PHP Tutorials

About the PHP Language

Syntax is inspired by C

Curly braces, semicolons, no signficant whitespace

Syntax inspired by perl

Dollar signs to start variable names, associative arrays

Extends HTML to add segments of PHP within an HTML file.

Philosphy of PHP

You are a responsible and intelligent programmer
You know what you want to do
Some flexibility in syntax is OK - style choices are OK
Lets make this as convienent as possible
Sometimes errors fail silently

History of PHP

PHP originally stood for “Personal Home Page”
It started out, in 1994, as a simple preprocessor of HTML files

built by Rasmus Lerdorf (born in Greenland, grew up in Denmark and Canada, graduated from U of Waterloo in 1993, now prominent member of Open Source movement)
original purpose was to log people who viewed his on-line resume

Since then, has been developed by a growing community of open source developers
Name now supposed to stand for “Hypertext Pre-Processor”

Advantages of PHP

Freely available
The PHP group provides complete source code free of charge
Similar syntax to C, Pearl
Works with many operating systems
Can be deployed on many web servers
Interacts with lots of databases
It is supported by many providers of webhosting

History – Released versions

PHP 3

The scripting core was rewritten by Zeev Suraski and Andi Gutmans
The name was changed to Hypertext preprocessor
It is able to work with MS Windows and Macintosh

PHP4

Added Zend engine
Introduced 'superglobals' ($_GET)

None of these versions is under development now

History of PHP

PHP began in 1995 when Rasmus Lerdorf developed a Perl/CGI script toolset he called the Personal Home Page or PHP
PHP 2 released 1997 (PHP now stands for Hypertex Processor). Lerdorf developed it further, using C instead
PHP3 released in 1998 (50,000 users)
PHP4 released in 2000 (3.6 million domains). Considered debut of functional language and including Perl parsing, with other major features
PHP5.0.0 released July 13, 2004 (113 libraries>1,000 functions with extensive object-oriented programming)
PHP5.0.5 released Sept. 6, 2005 for maintenance and bug fixes

PHP - What is it / does it do?

Static resources such as regular HTML are simply output to the client from the server
Dynamic resources such as PHP scripts are processed on the server prior to being output to the client
PHP has the capability of connecting to many database systems making the entire process transparent to the client

PHP Engine –
Run Script

Web Page Request

Load PHP File

PHP Results

HTML Response

Current version - PHP 5

The most recent extension (the 5.2.6) was published on May 1, 2008
Uses enhanced Zend II engine
It includes :

support for object-oriented programming,
the PHP Data Objects extension (simplifies accessing databases)
numerous performance enhancements

websites using PHP

More than 20 million Internet domains are hosted on servers with PHP installed
Significant examles

User-facing portion of Facebook
Wikipedia (MediaWiki)
Yahoo!
MyYearbook

What do You Need to work with PHP?

If your server supports PHP

You don’t need anything
Just create some .php files in your web directory

If your server does not support PHP, you must install PHP.

Download PHP
Download database (MySQL)
Download server (Apache)

WHY PHP – Sessions ?

Whenever you want to create a website that allows you to store and display information about a user, determine which user groups a person belongs to, utilize permissions on your website or you just want to do something cool on your site, PHP's Sessions are vital to each of these features.
Cookies are about 30% unreliable right now and it's getting worse every day. More and more web browsers are starting to come with security and privacy settings and people browsing the net these days are starting to frown upon Cookies because they store information on their local computer that they do not want stored there.
PHP has a great set of functions that can achieve the same results of Cookies and more without storing information on the user's computer. PHP Sessions store the information on the web server in a location that you chose in special files. These files are connected to the user's web browser via the server and a special ID called a "Session ID". This is nearly 99% flawless in operation and it is virtually invisible to the user.

PHP - Sessions

Sessions store their identifier in a cookie in the client’s browser
Every page that uses session data must be proceeded by the session_start() function
Session variables are then set and retrieved by accessing the global $_SESSION[]
Save it as session.php <?php

session_start();
if (!$_SESSION["count"])
$_SESSION["count"] = 0;
if ($_GET["count"] == "yes")
$_SESSION["count"] = $_SESSION["count"] + 1;
echo "<h1>".$_SESSION["count"]."</h1>";
?>
<a href="session.php?count=yes">Click here to count</a>

Avoid Error PHP - Sessions

PHP Example: <?php echo "Look at this nasty error below:<br />"; session_start(); ?> Error!

PHP Example: <?php session_start(); echo "Look at this nasty error below:"; ?> Correct

Warning: Cannot send session cookie - headers already sent by (output started at session_header_error/session_error.php:2) in session_header_error/session_error.php on line 3
Warning: Cannot send session cache limiter - headers already sent (output started at session_header_error/session_error.php:2) in session_header_error/session_error.php on line 3

Destroy PHP - Sessions

Destroying a Session
why it is necessary to destroy a session when the session will get destroyed when the user closes their browser. Well, imagine that you had a session registered called "access_granted" and you were using that to determine if the user was logged into your site based upon a username and password. Anytime you have a login feature, to make the users feel better, you should have a logout feature as well. That's where this cool function called session_destroy() comes in handy. session_destroy() will completely demolish your session (no, the computer won't blow up or self destruct) but it just deletes the session files and clears any trace of that session.
NOTE: If you are using the $_SESSION superglobal array, you must clear the array values first, then run session_destroy.
Here's how we use session_destroy():

Destroy PHP - Sessions

<?php // start the session session_start(); header("Cache-control: private"); //IE 6 Fix $_SESSION = array(); session_destroy(); echo "<strong>Step 5 - Destroy This Session </strong><br />"; if($_SESSION['name']){ echo "The session is still active"; } else { echo "Ok, the session is no longer active! <br />"; echo "<a href=\"page1.php\"><< Go Back Step 1</a>"; } ?>

Basics of syntax

Scripting block starts with <?php and ends with ?>
Each code line in PHP must end with a (;)
Comments

// ,# comment
/* comment */
Writing of the plain text

Echo “text”
print “text”

Variables in PHP

Each variable starts with $ symbol
Variable name can contain only a-Z,0-9,_
It does not need to be declared before its setting.
<?php
$txt = "Hello World!";
$number = 16;
?>

Object Oriented PHP

Encapsulation
Polymorphism
Inheritance
Multiple Inheritance: actually unsupported

Encapsulation

<?
class dayOfWeek {
var $day,$month,$year;
function dayOfWeek($day,$month,$year) {
$this->day = $day;
$this->month = $month;
$this->year = $year;
}

function calculate(){
if ($this->month==1){
$monthTmp=13;
$yearTmp = $this->year - 1;
}
if ($this->month == 2){
$monthTmp = 14;
$yearTmp = $this->year - 1;
}

$val4 = (($month+1)*3)/5;
$val5 = $year/4;
$val6 = $year/100;
$val7 = $year/400;
$val8 = $day+($month*2)+$val4+$val3+$val5-$val6+$val7+2;
$val9 = $val8/7;
$val0 = $val8-($val9*7);
return $val0;
}
}
// Main
$instance =
new dayOfWeek($_GET[“day”],$_GET[“week”],$_GET[“ month”]);
print “You born on “.$instance->calculate().”\n”;
?>

Inheritance

Allow the creation of a hierarchy of classes

Class reuseMe {

function reuseMe(){...}
function doTask1(){...}
function doTask2(){...}
function doTask3(){...}
}

Class extends reuseMe {

function example(){
... // local initializations
// call super constructor
reuseMe::reuseMe();
}
function doTask4(){...}
function doTask5(){...}
function doTask6(){...}
}

Polymorphism

Class extends reuseMe {

function example(){
... // local initializations
// call super constructor
reuseMe::reuseMe();
}
function doTask4(){...}
function doTask5(){...}
function doTask6(){...}
function doTask3(){...}
}

class reuseMe {

function reuseMe(){...}
function doTask1(){...}
function doTask2(){...}
function doTask3(){...}
}

A member function can override superclass implementation. Allow each subclass to reimplement a common interfaces.

Multiple Inheritance not actually supported by PHP

class extends reuseMe1,reuseMe2 {...}

class reuseMe1 {
function reuseMe1(){...}
function doTask1(){...}
function doTask2(){...}
function doTask3(){...}
}

class reuseMe2 {
function reuseMe2(){...}
function doTask3(){...}
function doTask4(){...}
function doTask5(){...}
}

Variable types

Numerical

Integer – positive as well as negative, including 0
Float – real numbers, 14 digits accuracy

Logical

Boolean - True x False, not case sensitive

Alphabetical

String – set of characters

Working with variables

Settype($var, “integer”)

allows you to set variable according to your wish

Gettype()

write the type of variable

Connects 2 variables of string type

strlen()

finds the length of a string

Enabling PHP in HTTP servers

PHP is available on many servers today, in Windows and all types of Unix environments
It is supported by Apache, AOLServer, Roxen and others
Servers can be configured to enable PHP in different ways
We will assume that the httpd recognizes a file who name has the suffix .php as a PHP file

<h1>Hello from Dr. Chuck's HTML Page</h1>
<p>
<?php
echo "Hi there.\n";
$answer = 6 * 7;
echo "The answer is $answer, what ";
echo "was the question again?\n";
?>
</p>
<p>Yes another paragraph.</p>

<h1>Hello from Dr. Chuck's HTML Page</h1>
<p>
<?php
echo "Hi there.\n";
$answer = 6 * 7;
echo "The answer is $answer, what ";
echo "was the question again?\n";
?>
</p>
<p>Yes another paragraph.</p>

PHP From the Command Line

You can run PHP from the command line - the output simply comes out on the terminal
It does not have to be part of a request-response cycle

<?php
echo("Hello World!");
echo("\n");
?>

Key Words

http://php.net/manual/en/reserved.php

abstract and array() as break case catch class clone const continue declare default do else elseif end declare endfor endforeach endif endswitch endwhile extends final for foreach function global goto if implements interface instanceof namespace new or private protected public static switch $this throw try use var while xor

Variable Names

Start with a dollar sign ($) followed by a letter or underscore, followed by any number of letters, numbers, or underscores
Case matters

$abc = 12;
$total = 0;
$largest_so_far = 0;

abc = 12;
$2php = 0;
$bad-punc = 0;

Variable Name Weirdness

Things that look like variables but are missing a dollar sign can be confusing

$x = 2;
$y = x + 5;
print $y;

$x = 2;
y = $x + 5;
print $x;

Parse error

Expressions

Completely normal like other languages ( + - / * )
More agressive implicit type conversion

<?php
$x = "15" + 27;
echo($x);
echo("\n");
?>

Output

echo is a language construct - can be treated like a function with one parameter. Without parenthesis, it accepts multiple parameters.
print is a function - only one parameter but parenthesis are optional so it can look like a language construct

<?php
$x = "15" + 27;
echo $x;
echo("\n");
echo $x, "\n";
print $x;
print "\n";
print($x);
print("\n");
?>

Conditional - if

Logical operators ( == != < > <= >= && || ! )
Curly braces

<?php
$ans = 42;
if ( $ans == 42 ) {
print "Hello world!\n";
} else {
print "Wrong answer\n";
}
?>

Hello World!

Whitespace does not matter

<?php
$ans = 42;
if ( $ans == 42 ) {
print "Hello world!\n";
} else {
print "Wrong answer\n";
}
?>

<?php $ans = 42; if ( $ans == 42 ) { print
"Hello world!\n"; } else { print "Wrong answer\n"; }
?>

What Style do You Prefer?

<?php
$ans = 42;
if ( $ans == 42 )
{
print "Hello world!\n";
}
else

{

print "Wrong answer\n";
}
?>

<?php
$ans = 42;
if ( $ans == 42 ) {
print "Hello world!\n";
} else {
print "Wrong answer\n";
}
?>

Aesthetics

Associative Arrays

Like Python Dictonaries+Lists - but more powerful
Can be key => value or simply indexed by numbers
Ignore two-dimensional arrays for now...
In PHP, there are three kind of arrays:
Numeric array - An array with a numeric index
Associative array - An array where each ID key is associated with a value
Multidimensional array - An array containing one or more arrays

PHP Numeric Arrays

> A numeric array stores each array element with a numeric index.
> There are two methods to create a numeric array.

PHP Numeric Arrays

In the following example the index is automatically assigned (the index starts at 0):
In the following example we assign the index manually:

PHP Numeric Arrays

In the following example you access the variable values by referring to the array name and index:
The code above will output:

PHP Associative Arrays

> With an associative array, each ID key is associated with a value.
> When storing data about specific named values, a numerical array is not always the best way to do it.
> With associative arrays we can use the values as keys and assign values to them.

PHP Associative Arrays

In this example we use an array to assign ages to the different persons:
This example is the same as the one above, but shows a different way of creating the array:

PHP Associative Arrays

PHP 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.

PHP Multidimensional Arrays

Array Example 1

<html>
<head><title>Array Demo</title></head>
<body>
<h1>Array Demo</h1>
<p>
<?php
$capital = array ('France'=>'Paris','Ireland'=>'Dublin');
echo 'The capital of Ireland is ';
echo $capital['Ireland'];
?>
</p>
</body>
</html>

Array Example 2

<html>
<head><title>Array Demo</title></head>
<body>
<h1>Array Demo</h1>
<p>
<?php
$capital = array ('France'=>'Paris', ‘Ireland'=>'Dublin');
echo "The various capitals are\n<ul>";
foreach ($capital as $city) { echo "<li>$city</li>"; };
echo "</ul>"
?>
</p>
</body>
</html>

Array Example 3

<html>
<head><title>Array Demo</title></head>
<body>
<h1>Array Demo</h1>
<p>
<?php
$capital = array ('France'=>'Paris', 'Ireland'=>'Dublin');
echo "The various capitals are\n<ul>";
foreach ($capital as $country => $city)
{ echo "<li>The capital of $country is $city</li>"; };
echo "</ul>"
?>
</p>
</body>
</html>

Array Example 4

<html>
<head>
<title>Details about Fred</title>
</head>
<body>
<h1>Details about Fred</h1>
<?php
$ages = array ("Fred" => 2, "Tom"=> 45);
$parents = array ("Fred" => array("father" => "Tom", "mother"=>"Mary"));
print "<p> Fred's age is ";
print $ages["Fred"];
print ".</p>";
print "<p>His father is ";
print $parents["Fred"]["father"];
print ".</p>";
?>
</body>
</html>

Array-manupulation functions

PHP provides a huge set of array-manipulation functions
array -- Create an array
array_change_key_case -- Returns an array with all string keys lowercased or uppercased
array_chunk -- Split an array into chunks
array_count_values -- Counts all the values of an array
array_diff -- Computes the difference of arrays
array_filter -- Filters elements of an array using a callback function
array_flip -- Flip all the values of an array
array_fill -- Fill an array with values
array_intersect -- Computes the intersection of arrays
array_key_exists -- Checks if the given key or index exists in the array
array_keys -- Return all the keys of an array
array_map -- Applies the callback to the elements of the given arrays
array_merge -- Merge two or more arrays
array_merge_recursive -- Merge two or more arrays recursively
array_multisort -- Sort multiple or multi-dimensional arrays
array_pad -- Pad array to the specified length with a value

array_pop -- Pop the element off the end of array

array_pop -- Pop the element off the end of array
array_push -- Push one or more elements onto the end of array
array_rand -- Pick one or more random entries out of an array
array_reverse -- Return an array with elements in reverse order
array_reduce -- Iteratively reduce the array to a single value using a callback function
array_shift -- Shift an element off the beginning of array
array_slice -- Extract a slice of the array
array_splice -- Remove a portion of the array and replace it with something else
array_sum -- Calculate the sum of values in an array.
array_unique -- Removes duplicate values from an array
array_unshift -- Prepend one or more elements to the beginning of array
array_values -- Return all the values of an array
array_walk -- Apply a user function to every member of an array
arsort -- Sort an array in reverse order and maintain index association
asort -- Sort an array and maintain index association
compact -- Create array containing variables and their values
count -- Count elements in a variable
current -- Return the current element in an array

each -- Return the current key and value pair from an array and advance the array cursor

each -- Return the current key and value pair from an array and advance the array cursor
end -- Set the internal pointer of an array to its last element
extract -- Import variables into the current symbol table from an array
in_array -- Return TRUE if a value exists in an array
array_search -- Searches the array for a given value and returns the corresponding key if successful
key -- Fetch a key from an associative array
krsort -- Sort an array by key in reverse order
ksort -- Sort an array by key
list -- Assign variables as if they were an array
natsort -- Sort an array using a "natural order" algorithm
natcasesort -- Sort an array using a case insensitive "natural order" algorithm
next -- Advance the internal array pointer of an array
pos -- Get the current element from an array
prev -- Rewind the internal array pointer
range -- Create an array containing a range of elements
reset -- Set the internal pointer of an array to its first element

rsort -- Sort an array in reverse order

rsort -- Sort an array in reverse order
shuffle -- Shuffle an array
sizeof -- Get the number of elements in variable
sort -- Sort an array
uasort -- Sort an array with a user-defined comparison function and maintain index association
uksort -- Sort an array by keys using a user-defined comparison function
usort -- Sort an array by values using a user-defined comparison function

Objects

PHP supports object-oriented programming
The subject is too big to cover here
But here’s an example

<?php
class thingAMeBob
{
function say_hello()
{ echo “Hello, World!"; }
}
$thing1 = new thingAMeBob;
$thing1->say_hello();
?>

Resources

This data type is used for maintaining links to external resources, such as data bases etc.
A full treatment is beyond our scope here

The NULL data type

This data type contains only one value
NULL
It is case-insensitive
This is a value which is returned when some expression has no value
Example
$capital = array ('France'=>'Paris', 'Ireland'=>'Dublin');
$capitalOfEngland = $capital[‘England’];
In this case, $capitalOfEngland would get the value NULL

Cs 3314 got here on 7/11/2005

Changing Data Type

PHP will, in some circumstances, change the type of a datum

For example, it will treat a string of digits as a number if it finds in an arithmetic expression

PHP also supports type casting

<?php $myInteger = 12;
$myFloat = 1.3;
$result = $myFloat + (float) $myInteger;
echo $result ?>

Integer Indices

<?php
$stuff = array("Hi", "There");
echo $stuff[1], "\n";
?>

There

Integer Indices

<?php
$stuff = array();
$stuff[] = "Hello";
$stuff[] = "World";
echo $stuff[1], "\n";
?>

World

Integer Indices

<?php
$stuff = array();
$stuff[2] = "Hello";
$stuff[9] = "World";
echo $stuff[9], "\n";
?>

World

Key / Value

<?php
$stuff = array("name" => "Chuck",
"course" => "SI664");
echo $stuff["course"], "\n";
?>

SI664

Dumping an Array

The function print_r() dumps out PHP data - it is used mostly for debugging

<?php
$stuff = array("name" => "Chuck",
"course" => "SI664");
print_r($stuff);
?>

Array
(
[name] => Chuck
[course] => SI664
)

Dumping an Array

The function print_r() dumps out PHP data - it is used mostly for debugging

<?php
$stuff = array();
$stuff[2] = "Hello";
$stuff[9] = "World";
print_r($stuff);
?>

Array
(
[2] => Chuck
[9] => SI664
)

var_dump .vs. print_r

<?php
$stuff = array("name" => "Chuck",
"course" => "SI664");
var_dump($stuff);
?>

array(2) {
["name"]=>
string(5) "Chuck"
["course"]=>
string(5) "SI664"
}

var_dump() is more verbose

<?php
$thing = FALSE;

echo("One\n");
print_r($thing);
echo("Two\n");
var_dump($thing);

One
Two
bool(false)

Looping Through an Array

<?php
$stuff = array("name" => "Chuck",
"course" => "SI664");
foreach($stuff as $k => $v ) {
echo "Key=",$k," Val=",$v,"\n";
}
?>

Key=name Val=Chuck
Key=course Val=SI664

Variable Name Weirdness

Things that look like variables but are missing a dollar sign as an array index are unpredictable....

$x = 5;
$y = array("x" => "Hello");
print $y[x];

Hello

Strings (I)

A string is a sequence of chars
$stringTest = “this is a sequence of chars”;
echo $stringTest[0]; output: t
echo $stringTest; output: this is a sequence of chars
A single quoted strings is displayed “as-is”
$age = 37;
$stringTest = 'I am $age years old'; // output: I am $age years old
$stringTest = “I am $age years old”; // output: I am 37 years old
Concatenation
$conc = ”is “.”a “.”composed “.”string”;
echo $conc; // output: is a composed string
$newConc = 'Also $conc '.$conc;
echo $newConc; // output: Also $conc is a composed string

Strings

Explode function
$sequence = “A,B,C,D,E,F,G”;
$elements = explode (“,”,$sequence);
// Now elements is an array with all substrings between “,” char
echo $elemets[0]; // output: A;
echo $elemets[1]; // output: B;
echo $elemets[2]; // output: C;
echo $elemets[3]; // output: D;
echo $elemets[4]; // output: E;
echo $elemets[5]; // output: F;
echo $elemets[6]; // output: G;

Strings / Different + Awesome

String literals can use single quotes or double quotes
The backslash (\) is used as an "escape" character
Strings can span multiple lines - the newline is part of the string
In double-quoted strings variable values are expanded
Concatenation is the "." not "+" (more later)

<?php
echo "this is a simple string\n";
echo "You can also have embedded newlines in
strings this way as it is
okay to do";
// Outputs: This will expand:
// a newline
echo "This will expand: \na newline";
// Outputs: Variables do 12
$expand = 12;
echo "Variables do $expand\n";

Double Quote

<?php
echo 'this is a simple string';
echo 'You can also have embedded newlines in
strings this way as it is
okay to do';
// Outputs: Arnold once said: "I'll be back"
echo 'Arnold once said: "I\'ll be back"';
// Outputs: This will not expand: \n a newline
echo 'This will not expand: \n a newline';
// Outputs: Variables do not $expand $either
echo 'Variables do not $expand $either';

Single Quote

<?php
echo 'This is a test'; // This is a c++ style comment
/* This is a multi line comment
yet another line of comment */
echo 'This is yet another test';
echo 'One Final Test'; # This is a shell-style comment
?>

PHP Looping

while

loops repeat until final condition is reached
$i =1;
while ($i<=10) {
echo $i;
$i++;
}

do...while

kind of reversed while function
Do { code to be executed;}
While(final condition);

PHP Looping

for

Repeats the specific part of code so many times we choose
for ($i=1; $i<=10; $i++)
Initial condition final condition running decsription

HTML inside PHP

If inside quotes, the Html tags are returned as a text by PHP module
Treated as a HTML tag by
<?php
echo
"<TR> <TD>".$i."</TD><TD>".$i*$i."</TD></TR>\n";
?>

PHP Functions

All function starts with function($parameter)
Requirements for naming functions are same as these for variables
The { mark opens the function code, while } mark closes it
It can have either defined or no parameter
More than 700 built-in functions available

Functions Covered

mysql_connect() mysql_select_db()
include()
mysql_query() mysql_num_rows()
mysql_fetch_array() mysql_close()

PHP Forms and User Input

Used to gain information from users by means of HTML
Information is worked up by PHP
<html>
<body>
<form action="welcome.php" method="post">
Name: <input type="text" name="name" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
</body>
</html>

PHP - embedded language

PHP can be placed directly inside HTML E.g.
<html>

<head><title>Basic PHP page</title></head>
<body>
<h1><?php echo “Hello World!; ?></h1>
</body>

</html>

Decision Making - Basics

Decision making involves evaluating Boolean expressions (true / false)
If($catishungry) { /* feed cat */ }
“true” and “false” are reserved words
Initialise as $valid = false;
Compare with ==
AND and OR for combinations

E.g. if($catishungry AND $havefood) {/* feed cat*/}

PHP - IF statement

Used to perform a conditional branch
If (Boolean expression) {

// one or more commands if true

} else {

// one or more commands if false

}

PHP - Switch Statements

Useful when a Boolean expression may have many options E.g.
switch($choice) {

case 0: { /* do things if choice equal 0 */ }
Case 1: {/* do things if choice equal 1 */ }
Case 2: {/* do things if choice equal 2 */ }
Default: {/* do if choice is none of the above */}

}

PHP - one small step for man…

… One giant leap for level 1 students
First few steps are crucial - topics covered:

Basic structure and syntax
Variables, constants and operators
Data types and conversions
Decision making

Any questions so far?

PHP - Dealing with the Client

All very nice but …
… How is it useful in your web site?
PHP allows you to use HTML forms
Forms require technology at the server to process them
PHP is a feasible and good choice for the processing of HTML forms

PHP - Dealing with the client

Quick re-cap on forms
Implemented with a <form> element in HTML
Contains other input, text area, list controls and options
Has some method of submitting

PHP - Dealing with the client

Text fields
Checkbox
Radio button
List boxes
Hidden form fields
Password box
Submit and reset buttons

PHP - Dealing with the client

<form method=“post” action=“file.php” name=“frmid” >

Method specifies how the data will be sent
Action specifies the file to go to. E.g. file.php
id gives the form a unique name

Post method sends all contents of a form with basically hidden headers (not easily visible to users)
Get method sends all form input in the URL requested using name=value pairs separated by ampersands (&)

E.g. process.php?name=trevor&number=345
Is visible in the URL shown in the browser

PHP - Dealing with the client

All form values are placed into an array
Assume a form contains one textbox called “txtName” and the form is submitted using the post method, invoking process.php
process.php could access the form data using:

$_POST[‘txtName’]

If the form used the get method, the form data would be available as:

$_GET[‘txtName’]

PHP - Dealing with the client

For example, an HTML form:

<form id=“showmsg” action=“show.php” method=“post”>

<input type=“text” id=“txtMsg” value=“Hello World” />
<input type=“submit” id=“submit” value=“Submit”>

</form>

PHP - Dealing with the client

A file called show.php would receive the submitted data
It could output the message, for example:
<html>

<head><title>Show Message</title></head>
<body>

<h1><?php echo $_POST[“txtMsg”]; ?></h1>

</body>

</html>

PHP - Dealing with the client

Summary

Form elements contain input elements
Each input element has an id
If a form is posted, the file stated as the action can use:

$_POST[“inputid”]

If a form uses the get method:

$_GET[“inputid”]

Ensure you set all id attributes for form elements and their contents

PHP - Dealing with the client

Summary

Form elements contain input elements
Each input element has an id
If a form is posted, the file stated as the action can use:

$_POST[“inputid”]

If a form uses the get method:

$_GET[“inputid”]

Ensure you set all id attributes for form elements and their contents

The $_GET Variable

Used to collect values from a form
Displays variable names and values are in the URL

http://www.w3schools.com/welcome.php?name=jo&age=39

Can send limited amount of information (max. 100 characters)
<html>
<body>
Welcome <?php echo $_GET["name"]; ?> <br />
You are <?php echo $_GET["age"]; ?> years old
</body>
</html>

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 lines in a script we can use loops to perform a task like this.
> In PHP, we have the following looping statements:

PHP Loops

> while - loops through a block of code while a specified condition is true
> do...while - loops through a block of code once, and then repeats the loop as long as a 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 Loops - While

The while loop executes a block of code while a condition is true. The example below defines a loop that starts with
i=1. The loop will
continue to run as
long as i is less
than, or equal to 5.
i will increase by 1
each time the loop
runs:

PHP Loops - While

PHP Loops – Do ... While

The do...while statement will always execute the block of code once, it will then check the condition, and repeat the loop while the condition is true.
The next example defines a loop that starts with i=1. It will then increment i with 1, and write some output. Then the condition is checked, and the loop will continue to run as long as i is less than, or equal to 5:

PHP Loops – Do ... While

PHP Loops - For

Parameters:
> init: Mostly used to set a counter (but can be any code to be executed once at the beginning of the loop)‏
> condition: Evaluated for each loop iteration. If it evaluates to TRUE, the loop continues. If it evaluates to FALSE, the loop ends.
> increment: Mostly used to increment a counter (but can be any code to be executed at the end of the loop)‏

PHP Loops - For

The example below defines a loop that starts with i=1. The loop will continue to run as long as i is less than, or equal to 5. i will increase by 1 each time the loop runs:

PHP Loops - For

PHP Loops - Foreach

For every loop iteration, the value of the current array element is assigned to $value (and the array pointer is moved by one) - so on the next loop iteration, you'll be looking at the next array value.

PHP Loops - Foreach

The following example demonstrates a loop that will print the values of the given array:

PHP Loops - Foreach

Winner of the most impressive slide award

PHP Functions

> We will now explore how to create your own functions.
> To keep the script from being executed when the page loads, you can put it into a function.
> A function will be executed by a call to the function.
> You may call a function from anywhere within a page.

PHP Functions

A function will be executed by a call to the function.
> Give the function a name that reflects what the function does
> The function name can start with a letter or underscore (not a number)‏

Functions

Functions MUST be defined before then can be called
Function headers are of the format

Note that no return type is specified

Unlike variables, function names are not case sensitive (foo(…) == Foo(…) == FoO(…))

function functionName($arg_1, $arg_2, …, $arg_n)

PHP Functions

A simple function that writes a name when it is called:

PHP Functions - Parameters

Adding parameters...
> To add more functionality to a function, we can add parameters. A parameter is just like a variable.
> Parameters are specified after the function name, inside the parentheses.

PHP Functions - Parameters

This example adds different punctuation.

PHP Functions - Parameters

Functions example

<?php
// This is a function

function foo($arg_1, $arg_2)
{ $arg_2 = $arg_1 * $arg_2;
return $arg_2; }
$result_1 = foo(12, 3); // Store the function
echo $result_1; // Outputs 36
echo foo(12, 3); // Outputs 36

PHP Forms - $_GET Function

> The built-in $_GET function is used to collect values from a form sent with method="get".
> Information sent from a form with the GET method is visible to everyone (it will be displayed in the browser's address bar) and has limits on the amount of information to send (max. 100 characters).

PHP Forms - $_GET Function

Notice how the URL carries the information after the file name.

PHP Forms - $_GET Function

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

PHP Forms - $_GET Function

> When using method="get" in HTML forms, all variable names and values are displayed in the URL.
> This method should not be used when sending passwords or other sensitive information!
> However, because the variables are displayed in the URL, it is possible to bookmark the page. This can be useful in some cases.
> The get method is not suitable for large variable values; the value cannot exceed 100 chars.

PHP Forms - $_POST Function

> The built-in $_POST function is used to collect values from a form sent with 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.
> Note: However, 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).

PHP Forms - $_POST Function

And here is what the code of action.php might look like:

PHP Forms - $_POST Function

Apart from htmlspecialchars() and (int), it should be obvious what this does. htmlspecialchars() makes sure any characters that are special in html are properly encoded so people can't inject HTML tags or Javascript into your page.
For the age field, since we know it is a number, we can just convert it to an integer which will automatically get rid of any stray characters. The $_POST['name'] and $_POST['age'] variables are automatically set for you by PHP.

PHP Forms - $_POST Function

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.
> However, because the variables are not displayed in the URL, it is not possible to bookmark the page.

Comments in PHP

Standard C, C++, and shell comment symbols

// C++ and Java-style comment
# Shell-style comments
/* C-style comments
These can span multiple lines */

Variables in PHP

PHP variables must begin with a “$” sign
Case-sensitive ($Foo != $foo != $fOo)
Global and locally-scoped variables

Global variables can be used anywhere
Local variables restricted to a function or class

Certain variable names reserved by PHP

Form variables ($_POST, $_GET)
Server variables ($_SERVER)
Etc.

Variable usage

<?php
$foo = 25; // Numerical variable $bar = “Hello”; // String variable
$foo = ($foo * 7); // Multiplies foo by 7 $bar = ($bar * 7); // Invalid expression
?>

Example Usage of Variables

<html>
<head>
<title>Greetings</title>
</head>
<body>
<h1>Greetings</h1>
<p>
<?php $person = "Tom";
$Person = "Dick";
echo "Hello $person and $Person";
?>
</p>
</body>
</html>

Automatic variables in PHP

One of the main benefits of PHP is that it provides lots of variables automatically
Consider, for example, the .php file on the next slide
It produces the output on the following two slides when viewed by MSIE 6.0 and Netscape 2.0

Example usage of automatic PHP variable

<html>
<head>
<title>Your browser</title>
</head>
<body>
<h1>Your Browser</h1>
<p>
You are using
<?php echo $HTTP_USER_AGENT; ?>
to view this page.
</p>
</body>
</html>

A warning about pre-defined variables

The way in which PHP supports pre-defined variables has changed recently.
This will be discussed in a future lecture

Data Types in PHP

PHP supports eight primitive data types
There are four scalar types

boolean
integer
floating-point number
string

There are two structured types

array
object

There are two special data types

resource
NULL

The programmer does not specify the type of a variable

a variable’s type is determined from the context of its usage

Booleans

The boolean data type admits two values

true (case-insensitive)
false (case-insensitive)

Example usage

$itIsRainingToday = true;
$thePrinterIsBusy = True;
$theQueueIsEmpty = FALSE;

Integers

Integers can be specified in decimal, hexadecimal or octal notation, optionally preceded by a sign

In octal notation, the number must have a leading 0
In hexadecimal notation, the number must have a leading 0x.

Examples

$a = 1234; # decimal number
$a = -123; # a negative number
$a = 0123; # octal number (equivalent to 83 decimal)
$a = 0x1B; # hexadecimal number (equivalent to 27 decimal)

The maximum size of an integer is platform-dependent, but usually it’s 32 bits signed – about 2,000,000,000
PHP does not support unsigned integers.

Floating Point Numbers

These can be specified using any of these forms:

$a = 1.234;
$a = 1.2e3;
$a = 7E-10;

The maximum size of a float is platform-dependent, although most support a maximum of about 1.8e308 with a precision of roughly 14 decimal digits

Strings

A string literal can be specified in three different ways:

single quoted
double quoted
heredoc syntax

Single-quoted Strings

In single-quoted strings, single-quotes and backslashes must be escaped with a preceding backslash
Example usage
echo 'this is a simple string';
echo 'You can embed newlines in strings,
just like this.';
echo ‘Douglas MacArthur said "I\'ll be back” when leaving the Phillipines';
echo 'Are you sure you want to delete C:\\*.*?';

Double-quoted Strings

In double-quoted strings,

variables are interpreted to their values, and
various characters can be escaped

\n linefeed
\r carriage return
\t horizontal tab
\\ backslash
\$ dollar sign
\” double quote
\[0-7]{1,3} a character in octal notation
\x[0-9A-Fa-f]{1,2} a character in hexadecimal notation

Heredoc Strings

Heredoc strings are like double-quoted strings without the double quotes
A heredoc string is delimited as follows

The string is preceded by <<< followed by a label
The string followed by a 2nd occurrence of the same label

Example usage
$str = <<<EOD
Example of string
spanning multiple lines
using heredoc syntax.
EOD;

String-manipulation functions

PHP provides huge range of string-manipulation functions:

addcslashes -- Quote string with slashes in a C style
addslashes -- Quote string with slashes
bin2hex -- Convert binary data into hexadecimal representation
chop -- Alias of rtrim()
chr -- Return a specific character
chunk_split -- Split a string into smaller chunks
convert_cyr_string -- Convert from one Cyrillic character set to another
count_chars -- Return information about characters used in a string
crc32 -- Calculates the crc32 polynomial of a string
crypt -- One-way string encryption (hashing)
echo -- Output one or more strings
explode -- Split a string by string
get_html_translation_table -- Returns the translation table used by htmlspecialchars() and htmlentities()

get_meta_tags -- Extracts all meta tag content attributes from a file and returns an array

get_meta_tags -- Extracts all meta tag content attributes from a file and returns an array
hebrev -- Convert logical Hebrew text to visual text
hebrevc -- Convert logical Hebrew text to visual text with newline conversion
htmlentities -- Convert all applicable characters to HTML entities
htmlspecialchars -- Convert special characters to HTML entities
implode -- Join array elements with a string
join -- Join array elements with a string
levenshtein -- Calculate Levenshtein distance between two strings
localeconv -- Get numeric formatting information
ltrim -- Strip whitespace from the beginning of a string
md5 -- Calculate the md5 hash of a string
md5_file -- Calculates the md5 hash of a given filename
metaphone -- Calculate the metaphone key of a string
nl2br -- Inserts HTML line breaks before all newlines in a string
ord -- Return ASCII value of character
parse_str -- Parses the string into variables
print -- Output a string
printf -- Output a formatted string

quoted_printable_decode -- Convert a quoted-printable string to an 8 bit string

quoted_printable_decode -- Convert a quoted-printable string to an 8 bit string
quotemeta -- Quote meta characters
str_rot13 -- Perform the rot13 transform on a string
rtrim -- Strip whitespace from the end of a string
sscanf -- Parses input from a string according to a format
setlocale -- Set locale information
similar_text -- Calculate the similarity between two strings
soundex -- Calculate the soundex key of a string
sprintf -- Return a formatted string
strncasecmp -- Binary safe case-insensitive string comparison of the first n characters
strcasecmp -- Binary safe case-insensitive string comparison
strchr -- Find the first occurrence of a character
strcmp -- Binary safe string comparison
strcoll -- Locale based string comparison
strcspn -- Find length of initial segment not matching mask
strip_tags -- Strip HTML and PHP tags from a string
stripcslashes -- Un-quote string quoted with addcslashes()
stripslashes -- Un-quote string quoted with addslashes()

stristr -- Case-insensitive strstr()

stristr -- Case-insensitive strstr()
strlen -- Get string length
strnatcmp -- String comparisons using a "natural order" algorithm
strnatcasecmp -- Case insensitive string comparisons using a "natural order" algorithm
strncmp -- Binary safe string comparison of the first n characters
str_pad -- Pad a string to a certain length with another string
strpos -- Find position of first occurrence of a string
strrchr -- Find the last occurrence of a character in a string
str_repeat -- Repeat a string
strrev -- Reverse a string
strrpos -- Find position of last occurrence of a char in a string
strspn -- Find length of initial segment matching mask
strstr -- Find first occurrence of a string
strtok -- Tokenize string
strtolower -- Make a string lowercase
strtoupper -- Make a string uppercase
str_replace -- Replace all occurrences of the search string with the replacement string

strtr -- Translate certain characters

strtr -- Translate certain characters
substr -- Return part of a string
substr_count -- Count the number of substring occurrences
substr_replace -- Replace text within a portion of a string
trim -- Strip whitespace from the beginning and end of a string
ucfirst -- Make a string's first character uppercase
ucwords -- Uppercase the first character of each word in a string
vprintf -- Output a formatted string
vsprintf -- Return a formatted string
wordwrap -- Wraps a string to a given number of characters using a string break character.
nl_langinfo -- Query language and locale information

Echo

The PHP command ‘echo’ is used to output the parameters passed to it

The typical usage for this is to send data to the client’s web-browser

Syntax

void echo (string arg1 [, string argn...])
In practice, arguments are not passed in parentheses since echo is a language construct rather than an actual function

Echo example

Notice how echo ‘5x5=$foo’ outputs $foo rather than replacing it with 25
Strings in single quotes (‘ ’) are not interpreted or evaluated by PHP
This is true for both variables and character escape-sequences (such as “\n” or “\\”)

<?php
$foo = 25; // Numerical variable $bar = “Hello”; // String variable
echo $bar; // Outputs Hello
echo $foo,$bar; // Outputs 25Hello
echo “5x5=”,$foo; // Outputs 5x5=25
echo “5x5=$foo”; // Outputs 5x5=25 echo ‘5x5=$foo’; // Outputs 5x5=$foo
?>

Arithmetic Operations

$a - $b // subtraction
$a * $b // multiplication
$a / $b // division
$a += 5 // $a = $a+5 Also works for *= and /=

<?php
$a=15;
$b=30;
$total=$a+$b;
Print $total;
Print “<p><h1>$total</h1>”;
// total is 45
?>

Arithmetic Operations

$a - $b // subtraction
$a * $b // multiplication
$a / $b // division
$a += 5 // $a = $a+5 Also works for *= and /=

<?php
$a=15;
$b=30;
$total=$a+$b;
Print $total;
Print “<p><h1>$total</h1>”;
// total is 45
?>

Concatenation

Use a period to join strings into one.

<?php
$string1=“Hello”;
$string2=“PHP”;
$string3=$string1 . “ ” . $string2;
Print $string3;
?>

Hello PHP

Concatenation

Use a period to join strings into one.

<?php
$string1=“Hello”;
$string2=“PHP”;
$string3=$string1 . “ ” . $string2;
Print $string3;
?>

Hello PHP

Echo

The PHP command ‘echo’ is used to output the parameters passed to it

The typical usage for this is to send data to the client’s web-browser

Syntax

void echo (string arg1 [, string argn...])
In practice, arguments are not passed in parentheses since echo is a language construct rather than an actual function

Echo example

Notice how echo ‘5x5=$foo’ outputs $foo rather than replacing it with 25
Strings in single quotes (‘ ’) are not interpreted or evaluated by PHP
This is true for both variables and character escape-sequences (such as “\n” or “\\”)

<?php
$foo = 25; // Numerical variable $bar = “Hello”; // String variable
echo $bar; // Outputs Hello
echo $foo,$bar; // Outputs 25Hello
echo “5x5=”,$foo; // Outputs 5x5=25
echo “5x5=$foo”; // Outputs 5x5=25 echo ‘5x5=$foo’; // Outputs 5x5=$foo
?>

Constants

A constant is an identifier (name) for a simple value. A constant is case-sensitive by
default. By convention, constant identifiers are always uppercase.

<?php
// Valid constant names
define("FOO", "something");
define("FOO2", "something else");
define("FOO_BAR", "something more");
// Invalid constant names (they shouldn’t start
// with a number!)
define("2FOO", "something");
// This is valid, but should be avoided:
// PHP may one day provide a “magical” constant
// that will break your script
define("__FOO__", "something");
?>

You can access constants anywhere in your script without regard to scope.

Escaping the Character

If the string has a set of double quotation marks that must remain visible, use the \ [backslash] before the quotation marks to ignore and display them.

<?php
$heading=“\”Computer Science\””;
Print $heading;
?>

“Computer Science”

Scalars

All variables in PHP start with a $ sign symbol. A variable's type is determined by the
context in which that variable is used (i.e. there is no strong-typing in PHP).

<html><head></head>
<body> <p>
<?php
$foo = true; if ($foo) echo "It is TRUE! <br /> \n";
$txt='1234'; echo "$txt <br /> \n";
$a = 1234; echo "$a <br /> \n";
$a = -123;
echo "$a <br /> \n";
$a = 1.234;
echo "$a <br /> \n";
$a = 1.2e3;
echo "$a <br /> \n";
$a = 7E-10;
echo "$a <br /> \n";
echo 'Arnold once said: "I\'ll be back"', "<br /> \n";
$beer = 'Heineken';
echo "$beer's taste is great <br /> \n";
$str = <<<EOD
Example of string
spanning multiple lines
using “heredoc” syntax.
EOD;
echo $str;
?>
</p>
</body>
</html>

Four scalar types:
boolean
true or false
integer,
float,
floating point numbers
string
single quoted
double quoted

PHP Control Structures

Control Structures: Are the structures within a language that allow us to control the flow of execution through a program or script.
Grouped into conditional (branching) structures (e.g. if/else) and repetition structures (e.g. while loops).
Example if/else if/else statement:

if ($foo == 0) {
echo ‘The variable foo is equal to 0’;
}
else if (($foo > 0) && ($foo <= 5)) {
echo ‘The variable foo is between 1 and 5’;
}
else {
echo ‘The variable foo is equal to ‘.$foo;
}

If ... Else...

If (condition)
{
Statements;
}
Else
{
Statement;
}

<?php
If($user==“John”)
{
Print “Hello John.”;
}
Else
{
Print “You are not John.”;
}
?>

No THEN in PHP

While Loops

While (condition)
{
Statements;
}

<?php
$count=0;
While($count<3)
{
Print “hello PHP. ”;
$count += 1;
// $count = $count + 1;
// or
// $count++;
?>

hello PHP. hello PHP. hello PHP.

Date Display

$datedisplay=date(“yyyy/m/d”);
Print $datedisplay;
# If the date is April 1st, 2009
# It would display as 2009/4/1

2009/4/1

$datedisplay=date(“l, F m, Y”);
Print $datedisplay;
# If the date is April 1st, 2009
# Wednesday, April 1, 2009

Wednesday, April 1, 2009

Month, Day & Date Format Symbols

M	Jan
F	January
m	01
n	1

Day of Month	d	01
Day of Month	J	1
Day of Week	l	Monday
Day of Week	D	Mon

Include Files

Include “opendb.php”;
Include “closedb.php”;
This inserts files; the code in files will be inserted into current code. This will provide useful and protective means once you connect to a database, as well as for other repeated functions.
Include (“footer.php”);
The file footer.php might look like:
<hr SIZE=11 NOSHADE WIDTH=“100%”>
<i>URL: http://www.kent.edu</i></font><br>

PHP - Forms

Access to the HTTP POST and GET data is simple in PHP
The global variables $_POST[] and $_GET[] contain the request data <?php

if ($_POST["submit"])
echo "<h2>You clicked Submit!</h2>";
else if ($_POST["cancel"])
echo "<h2>You clicked Cancel!</h2>";
?>
<form action="form.php" method="post">
<input type="submit" name="submit" value="Submit">
<input type="submit" name="cancel" value="Cancel">
</form>

http://www.cs.kent.edu/~nruan/form.php

Save as sample.php:

Save as sample.php:

<!– sample.php -->
<html><body>

<strong>Hello World!</strong><br />
<?php

echo “<h2>Hello, World</h2>”; ?>

<?php

$myvar = "Hello World";
echo $myvar;
?>
</body></html>

First PHP script

http://www.cs.kent.edu/~nruan/sample.php

Example – show data in the tables

Function: list all tables in your database. Users can select one of tables, and show all contents in this table.
second.php
showtable.php

http://www.cs.kent.edu/~nruan/second.php

PHP Information

The phpinfo() function is used to output PHP information about the version installed on the server, parameters selected when installed, etc.

<html><head></head>
<!– info.php
<body>
<?php
// Show all PHP information
phpinfo();
?>
<?php
// Show only the general information
phpinfo(INFO_GENERAL);
?>
</body>
</html>

INFO_GENERAL The configuration line,
php.ini location,
build date,
Web Server,
System and more
INFO_CREDITS PHP 4 credits
INFO_CONFIGURATION Local and master values
for php directives
INFO_MODULES Loaded modules
INFO_ENVIRONMENT Environment variable
information
INFO_VARIABLES All predefined variables
from EGPCS
INFO_LICENSE PHP license information
INFO_ALL Shows all of the above (default)

Server Variables

The $_SERVER array variable is a reserved variable that contains all server information.

<html><head></head>
<body>
<?php
echo "Referer: " . $_SERVER["HTTP_REFERER"] . "<br />";
echo "Browser: " . $_SERVER["HTTP_USER_AGENT"] . "<br />";
echo "User's IP address: " . $_SERVER["REMOTE_ADDR"];
?>
<?php
echo "<br/><br/><br/>";
echo "<h2>All information</h2>";
foreach ($_SERVER as $key => $value)
{
echo $key . " = " . $value . "<br/>";
}
?>
</body>
</html>

The $_SERVER is a super global variable, i.e. it's available in all scopes of a PHP script.

$_SERVER info on php.net

File Open

The fopen("file_name","mode") function is used to open files in PHP.

<?php
$fh=fopen("welcome.txt","r");
?>

r Read only. r+ Read/Write.
w Write only. w+ Read/Write.
a Append. a+ Read/Append.
x Create and open for write only. x+ Create and open for read/write.

If the fopen() function is unable to open the specified file, it returns 0 (false).

<?php
if
( !($fh=fopen("welcome.txt","r")) )
exit("Unable to open file!");
?>

For w, and a, if no file exists, it tries to create it (use with caution, i.e. check that this is the case, otherwise you’ll overwrite an existing file).

For x if a file exists, this function fails (and returns 0).

File Workings

fclose() closes a file.

feof() determines if the end is true.

fgetc() reads a single character

<?php
$myFile = "welcome.txt";
if (!($fh=fopen($myFile,'r')))
exit("Unable to open file.");
while (!feof($fh))
{
$x=fgetc($fh);
echo $x;
}
fclose($fh);
?>

<?php
$myFile = "welcome.txt";
$fh = fopen($myFile, 'r');
$theData = fgets($fh);
fclose($fh);
echo $theData;
?>

fgets() reads a line of data

fwrite(), fputs () writes a string with and without \n

<?php
$myFile = "testFile.txt";
$fh = fopen($myFile, 'a') or die("can't open file");
$stringData = "New Stuff 1\n";
fwrite($fh, $stringData);
$stringData = "New Stuff 2\n";
fwrite($fh, $stringData);
fclose($fh);
?>

file() reads entire file into an array

<?php
$lines = file('welcome.txt');
foreach ($lines as $l_num => $line)
{
echo "Line #{$l_num}:“ .$line.”<br/>”;
}
?>

Form Handling

Any form element is automatically available via one of the built-in PHP variables (provided that element has a “name” defined with it).

<html>
<-- form.html -->
<body>
<form action="welcome.php" method="POST">
Enter your name: <input type="text" name="name" /> <br/>
Enter your age: <input type="text" name="age" /> <br/>
<input type="submit" /> <input type="reset" />
</form>
</body>
</html>

<html>
<!–- welcome.php -->
<body>
Welcome <?php echo $_POST["name"].”.”; ?><br />
You are <?php echo $_POST["age"]; ?> years old!
</body>
</html>

$_POST
contains all POST data.
$_GET
contains all GET data.

Cookie Workings

setcookie(name,value,expire,path,domain) creates cookies.

<?php
setcookie("uname", $_POST["name"], time()+36000);
?>
<html>
<body>
<p>
Dear <?php echo $_POST["name"] ?>, a cookie was set on this
page! The cookie will be active when the client has sent the
cookie back to the server.
</p>
</body>
</html>

NOTE:
setcookie() must appear
BEFORE <html> (or any output) as it’s part of the header information sent with the page.

<html>
<body>
<?php
if ( isset($_COOKIE["uname"]) )
echo "Welcome " . $_COOKIE["uname"] . "!<br />";
else
echo "You are not logged in!<br />";
?>
</body>
</html>

use the cookie name as a variable

isset()
finds out if a cookie is set

$_COOKIE
contains all COOKIE data.

Getting Time and Date

date() and time () formats a time or a date.

<?php
//Prints something like: Monday
echo date("l");
//Like: Monday 15th of January 2003 05:51:38 AM
echo date("l jS \of F Y h:i:s A");
//Like: Monday the 15th
echo date("l \\t\h\e jS");
?>

date() returns a string formatted according to the specified format.

<?php
$nextWeek = time() + (7 * 24 * 60 * 60);
// 7 days; 24 hours; 60 mins; 60secs
echo 'Now: '. date('Y-m-d') ."\n";
echo 'Next Week: '. date('Y-m-d', $nextWeek) ."\n";
?>

time() returns current Unix timestamp

Required Fields in User-Entered Data

A multipurpose script which asks users for some basic contact information and then checks to
see that the required fields have been entered.

<html>
<head>
<title>PHP Form example</title>
</head>
<body>
<?php
/*declare some functions*/

function print_form($f_name, $l_name, $email, $os)
{
?>
<form action="form_checker.php" method=“POST">
First Name: <input type="text" name="f_name" value="<?php echo $f_name?>“ /> <br/>
Last Name <b>*</b>:<input type="text" name="l_name" value="<?php echo $l_name?>“ /> <br/>
Email Address <b>*</b>:<input type="text" name="email" value="<?php echo $email?>“ /> <br/>
Operating System: <input type="text" name="os" value="<?php echo $os?>“ /> <br/><br/>
<input type="submit" name="submit" value="Submit“ /> <input type=“reset“ />
</form>
<?php
} //** end of “print_from” function

Print Function

Check and Confirm Functions

function check_form($f_name, $l_name, $email, $os)
{
if (!$l_name||!$email){
echo "<h3>You are missing some required fields!</h3>";
print_form($f_name, $l_name, $email, $os);
}
else{
confirm_form($f_name, $l_name, $email, $os);
}
} //** end of “check_form” function

function confirm_form($f_name, $l_name, $email, $os)
{
?>
<h2>Thanks! Below is the information you have sent to us.</h2>
<h3>Contact Info</h3>
<?php
echo "Name: $f_name $l_name <br/>";
echo "Email: $email <br/>";
echo "OS: $os";
} //** end of “confirm_form” function

Main Program

/*Main Program*/
if (!$_POST["submit"])
{
?>
<h3>Please enter your information</h3>
<p>Fields with a "<b>*</b>" are required.</p>
<?php
print_form("","","","");
}
else{
check_form($_POST["f_name"],$_POST["l_name"],$_POST["email"],$_POST["os"]);
}
?>
</body>
</html>

second.php

<html><head><title>MySQL Table Viewer</title></head><body>
<?php
// change the value of $dbuser and $dbpass to your username and password
$dbhost = 'hercules.cs.kent.edu:3306';
$dbuser = 'nruan';
$dbpass = ‘*****************’;
$dbname = $dbuser;
$table = 'account';
$conn = mysql_connect($dbhost, $dbuser, $dbpass);
if (!$conn) {
die('Could not connect: ' . mysql_error());
}
if (!mysql_select_db($dbname))
die("Can't select database");

second.php (cont.)

$result = mysql_query("SHOW TABLES");
if (!$result) {
die("Query to show fields from table failed");
}
$num_row = mysql_num_rows($result);
echo "<h1>Choose one table:<h1>";
echo "<form action=\"showtable.php\" method=\"POST\">";
echo "<select name=\"table\" size=\"1\" Font size=\"+2\">";
for($i=0; $i<$num_row; $i++) {
$tablename=mysql_fetch_row($result);
echo "<option value=\"{$tablename[0]}\" >{$tablename[0]}</option>";
}
echo "</select>";
echo "<div><input type=\"submit\" value=\"submit\"></div>";
echo "</form>";
mysql_free_result($result);
mysql_close($conn);
?>
</body></html>

showtable.php

<html><head>
<title>MySQL Table Viewer</title>
</head>
<body>
<?php
$dbhost = 'hercules.cs.kent.edu:3306';
$dbuser = 'nruan';
$dbpass = ‘**********’;
$dbname = 'nruan';
$table = $_POST[“table”];
$conn = mysql_connect($dbhost, $dbuser, $dbpass);
if (!$conn)
die('Could not connect: ' . mysql_error());
if (!mysql_select_db($dbname))
die("Can't select database");
$result = mysql_query("SELECT * FROM {$table}");
if (!$result) die("Query to show fields from table failed!" . mysql_error());

showtable.php (cont.)

$fields_num = mysql_num_fields($result);
echo "<h1>Table: {$table}</h1>";
echo "<table border='1'><tr>";
// printing table headers
for($i=0; $i<$fields_num; $i++) {
$field = mysql_fetch_field($result);
echo "<td><b>{$field->name}</b></td>";
}
echo "</tr>\n";
while($row = mysql_fetch_row($result)) {
echo "<tr>";
// $row is array... foreach( .. ) puts every element
// of $row to $cell variable
foreach($row as $cell)
echo "<td>$cell</td>";
echo "</tr>\n";
}
mysql_free_result($result);
mysql_close($conn);
?>
</body></html>

A FORM and its handler in one file

<html>
<head>
<title>Application Handler</title>
</head>
<body>
<?php
if (!$surname)
{ ?> <form method="POST"

action="http://student.cs.ucc.ie/cs4400/jabowen/php/file012.php">
<p>Your surname: <input type="text" name="surname"></p>
<p>Your address: <input type="text" name="address"></p>
<button type="submit">Please send me the brochure.</button>
</form>

<?php }
else { echo "<p>Thank you, $surname.</p>";
echo "<p> We will write to you at $address.</p>";} ?>
</body>
</html>

One request for this resource: no Query or Message Body

interzone.ucc.ie> telnet student.cs.ucc.ie 80
Trying 143.239.211.125...
Connected to student.cs.ucc.ie.
Escape character is '^]'.
GET http://student.cs.ucc.ie/cs4400/jabowen/php/file012.php HTTP/1.1
Host: student.cs.ucc.ie

Response to request with no query or message body

HTTP/1.1 200 OK
Date: Fri, 08 Feb 2002 11:21:40 GMT
Server: Apache/1.3.20 (Unix) PHP/4.0.6
X-Powered-By: PHP/4.0.6
Transfer-Encoding: chunked
Content-Type: text/html
160
<html>
<head><title>Application Handler</title></head>
<body>
<form method="POST"
action="http://student.cs.ucc.ie/cs4400/jabowen/php/file012.php">
<p>Your surname: <input type="text" name="surname"></p>
<p>Your address: <input type="text" name="address"></p>
<button type="submit">Please send me the brochure.</button>
</form>
</body>
</html>
0
Connection closed by foreign host.
interzone.ucc.ie>

Another request – containing a query

interzone.ucc.ie> telnet student.cs.ucc.ie 80
Trying 143.239.211.125...
Connected to student.cs.ucc.ie.
Escape character is '^]'.
GET http://student.cs.ucc.ie/cs4400/jabowen/php/file012.php?surname=doyle HTTP/1.1
Host: student.cs.ucc.ie

Response to request containing a query

HTTP/1.1 200 OK
Date: Fri, 08 Feb 2002 11:31:01 GMT
Server: Apache/1.3.20 (Unix) PHP/4.0.6
X-Powered-By: PHP/4.0.6
Transfer-Encoding: chunked
Content-Type: text/html
88
<html>
<head><title>Application Handler</title></head>
<body>
<p>Thank you, doyle.</p><p> We will write to you at .</p></body>
</html>
0
Connection closed by foreign host.
interzone.ucc.ie>

Finding out about your PHP environment

One of the many pre-defined PHP functions is phpinfo()
<html>
<body>
<h1>Your PHP Environment</h1>
<?php phpinfo(); ?>
</body>
</html>
In what follows, notice that mySQL support is enabled

A mysql database

mysql>
mysql> use cs4400db
mysql> select * from student;
+------------+------+------------+
| name | sex | birth |
+------------+------+------------+
| john brown | m | 1980-01-05 |
| bill brown | m | 1980-11-23 |
+------------+------+------------+
mysql>

A PHP program which displays this database

<html>
<head><title>The Student Database</title></head>
<body>
<h1>The Student Database</h1>
<?php
$db = mysql_connect("localhost", "root", “myRealPassword");
mysql_select_db("cs4400db",$db);
$result = mysql_query("SELECT * FROM student",$db); ?>
<table rules=all>
<thead><tr><th>Name</th><th>Sex</th><th>Position</th></tr></thead>
<tbody>
<?php
while ($myrow = mysql_fetch_row($result))
{ printf("<tr><td>%s</td><td>%s</td><td>%s</td></tr>\n",
$myrow[0], $myrow[1], $myrow[2]); } ?>
</tbody>
</table>
</body>
</html>

File upload form

<html>
<head>
<title>Upload a File</title>
</head>
<body>
<h1>Upload a File</h1>
<form enctype="multipart/form-data" method="post" action="uploadFile.php">
<p>File to Upload:
<input type="file" name=“file1" size="30"></p>
<p><button type="submit“> "Upload File“</button></p>
</form>
</body>
</html>

File upload script

<?php
if ( $file1_name != "“ )
{ copy("$file1", "/full/path/to/your/target/directory/$file1_name")
or die("Could not copy the file! Are directory permissions correct?"); }
else { die(“You did not specify an input file"); } ?>
<html>
<head>
<title>File Received</title>
<body>
<h1>File Received</h1>
<p>The following file has been received:
<?php echo “$file1_name"; ?>, containing <?php echo “$file1_size"; ?> bytes
and of MIME type <?php echo “$file1_type"; ?>
.</p>
</body>
</html>

Normally, when a browser sends HTML form data in the message body of a POST request, the value in the CONTENT-TYPE header is:

Normally, when a browser sends HTML form data in the message body of a POST request, the value in the CONTENT-TYPE header is:

application/x-www-form-urlencoded

The new attribute, enctype, in the FORM tag tells the browser that it should send the following value in the CONTENT-TYPE header:

multipart/form-data

Controlling Headers/Status lines with PHP

Sending Headers in PHP

You have seen that, if you use the CGI protocol, you can have complete control over the status line and headers that are sent in a HTTP response – to do so, you must use nph files
PHP does not seem to provide the same level of control

For example, it seems to prevent one sending status lines involving status codes that you have invented yourself – even though HTTP allows this

Nevertheless, PHP does enable you to have some control over status lines and response headers

Sending Headers in PHP (contd.)

PHP provides a built-in function, header(), which can be used to set HTTP header lines in a response message

The function name is mis-leading – it can also, within limits, be used to control the HTTP status line

Format:

header ( some-string [, some-boolean]);

Example calls:

header('WWW-Authenticate: Negotiate');
header('WWW-Authenticate: NTLM‘,false);

By default, a second header of the same type will replace an earlier one of the same type

If false is sent as the optional boolean parameter, the header will not replace an earlier one of the same type

Sending Headers in PHP (contd.)

PHP treats two type of call to header() in a special way
If you use header() to send a Location: header, PHP will auatomatgically change the code in the status line of the response to be 302 (REDIRECT)
The second special case is any header that starts with the string, "HTTP/" (case is not significant)

this will be used, within the limits of predefined standard values, to control the status line
header("HTTP/1.0 404 Not Found");

Introduced php handling of multiple selections in forms

Introduced php handling of multiple selections in forms

User-authentication in PHP

The header() function can be used to send headers requiring authentication

This will cause a browser to pop up a username/password/realm dialog window and
When the values have been provided, send a new request back to the same page containing the appropriate information

This time, some special PHP variables will be set:

$PHP_AUTH_USER,
$PHP_AUTH_PW and
$PHP_AUTH_TYPE

User-authentication in PHP (contd.)

The code below captures the user’s name and password
An improved version would check this against the contents of some file
<?php
if (!isset( $PHP_AUTH_USER ))
{header("HTTP/1.0 401 Unauthorized");
header("WWW-Authenticate: Basic realm=\“Bank Accounts\"");
echo “You must identify yourself.";}
else { echo "<p>Hello $PHP_AUTH_USER.</p>";
echo "<p>Your password is $PHP_AUTH_PW </p>"; }
?>

User-authentication in PHP (contd.)

The PHP_AUTH variables will not be set if external authentication is enabled for that particular page.

This is to prevent a script which reveals the password for a page that was protected through a traditional external mechanism, such as the .htpasswd mechanism

In this case, the $REMOTE_USER variable can be used to identify the externally-authenticated user.

Handling Cookies in PHP

PHP provides a function called setcookie() which can be used to send cookies to a browser

Since cookies are sent in HTTP headers, this function must be called before any ordinary content (such as HTML) is sent

Cookies sent from a broswer to a client will be converted into automatically created variables – just like those that are created to present data which come in GET and POST requests