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Home / How to Validate Login Form in Php With Database

How to Validate Login Form in Php With Database

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A user login and registration system is super helpful when we want to store information about the users of our website. This applies to everything from educational websites, which might store course progress and marks, to e-commerce websites, which will store information about customers' past purchases.

In this tutorial, I'll teach you how to create your own PHP login and registration forms from scratch.

Creating the Login and Registration Forms

Our first step will be the creation of a login form and a registration form. The forms will actually be pretty simple. The registration form will only ask for a username, email, and password. The username and email will be unique for everyone who registers. If anyone tries to create two accounts using the same email address, we'll show them an error message letting them know that the email is already in use.

Coding the Registration Form

Here is the HTML for creating the registration form. You have to put it in a file namedregister.php.

<form method="post" action="" name="signup-form"> <div class="form-element"> <label>Username</label> <input type="text" name="username" pattern="[a-zA-Z0-9]+" required /> </div> <div class="form-element"> <label>Email</label> <input type="email" name="email" required /> </div> <div class="form-element"> <label>Password</label> <input type="password" name="password" required /> </div> <button type="submit" name="register" value="register">Register</button> </form>

The form is very basic, but we do use HTML5 to do some very basic input validation. For instance, the use oftype="email" will alert users when the email address that they entered isn't in the proper format. Similarly, the use of the pattern attribute on the username will make sure that the username only consists of alphanumeric characters.

You can read the tutorial titled Form Input Validation Using Only HTML5 and Regex if you want to learn more about the topic. You can also take client-side form validation to the next level with jQuery by getting more power over the error messages that are shown and their placement and appearance. If you want to learn more about client-side validation, check out those posts.

Coding the Login Form

Here is the HTML for the login form. You can put it in a file namedlogin.php.

<form method="post" action="" name="signin-form">   <div class="form-element">     <label>Username</label>     <input type="text" name="username" pattern="[a-zA-Z0-9]+" required />   </div>   <div class="form-element">     <label>Password</label>     <input type="password" name="password" required />   </div>   <button type="submit" name="login" value="login">Log In</button> </form>

Style the Forms With CSS

Here is some CSS that you can apply to these forms:

* {     padding: 0;     margin: 0;     box-sizing: border-box; } body {     margin: 50px auto;     text-align: center;     width: 800px; } h1 {     font-family: 'Passion One';     font-size: 2rem;     text-transform: uppercase; } label {     width: 150px;     display: inline-block;     text-align: left;     font-size: 1.5rem;     font-family: 'Lato'; } input {     border: 2px solid #ccc;     font-size: 1.5rem;     font-weight: 100;     font-family: 'Lato';     padding: 10px; } form {     margin: 25px auto;     padding: 20px;     border: 5px solid #ccc;     width: 500px;     background: #eee; } div.form-element {     margin: 20px 0; } button {     padding: 10px;     font-size: 1.5rem;     font-family: 'Lato';     font-weight: 100;     background: yellowgreen;     color: white;     border: none; } p.success, p.error {     color: white;     font-family: lato;     background: yellowgreen;     display: inline-block;     padding: 2px 10px; } p.error {     background: orangered; }

This contains some additional styling rules for error messages and headings. The HTML and CSS from this section can be used as the basis of your project when you create your own forms, which might require different styling and input fields.

Creating the User Table and Connecting to the Database

The next step is the creation of a user table that will store all the information about the registered users. In our case, the table simply consists of four columns:

  1. an auto-incrementing id
  2. a unique username
  3. an email
  4. a password

You can use the following SQL to create the table quickly.

CREATE TABLE `users` (     `id` int(10) unsigned NOT NULL AUTO_INCREMENT,     `username` varchar(25) NOT NULL,     `password` varchar(255) NOT NULL,     `email` varchar(100) NOT NULL,     PRIMARY KEY (`id`),     UNIQUE KEY `username` (`username`) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1;

Now, create a file calledconfig.php and write the following code in it to connect to the database.

<?php     define('USER', 'root');     define('PASSWORD', '');     define('HOST', 'localhost');     define('DATABASE', 'test');     try {         $connection = new PDO("mysql:host=".HOST.";dbname=".DATABASE, USER, PASSWORD);     } catch (PDOException $e) {         exit("Error: " . $e->getMessage());     } ?>

Change the database name to whatever the name of your database is. This file will be used to establish a connection to the database.

Code the User Registration

It's finally time to implement the registration functionality. The main function of this code is to check if the supplied email is already registered. If it's not, we enter the username, email, and password into the database.

Place the following code at the top ofregistration.php.

<?php     session_start();     include('config.php');     if (isset($_POST['register'])) {         $username = $_POST['username'];         $email = $_POST['email'];         $password = $_POST['password'];         $password_hash = password_hash($password, PASSWORD_BCRYPT);         $query = $connection->prepare("SELECT * FROM users WHERE email=:email");         $query->bindParam("email", $email, PDO::PARAM_STR);         $query->execute();         if ($query->rowCount() > 0) {             echo '<p class="error">The email address is already registered!</p>';         }         if ($query->rowCount() == 0) {             $query = $connection->prepare("INSERT INTO users(username,password,email) VALUES (:username,:password_hash,:email)");             $query->bindParam("username", $username, PDO::PARAM_STR);             $query->bindParam("password_hash", $password_hash, PDO::PARAM_STR);             $query->bindParam("email", $email, PDO::PARAM_STR);             $result = $query->execute();             if ($result) {                 echo '<p class="success">Your registration was successful!</p>';             } else {                 echo '<p class="error">Something went wrong!</p>';             }         }     } ?>

The first step is to includeconfig.php and start the session. This helps us store any information that we want to preserve across the pages.

Next, we check if the user has clicked on theRegister button to submit the form by checking if$_POST['register'] has been set. Always remember that it isn't a good idea to store passwords as plain text. For this reason, we use the password_hash() function and then store that hash in our database. This particular function creates a 60-character hash using a randomly generated salt.

Finally, we execute the query and check if a non-zero row number exists for a given email address. If it does, the user will get a message saying the email address is already registered.

If no row exists with the given email address, we enter the supplied information into our database and let the users know that the registration was successful.

Implementing the Login Functionality

In our last step, we wrote the code for logging users in. This time, we simply check the information in the database to see if the username and password combination entered into the form is correct.

Here is the code that goes at the top oflogin.php.

<?php     session_start();     include('config.php');     if (isset($_POST['login'])) {         $username = $_POST['username'];         $password = $_POST['password'];         $query = $connection->prepare("SELECT * FROM users WHERE username=:username");         $query->bindParam("username", $username, PDO::PARAM_STR);         $query->execute();         $result = $query->fetch(PDO::FETCH_ASSOC);         if (!$result) {             echo '<p class="error">Username password combination is wrong!</p>';         } else {             if (password_verify($password, $result['password'])) {                 $_SESSION['user_id'] = $result['id'];                 echo '<p class="success">Congratulations, you are logged in!</p>';             } else {                 echo '<p class="error">Username password combination is wrong!</p>';             }         }     } ?>

One important thing to note here is that we don't compare the username and password in a single step. Because the password is actually stored in a hashed form, we first need to fetch the hash with the help of the supplied username. Once we have the hash, we can use the password_verify() function to compare the password and the hash.

Once we've successfully confirmed the password, we set the$_SESSION['user_id'] variable to the ID of that user in the database. You can also set the value of other variables here.

Restricting Access to Pages

Most websites where users are asked to register have some other pages where users access and store private data. You can use session variables to protect these pages. If the session variable isn't set, simply redirect the users to the login page. Otherwise, show them the contents of the page.

<?php     session_start();     if(!isset($_SESSION['user_id'])){         header('Location: login.php');         exit;     } else {         // Show users the page!     } ?>

The only thing that you have to do is to ensure the script containssession_start() at the beginning.

Resolving Common Errors

There are three types of errors that you might encounter when using this script:

1. Errors Due to Incorrect Variable Names

One of the most common sources of error is having the wrong capitalization for a variable somewhere. Therefore, it's important to stick with the same naming convention for all your variables. As an example, the keys in the $_POST superglobal are based on the value of name assigned to input elements in the form. This means that$_POST['USERNAME'] and$_POST['username'] will have different values.

2. The "Headers already sent" Error

Some functions likesession_start() andheader() modify HTTP headers. Since PHP flushes all headers before it outputs something, it's important to call all such functions before you output anything. This includes any raw HTML or unintentional spaces before the opening <?php tag.

3. Session Variables Not Persisting Across Pages

You can access session variables on a page only if you called the functionsession_start() on that page. If you cannot access the values in the $_SESSION superglobal on a page, this is probably because you forgot to callsession_start(). Also remember to call the function before you output anything on the page. Otherwise, you'll encounter the " Headers already sent" error.

PHP Forms From CodeCanyon

It's good to know how to create a login page in PHP. But it can take some time, and you'll need more forms to fill out your site. If you're looking to cut down on coding time, you can try some of these PHP form templates found on CodeCanyon.

1. Quform: Responsive Ajax Contact Form

Create awesome contact forms with Quform. It's the most popular PHP script available on CodeCanyon today. The results are responsive, which means they can scale to fit multiple screen sizes. Play around with the different themes to find one which fits your site's look.

Quform - Responsive Ajax Contact Form Quform - Responsive Ajax Contact Form Quform - Responsive Ajax Contact Form

2. PHP Form Builder

You'll be able to make more than a login page with PHP with this download. It's a comprehensive form builder that will save you time and is easy to use. With PHP Form Builder, you can make:

  • contact forms
  • registration forms
  • dynamic field forms
  • order forms
  • and a lot more
PHP Form Builder PHP Form Builder PHP Form Builder

3. Easy Forms: Advanced Form Builder and Manager

Create online forms quickly with Easy Forms. It's an advanced form creator that's also simple to navigate. Just drag and drop the different components to make the form you need. It's perfect if you're looking to create a unique HTML PHP login script but don't have time to code from scratch.

Easy Forms: Advanced Form Builder and Manager Easy Forms: Advanced Form Builder and Manager Easy Forms: Advanced Form Builder and Manager

4. ContactMe: Responsive AJAX Contact Form

Simple and powerful, ContactMe is a great set of forms to use for your website. It has four unique themes and multiple premade forms included. But that's not all. There are more than 25 combinations you can create using ContactMe's components.

ContactMe - Responsive AJAX Contact Form - HTML5 PHP

Final Thoughts

In this tutorial, we learned how to create a basic user registration and login system using PHP. Once you've grasped the basics of login and registration systems, you can create more complicated logic, such as allowing users to reset their password or verify their email address.

You can also add more front-end validation with HTML5 attributes or jQuery to make the form more user-friendly.

Learn PHP With a Free Online Course

If you want to learn PHP, check out our free online course on PHP fundamentals!

In this course, you'll learn the fundamentals of PHP programming. You'll start with the basics, learning how PHP works and writing simple PHP loops and functions. Then you'll build up to coding classes for simple object-oriented programming (OOP). Along the way, you'll learn all the most important skills for writing apps for the web: you'll get a chance to practice responding to GET and POST requests, parsing JSON, authenticating users, and using a MySQL database.

There's more to learn from Envato Tuts+ than making user login code in PHP. If you want additional PHP resources, check out these great tutorials and articles.

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Monty Shokeen

Freelancer, India

I am a full-stack developer who also loves to write tutorials. After trying out a bunch of things till second year of college, I decided to work on my web development skills. Starting with just HTML and CSS, I kept moving forward and gained experience in PHP, JavaScript and Python. I usually spend my free time either working on some side projects or traveling around.

How to Validate Login Form in Php With Database

Source: https://code.tutsplus.com/tutorials/create-a-php-login-form--cms-33261