A brief analysis of the use of .env files in laravel

When developing applications using the Laravel framework, you may need to set some environment variables. In a Laravel application, you can set these environment variables through the .env file. This article will introduce how to use Laravel .env file.

What is an .env file

The .env file is a file that stores environment variables. In the Laravel framework, the .env file usually stores some configuration information in the development environment, such as database connection information, email configuration information, etc. This information can be used anywhere in the application.

By default, the Laravel framework provides a .env.example file in the root directory of the application. This file contains all available environment variables and their default values. You can make a copy and rename it to .env, and then modify the variable values ​​in it.

You can also use the putenv() function that comes with PHP to set environment variables, but this method is not as convenient as the .env file. When using this method, if you need to modify the environment variable value, you need to modify the code manually.

.env file format

The .env file is a plain text file. It's very simple, just a set of key-value pairs, one per row. Keys and values ​​are separated by =. Each key-value pair needs to occupy one line, and there can be no spaces between the key name and the key value. For example:

APP_NAME=Laravel
APP_ENV=local
APP_DEBUG=true
APP_URL=http://localhost
DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=homestead
DB_USERNAME=homestead
DB_PASSWORD=secret

In this example, we set some basic environment variables, such as APP_NAME, APP_ENV, etc. These environment variables are usually used when your project is running.

How to use .env files

Reading environment variables in a Laravel application is very simple. You can access these variables using the built-in env() function. This function accepts a key as a parameter and returns the value corresponding to the key. If the specified key is not found, returns the specified default value, if available.

The following is an example of using the .env file:

// 从 .env 文件中获取 APP_ENV 环境变量的值
$env = env('APP_ENV');

// 从 .env 文件中获取 APP_DEBUG 环境变量的值
$debug = env('APP_DEBUG', false);

In this example, we use the env() function to read The values ​​of the APP_ENV and APP_DEBUG environment variables in the .env file. For APP_DEBUG, we also passed in a default value false, indicating that this default value is used when the variable is not set in .env.

The Laravel framework also provides a concise syntax to directly access variables in the .env file, as shown below:

// 访问 APP_ENV 环境变量的值
$env = config('app.env');

// 访问 APP_DEBUG 环境变量的值
$debug = config('app.debug');

Here, we use ## directly #config() function, pass app.env and app.debug as arguments to it to access variables in the .env file. Comments in the

.env file

If you need to add comments in the

.env file, you can add a # before each key-value pair. Number. Everything after this symbol will be treated as a comment and ignored. For example:

# 这是一个注释
APP_NAME=Laravel
APP_ENV=local # 这是另一个注释
APP_DEBUG=true
APP_URL=http://localhost

Summary

In a Laravel application, the

.env file is used to store information about environment variables. These variables can be used anywhere in the application. You can use the env() function or the config() function to read these variables. .env The file format is very simple, just a set of key-value pairs, one per line. If you need to add comments, you can add # at the beginning of each line.

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