Added new chapter to web section

assets/templates/_table_of_contents.phtml

@@ -31,6 +31,7 @@
     <ol>
         <li><a href="<?= page_path('web/http') ?>">HTTP</a></li>
         <li><a href="<?= page_path('web/http-post') ?>">HTTP POST</a></li>
+        <li><a href="<?= page_path('web/http-server') ?>">PHP HTTP Server</a></li>
     </ol>
 
     <a href="<?= page_path('credits') ?>">Credits</a>

chapters/web/03-http-server.md

@@ -0,0 +1,58 @@
+In PHP, you usually use a separate web server program that accepts HTTP requests and passes them to PHP to create a response. Common examples of separate web server programs are Apache and Nginx. However, PHP has a built in web server we can use during development.
+
+To use the development web server, open a terminal and a new folder for holding your code. Create a file called `index.php` and put this PHP code in it:
+```php
+<?php
+
+echo 'Hello World!';
+```
+Go back to your terminal and start a PHP web server using this command:
+```bash
+php -S localhost:8080
+```
+Now, you can open `localhost:8080` in your web browser and you will see 'Hello World!' in the content of the page.
+
+Next, we can use PHP to analyze all the information about the HTTP request sent from the browser to your PHP script. Change your `index.php` to have this code:
+```php
+<?php
+
+$method = $_SERVER['REQUEST_METHOD'];
+$uri = $_SERVER['REQUEST_URI'];
+$protocol = $_SERVER['SERVER_PROTOCOL'];
+$headers = getallheaders();
+
+echo "$method $uri $protocol <br/>";
+foreach ($headers as $key => $header) {
+    echo "$key: $header <br/>";
+}
+```
+Reload `localhost:8080` and you will see the main request line and all of the headers printed on the web page. The `<br/>` tag is HTML for a new line. Since we are outputting to a web browser, we can no longer use `"\n"` to create a new line.
+
+By default, PHP will generate the necessary response line and headers. If you open your browser console and open the network tab, you can see the response code and headers.
+```http
+HTTP/1.1 200 OK
+Host: localhost:8080
+Date: Sun, 28 Apr 2019 10:19:25 -0500
+Connection: close
+X-Powered-By: PHP/7.2.17
+Content-type: text/html; charset=UTF-8
+```
+PHP set the response code to `200 OK` and the content type to `text/html`. Even though PHP will output good defaults, we can change them in our code if we want. Update your `index.php` file with this code:
+```php
+<?php
+
+http_response_code(404);
+header('Content-Type: text/plain');
+
+echo "Not Found!";
+```
+We are changing the status code to `404 Not Found` and the content type to plain text. If you open `localhost:8080` in your browser, you will now see this HTTP response in your console:
+```http
+HTTP/1.1 404 Not Found
+Host: localhost:8080
+Date: Sun, 28 Apr 2019 10:26:40 -0500
+Connection: close
+X-Powered-By: PHP/7.2.17
+Content-type: text/plain;charset=UTF-8
+```
+PHP added the other necessary headers for the response, but this time used `404` in the main response line and set the `Content-type` header to `text/plain`.

config.php

@@ -165,6 +165,12 @@ return [
             'title' => 'HTTP POST',
             'subtitle' => 'Sending data to a server',
             'previous' => 'web/http',
+            'next' => 'web/http-server',
+        ]),
+        Page::create('web/http-server', 'web/03-http-server.md', [
+            'title' => 'PHP HTTP Server',
+            'subtitle' => 'Handling HTTP Requests in PHP',
+            'previous' => 'web/http-post',
             'next' => '',
         ]),
     ],