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Design an Online Chat Room with PHP and MySQL

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Rory Canyon
May 04, 2007


Rory Canyon
Rory Canyon is the founder of ScriptMenu.com, a free web directory for PHP, ASP, ASP.NET, PERL, XML, Java, JavaScript, Flash, CFML, Python and other web programming resources. For more information, visit http://www.scriptmenu.com
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In this article, you will learn how to design and develop a simple online chat room with PHP and MySQL. This tutorial explains every steps of the development, including both database design and PHP programming. Basic computer skills and knowledge of HTML and PHP are required. Ok, let's begin now.

Step 1: Design Database Table. Create table "chat" in MySQL database to store basic chat information: chtime (chat time), nick (user nickname) and words (chat message, less than 150 characters)

mysql> CREATE TABLE chat

-> chtime DATATIME,

-> nick CHAR (10) NOT NULL,

-> words CHAR (150);

Step 2: Design Structure. This simple online chat room includes the following four sections: user login, message display, message input and a main frame integrating the display and input sections. Thus, it needs the following four files to work: login.php, main.php, display.php and speak.php.

Step 3: Write the code

1. login.php (just a HTML form)

<html>

<head>

<title>User Login</title>

</head>

<body>

Please input your nickname and enter


<form action="main.php" method="post" target="_self">

<input type="text" name="nick" cols="20">

<input type="submit" value="login">

</form>

</body>

</html>

2. main.php

<?

setcookie("nick",$nick) //use cookie to store user nickname

?>

<html>

<title>My Chat Room</title>

<frameset rows="80%,*">

<frame src="display.php" name="chatdisplay">

<frame src="speak.php" name="speak">

</frameset>

</html>

3. display.php

This file is used to get message records from database and display the results. To keep the size of database, old messages are deleted and only the newest 15 messages are displayed.

<html>

<head>

<title>Display Messages</title>

<meta http-equiv="refresh" content="5;url=display.php">

</head>

<body>

<?

//connect to mysql server, server name: main, database username: root

$link_ID=mysql_connect("main","root");

mysql_select_db("abc"); //abc is the database name

$str="select * from chat ORDER BY chtime;" ;

$result=mysql_query($str, $link_ID);

$rows=mysql_num_rows($result);

//get the latest 15 messages

@mysql_data_seek($resut,$rows-15);

//if the number of messages<15, get all of the messages

if ($rows<15) $l=$rows; else $l=15; for ($i=1;$i<=$l; $i++) {

list($chtime, $nick, $words)=mysql_fetch_row($result);

echo $chtime; echo " "; echo $nick; echo":" ; echo $words; echo "
";

} //delete the old messages(only keep the newest 20 only)

@mysql_data_seek($result,$rows-20);

list($limtime)=mysql_fetch_row($result);

$str="DELETE FROM chat WHERE chtime<'$limtime' ;" ;

$result=mysql_query($str,$link_ID);

mysql_close($link_ID);

?>

</body>

</html>

4. speak.php

<html>

<head>

<title>Speak</title>

</head>

<body>

<?

If ($words)

{ $link_ID=mysql_connect("main","root");

mysql_select_db("abc"); // abc is the database name

$time=date(y).date(m).date(d).date(h).date(i).(date(s); //get current time

$str="INSERT INTO chat(chtime,nick,words) values ('$time','$nick','$words');" ;

mysql_query($str,$link_ID); //save message record into database

mysql_close($link_ID); )

?>

//the following is the message input form

<form action="speak.php" method="post" target=" _self">

<input type="text" name="words" cols="20">

<input type="submit" value="Speak">

</form>

</body>

</html>

Now, you have finished the design and coding of a simple online chat system. Put all the files into your website root and see how it works, :)


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