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> Php Simple Login Tutorial, Learn how to make a simple login!
HmmZ
post Mar 3 2005, 08:56 AM
Post #1


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I have been quite busy lately, trying to design and code my site (far from done XD). And after having learned how to make a simple login, I will try to write my own tutorial, for you smile.gif

the tutorial

Step 1:
The first step in designing a member system is to plan out exactly what you need. A common impulse among programmers is to jump right in and start coding. I'll be honest and admit that I'm guilty of this more so than anyone. However, since I'm in control of this conversation (yes!), you'll have it all planned out by reading through this before you even see any code.

What will you need to start?
First of all, you need a server that supports a CGI or Server-side language. For this tutorial, it's PHP. I won't be directing any attention to any other language at this time, so although the concepts will be similar, the code will be entirely different than something you might use in Perl or ASP. As a side note, it is possible to perform a member system simply using JavaScript, but it would not be remotely secure because JavaScript is client-side (thus able to be viewed by anyone), and even if you had a one-way encryption script it would not be feasible because of the pain of hard-coding usernames and encrypted passwords into the HTML document.

Second, at least for our purposes, you need a database. Preferably MySQL. PHP and MySQL go hand-in-hand, so a lot of servers tend to match the two up. Thus, since we're talking PHP, we may as well talk MySQL.

Third, you will need 4 blank PHP web pages entitled: register.php, login.php, members.php, and logout.php. After you have these pages created and open, we're ready to start.

Step 2: Database

If we want to design a members system, we'll need a database. So all we need to do in this step is to create the table we will use to manage the user's login information. Note that the schema we use here is quite simple, and is only simplified to help you see how it works.

CODE
Name the table "dbUsers." It will need 4 fields:

[I]Name             Type                 Addition[/I]
id                  int(10)              Primary Key, AUTO_INCREMENT
username            varchar(16)          Unique
password            char(16)          
email               varchar(25)


Once you've made the database table, you're ready to design and code the registration page.

Create a File to Connect to your Database

Create a new file and name it dbConfig.php. This file will contain the PHP code that will connect to the MySQL database, and select the correct database. Make sure you have added users to your MySQL database with read/write or admin access, then place this type of code into the dbConfig.php file:

CODE
<?
// Replace the variable values below
// with your specific database information.
$host = "localhost";
$user = "UserName";
$pass = "Password";
$db   = "dbName";

// This part sets up the connection to the
// database (so you don't need to reopen the connection
// again on the same page).
$ms = mysql_pconnect($host, $user, $pass);
if ( !$ms )
{
echo "Error connecting to database.\n";
}

// Then you need to make sure the database you want
// is selected.
mysql_select_db($db);
?>


Step 3: Register

register.php

On your registration page, you need to create a web form that will allow the user to plugin a username, password, and their e-mail address. Then, also on your page, add code that runs only when information has been passed via the form. Finally, display a "Registration Successful!" message to the user.

CODE
<?php

// dbConfig.php is a file that contains your
// database connection information. This
// tutorial assumes a connection is made from
// this existing file.
include ("dbConfig.php");


//Input vaildation and the dbase code
if ( $_GET["op"] == "reg" )
 {
 $bInputFlag = false;
 foreach ( $_POST as $field )
  {
  if ($field == "")
   {
   $bInputFlag = false;
   }
  else
   {
   $bInputFlag = true;
   }
  }
 // If we had problems with the input, exit with error
 if ($bInputFlag == false)
  {
  die( "Problem with your registration info. "
   ."Please go back and try again.");
  }

 // Fields are clear, add user to database
 //  Setup query
 $q = "INSERT INTO `dbUsers` (`username`,`password`,`email`) "
  ."VALUES ('".$_POST["username"]."', "
  ."PASSWORD('".$_POST["password"]."'), "
  ."'".$_POST["email"]."')";
 //  Run query
 $r = mysql_query($q);
 
 // Make sure query inserted user successfully
 if ( !mysql_insert_id() )
  {
  die("Error: User not added to database.");
  }
 else
  {
  // Redirect to thank you page.
  Header("Location: register.php?op=thanks");
  }
 } // end if


//The thank you page
elseif ( $_GET["op"] == "thanks" )
 {
 echo "<h2>Thanks for registering!</h2>";
 }
 
//The web form for input ability
else
 {
 echo "<form action=\"?op=reg\" method=\"POST\">\n";
 echo "Username: <input name=\"username\" MAXLENGTH=\"16\"><br />\n";
 echo "Password: <input type=\"password\" name=\"password\" MAXLENGTH=\"16\"><br />\n";
 echo "Email Address: <input name=\"email\" MAXLENGTH=\"25\"><br />\n";
 echo "<input type=\"submit\">\n";
 echo "</form>\n";
 }
// EOF
?>


Step 4: Login

login.php

Now in PHP, first we need to check the username and password against the information stored in the database. Since when the user registered, we encrypted their password using the MySQL PASSWORD() function, we re-encrypt the password the user supplied in the login form and cross-check this with the existing value in the dBase. If login information is O.K., then we need to use sessions to store the user's ID so they can access member-only content.

CODE
<?php
session_start();
// dBase file
include "dbConfig.php";

if ($_GET["op"] == "login")
 {
 if (!$_POST["username"] || !$_POST["password"])
  {
  die("You need to provide a username and password.");
  }
 
 // Create query
 $q = "SELECT * FROM `dbUsers` "
  ."WHERE `username`='".$_POST["username"]."' "
  ."AND `password`=PASSWORD('".$_POST["password"]."') "
  ."LIMIT 1";
 // Run query
 $r = mysql_query($q);

 if ( $obj = @mysql_fetch_object($r) )
  {
  // Login good, create session variables
  $_SESSION["valid_id"] = $obj->id;
  $_SESSION["valid_user"] = $_POST["username"];
  $_SESSION["valid_time"] = time();

  // Redirect to member page
  Header("Location: members.php");
  }
 else
  {
  // Login not successful
  die("Sorry, could not log you in. Wrong login information.");
  }
 }
else
 {
//If all went right the Web form appears and users can log in
 echo "<form action=\"?op=login\" method=\"POST\">";
 echo "Username: <input name=\"username\" size=\"15\"><br />";
 echo "Password: <input type=\"password\" name=\"password\" size=\"8\"><br />";
 echo "<input type=\"submit\" value=\"Login\">";
 echo "</form>";
 }
?>


Step 5: Members Area

members.php

Now that the user has logged in successfully, and has his id, username, and login stored in session variables, we can start working with member-only content. A major thing to remember is that any page you want to carry session data over to you must declare a session_start(); at the top of your code.

CODE
<?php
session_start();

if (!$_SESSION["valid_user"])
{
// User not logged in, redirect to login page
Header("Location: login.php");
}

// Member only content
// ...
// ...
// ...

// Display Member information
echo "<p>User ID: " . $_SESSION["valid_id"];
echo "<p>Username: " . $_SESSION["valid_user"];
echo "<p>Logged in: " . date("m/d/Y", $_SESSION["valid_time"]);

// Display logout link
echo "<p><a href=\"logout.php\">Click here to logout!</a></p>";
?>


Step 6: Logout

logout.php

Ah, although it would be nice if our user's never left our web sites, we should give them to opportunity to log out and destroy the session variables if they so choose. It's quite easy to do, and you can just copy and paste this one.

CODE
<?php
session_start();
session_unset();

session_destroy();
// Logged out, return home.
Header("Location: index.php");
?>


That's about it!. I used many simple examples hoping that you will learn how the internal systems work so you can expand on them and design a system that's just right for your needs. Have fun! ph34r.gif

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Dragonfly
post Mar 3 2005, 04:40 PM
Post #2


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Thanks, I have both php and MySQL installed in my laptop. I think that steps you've mentioned here are easy to follow and easy to understand. I'm beginner in PHP and have been following closely any topic related to php.

Hope I can implement the above code and make use of it in the future. I should start testing it in my local computer. Thanks.

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HmmZ
post Mar 3 2005, 08:57 PM
Post #3


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Thanks for the positive feedback, I haven't implemented, nor tested the code myself (just checked to see if it actually showed up), so if any problems persist, tell me about it, so I can adjust the code hoping it could fix it, if there is a flaw and you know the solution, replying with both the flaw and the solution is always welcome of course smile.gif

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bjrn
post Mar 3 2005, 10:33 PM
Post #4


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If someone is planning on implementing something like this here on their Trap17 account, I suggest you use Pear. When you have people logging into things on your site, you want to make sure that there is no possibility of sql injection. Pear's DB prepared statement function prevents SQL injection attacks. It's very handy.

Something like this could work
CODE
require_once("PEAR.php");
require_once("DB.php");
PEAR::setErrorHandling(PEAR_ERROR_DIE, "Aaaaargh! Error: %s");
$conn = DB::connect("mysql://dbuser:dbpassword@localhost/dbname");
$preparedstatement = $conn->prepare('INSERT INTO dbUsers (username, password, email) VALUES (?, ?, ?)');
$data = array($_POST['username'], $_POST['password'], $_POST['email']);
$conn->execute($preparedstatement, $data);

Please note that I haven't tested this code, it should work, but there might be some stupid typo somewhere. smile.gif

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karlo
post Mar 4 2005, 04:44 AM
Post #5


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From: Philippines
Member No.: 2,049
QUOTE(bjrn @ Mar 4 2005, 06:33 AM)
If someone is planning on implementing something like this here on their Trap17 account, I suggest you use Pear. When you have people logging into things on your site, you want to make sure that there is no possibility of sql injection. Pear's DB prepared statement function prevents SQL injection attacks. It's very handy.

Something like this could work
CODE
require_once("PEAR.php");
require_once("DB.php");
PEAR::setErrorHandling(PEAR_ERROR_DIE, "Aaaaargh! Error: %s");
$conn = DB::connect("mysql://dbuser:dbpassword@localhost/dbname");
$preparedstatement = $conn->prepare('INSERT INTO dbUsers (username, password, email) VALUES (?, ?, ?)');
$data = array($_POST['username'], $_POST['password'], $_POST['email']);
$conn->execute($preparedstatement, $data);

Please note that I haven't tested this code, it should work, but there might be some stupid typo somewhere. smile.gif
*


What are those? $conn->execute? How can I use "Classes"? how can I create my own? Where to use them? what's pear? do you know a tutorial for the classes/objects and pear? I thought to fetch the results, you must use a loop function. why did you only use "if" function?

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mahesh2k
post Mar 4 2005, 06:46 AM
Post #6


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That was an exceelnt login tutorial from you,i m looking for some of tutorials like this.anyway can you explain me
code below
CODE
echo "<p>User ID: " . $_SESSION["valid_id"];
echo "<p>Username: " . $_SESSION["valid_user"];
echo "<p>Logged in: " . date("m/d/Y", $_SESSION["valid_time"]);

code end

pls explain

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HmmZ
post Mar 4 2005, 09:01 AM
Post #7


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Ouch, a double post smile.gif

as for the code, the login script uses sessions, to store user id's and info to be able to show some stats of the user next time he logs on.

Besides that it looks nice, it also has a security feature, when a user sees the last logged in time, he can see if someone else has been on his account.

Hope that helped you explain?smile.gif

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bjrn