Knowledge Base

What is Localhost?

Localhost is a term used to refer to your computer itself. Technically, it is a hostname with the IP address 127.0.0.1. This address is always available, even if you don't have a network card. By using localhost, you can test your websites or applications on your own computer before uploading them to the internet. This provides a great advantage in the development process because you can identify and fix errors and problems more quickly.

Localhost is used by setting up a local server. A local server is software that runs on your computer and hosts your websites or applications. This server responds to requests from your internet browser and sends the relevant files (HTML, CSS, JavaScript, PHP, etc.) to your browser. This allows you to view your website or application on your own computer as if it were on the internet, without uploading it to the internet.

Important Points:

• Localhost refers to your computer itself (127.0.0.1).
• A local server hosts your websites or applications on your computer.
• It is used for testing and debugging during the development process.
• It does not require an internet connection.

Real-Life Example: A web developer is developing a new e-commerce site. Before uploading the site to the internet, they test all its features and functions on localhost. This allows them to identify and fix errors in the payment system, product listing problems, and other potential issues early on. Once the site is complete and all tests have passed successfully, they upload the site to the internet.

Which Software is Used to Set Up a Local Server?

There are many different software options for setting up a local server. Some of the most popular and widely used are:

• XAMPP: A free and open-source software package containing Apache, MySQL, PHP, and Perl for Windows, Linux, and macOS. It is very easy to install and use.
• WAMP: A free software package designed for the Windows operating system, containing Apache, MySQL, and PHP.
• MAMP: A free software package designed for the macOS operating system, containing Apache, MySQL, and PHP.
• Laragon: A fast, lightweight, and easy-to-use local development environment for Windows.
• Docker: A platform that allows you to run applications in containers. It can also be used for local development.

Which software you choose depends on your operating system, needs, and preferences. XAMPP, WAMP, and MAMP are generally the easiest options for beginners. Laragon may be suitable for those looking for a faster and more flexible solution. Docker is ideal for more complex projects and environments.

Step-by-Step XAMPP Installation (Windows):

1. Download XAMPP from the official website.
2. Run the downloaded installation file.
3. Follow the steps in the installation wizard. You can accept the default settings.
4. After the installation is complete, open the XAMPP Control Panel.
5. Start the Apache and MySQL services.
6. Verify that XAMPP is running by visiting http://localhost in your browser.

Important Points:

• Allow your firewall to access XAMPP during installation.
• To prevent conflicts between Apache and MySQL services, close other applications that use these services.
• Place your websites in the C:\xampp\htdocs folder (or the htdocs folder in the directory where you installed XAMPP).

How to Use a Local Server?

After completing the local server installation, you can follow these steps to run your websites or applications:

1. Place the files of your website or application (HTML, CSS, JavaScript, PHP, etc.) in the root directory of the local server (usually the htdocs folder).
2. Open your browser and visit http://localhost. If you have placed the files of your website or application in a subfolder, use http://localhost/foldername.
3. Your website or application will be displayed in your browser.

Working with PHP: If your website or application contains PHP code, make sure that the PHP module of the Apache server is enabled. Software such as XAMPP and WAMP usually enable PHP automatically. Save your PHP files with the .php extension and access them through the local server.

Using MySQL Database: If your website or application uses a database, start the MySQL server and create a database. XAMPP and WAMP include a database management tool called phpMyAdmin. You can use this tool to create databases, create tables, and manage data.

Code Example (PHP):

<?php
  $servername = "localhost";
  $username = "root";
  $password = "";
  $dbname = "mydatabase";

  // Create database connection
  $conn = new mysqli($servername, $username, $password, $dbname);

  // Check connection
  if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
  }

  echo "Successfully connected to the database";

  $conn->close();
?>

This code example shows how to connect to a MySQL database using PHP. You need to replace the $servername, $username, $password, and $dbname variables with your own database information.

What are the Advantages and Disadvantages of Localhost?

Advantages:

• Fast Development: You can test and develop your websites or applications on your own computer before uploading them to the internet. This speeds up the development process and allows you to identify errors more quickly.
• Offline Work: You can test your websites or applications without an internet connection. This allows you to work while traveling or in places where there is no internet connection.
• Security: You can identify and fix security vulnerabilities before uploading your websites or applications to the internet. This increases the security of your website or application.
• Cost Savings: You do not need to purchase a hosting service to host your websites or applications. This reduces your costs.

Disadvantages:

• Limited Access: You can only access websites or applications running on localhost from your own computer. If you want others to access it, you need to upload your website or application to the internet.
• Performance Differences: The performance results you get on localhost may differ from the results you get in a real hosting environment. Therefore, it is important to perform performance tests after uploading your website or application to the internet.
• Configuration Difficulties: In some cases, it may be difficult to configure your local server or make certain settings. This can be confusing, especially for beginners.

How to Debug on Localhost?

Localhost is an ideal environment for debugging your websites or applications while developing them. Debugging is the process of finding and fixing errors in your code. Here are some methods you can use when debugging on localhost:

• Browser Developer Tools: Modern browsers like Chrome, Firefox, and Safari include built-in developer tools. These tools allow you to inspect your HTML, CSS, and JavaScript code, identify errors, and troubleshoot performance issues. To open the developer tools, you can usually press F12.
• PHP Error Reporting: If there are errors in your PHP code, you can display them using PHP's error reporting feature. By enabling the error_reporting and display_errors settings in the php.ini file, you can ensure that errors are displayed in the browser.
• Xdebug: Xdebug is a powerful debugging tool for PHP. By installing Xdebug, you can step through your code, examine the values of variables, and identify errors more easily.
• Log Files: Server software such as Apache and MySQL keeps log files. These log files contain server errors and warnings. By examining the log files, you can identify problems that occur on your website or application.

Example: You have defined a variable in a PHP page, but you are getting an error when you try to use this variable later. By using browser developer tools or enabling PHP error reporting, you can see the "Undefined variable" error. This error means that you have not defined the variable or have defined it incorrectly. You can fix the error by correcting the code.

Step-by-Step Xdebug Installation (XAMPP):

1. Download Xdebug from the official website. The version you need to download must be compatible with your PHP version.
2. Copy the downloaded DLL file to XAMPP's PHP extensions folder (usually C:\xampp\php\ext).
3. Open the php.ini file (usually C:\xampp\php\php.ini).
4. Add the following lines to the php.ini file:

   
   zend_extension = "php_xdebug-3.x.x-7.x-vc15-nts-x86_64.dll" ; (Change the file name according to the version you downloaded)
   xdebug.remote_enable = 1
   xdebug.remote_host = localhost
   xdebug.remote_port = 9000
   xdebug.remote_autostart = 1
   

5. Restart the Apache server.
6. To verify that Xdebug is installed correctly, view the PHP configuration information using the phpinfo() function. Make sure the Xdebug section is listed.

How to Transition from Localhost to a Real Server?

After developing and testing your website or application on localhost, you need to move it to a real server (hosting) to publish it on the internet. This transition process requires careful planning and implementation. Here is the step-by-step process of transitioning from localhost to a real server:

1. Hosting Selection: Choose a hosting service that suits your needs. Hosting selection depends on the type of your website or application, traffic expectations, and budget. There are different hosting options such as shared hosting, VPS hosting, or dedicated server.
2. Domain Registration: Register the internet address (domain name) of your website or application. You can purchase the domain name from your hosting provider or a different domain name registration company.
3. Database Creation: If your website or application uses a database, create a database in your hosting account. Note the database name, username, and password.
4. File Upload: Upload the files of your website or application (HTML, CSS, JavaScript, PHP, etc.) to the hosting server. You can usually do this via FTP (File Transfer Protocol) or the file manager in the hosting control panel.
5. Database Transfer: Transfer your database from localhost to the hosting server. You can do this using a database management tool such as phpMyAdmin. Export your database from localhost and import it into the database on the hosting server.
6. Configuration File Update: Update the configuration files of your website or application (e.g., wp-config.php or .env file). These files contain database connection information (server name, database name, username, password) and other important settings.
7. Domain DNS Settings Configuration: Point your domain name's DNS (Domain Name System) settings to your hosting server's IP address. This process allows users visiting your domain name to reach your website or application. DNS settings may take a few hours to update.
8. Test and Control: Visit your website or application over the internet to make sure everything is working correctly. Test all pages, links, forms, and other functions.
9. Security Measures: Take the necessary measures to increase the security of your website or application. Install an SSL certificate, configure a firewall, and perform regular backups.

Case Study: A blogger developed a WordPress blog on localhost. To publish the blog on the internet, they purchased a hosting service and registered a domain name. They uploaded the WordPress files to the hosting server, transferred the database from localhost to the hosting server, and updated the database information in the wp-config.php file. They pointed the domain name's DNS settings to the hosting server. They visited the blog over the internet and verified that everything was working correctly. They increased the blog's security by installing an SSL certificate.

Common Localhost Errors and Solutions

You may encounter some errors while using localhost. Here are the most common errors and their solutions:

• "Connection refused" or "Site cannot be reached" error: This error means that your local server is not running or your browser cannot connect to the correct address. To solve this, make sure your server software such as XAMPP or WAMP is running. Make sure the Apache and MySQL services are started. Also, make sure you are typing the correct address (http://localhost or http://127.0.0.1) in your browser.
• "File not found" error (404 Not Found): This error means that the file your browser is requesting is not found on your local server. To solve this, make sure the file is in the correct directory (usually the htdocs folder). Make sure the file name and extension are correct.
• "Internal Server Error" error (500 Internal Server Error): This error means that an error has occurred on your server. This error is usually caused by errors in the PHP code. To solve this, enable PHP error reporting to find out what the error is and fix the code. You can also find the source of the error by examining the server log files.
• Database connection error: This error means that your website or application cannot connect to the database. To solve this, make sure the database connection information (server name, database name, username, password) in the configuration files (e.g., wp-config.php) is correct. Make sure the MySQL server is running.
• Port Conflict: If Apache or MySQL services cannot be started, there may be a port conflict. In this case, another application may be using the same port. To solve this, you can change the ports in the XAMPP control panel. For example, make sure Apache is using ports 80 and 443. If these ports are being used by another application, you can choose different ports.

Important Points:

• Read the error messages carefully. Error messages help you understand what the error is and how to fix it.
• Examine the server log files. Log files contain server errors and warnings.
• Do research on the internet. By searching for the error you encountered on the internet, you can find solutions from other users.
• Ask for help. If you cannot solve the error, ask for help in a forum or community.