PHP/MySQLPHP/MySQL

Introduction

GoalGoal• Not to teach everything about PHP, but provide the basic

knowledge • Explain code of examples• Provide some useful references

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

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.

• 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.

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

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).

• 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.)

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

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

What does PHP code look What does PHP code look like?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 …?>

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 */

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.

ConstantsA 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 namesdefine("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.

Operators• Arithmetic Operators: +, -, *,/ , %, ++, --• Assignment Operators: =, +=, -=, *=, /=, %=

• Comparison Operators: ==, !=, >, <, >=, <= • Logical Operators: &&, ||, !• String Operators: . and .= (for string concatenation)

Example Is the same asx+=y x=x+yx-=y x=x-yx*=y x=x*yx/=y x=x/yx%=y x=x%y

$a = "Hello ";$b = $a . "World!"; // now $b contains "Hello World!"

$a = "Hello ";$a .= "World!";

Variable usageVariable usage

<?php$foo = 25; // Numerical variable$bar = “Hello”; // String variable

$foo = ($foo * 7); // Multiplies foo by 7$bar = ($bar * 7); // Invalid expression ?>

Basic PHP syntaxA 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 echofor output

a semicolon (;) at the end of each statement

// for a single-line comment

/* and */ for a large comment block.

ScalarsAll 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 = <<<EODExample of stringspanning multiple linesusing “heredoc” syntax.EOD;echo $str;?> </p></body></html>

Four scalar types: boolean true or falseinteger, float, floating point numbersstring single quoted double quoted

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

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 Helloecho $foo,$bar; // Outputs 25Helloecho “5x5=”,$foo; // Outputs 5x5=25echo “5x5=$foo”; // Outputs 5x5=25echo ‘5x5=$foo’; // Outputs 5x5=$foo?>

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

?>

ConcatenationConcatenation• Use a period to join strings into one.

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

Hello PHP

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”

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;}

If ... Else...If ... Else...• If (condition)

{Statements;

}Else{

Statement;}

<?phpIf($user==“John”){

Print “Hello John.”;}Else{

Print “You are not John.”;}?>

No THEN in PHP

Conditionals: if elseCan 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;elsecode 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.

While LoopsWhile 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.

Looping: for and foreachCan loop depending on a "counter"

<?phpfor ($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";}?>

Conditionals: switchCan select one of many sets of lines to execute

<html><head></head><body><!–- switch-cond.php --><?php$x = rand(1,5); // random integerecho “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;}

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

ArraysAn 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"]; // barecho $arr[12]; // 1?>

key = either an integer or a string.

value = any PHP type.

<?phparray(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 elementunset($arr[5]); // removes the elementunset($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)

Month, Day & Date Format SymbolsMonth, 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

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)

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

?>

User Defined FunctionsCan define a function using syntax such as the following:

<?phpfunction foo($arg_1, $arg_2, /* ..., */ $arg_n){ echo "Example function.\n"; return $retval;}?>

Can also define conditional functions, functions within functions, and recursive functions.

<?phpfunction square($num){ return $num * $num;}echo square(4);?>

<?phpfunction small_numbers(){ return array (0, 1, 2);}list ($zero, $one, $two) = small_numbers();echo $zero, $one, $two;?>

Can return a value of any type

<?phpfunction takes_array($input){ echo "$input[0] + $input[1] = ", $input[0]+$input[1];} takes_array(array(1,2));?>

Variable ScopeThe 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.

<?phpfunction Test(){ static $a = 0; echo $a; $a++;}Test1(); Test1();Test1();?>

static

does not lose its value.

Including FilesThe 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 appleecho "A $color $fruit"; // A green

?>

Include FilesInclude FilesInclude “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>Copyright © 2001-2012 gsu</i></font><br><i>ALL RIGHTS RESERVED</i></font><br><i>URL: http://www.gsu.edu.edu</i></font><br>

PHP - FormsPHP - Forms•Access to the HTTP POST and GET data is simple in Access to the HTTP POST and GET data is simple in PHPPHP•The global variables $_POST[] and $_GET[] contain the The 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>

WHY PHP – Sessions ?WHY PHP – Sessions ?Whenever you want to create a Whenever you want to create a website that allows you to store that allows you to store and display information about a user, determine which user groups and display information about a user, determine which user groups a person belongs to, utilize permissions on your a person belongs to, utilize permissions on your website or you just or you just want to do something cool on your site, want to do something cool on your site, PHP's Sessions are vital to are vital to each of these features. of these features.

Cookies are about 30% unreliable right now and it's getting worse Cookies are about 30% unreliable right now and it's getting worse every day. More and more web browsers are starting to come with every day. More and more web browsers are starting to come with security and privacy settings and people browsing the net these security and privacy settings and people browsing the net these days are starting to frown upon Cookies because they store days are starting to frown upon Cookies because they store information on their local computer that they do not want stored information on their local computer that they do not want stored there.there.

PHP has a great set of functions that can achieve the same results PHP has a great set of functions that can achieve the same results of Cookies and more without storing information on the user's of Cookies and more without storing information on the user's computer. PHP Sessions store the information on the web server in computer. PHP Sessions store the information on the web server in a location that you chose in special files. These files are connected 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 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 "Session ID". This is nearly 99% flawless in operation and it is virtually invisible to the user.virtually invisible to the user.

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 the Every page that uses session data must be proceeded by the session_start()session_start() function function•Session variables are then set and retrieved by accessing the Session variables are then set and retrieved by accessing the global global $_SESSION[]$_SESSION[]

•Save it as Save 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>

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

Destroy PHP - SessionsDestroy PHP - SessionsDestroying 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 - 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>"; } ?>

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.

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.

• 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

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.

Example – show data in the Example – 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

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");

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>

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());

showtable.php (cont.)showtable.php (cont.)$fields_num = mysql_num_fields($result);echo "<h1>Table: {$table}</h1>";echo "<table border='1'><tr>";// printing table headersfor($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 $cell variableforeach($row as $cell)

echo "<td>$cell</td>";echo "</tr>\n";

}mysql_free_result($result);mysql_close($conn);?></body></html>

Functions CoveredFunctions Covered• mysql_connect() mysql_select_db()• include()• mysql_query() mysql_num_rows()• mysql_fetch_array() mysql_close()

PHP InformationThe 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 informationphpinfo();?><?php// Show only the general informationphpinfo(INFO_GENERAL);?></body></html>

INFO_GENERAL The configuration line, php.ini location, build date, Web Server, System and more

INFO_CREDITS PHP 4 creditsINFO_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 VariablesThe $_SERVER array variable is a reserved variable that contains all server information.

<html><head></head><body>

<?phpecho "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 OpenThe 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).

<?phpif( !($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 datafwrite(), 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 HandlingAny 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 Workingssetcookie(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 thispage! The cookie will be active when the client has sent thecookie 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><?phpif ( isset($_COOKIE["uname"]) )echo "Welcome " . $_COOKIE["uname"] . "!<br />";elseecho "You are not logged in!<br />";?></body></html>

use the cookie name as a variable

isset()finds out if a cookie is set

$_COOKIEcontains all COOKIE data.

Getting Time and Datedate() and time () formats a time or a date.

<?php//Prints something like: Mondayecho date("l");

//Like: Monday 15th of January 2003 05:51:38 AMecho date("l jS \of F Y h:i:s A");

//Like: Monday the 15thecho 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; 60secsecho '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 DataA 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

Check and Confirm Functionsfunction 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>

<?phpecho "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>

Recommended Texts for Learning Recommended Texts for Learning PHPPHP• 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)

PHP ReferencesPHP Referenceshttp://www.php.net <-- php home pagehttp://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.phphttp://www.codeproject.com/asp/CDIChatSubmit.asphttp://www.php.net/downloads <-- php download pagehttp://www.php.net/manual/en/install.windows.php <-- php installation manualhttp://php.resourceindex.com/ <-- PHP resources like sample programs, text book references, etc.http://www.daniweb.com/techtalkforums/forum17.html php forums