PHP What is PHP? • • • • PHP stands for PHP: Hypertext Preprocessor PHP is a server-side scripting language, like ASP PHP scripts are executed on the server PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.) • PHP is an open source software • PHP is free to download and use Why PHP? • PHP runs on different platforms (Windows, Linux, Unix, etc.) • PHP is compatible with almost all servers used today (Apache, IIS, etc.) • PHP is FREE to download from the official PHP resource: www.php.net • PHP is easy to learn and runs efficiently on the server side Basic PHP Syntax • PHP script always starts with <?php and ends with ?>. • <html> < body> < ?php echo "Hello World"; ?> < /body> < /html> Comments in PHP • use // to make a one-line comment or /* and */ to make a comment block • <html> < body> < ?php //This is a comment /* This is a comment block */ ?> < /body> < /html> PHP Variables • Variables in PHP starts with a $ sign • Variable names are case sensitive • <?php $txt="Hello World!"; $x=16; • $myCar="Volvo"; ?> PHP Variable Scope • The scope of a variable is the portion of the script in which the variable can be referenced. • PHP has four different variable scopes: • local • global • static • parameter Local Scope • A variable declared within a PHP function is local and can only be accessed within that function • <?php $a = 5; // global scope function myTest() { echo $a; // local scope } myTest(); ?> • The script above will not produce any output because the echo statement refers to the local scope variable $a, which has not been assigned a value within this scope Global Scope • Global variables can be accessed from any part of the script that is not inside a function • Just use the global keyword • <?php $a = 5; $b = 10; function myTest() { global $a, $b; $b = $a + $b; } myTest(); echo $b; ?> • The script above will output 15 • The example above can be rewritten as this • <?php $a = 5; $b = 10; function myTest() { $GLOBALS['b'] = $GLOBALS['a'] + $GLOBALS['b']; } myTest(); echo $b; ?> Static Scope • When a function is completed, all of its variables are normally deleted. However, sometimes you want a local variable to not be deleted. • To do this, use the static keyword when you first declare the variable • <?php $a = 5; $b = 10; • static $rememberMe; • function myTest() { global $a, $b; $b = $a + $b; } myTest(); echo $b; ?> Parameters or arguments • A parameter is a local variable whose value is passed to the function by the calling code • ارجومنت الدوال • function myTest($para1,$para2,...) { // function code } String Variables in PHP • <?php $txt="Hello World"; echo $txt; ?> Hello World The Concatenation Operator • The concatenation operator (.) is used to put two string values together • <?php $txt1="Hello World!"; $txt2="What a nice day!"; echo $txt1 . " " . $txt2; ?> Hello World! What a nice day! The strlen() function • The strlen() function is used to return the length of a string. • <?php echo strlen("Hello world!"); ?> 12 The strpos() function • The strpos() function is used to search for a character/text within a string • <?php echo strpos("Hello world!","world"); ?> 6 first character position in the string is 0, and not 1 Arithmetic Operators Assignment Operators Incrementing/Decrementing Operators Comparison Operators Logical Operators Array Operators PHP If...Else Statements • <html> < body> < ?php $d=date("D"); if ($d=="Fri") echo "Have a nice weekend!"; ?> < /body> < /html> • <html> < body> < ?php $d=date("D"); if ($d=="Fri") echo "Have a nice weekend!"; else echo "Have a nice day!"; ?> < /body> < /html> • <html> < body> < ?php $d=date("D"); if ($d=="Fri") { echo "Hello! <br />"; echo "Have a nice weekend!"; echo "See you on Monday!"; } ?> < /body> < /html> • <html> < body> < ?php $d=date("D"); if ($d=="Fri") echo "Have a nice weekend!"; elseif ($d=="Sun") echo "Have a nice Sunday!"; else echo "Have a nice day!"; ?> < /body> < /html> PHP • <html> < body> Switch Statement < ?php $x=1; switch ($x) { case 1: echo "Number 1"; break; case 2: echo "Number 2"; break; case 3: echo "Number 3"; break; default: echo "No number between 1 and 3"; } ?> < /body> < /html> PHP Arrays • An array stores multiple values in one single variable. • $cars=array("Saab","Volvo","BMW","Toyota"); • OR • $cars[0]="Saab"; $cars[1]="Volvo"; $cars[2]="BMW"; $cars[3]="Toyota"; • <?php $cars[0]="Saab"; $cars[1]="Volvo"; $cars[2]="BMW"; $cars[3]="Toyota"; echo $cars[0] . " and " . $cars[1] . " are Swedish cars."; ?> Saab and Volvo are Swedish cars. Associative Arrays • In this example we use an array to assign ages to the different persons: • $ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34); • OR • $ages['Peter'] = "32"; $ages['Quagmire'] = "30"; $ages['Joe'] = "34"; • <?php $ages['Peter'] = "32"; $ages['Quagmire'] = "30"; $ages['Joe'] = "34"; echo "Peter is " . $ages['Peter'] . " years old."; ?> Peter is 32 years old. Multidimensional Arrays • In a multidimensional array, each element in the main array can also be an array. And each element in the sub-array can be an array, and so on. $families = array ( "Griffin"=>array ( "Peter", "Lois", "Megan" ), "Quagmire"=>array ( "Glenn" ), "Brown"=>array ( "Cleveland", "Loretta", "Junior" ) ); Array ( [Griffin] => Array ( [0] => Peter [1] => Lois [2] => Megan ) [Quagmire] => Array ( [0] => Glenn ) [Brown] => Array ( [0] => Cleveland [1] => Loretta [2] => Junior ) ) • Add this code to the previous example • • echo "Is " . $families['Griffin'][2] . " a part of the Griffin family?"; • The out will be Is Megan a part of the Griffin family? PHP Looping - While Loops • <html> < body> < ?php $i=1; while($i<=5) { echo "The number is " . $i . "<br />"; $i++; } ?> < /body> < /html> The number is 1 The number is 2 The number is 3 The number is 4 The number is 5 The • <html> < body> do...while Statement < ?php $i=1; do { $i++; echo "The number is " . $i . "<br />"; } while ($i<=5); ?> < /body> < /html> The number is 2 The number is 3 The number is 4 The number is 5 The number is 6 PHP Looping - For Loops • <html> < body> < ?php for ($i=1; $i<=5; $i++) { echo "The number is " . $i . "<br />"; } ?> < /body> < /html> The number is 1 The number is 2 The number is 3 The number is 4 The number is 5 The foreach Loop • <html> < body> < ?php $x=array("one","two","three"); foreach ($x as $value) { echo $value . "<br />"; } ?> < /body> < /html> one two three PHP Functions • The real power of PHP comes from its functions. • In PHP, there are more than 700 built-in functions • <html> < body> < ?php function writeName() { echo "Kai Jim Refsnes"; } echo "My name is "; writeName(); ?> < /body> < /html> My name is Kai Jim Refsnes • <html> < body> < ?php function writeName($fname) { echo $fname . " Refsnes.<br />"; } echo "My name is "; writeName("Kai Jim"); echo "My sister's name is "; writeName("Hege"); echo "My brother's name is "; writeName("Stale"); ?> My name is Kai Jim Refsnes. < /body> < /html> My sister's name is Hege Refsnes. My brother's name is Stale Refsnes. • <html> < body> < ?php function writeName($fname,$punctuation) { echo $fname . " Refsnes" . $punctuation . "<br />"; } echo "My name is "; writeName("Kai Jim","."); echo "My sister's name is "; writeName("Hege","!"); echo "My brother's name is "; writeName("Ståle","?"); ?> < /body> < /html> My name is Kai Jim Refsnes. My sister's name is Hege Refsnes! My brother's name is Ståle Refsnes? PHP Functions - Return values • <html> < body> < ?php function add($x,$y) { $total=$x+$y; return $total; } 1 + 16 = 17 echo "1 + 16 = " . add(1,16); ?> < /body> < /html> PHP Forms and User <html> < body> < form action="welcome.php" method="post"> Name: <input type="text" name="fname" /> Age: <input type="text" name="age" /> < input type="submit" /> < /form> < /body> < /html> Welcome John! You are 28 years old. Input "welcome.php" looks like this: < html> < body> Welcome <?php echo $_POST["fname"]; ?>!<br /> You are <?php echo $_POST["age"]; ?> years old. < /body> < /html> The PHP $_GET and $_POST variables <form action="welcome.php" method="get"> Name: <input type="text" name="fname" /> Age: <input type="text" name="age" /> < input type="submit" /> < /form> When the user clicks the "Submit" button, the URL sent to the server could look something like this: http://www.w3schools.com/welcome.ph p?fname=Peter&age=37 The "welcome.php" file can now use the $_GET variable to collect form data (the names of the form fields will automatically be the keys in the $_GET array): Welcome <?php echo $_GET["fname"]; ?>.<br /> You are <?php echo $_GET["age"]; ?> years old! When to use method="get"? • When using method="get" in HTML forms, all variable names and values are displayed in the URL PHP $_POST Function • The predefined $_POST variable is used to collect values from a form sent with method="post“. <form action="welcome.php" method="post"> Name: <input type="text" name="fname" /> Age: <input type="text" name="age" /> < input type="submit" /> < /form> When the user clicks the "Submit" button, the URL will look like this: http://www.w3schools.com/welcome.php The "welcome.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): Welcome <?php echo $_POST["fname"]; ?>!<br /> You are <?php echo $_POST["age"]; ?> years old. When to use method="post"? Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send. The PHP $_ REQUEST Variable • The predefined $_REQUEST variable contains the contents of both $_GET, $_POST, and $_COOKIE. • The $_REQUEST variable can be used to collect form data sent with both the GET and POST methods. • Welcome <?php echo $_REQUEST["fname"]; ?>!<br /> You are <?php echo $_REQUEST["age"]; ?> years old. PHP Date() Function • <?php echo date("Y/m/d") . "<br />"; echo date("Y.m.d") . "<br />"; echo date("Y-m-d"); ?> 2009/05/11 2009.05.11 2009-05-11 <?php $tomorrow = mktime(0,0,0,date("m"),date("d")+1,date("Y")); echo "Tomorrow is ".date("Y/m/d", $tomorrow); ?> Tomorrow is 2009/05/12 PHP Include File • Assume that you have a standard header file, called "header.php". To include the header file in a page, use the include() function: • You can insert the content of one PHP file into another PHP file before the server executes it, with the include() or require() function. • The two functions are identical in every way, except how they handle errors: • include() generates a warning, but the script will continue execution • require() generates a fatal error, and the script will stop Example • Assume that you have a standard header file, called "header.php". To include the header file in a page, use the include() function: • < html> < body> < ?php include("header.php"); ?> < h1>Welcome to my home page!</h1> < p>Some text.</p> < /body> < /html> Assume we have a standard menu file, called "menu.php", that should be used on all pages <a href="/default.php">Home</a> <a href="/tutorials.php">Tutorials</a> <a href="/references.php">References</ a> <a href="/examples.php">Examples</a> < a href="/about.php">About Us</a> < a href="/contact.php">Contact Us</a> All pages in the Web site should include this menu file. Here is how it can be done: <html> < body> < div class="leftmenu"> < ?php include("menu.php"); ?> < /div> < h1>Welcome to my home page.</h1> < p>Some text.</p> < /body> < /html> • If you look at the source code of the page above (in a browser), it will look like this: • <html> < body> < div class="leftmenu"> < a href="/default.php">Home</a> < a href="/tutorials.php">Tutorials</a> < a href="/references.php">References</a> < a href="/examples.php">Examples</a> < a href="/about.php">About Us</a> < a href="/contact.php">Contact Us</a> < /div> < h1>Welcome to my home page!</h1> < p>Some text.</p> < /body> < /html> File handling • <html> < body> < ?php $file=fopen("welcome.txt","r"); ?> < /body> < /html> • The following example generates a message if the fopen() function is unable to open the specified file: • < html> < body> < ?php $file=fopen("welcome.txt","r") or exit("Unable to open file!"); ?> < /body> < /html> Closing a File • The fclose() function is used to close an open file: • < ?php $file = fopen("test.txt","r"); //some code to be executed fclose($file); ?> Check End-of-file • The feof() function checks if the "end-of-file" (EOF) has been reached. The feof() function is useful for looping through data of unknown length. • Note: You cannot read from files opened in w, a, and x mode! • if (feof($file)) echo "End of file"; Reading a File Line by Line • The example below reads a file line by line, until the end of file is reached: • < ?php $file = fopen("welcome.txt", "r") or exit("Unable to open file!"); //Output a line of the file until the end is reached while(!feof($file)) { echo fgets($file). "<br />"; } fclose($file); ?> Reading a File Character by Character • The example below reads a file character by character, until the end of file is reached: • < ?php $file=fopen("welcome.txt","r") or exit("Unable to open file!"); while (!feof($file)) { echo fgetc($file); } fclose($file); ?> Create an Upload-File Form • To allow users to upload files from a form can be very useful. • Look at the following HTML form for uploading files: • < html> < body> < form action="upload_file.php" method="post" enctype="multipart/form-data"> < label for="file">Filename:</label> < input type="file" name="file" id="file" /> < br /> < input type="submit" name="submit" value="Submit" /> < /form> < /body> < /html> Create The Upload Script • The "upload_file.php" file contains the code for uploading a file: • < ?php if ($_FILES["file"]["error"] > 0) { echo "Error: " . $_FILES["file"]["error"] . "<br />"; } else { echo "Upload: " . $_FILES["file"]["name"] . "<br />"; echo "Type: " . $_FILES["file"]["type"] . "<br />"; echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />"; echo "Stored in: " . $_FILES["file"]["tmp_name"]; } ?> • $_FILES["file"]["name"] - the name of the uploaded file • $_FILES["file"]["type"] - the type of the uploaded file • $_FILES["file"]["size"] - the size in bytes of the uploaded file • $_FILES["file"]["tmp_name"] - the name of the temporary copy of the file stored on the server • $_FILES["file"]["error"] - the error code resulting from the file upload Restrictions on Upload • • The user may only upload .gif or .jpeg files and the file size must be under 20 kb: <?php if ((($_FILES["file"]["type"] == "image/gif") || ($_FILES["file"]["type"] == "image/jpeg") || ($_FILES["file"]["type"] == "image/pjpeg")) && ($_FILES["file"]["size"] < 20000)) { if ($_FILES["file"]["error"] > 0) { echo "Error: " . $_FILES["file"]["error"] . "<br />"; } else { echo "Upload: " . $_FILES["file"]["name"] . "<br />"; echo "Type: " . $_FILES["file"]["type"] . "<br />"; echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />"; echo "Stored in: " . $_FILES["file"]["tmp_name"]; } } else { echo "Invalid file"; } ?> • • Saving the Uploaded File To store the uploaded file we need to copy it to a different location: <?php if ((($_FILES["file"]["type"] == "image/gif") || ($_FILES["file"]["type"] == "image/jpeg") || ($_FILES["file"]["type"] == "image/pjpeg")) && ($_FILES["file"]["size"] < 20000)) { if ($_FILES["file"]["error"] > 0) { echo "Return Code: " . $_FILES["file"]["error"] . "<br />"; } else { echo "Upload: " . $_FILES["file"]["name"] . "<br />"; echo "Type: " . $_FILES["file"]["type"] . "<br />"; echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />"; echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />"; if (file_exists("upload/" . $_FILES["file"]["name"])) { echo $_FILES["file"]["name"] . " already exists. "; } else { move_uploaded_file($_FILES["file"]["tm p_name"], "upload/" . $_FILES["file"]["name"]); echo "Stored in: " . "upload/" . $_FILES["file"]["name"]; }}} else { echo "Invalid file"; } ?>