP Loops

Often when you write code, you want the same block of code to run over and over again in a row. Instead of adding several almost equal code-lines in a script, we can use loops to perform a task like this.

In PHP, we have the following looping statements:

• while - loops through a block of code as long as the specified condition is true
• do...while - loops through a block of code once, and then repeats the loop as long as the specified condition is true
• for - loops through a block of code a specified number of times
• foreach - loops through a block of code for each element in an array

PHP while Loop

Example

<?php

$x = 1;

while($x <= 5) {

echo "The number is: $x <br>";

$x++;

}

?>

PHP do...while Loop

Example

<?php

$x = 1;

do {

echo "The number is: $x <br>";

$x++;

} while ($x <= 5);

?>

or

<?php

$x = 6;

do {

   echo "The number is: $x <br>";

$x++;

} while ($x <= 5);

?>

PHP for Loop

Example

<?php

for ($x = 0; $x <= 10; $x++) {

echo "The number is: $x <br>";

}

?>

PHP foreach Loop

Example

<?php

$colors = array("red", "green", "blue", "yellow");

foreach ($colors as $value) {

echo "$value <br>";

}

?>

Create a User Defined Function in PHP

Example

<?php

function writeMsg() {

echo "Hello world!";

}

writeMsg(); // call the function

?>

PHP 5 Arrays

Example

<?php

$cars = array("Volvo", "BMW", "Toyota");

echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";

?>

PHP Indexed Arrays

Example

<?php

$cars = array("Volvo", "BMW", "Toyota");

echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";

?>

Get The Length of an Array - The count() Function

The count() function is used to return the length (the number of elements) of an array:

Example

<?php

$cars = array("Volvo", "BMW", "Toyota");

echo count($cars);

?>

Loop Through an Indexed Array

To loop through and print all the values of an indexed array, you could use a for loop, like this:

Example

<?php

$cars = array("Volvo", "BMW", "Toyota");

$arrlength = count($cars);

for($x = 0; $x < $arrlength; $x++) {

   echo $cars[$x];

echo "<br>";

}

?>

PHP Associative Arrays

Associative arrays are arrays that use named keys that you assign to them.

There are two ways to create an associative array:

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

or:

$age['Peter'] = "35";

$age['Ben'] = "37";

$age['Joe'] = "43";

The named keys can then be used in a script:

Example

<?php

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

echo "Peter is " . $age['Peter'] . " years old.";

?>

Loop Through an Associative Array

To loop through and print all the values of an associative array, you could use a foreach loop, like this:

Example

<?php

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

foreach($age as $x => $x_value) {

   echo "Key=" . $x . ", Value=" . $x_value;

echo "<br>";

}

?>

Sort Array in Ascending Order - sort()

The following example sorts the elements of the $cars array in ascending alphabetical order:

Example

<?php

$cars = array("Volvo", "BMW", "Toyota");

sort($cars);

?>

Example

<?php

$numbers = array(4, 6, 2, 22, 11);

sort($numbers);

?>

Sort Array in Descending Order - rsort()

The following example sorts the elements of the $cars array in descending alphabetical order:

Example

<?php

$cars = array("Volvo", "BMW", "Toyota");

rsort($cars);

?>

Example

<?php

$numbers = array(4, 6, 2, 22, 11);

rsort($numbers);

?>

Sort Array (Ascending Order), According to Value - asort()

The following example sorts an associative array in ascending order, according to the value:

Example

<?php

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

asort($age);

?>

Sort Array (Ascending Order), According to Key - ksort()

The following example sorts an associative array in ascending order, according to the key:

Example

<?php

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

ksort($age);

?>

Sort Array (Descending Order), According to Value - arsort()

The following example sorts an associative array in descending order, according to the value:

Example

<?php

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

arsort($age);

?>

Sort Array (Descending Order), According to Key - krsort()

The following example sorts an associative array in descending order, according to the key:

Example

<?php

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

krsort($age);

?>

PHP $GLOBALS

$GLOBALS is a PHP super global variable which is used to access global variables from anywhere in the PHP script (also from within functions or methods).

PHP stores all global variables in an array called $GLOBALS[index]. The index holds the name of the variable.

The example below shows how to use the super global variable $GLOBALS:

Example

<?php

$x = 75;

$y = 25;

function addition() {

$GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y'];

}

addition();

echo $z;

?>

PHP $_SERVER

$_SERVER is a PHP super global variable which holds information about headers, paths, and script locations.

The example below shows how to use some of the elements in $_SERVER:

Example

<?php

echo $_SERVER['PHP_SELF'];

echo "<br>";

echo $_SERVER['SERVER_NAME'];

echo "<br>";

echo $_SERVER['HTTP_HOST'];

echo "<br>";

echo $_SERVER['HTTP_REFERER'];

echo "<br>";

echo $_SERVER['HTTP_USER_AGENT'];

echo "<br>";

echo $_SERVER['SCRIPT_NAME'];

?>

PHP $_REQUEST

PHP $_REQUEST is used to collect data after submitting an HTML form.

The example below shows a form with an input field and a submit button. When a user submits the data by clicking on "Submit", the form data is sent to the file specified in the action attribute of the <form> tag. In this example, we point to this file itself for processing form data. If you wish to use another PHP file to process form data, replace that with the filename of your choice. Then, we can use the super global variable $_REQUEST to collect the value of the input field:

Example

<html>

<body>

<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">

 Name: <input type="text" name="fname">

 <input type="submit">

</form>

<?php

if ($_SERVER["REQUEST_METHOD"] == "POST") {

// collect value of input field

$name = $_REQUEST['fname'];

if (empty($name)) {

    echo "Name is empty";

} else {

    echo $name;

}

}

?>

</body>

</html>

PHP $_POST

PHP $_POST is widely used to collect form data after submitting an HTML form with method="post". $_POST is also widely used to pass variables.

The example below shows a form with an input field and a submit button. When a user submits the data by clicking on "Submit", the form data is sent to the file specified in the action attribute of the <form> tag. In this example, we point to the file itself for processing form data. If you wish to use another PHP file to process form data, replace that with the filename of your choice. Then, we can use the super global variable $_POST to collect the value of the input field:

Example

<html>

<body>

<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">

 Name: <input type="text" name="fname">

 <input type="submit">

</form>

<?php

if ($_SERVER["REQUEST_METHOD"] == "POST") {

// collect value of input field

$name = $_POST['fname'];

if (empty($name)) {

    echo "Name is empty";

} else {

    echo $name;

}

}

?>

</body>

</html>

PHP $_GET

PHP $_GET can also be used to collect form data after submitting an HTML form with method="get".

$_GET can also collect data sent in the URL.

Assume we have an HTML page that contains a hyperlink with parameters:

<html>

<body>

<?php

echo "Study " . $_GET['subject'] . " at " . $_GET['web'];

?>

</body>

</html>

PHP - A Simple HTML Form

The example below displays a simple HTML form with two input fields and a submit button:

Example

<html>

<body>

<form action="welcome.php" method="post">

Name: <input type="text" name="name"><br>

E-mail: <input type="text" name="email"><br>

<input type="submit">

</form>

</body>

</html>

Validate Form Data With PHP

The first thing we will do is to pass all variables through PHP's htmlspecialchars() function.

When we use the htmlspecialchars() function; then if a user tries to submit the following in a text field:

<script>location.href('http://www.hacked.com')</script>

- this would not be executed, because it would be saved as HTML escaped code, like this:

&lt;script&gt;location.href('http://www.hacked.com')&lt;/script&gt;

The code is now safe to be displayed on a page or inside an e-mail.

We will also do two more things when the user submits the form:

1. Strip unnecessary characters (extra space, tab, newline) from the user input data (with the PHP trim() function)
2. Remove backslashes (\) from the user input data (with the PHP stripslashes() function)

The next step is to create a function that will do all the checking for us (which is much more convenient than writing the same code over and over again).

We will name the function test_input().

Now, we can check each $_POST variable with the test_input() function, and the script looks like this:

Example

<?php

// define variables and set to empty values

$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {

 $name = test_input($_POST["name"]);

 $email = test_input($_POST["email"]);

 $website = test_input($_POST["website"]);

 $comment = test_input($_POST["comment"]);

 $gender = test_input($_POST["gender"]);

}

function test_input($data) {

 $data = trim($data);

 $data = stripslashes($data);

 $data = htmlspecialchars($data);

 return $data;

}

?>

PHP - Display The Error Messages

Then in the HTML form, we add a little script after each required field, which generates the correct error message if needed (that is if the user tries to submit the form without filling out the required fields):

Example

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">

Name: <input type="text" name="name">

<span class="error">* <?php echo $nameErr;?></span>

<br><br>

E-mail:

<input type="text" name="email">

<span class="error">* <?php echo $emailErr;?></span>

<br><br>

Website:

<input type="text" name="website">

<span class="error"><?php echo $websiteErr;?></span>

<br><br>

Comment: <textarea name="comment" rows="5" cols="40"></textarea>

<br><br>

Gender:

<input type="radio" name="gender" value="female">Female

<input type="radio" name="gender" value="male">Male

<span class="error">* <?php echo $genderErr;?></span>

<br><br>

<input type="submit" name="submit" value="Submit">

</form>

PHP - Validate Name

The code below shows a simple way to check if the name field only contains letters and whitespace. If the value of the name field is not valid, then store an error message:

$name = test_input($_POST["name"]);

if (!preg_match("/^[a-zA-Z ]*$/",$name)) {

 $nameErr = "Only letters and white space allowed";

}

PHP - Validate E-mail

The easiest and safest way to check whether an email address is well-formed is to use PHP's filter_var() function.

In the code below, if the e-mail address is not well-formed, then store an error message:

$email = test_input($_POST["email"]);

if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {

 $emailErr = "Invalid email format";

}

PHP - Validate URL

The code below shows a way to check if a URL address syntax is valid (this regular expression also allows dashes in the URL). If the URL address syntax is not valid, then store an error message:

$website = test_input($_POST["website"]);

if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {

 $websiteErr = "Invalid URL";

}

PHP - Validate Name, E-mail, and URL

Now, the script looks like this:

Example

<?php

// define variables and set to empty values

$nameErr = $emailErr = $genderErr = $websiteErr = "";

$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {

 if (empty($_POST["name"])) {

$nameErr = "Name is required";

 } else {

$name = test_input($_POST["name"]);

// check if name only contains letters and whitespace

if (!preg_match("/^[a-zA-Z ]*$/",$name)) {

  $nameErr = "Only letters and white space allowed";

}

 }

 if (empty($_POST["email"])) {

$emailErr = "Email is required";

 } else {

$email = test_input($_POST["email"]);

// check if e-mail address is well-formed

if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {

  $emailErr = "Invalid email format";

}

 }

 if (empty($_POST["website"])) {

$website = "";

 } else {

$website = test_input($_POST["website"]);

// check if URL address syntax is valid (this regular expression also allows dashes in the URL)

if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {

  $websiteErr = "Invalid URL";

}

 }

 if (empty($_POST["comment"])) {

$comment = "";

 } else {

$comment = test_input($_POST["comment"]);

 }

 if (empty($_POST["gender"])) {

$genderErr = "Gender is required";

 } else {

$gender = test_input($_POST["gender"]);

 }

}

?>

Get a Simple Date

The required format parameter of the date() function specifies how to format the date (or time).

Here are some characters that are commonly used for dates:

• d - Represents the day of the month (01 to 31)
• m - Represents a month (01 to 12)
• Y - Represents a year (in four digits)
• l (lowercase 'L') - Represents the day of the week

Other characters, like"/", ".", or "-" can also be inserted between the characters to add additional formatting.

The example below formats today's date in three different ways:

Example

<?php

echo "Today is " . date("Y/m/d") . "<br>";

echo "Today is " . date("Y.m.d") . "<br>";

echo "Today is " . date("Y-m-d") . "<br>";

echo "Today is " . date("l");

?>

PHP Tip - Automatic Copyright Year

Use the date() function to automatically update the copyright year on your website:

Example

&copy; 2010-<?php echo date("Y");?>

Get a Simple Time

Here are some characters that are commonly used for times:

• h - 12-hour format of an hour with leading zeros (01 to 12)
• i - Minutes with leading zeros (00 to 59)
• s - Seconds with leading zeros (00 to 59)
• a - Lowercase Ante meridiem and Post meridiem (am or pm)

The example below outputs the current time in the specified format:

Example

<?php

echo "The time is " . date("h:i:sa");

?>

Get Your Time Zone

If the time you got back from the code is not the right time, it's probably because your server is in another country or set up for a different timezone.

So, if you need the time to be correct according to a specific location, you can set a timezone to use.

The example below sets the timezone to "America/New_York", then outputs the current time in the specified format:

Example

<?php

date_default_timezone_set("America/New_York");

echo "The time is " . date("h:i:sa");

?>

Create a Date With PHP mktime()

The optional timestamp parameter in the date() function specifies a timestamp. If you do not specify a timestamp, the current date and time will be used (as shown in the examples above).

The mktime() function returns the Unix timestamp for a date. The Unix timestamp contains the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time specified.

Syntax

mktime(hour,minute,second,month,day,year)

The example below creates a date and time from a number of parameters in the mktime() function:

Example

<?php

$d=mktime(11, 14, 54, 8, 12, 2014);

echo "Created date is " . date("Y-m-d h:i:sa", $d);

?>

Create a Date From a String With PHP strtotime()

The PHP strtotime() function is used to convert a human readable string to a Unix time.

Syntax

strtotime(time,now)

The example below creates a date and time from the strtotime() function:

Example

<?php

$d=strtotime("10:30pm April 15 2014");

echo "Created date is " . date("Y-m-d h:i:sa", $d);

?>

Example

<?php

$d=strtotime("tomorrow");

echo date("Y-m-d h:i:sa", $d) . "<br>";

$d=strtotime("next Saturday");

echo date("Y-m-d h:i:sa", $d) . "<br>";

$d=strtotime("+3 Months");

echo date("Y-m-d h:i:sa", $d) . "<br>";

?>

More Date Examples

The example below outputs the dates for the next six Saturdays:

Example

<?php

$startdate = strtotime("Saturday");

$enddate = strtotime("+6 weeks", $startdate);

while ($startdate < $enddate) {

 echo date("M d", $startdate) . "<br>";

 $startdate = strtotime("+1 week", $startdate);

}

?>

Example

<?php

$d1=strtotime("July 04");

$d2=ceil(($d1-time())/60/60/24);

echo "There are " . $d2 ." days until 4th of July.";

?>

Create The HTML Form File Upload

Next, create an HTML form that allow users to choose the image file they want to upload:

<!DOCTYPE html>

<html>

<body>

<form action="upload.php" method="post" enctype="multipart/form-data">

Select image to upload:

<input type="file" name="fileToUpload" id="fileToUpload">

<input type="submit" value="Upload Image" name="submit">

</form>

</body>

</html>

Create The Upload File PHP Script

The "upload.php" file contains the code for uploading a file:

<?php

$target_dir = "uploads/";

$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);

$uploadOk = 1;

$imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);

// Check if image file is a actual image or fake image

if(isset($_POST["submit"])) {

$check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);

if($check !== false) {

    echo "File is an image - " . $check["mime"] . ".";

    $uploadOk = 1;

} else {

    echo "File is not an image.";

    $uploadOk = 0;

}

}

?>

Complete Upload File PHP Script

The complete "upload.php" file now looks like this:

<?php

$target_dir = "uploads/";

$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);

$uploadOk = 1;

$imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);

// Check if image file is a actual image or fake image

if(isset($_POST["submit"])) {

$check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);

if($check !== false) {

    echo "File is an image - " . $check["mime"] . ".";

    $uploadOk = 1;

} else {

    echo "File is not an image.";

    $uploadOk = 0;

}

}

// Check if file already exists

if (file_exists($target_file)) {

echo "Sorry, file already exists.";

$uploadOk = 0;

}

// Check file size

if ($_FILES["fileToUpload"]["size"] > 500000) {

echo "Sorry, your file is too large.";

$uploadOk = 0;

}

// Allow certain file formats

if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"

&& $imageFileType != "gif" ) {

echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";

$uploadOk = 0;

}

// Check if $uploadOk is set to 0 by an error

if ($uploadOk == 0) {

echo "Sorry, your file was not uploaded.";

// if everything is ok, try to upload file

} else {

if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {

    echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";

} else {

    echo "Sorry, there was an error uploading your file.";

}

}

?>

PHP Create/Retrieve a Cookie

The following example creates a cookie named "user" with the value "John Doe". The cookie will expire after 30 days (86400 * 30). The "/" means that the cookie is available in entire website (otherwise, select the directory you prefer).

We then retrieve the value of the cookie "user" (using the global variable $_COOKIE). We also use the isset() function to find out if the cookie is set:

Example

<?php

$cookie_name = "user";

$cookie_value = "John Doe";

setcookie($cookie_name, $cookie_value, time() + (86400 * 30), "/"); // 86400 = 1 day

?>

<html>

<body>

<?php

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];

}

?>

</body>

</html>

Modify a Cookie Value

To modify a cookie, just set (again) the cookie using the setcookie() function:

Example

<?php

$cookie_name = "user";

$cookie_value = "Alex Porter";

setcookie($cookie_name, $cookie_value, time() + (86400 * 30), "/");

?>

<html>

<body>

<?php

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];

}

?>

</body>

</html>

Start a PHP Session

A session is started with the session_start() function.

Session variables are set with the PHP global variable: $_SESSION.

Now, let's create a new page called "demo_session1.php". In this page, we start a new PHP session and set some session variables:

Example

<?php

// Start the session

session_start();

?>

<!DOCTYPE html>

<html>

<body>

<?php

// Set session variables

$_SESSION["favcolor"] = "green";

$_SESSION["favanimal"] = "cat";

echo "Session variables are set.";

?>

</body>

</html>

Get PHP Session Variable Values

Next, we create another page called "demo_session2.php". From this page, we will access the session information we set on the first page ("demo_session1.php").

Notice that session variables are not passed individually to each new page, instead they are retrieved from the session we open at the beginning of each page (session_start()).

Also notice that all session variable values are stored in the global $_SESSION variable:

Example

<?php

session_start();

?>

<!DOCTYPE html>

<html>

<body>

<?php

// Echo session variables that were set on previous page

echo "Favorite color is " . $_SESSION["favcolor"] . ".<br>";

echo "Favorite animal is " . $_SESSION["favanimal"] . ".";

?>

</body>

</html>

Destroy a PHP Session

To remove all global session variables and destroy the session, use session_unset() and session_destroy():

Example

<?php

session_start();

?>

<!DOCTYPE html>

<html>

<body>

<?php

// remove all session variables

session_unset();

// destroy the session

session_destroy();

?>

</body>

</html>

The PHP Filter Extension

PHP filters are used to validate and sanitize external input.

The PHP filter extension has many of the functions needed for checking user input, and is designed to make data validation easier and quicker.

The filter_list() function can be used to list what the PHP filter extension offers:

Example

<table>

 <tr>

<td>Filter Name</td>

<td>Filter ID</td>

 </tr>

 <?php

 foreach (filter_list() as $id =>$filter) {

  echo '<tr><td>' . $filter . '</td><td>' . filter_id($filter) . '</td></tr>';

 }

 ?>

</table>

Sanitize a String

The following example uses the filter_var() function to remove all HTML tags from a string:

Example

<?php

$str = "<h1>Hello World!</h1>";

$newstr = filter_var($str, FILTER_SANITIZE_STRING);

echo $newstr;

?>

Validate an Integer

The following example uses the filter_var() function to check if the variable $int is an integer. If $int is an integer, the output of the code above will be: "Integer is valid". If $int is not an integer, the output will be: "Integer is not valid":

Example

<?php

$int = 100;

if (!filter_var($int, FILTER_VALIDATE_INT) === false) {

echo("Integer is valid");

} else {

echo("Integer is not valid");

}

?>

Validate an IP Address

The following example uses the filter_var() function to check if the variable $ip is a valid IP address:

Example

<?php

$ip = "127.0.0.1";

if (!filter_var($ip, FILTER_VALIDATE_IP) === false) {

echo("$ip is a valid IP address");

} else {

echo("$ip is not a valid IP address");

}

?>

Sanitize and Validate an Email Address

The following example uses the filter_var() function to first remove all illegal characters from the $email variable, then check if it is a valid email address:

Example

<?php

$email = "john.doe@example.com";

// Remove all illegal characters from email

$email = filter_var($email, FILTER_SANITIZE_EMAIL);

// Validate e-mail

if (!filter_var($email, FILTER_VALIDATE_EMAIL) === false) {

echo("$email is a valid email address");

} else {

echo("$email is not a valid email address");

}

?>

Sanitize and Validate a URL

The following example uses the filter_var() function to first remove all illegal characters from a URL, then check if $url is a valid URL:

Example

<?php

$url = "http://www.w3schools.com";

// Remove all illegal characters from a url

$url = filter_var($url, FILTER_SANITIZE_URL);

// Validate url

if (!filter_var($url, FILTER_VALIDATE_URL) === false) {

echo("$url is a valid URL");

} else {

echo("$url is not a valid URL");

}

?>

Validate an Integer Within a Range

The following example uses the filter_var() function to check if a variable is both of type INT, and between 1 and 200:

Example

<?php

$int = 122;

$min = 1;

$max = 200;

if (filter_var($int, FILTER_VALIDATE_INT, array("options" => array("min_range"=>$min, "max_range"=>$max))) === false) {

echo("Variable value is not within the legal range");

} else {

echo("Variable value is within the legal range");

}

?>

Validate IPv6 Address

The following example uses the filter_var() function to check if the variable $ip is a valid IPv6 address:

Example

<?php

$ip = "2001:0db8:85a3:08d3:1319:8a2e:0370:7334";

if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) === false) {

echo("$ip is a valid IPv6 address");

} else {

echo("$ip is not a valid IPv6 address");

}

?>

Validate URL - Must Contain QueryString

The following example uses the filter_var() function to check if the variable $url is a URL with a querystring:

Example

<?php

$url = "http://www.w3schools.com";

if (!filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED) === false) {

echo("$url is a valid URL");

} else {

echo("$url is not a valid URL");

}

?>

Remove Characters With ASCII Value > 127

The following example uses the filter_var() function to sanitize a string. It will both remove all HTML tags, and all characters with ASCII value > 127, from the string:

Example

<?php

$str = "<h1>Hello WorldÆØÅ!</h1>";

$newstr = filter_var($str, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_HIGH);

echo $newstr;

?>

Basic Use of Exceptions

When an exception is thrown, the code following it will not be executed, and PHP will try to find the matching "catch" block.

If an exception is not caught, a fatal error will be issued with an "Uncaught Exception" message.

Lets try to throw an exception without catching it:

<?php

//create function with an exception

function checkNum($number) {

 if($number>1) {

   throw new Exception("Value must be 1 or below");

 }

 return true;

}

//trigger exception

checkNum(2);

?>

Creating a Custom Exception Class

To create a custom exception handler you must create a special class with functions that can be called when an exception occurs in PHP. The class must be an extension of the exception class.

The custom exception class inherits the properties from PHP's exception class and you can add custom functions to it.

Lets create an exception class:

<?php

class customException extends Exception {

 public function errorMessage() {

   //error message

   $errorMsg = 'Error on line '.$this->getLine().' in '.$this->getFile()

   .': <b>'.$this->getMessage().'</b> is not a valid E-Mail address';

   return $errorMsg;

 }

}

$email = "someone@example...com";

try {

 //check if

 if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE) {

   //throw exception if email is not valid

   throw new customException($email);

 }

}

catch (customException $e) {

 //display custom message

 echo $e->errorMessage();

}

?>