After you understand how to install a local server and running PHP files on it, here you are going to discover how a web server works to run PHP code. A local server works the same as a web server or web hosting to run PHP code. A local server allows you to install or run a website on your computer, and with some settings, you can make your local server accessible from anywhere. Meanwhile, a web server provides the environment that allows you to install and run a website. In this article, we specifically discuss how a web server works to run PHP code.
PHP Scripting Language Understanding
PHP is one of web programming languages, which is also called as a scripting language. Simply, the Script Programming Language is a programming language type that doesn’t require a specific environment to run.
The Apache web server will sort out how to run the script code. So, it takes a way to tell the web server whether a certain code is PHP or HTML.
Web Server Works to Run PHP Code
PHP is a web coding that helps to simplify HTML writing. Take a look how simpler HTML writing using PHP code than a manual HTML writing. The example of a PHP file to show a list of product numbers. The code to make a list using PHP would be like the following code.
<title>Making a list using PHP</title>
<h2>List of Product Numbers</h2>
for ($i= 1; $i <= 20; $i++)
echo "<li>Product number $i</li>";
Although that code consists of HTML and PHP, you must save them in a form of a PHP file with a .php suffix in order a web server wants to execute the PHP code that is contained in it.
I save the code as product-numbers.php file into a folder on my local server at D:\xampp\htdocs\learn-php. Then, to show the outcome of that code, I use a web browser open the browser and open the address of that file at localhost/learn-php/product-numbers.php. If there is no any problem, the result is like the following.
Meanwhile, to create the same outcome of the list of product numbers using HTML, the code is pretty long. Below is the code for making such list.
<title>List of Product Numbers</title>
<h2>List of Product Numbers</h2>
<li>Product number 1</li>
<li>Product number 2</li>
<li>Product number 3</li>
<li>Product number 4</li>
<li>Product number 5</li>
<li>Product number 6</li>
<li>Product number 7</li>
<li>Product number 8</li>
<li>Product number 9</li>
<li>Product number 10</li>
<li>Product number 11</li>
<li>Product number 12</li>
<li>Product number 13</li>
<li>Product number 14</li>
<li>Product number 15</li>
<li>Product number 16</li>
<li>Product number 17</li>
<li>Product number 18</li>
<li>Product number 19</li>
<li>Product number 20</li>
So, making a list of 1,000 units using a manual HTML would be very long, but using PHP language we can now simplify making a list using PHP.
Next, let’s we discover more about how a web server works to run PHP code.
- A web server will see an extension type of a file that is being accessed. When the executable file is learn.html for example, the web server will not call its PHP module to run PHP code. It’s because the web server assumes it is a plain HTML file that displays it directly without processing. But if the executable file is learn.php for example, the web server will run its PHP module, and execute the PHP code within the file.
- Apache Web Server will process learn.php starts from the very first line until the last line of the code in sequence.
- At the first line, the web server will find an HTML opening tag, i.e. <! DOCTYPE html> and followed by other HTML tags. Due to not finding instructions to enter PHP mode, these HTML tags do not require any process and are sent directly to the web browser. It’s why you can process the data within an HTML file without using local server or web server using your web browser.
- Once the web server finds the <?php tag on line 7, then that tag instructs the web server to process the next code which consists of PHP code. So, anything that is written after this tag will be processed by following the PHP programming language rules. We call this process as PHP mode.
- The entire code starts from the <?Php tag is PHP mode. In this mode, we will make the PHP programming code. As you can see the PHP code example above, there’s a simple PHP command, i.e. echo. Echo is a command in PHP language that is used to display text where in between the two quotes (“) into the browser. In that example, the echo will display a text: “<li>Product number $i</li>” into the web browser. So, you will see a preview of the text appears in the web browser.
- The web server will continue to be in PHP mode until it finds the ?> closing tag. It signifies the end of the PHP mode.
- Besides the ?> tag ends the PHP mode, it also instructs the web server that the next code is plain HTML.
PHP Loading Speed
In the example above, the PHP code is in between HTML code. But we can also create a file that is entirely PHP and still exactly the same outcome on the browser. The only difference is how we process and divide a page, which can be written with plain HTML code, and which have to be written using PHP code.
You are free to use what feels easier, whether using a PHP code between an HTML document or entirely PHP code. Although, most web developers will love to use PHP code when it is necessary as it makes the web server loads faster without too many PHP processing. But the speed of PHP has been optimized in such a way that can be executed quickly like normal HTML files. Besides, a loading speed is one of the onpage SEO factors.