Basics of How Routing Works
====

The usual "the very thing you're trying to do is wrong" question.
https://teratail.com/questions/jyl7cyfq0dcnkv

There are many questions about wanting to display `http://localhost/test.php` without the `.php` extension as `http://localhost/test`. However, the initial idea that "simply omitting the `.php` should work" is incorrect.
Since the initial idea is wrong, no matter how much you search, you will only arrive at incorrect answers.

In frameworks like Laravel, `.php` is not visible, but it's not because it is omitted.

### Simple Flow Explanation
1. All requests are routed to `http://localhost/index.php`.
2. Inside `index.php`, the nature of the incoming request is examined. If it’s `http://localhost/test`, it is determined that a request to `/test` has been made.
3. The request is dispatched based on the request information.
Laravel’s routing writes this dispatching method.
```php
Route::get('test', TestController::class);
```

### Implementation Methods
1. Routing everything to `index.php` is the job of the web server.

For nginx:
```    
    location / {
        try_files $uri $uri/ /index.php?$query_string;
    }
```
For Apache, using `.htaccess`:
```
    # Send Requests To Front Controller...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ index.php [L]
```

2. Inspecting the request is the job of the framework, so you don’t need to know the details.
3. Dispatching is also the job of the framework.

In the end, what the user needs to do is just configure the web server and write routing.
Even if you don’t know the details, you can use the framework.
As long as you route everything to `index.php`, the framework will handle the rest smoothly.
Explanation that `.php` is not being omitted ends here.

### Before the Era of Frameworks
Around the 2000s, people would write code to inspect requests themselves.
For a request to `http://localhost/index.php/test`, `/test` would be extracted and dispatched.
Request details could be obtained with the `$_SERVER` variable, using `$_SERVER['PATH_INFO']` or `$_SERVER['REQUEST_URI']`.

From the stage of `http://localhost/index.php/test`, if you also configure the web server to route everything to `index.php`, `/index.php` will disappear, leading to modern routing.

While frameworks may be doing more complicated things, the basic mechanism is the same.