# LEMP Stack

LEMP refers to a collection of open-source software that is commonly used together to serve web applications. The term **LEMP** is an acronym that represents the configuration of a **L**inux operating system with an Nginx (pronounced *engine-x*, hence the **E** in the acronym) web server, with site data stored in a **M**ySQL database and dynamic content processed by **P**HP.

The LEMP stack represents one way to configure a web server and is used in many highly-scaleable applications across the web.

The setup for a LEMP vs LAMP stack is quite similar as they share the same technologies other than the web server. We will make use of `ubuntu` for this project as well on an `ec2` instance.

## STEP 1: Install Nginx

```bash
sudo apt update -y
sudo apt install -y nginx
sudo systemctl status nginx
```

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1674843320996/315a280a-ba69-4fd6-a2c2-f21cbfe1c401.png align="center")

We need to have port `80` open for our instance just like in Project 1. It's wise to have different security groups depending on what port access your technologies require. For web access, I have the `default` security group (SG) limited to just port 22 (for ssh access) and `80` for web server access. For projects requiring additional rules, I will clone the `default` SG and append the new rules.

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1674753623011/b8126038-a694-43f6-961b-7c07976ec4f3.png align="center")

Our server is now accessible on port `80` using our public IP Address (ex. `http://35.93.24.167`.

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1674844276826/1a404f4a-661c-4b43-bb88-13e90ff4304d.png align="center")

## STEP 2: Setup MySQL

Setting MySQL for LEMP is identical to LAMP so I have just copied the steps from the last project into a gist and embedded it below.

%[https://gist.github.com/cdrani/037763d3524dd23f0a3add18a6e5784d] 

## STEP 3: Install PHP

Nginx requires an external program to handle PHP processing and act as a bridge between the PHP interpreter itself and the web server. We need `php-fpm` (“PHP fastCGI process manager”) which tells Nginx to pass PHP requests to itself for processing. Additionally, we will need `php-mysql`, a PHP module that allows PHP to communicate with MySQL-based databases.

```bash
sudo apt install -y php-fpm php-mysql
```

## STEP 4: Configure Nginx to use PHP-FPM

Nginx has something similar to Apache's virtual hosts called server blocks. They both encapsulate configuration details and allow hosting multiple domains on a single server.

Let's create a domain for this project and transfer its ownership from `root` to the `USER`.

```bash
sudo mkdir /var/www/lemp
sudo chown -R $USER:$USER /var/www/lemp
```

### Configuration

```nginx
#/etc/nginx/sites-available/lemp

server {
    listen 80;
    server_name lemp www.lemp;
    root /var/www/lemp;

    index index.html index.htm index.php;

    location / {
        try_files $uri $uri/ =404;
    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php8.1-fpm.sock;
     }

    location ~ /\.ht {
        deny all;
    }

}
```

| Config Keyword | Purpose |
| --- | --- |
| `listen` | sets port Nginx will listen on |
| `root` | document root where the files served by this website are stored |
| `index` | Order in which nginx will prioritize index files. |
| `server_name` | domain names and/or IP address this server block should respond |
| `location /` | checks for the existence of files or directories matching a URI request. If Nginx cannot find the appropriate resource, it will return a 404 error |
| `location ~ \.php$` | **h**andles PHP processing by pointing Nginx to the `fastcgi-php.conf` configuration file and the `php8.1-fpm.sock file`, which declares what socket is associated with `php-fpm` |
| `location ~ /\.ht` | deals `.htaccess` files, which Nginx does not process. |

After setting the configuration above, we need to let Nginx be aware of it, verify it has no syntax errors, unlink the default site (with the Nginx landing page pictured above), and reload the Nginx:

```bash
sudo ln -s /etc/nginx/sites-available/lemp /etc/nginx/sites-enabled/
sudo nginx -t
sudo unlink /etc/nginx/sites-enabled/default
sudo systemctl reload nginx
```

Our site is currently empty as it's bereft of any files - `*.html` or `*.php` , and will thus show a 403 message. Let's rectify this by adding a simple `index.html` file:

```bash
sudo echo 'Hello LEMP from hostname' $(curl -s http://169.254.169.254/latest/meta-data/public-hostname) 'with public IP' $(curl -s http://169.254.169.254/latest/meta-data/public-ipv4) > /var/www/lemp/index.html
```

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1674847447899/1046aa92-5383-4b16-ac40-45b2dfd54a5e.png align="center")

## Step 5: Testing PHP with Nginx

Let's verify that our nginx + php integration (using `php-fpm`) can process `.php` files.

```bash
sudo echo '<?php phpinfo();' > /var/www/lemp/info.php
```

We should see the following PHP info page on the `http:35.93.24.167/info.php` URL:

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1674847851887/67df053a-9325-4e57-93f3-89891762986f.png align="center")

## Step 6: Retrieve Data from MySQL DB with PHP

For a final integration, let's create a `todolist` database, configure access to it and have Nginx query our database and display it.

In the MySQL console, we'll create a database and an `admin` user with all privileges to the new database. This user will now be able to create a table in the database and insert data into it.

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1674853938554/756443c2-0672-44e0-a247-178e51b30fd5.png align="center")

What's the use of a database without any data? Let's populate it with some sample todo list items:

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1674855202360/63445e94-e546-42a8-9d50-11ce6f2d2cc5.png align="center")

### Display Todo

To display our data from our `todo_list` we need access our `test_db`database, query our `todo_list` table, and finally create an HTML skeleton to display the data in a list:

```php
# /var/www/lemp/todo_list.php

<?php
$user = "admin";
$password = "Super01!";
$database = "test_db";
$table = "todo_list";

try {
  $db = new PDO("mysql:host=localhost;dbname=$database", $user, $password);
  echo "<h2>TODO</h2><ol>";
  foreach($db->query("SELECT content FROM $table") as $row) {
    echo "<li>" . $row['content'] . "</li>";
  }
  echo "</ol>";
} catch (PDOException $e) {
    print "Error!: " . $e->getMessage() . "<br/>";
    die();
}
```

Visiting `http://35.93.24.167/todo_list.php` , should display our todo list:

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1674855907625/50cbf48e-ff4f-4bbd-9501-f3b202ff3135.png align="center")

## Learning Outcomes

1. Set up Nginx Server & connect with PHP.
    
2. Use PHP to connect to MySQL database, query a table, and display data.