2. GoalGoal
Not to teach everything about PHP, but provide the
basic knowledge
Explain code of examples
Provide some useful references
For educational purpose only
3. PHP Basics:
Introduction to PHP
• a PHP file, PHP workings, running PHP.
Basic PHP syntax
• variables, operators, if...else...and switch, while, do while,
and for.
Some useful PHP functions
How to work with
• HTML forms, cookies, files, time and date.
How to create a basic checker for user-entered data
For educational purpose only
4. Server-Side Dynamic Web Programming
• CGI is one of the most common approaches to server-side programming
Universal support: (almost) Every server supports CGI programming. A great deal
of ready-to-use CGI code. Most APIs (Application Programming Interfaces) also
allow CGI programming.
Choice of languages: CGI is extremely general, so that programs may be written in
nearly any language. Perl is by far the most popular, with the result that many
people think that CGI means Perl. But C, C++, Ruby, and Python are also used for
CGI programming.
Drawbacks: A separate process is run every time the script is requested. A
distinction is made between HTML pages and code.
For educational purpose only
5. • Other server-side alternatives try to avoid the drawbacks
Server-Side Includes (SSI): Code is embedded in HTML pages, and evaluated on
the server while the pages are being served. Add dynamically generated content to
an existing HTML page, without having to serve the entire page via a CGI program.
Active Server Pages (ASP, Microsoft) : The ASP engine is integrated into the web
server so it does not require an additional process. It allows programmers to mix
code within HTML pages instead of writing separate programs. (Drawback(?) Must
be run on a server using Microsoft server software.)
Java Servlets (Sun): As CGI scripts, they are code that creates documents. These
must be compiled as classes which are dynamically loaded by the web server
when they are run.
Java Server Pages (JSP): Like ASP, another technology that allows developers to
embed Java in web pages.
For educational purpose only
6. PHP• developed in 1995 by Rasmus Lerdorf (member of the Apache Group)
originally designed as a tool for tracking visitors at Lerdorf's Web site
within 2 years, widely used in conjunction with the Apache server
developed into full-featured, scripting language for server-side programming
free, open-source
server plug-ins exist for various servers
now fully integrated to work with mySQL databases
• PHP is similar to JavaScript, only it’s a server-side language
PHP code is embedded in HTML using tags
when a page request arrives, the server recognizes PHP content via the file extension
(.php or .phtml)
the server executes the PHP code, substitutes output into the HTML page
the resulting page is then downloaded to the client
user never sees the PHP code, only the output in the page
For educational purpose only
7. What do You Need?
Our server supports PHP
You don't need to do anything special! *
You don't need to compile anything or install any extra tools!
Create some .php files in your web directory - and the server will
parse them for you.
* Slightly different rules apply when dealing with an SQL
database (as will be explained when we get to that point).
For educational purpose only
8. Most servers support PHP
Download PHP for free here:
http://www.php.net/downloads.php
Download MySQL for free here:
http://www.mysql.com/downloads/index.html
Download Apache for free here:
http://httpd.apache.org/download.cgi
(Note: All of this is already present on the CS servers, so you
need not do any installation yourself to utilize PHP on our
machines.)
For educational purpose only
9. What is PHP?What is PHP?
PHP == ‘Hypertext Preprocessor’
Open-source, server-side scripting language
Used to generate dynamic web-pages
PHP scripts reside between reserved PHP tags
This allows the programmer to embed PHP scripts within
HTML pages
• The acronym PHP means (in a slightly recursive definition)
PHP: Hypertext Preprocessor
For educational purpose only
10. What is PHP (cont’d)What is PHP (cont’d)Interpreted language, scripts are parsed at run-time
rather than compiled beforehand
Executed on the server-side
Source-code not visible by client
‘View Source’ in browsers does not display the PHP code
Various built-in functions allow for fast development
Compatible with many popular databases
For educational purpose only
11. What does PHP code look like?What does PHP code look like?
Structurally similar to C/C++
Supports procedural and object-oriented paradigm (to
some degree)
All PHP statements end with a semi-colon
Each PHP script must be enclosed in the reserved PHP
tag
<?php
…
?>
For educational purpose only
12. Comments in PHPComments 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 */
For educational purpose only
13. Variables in PHPVariables 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.
For educational purpose only
14. 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.
For educational purpose only
15. Operators Arithmetic Operators: +, -, *,/ , %, ++, --
Assignment Operators: =, +=, -=, *=, /=, %=
Comparison Operators: ==, !=, >, <, >=, <=
Logical Operators: &&, ||, !
String Operators: . and .= (for string concatenation)
Example Is the same as
x+=y x=x+y
x-=y x=x-y
x*=y x=x*y
x/=y x=x/y
x%=y x=x%y
$a = "Hello ";
$b = $a . "World!"; // now $b contains "Hello World!"
$a = "Hello ";
$a .= "World!";
For educational purpose only
17. Basic PHP syntax
A PHP scripting block always starts with <?php and ends with ?>. A PHP scripting block
can be placed (almost) anywhere in an HTML document.
<html>
<!-- hello.php -->
<head><title>Hello World</title></head>
<body>
<p>This is going to be ignored by the PHP interpreter.</p>
<?php echo ‘<p>While this is going to be parsed.</p>‘; ?>
<p>This will also be ignored by the PHP preprocessor.</p>
<?php print(‘<p>Hello and welcome to <i>my</i> page!</p>');
?>
<?php
//This is a comment
/*
This is
a comment
block
*/
?>
</body>
</html>
The server executes the print and echo statements, substitutes output.
print and echo
for output
a semicolon (;)
at the end of each
statement
// for a single-line comment
/* and */ for a large
comment block.
For educational purpose only
18. 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>
<!-- scalars.php -->
<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 $str;
?>
</p>
</body>
</html>
Four scalar types:
boolean
true or false
integer,
float,
floating point numbers
string
single quoted
double quoted
For educational purpose only
19. EchoEcho
• The PHP command ‘echo’ is used to output the
parameters passed to it
• The typical usage for this is to send data to the client’s
web-browser
• Syntax
• void echo (string arg1 [, string argn...])
• In practice, arguments are not passed in parentheses since
echo is a language construct rather than an actual
function
For educational purpose only
20. Echo exampleEcho example
Notice how echo ‘5x5=$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
?>
For educational purpose only
21. Arithmetic OperationsArithmetic 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
?>
For educational purpose only
22. ConcatenationConcatenation
Use a period to join strings into one.
<?php
$string1=“Hello”;
$string2=“PHP”;
$string3=$string1 . “ ” .
$string2;
Print $string3;
?>
Hello PHP
For educational purpose only
23. Escaping the CharacterEscaping 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 $heading;
?>
“Computer Science”
For educational purpose only
24. PHP Control StructuresPHP Control Structures
Control Structures: Are the structures within a language that allow
us to control the flow of execution through a program or script.
Grouped into conditional (branching) structures (e.g. if/else) and
repetition structures (e.g. while loops).
Example if/else if/else statement:
if ($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 ‘.$foo;
}
For educational purpose only
25. If ... Else...If ... Else...
If (condition)
{
Statements;
}
Else
{
Statement;
}
<?php
If($user==“John”)
{
Print “Hello John.”;
}
Else
{
Print “You are not John.”;
}
?>
No THEN in PHP
For educational purpose only
26. Conditionals: if else
Can execute a set of code depending on a condition
<html><head></head>
<!-- if-cond.php -->
<body>
<?php
$d=date("D");
echo $d, “<br/>”;
if ($d=="Fri")
echo "Have a nice weekend! <br/>";
else
echo "Have a nice day! <br/>";
$x=10;
if ($x==10)
{
echo "Hello<br />";
echo "Good morning<br />";
}
?>
</body>
</html>
if (condition)
code to be executed if condition
is true;
else
code to be executed if condition
is false;
date() is a built-in PHP function that
can be called with many different
parameters to return the date
(and/or local time) in various formats
In this case we get a three letter
string for the day of the week.
For educational purpose only
28. Looping: for and foreach
Can loop depending on a "counter"
<?php
for ($i=1; $i<=5; $i++)
{
echo "Hello World!<br />";
}
?>
loops through a block of code a
specified number of times
<?php
$a_array = array(1, 2, 3, 4);
foreach ($a_array as $value)
{
$value = $value * 2;
echo “$value <br/> n”;
}
?>
loops through a block of code for each
element in an array
<?php
$a_array=array("a","b","c");
foreach ($a_array as $key => $value)
{
echo $key." = ".$value."n";
}
?>
For educational purpose only
29. Conditionals: switch
Can select one of many sets of lines to execute
<html><head></head>
<body>
<!–- switch-cond.php -->
<?php
$x = rand(1,5); // random integer
echo “x = $x <br/><br/>”;
switch ($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";
break;
}
?>
</body>
</html>
switch (expression)
{
case label1:
code to be executed if
expression = label1;
break;
case label2:
code to be executed if
expression = label2;
break;
default:
code to be executed
if expression is different
from both label1 and label2;
break;
}
For educational purpose only
30. Date DisplayDate Display
$datedisplay=date(“yyyy/m/d”);
Print $datedisplay;
# If the date is June 25th, 2012
# It would display as 2012/25/6
2012/25/6
$datedisplay=date(“l, F m, Y”);
Print $datedisplay;
# If the date is June 25th
,2012
# Monday, June 25th
,2012
Monday, June 25, 2012
For educational purpose only
31. Arrays
An array in PHP is actually an ordered map. A map is a type that maps values to keys.
array() = creates arrays<?php
$arr = array("foo" => "bar", 12 => true);
echo $arr["foo"]; // bar
echo $arr[12]; // 1
?>
key = either an integer or a string.
value = any PHP type.
<?php
array(5 => 43, 32, 56, "b" => 12);
array(5 => 43, 6 => 32, 7 => 56, "b" => 12);
?>
if no key given (as in example), the PHP
interpreter uses (maximum of the integer
indices + 1).
if an existing key, its value will be
overwritten.
<?php
$arr = array(5 => 1, 12 => 2);
foreach ($arr as $key => $value) { echo $key, ‘=>’,
$value); }
$arr[] = 56; // the same as $arr[13] = 56;
$arr["x"] = 42; // adds a new element
unset($arr[5]); // removes the element
unset($arr); // deletes the whole array
$a = array(1 => 'one', 2 => 'two', 3 => 'three');
unset($a[2]);
$b = array_values($a);
can set values in an array
unset() removes a
key/value pair
*Find more on arrays
array_values() makes
reindexing effect (indexing numerically)
For educational purpose only
32. Month, Day & Date FormatMonth, Day & Date Format
SymbolsSymbols
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
For educational purpose only
33. FunctionsFunctions
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, …, $arg_n)
For educational purpose only
34. Functions exampleFunctions example
<?php
// This is a function
function foo($arg_1, $arg_2)
{
$arg_2 = $arg_1 * $arg_2;
return $arg_2;
}
$result_1 = foo(12, 3); // Store the function
echo $result_1; // Outputs 36
echo foo(12, 3); // Outputs 36
?>
For educational purpose only
35. User Defined Functions
Can define a function using syntax such as the following:
<?php
function foo($arg_1, $arg_2, /* ..., */ $arg_n)
{
echo "Example function.n";
return $retval;
}
?>
Can also define conditional
functions, functions within functions,
and recursive functions.
<?php
function square($num)
{
return $num * $num;
}
echo square(4);
?>
<?php
function small_numbers()
{
return array (0, 1, 2);
}
list ($zero, $one, $two) = small_numbers();
echo $zero, $one, $two;
?>
Can return a value of any type
<?php
function takes_array($input)
{
echo "$input[0] + $input[1] = ", $input[0]+$input[1];
}
takes_array(array(1,2));
?>
For educational purpose only
36. Variable Scope
The scope of a variable is the context within which it is defined.
<?php
$a = 1; /* limited variable scope */
function Test()
{
echo $a;
/* reference to local scope variable */
}
Test();
?>
The scope is local within functions,
and hence the value of $a is
undefined in the “echo” statement.
<?php
$a = 1;
$b = 2;
function Sum()
{
global $a, $b;
$b = $a + $b;
}
Sum();
echo $b;
?>
global
refers to its
global
version.
<?php
function Test()
{
static $a = 0;
echo $a;
$a++;
}
Test1();
Test1();
Test1();
?>
static
does not lose
its value.
For educational purpose only
37. Including Files
The include() statement includes and evaluates the specified file.
vars.php
<?php
$color = 'green';
$fruit = 'apple';
?>
test.php
<?php
echo "A $color $fruit"; // A
include 'vars.php';
echo "A $color $fruit"; // A green apple
?>
*The scope of variables in “included” files depends on where the “include” file is added!
You can use the include_once, require, and require_once statements in similar ways.
<?php
function foo()
{
global $color;
include ('vars.php‘);
echo "A $color $fruit";
}
/* vars.php is in the scope of foo() so *
* $fruit is NOT available outside of this *
* scope. $color is because we declared it *
* as global. */
foo(); // A green apple
echo "A $color $fruit"; // A green
?>
For educational purpose only
39. PHP - FormsPHP - Forms
•Access to the HTTP POST and GET data is simple in PHPAccess to the HTTP POST and GET data is simple in PHP
•The global variables $_POST[] and $_GET[] contain theThe global variables $_POST[] and $_GET[] contain the
request datarequest data
<?php
if ($_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>
For educational purpose only
40. WHY PHP – Sessions ?WHY PHP – Sessions ?Whenever you want to create aWhenever you want to create a websitewebsite that allows you to store and displaythat allows you to store and display
information about a user, determine which user groups a person belongs to,information about a user, determine which user groups a person belongs to,
utilize permissions on yourutilize permissions on your websitewebsite or you just want to do something cool onor you just want to do something cool on
your site,your site, PHP's SessionsPHP's Sessions are vital toare vital to eacheach of these features.of these features.
Cookies are about 30% unreliable right now and it's getting worse every day.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 privacyMore and more web browsers are starting to come with security and privacy
settings and people browsing the net these days are starting to frown uponsettings and people browsing the net these days are starting to frown upon
Cookies because they store information on their local computer that they doCookies because they store information on their local computer that they do
not want stored there.not want stored there.
PHP has a great set of functions that can achieve the same results ofPHP has a great set of functions that can achieve the same results of
Cookies and more without storing information on the user's computer. PHPCookies and more without storing information on the user's computer. PHP
Sessions store the information on the web server in a location that you choseSessions 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 thein 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 inserver and a special ID called a "Session ID". This is nearly 99% flawless in
operation and it is virtually invisible to the user.operation and it is virtually invisible to the user.
For educational purpose only
41. PHP - SessionsPHP - Sessions
•Sessions store their identifier in a cookie in the client’s browserSessions store their identifier in a cookie in the client’s browser
•Every page that uses session data must be proceeded by theEvery page that uses session data must be proceeded by the
session_start()session_start() functionfunction
•Session variables are then set and retrieved by accessing the globalSession variables are then set and retrieved by accessing the global
$_SESSION[]$_SESSION[]
•Save it asSave it as session.phpsession.php
<?php<?php
session_start();session_start();
if (!$_SESSION["count"])if (!$_SESSION["count"])
$_SESSION["count"] = 0;$_SESSION["count"] = 0;
if ($_GET["count"] == "yes")if ($_GET["count"] == "yes")
$_SESSION["count"] = $_SESSION["count"] + 1;$_SESSION["count"] = $_SESSION["count"] + 1;
echo "<h1>".$_SESSION["count"]."</h1>";echo "<h1>".$_SESSION["count"]."</h1>";
?>?>
<a href="session.php?count=yes">Click here to count</a><a href="session.php?count=yes">Click here to count</a>
For educational purpose only
42. Avoid Error PHP - SessionsAvoid 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
For educational purpose only
43. Destroy PHP - SessionsDestroy 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():
For educational purpose only
44. Destroy PHP - SessionsDestroy 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>";
}
?>
For educational purpose only
45. PHP OverviewPHP Overview
Easy learning
Syntax Perl- and C-like syntax. Relatively easy to learn.
Large function library
Embedded directly into HTML
Interpreted, no need to compile
Open Source server-side scripting language designed specifically
for the web.
For educational purpose only
46. PHP Overview (cont.)PHP Overview (cont.)
Conceived in 1994, now used on +10 million web sites.
Outputs not only HTML but can output XML, images (JPG
& PNG), PDF files and even Flash movies all generated on
the fly. Can write these files to the file system.
Supports a wide-range of databases (20+ODBC).
PHP also has support for talking to other services using
protocols such as LDAP, IMAP, SNMP, NNTP, POP3,
HTTP.
For educational purpose only
47. • Save as sample.php:
<!– sample.php -->
<html><body>
<strong>Hello World!</strong><br />
<?php
echo “<h2>Hello, World</h2>”; ?>
<?php
$myvar = "Hello World";
echo $myvar;
?>
</body></html>
First PHP scriptFirst PHP script
For educational purpose only
48. Example of parameter reading
Consider:
contents of php_exec/form.php...
<html><body>
<h1>Hi there</h1>
<? if (!isset($_POST['foo'])): ?>
<h1>'foo' is not set</h1>
<? elseif (!is_array($_POST['foo'])) : ?>
<h1>'foo' has one value <?=
$_POST['foo'] ?> </h1>
<? else: ?>
<h1>'foo' has multiple values <?= join(',',
$_POST['foo']) ?> </h1>
<? endif ?>
</body></html>
...end of php_exec/form.php
Call with form:
contents of php_exec/form01.txt... <form
action='php_exec/form.php'
method='post'> <ul> <li> <input
type='checkbox' name='foo[]'
value='raisins'> raisins. <li> <input
type='checkbox' name='foo[]'
value='cranberries'> cranberries. <li>
<input type='checkbox' name='foo[]'
value='plums'> plums. </ul> <input
type='submit'> </form> ...end of
php_exec/form01.txt
Here is what it looks like:
raisins.
cranberries.
plums.
For educational purpose only
49. Example – show data in theExample – show data in the
tablestables
Function: list all tables in your database. Users can select one
of tables, and show all contents in this table.
second.php
showtable.php
For educational purpose only
50. second.phpsecond.php
<html><head><title>MySQL Table Viewer</title></head><body>
<?php
// change the value of $dbuser and $dbpass to your username and password
$dbhost = ‘ codd.cs…….. ';
$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($dbname))
die("Can't select database");
For educational purpose only
51. second.php (cont.)second.php (cont.)$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>
For educational purpose only
52. showtable.phpshowtable.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());
For educational purpose only
53. showtable.php (cont.)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>
For educational purpose only
55. 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)
For educational purpose only
56. 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
For educational purpose only
57. 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).
For educational purpose only
58. 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");
$stringData = "New Stuff 1n";
fwrite($fh, $stringData);
$stringData = "New Stuff 2n";
fwrite($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/>”;
}
?>
For educational purpose only
59. 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.
For educational purpose only
60. 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.
For educational purpose only
61. 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 the 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', $nextWeek) ."n";
?>
time() returns
current Unix
timestamp
For educational purpose only
62. Required Fields in User-Entered Data
A multipurpose script which asks users for some basic contact information and then checks to
see that the required fields have been entered.
<html>
<!-- form_checker.php COMP519 -->
<head>
<title>PHP Form example</title>
</head>
<body>
<?php
/*declare some functions*/
function print_form($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 $os?>“ /> <br/><br/>
<input type="submit" name="submit" value="Submit“ /> <input type=“reset“ />
</form>
<?php
} //** end of “print_from” function
Print Function
For educational purpose only
63. Check and Confirm Functions
function check_form($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: $os";
} //** end of “confirm_form” function
For educational purpose only
64. Main Program
/*Main Program*/
if (!$_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>
For educational purpose only
65. Recommended Texts forRecommended Texts for
Learning PHPLearning PHP
Larry Ullman’s books from the Visual Quickpro series
PHP & MySQL for Dummies
Beginning PHP 5 and MySQL: From Novice to Professional by
W. Jason Gilmore
(This is more advanced and dense than the others, but great to read
once you’ve finished the easier books. One of the best
definition/description of object oriented programming I’ve read)
For educational purpose only
66. PHP ReferencesPHP References
http://www.php.net <-- php home page
http://www.phpbuilder.com/
http://www.devshed.com/
http://www.phpmyadmin.net/
http://www.hotscripts.com/PHP/
http://geocities.com/stuprojects/ChatroomDescription.htm
http://www.academic.marist.edu/~kbhkj/chatroom/chatroom.htm
http://www.aus-etrade.com/Scripts/php.php
http://www.codeproject.com/asp/CDIChatSubmit.asp
http://www.php.net/downloads <-- php download page
http://www.php.net/manual/en/install.windows.php <-- php
installation manual
http://php.resourceindex.com/ <-- PHP resources like sample
programs, text book references, etc.
http://www.daniweb.com/techtalkforums/forum17.html php
forums
For educational purpose only