The .env file is a configuration file used in the Laravel project to store environment variables. It separates sensitive information from code and supports multi-environment switching. Its core functions include: 1. Centrally manage database connections, API keys and other configurations; 2. Call variables through env() or config() functions; 3. The configuration needs to be refreshed after modification to take effect; 4. It should not be submitted to version control to prevent leakage; 5. Multiple .env files can be created for different environments. When using it, you should first define variables and then call them in conjunction with configuration file to avoid direct hard coding.

Laravel's .env file is one of the cores of project configuration, which is used to store application environment variables. These variables include settings that are sensitive to database connection information, API keys, application keys, etc. or that need to be changed according to different environments (such as local development, testing, production).

Writing this information directly in the code is not only unsafe, but also difficult to maintain. Through the .env file, you can manage these configurations in a unified manner and not expose them to external users.

What is a .env file?

.env is a text file in the root directory of the Laravel project, which is used to save configuration parameters in the current environment. When you use php artisan serve to start the application, Laravel will automatically read the contents of this file and inject the variables inside into the entire application.

For example, common contents are as follows:

 APP_NAME=Laravel
APP_ENV=local
APP_KEY=base64:xxxxx
APP_DEBUG=true
DB_HOST=127.0.0.1
DB_DATABASE=homestead
DB_USERNAME=homestead
DB_PASSWORD=secret

These variables can be accessed in the code through env() or config() function.

Note: .env files should not be submitted to version control systems (such as Git), you should add them to .gitignore to prevent sensitive information from leaking.

How to use variables in .env ?

Using .env variables in Laravel is mainly divided into two steps: defining variables and calling variables .

Define variables

Open the .env file and add your own key-value pairs, the format is:

 KEY=VALUE

For example:

 MAIL_HOST=smtp.mailtrap.io
MAIL_PORT=2525

Calling variables

• Use env('KEY') to get the value directly:

   $host = env('MAIL_HOST');

• The more recommended way is to use it in conjunction with the configuration file under config/ :

  For example, you write this in config/mail.php :

   'host' => env('MAIL_HOST', 'smtp.example.com'),

  Then in the code pass:

   config('mail.host');

  Get the value. This method is more flexible and also facilitates cache configuration to improve performance.

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  Frequently Asked Questions and Notes

  • After modifying .env you need to refresh the configuration

    After modifying the .env file, some configurations may not take effect immediately. You can run the following command to clear the cache and reload the configuration:

    • php artisan config:clear
    • php artisan cache:clear
    • php artisan config:cache

  • Don't store large amounts of data in .env

    .env is used to store configuration items, not a database replacement. If you have structured data, there should be a database or other suitable place.

  • Different environments use different .env files

    For example, you can save configurations of different environments in files such as .env.local , .env.production , etc., and rename them to the main .env file according to the situation when deploying.

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  Let's summarize

  The .env file is an important way for Laravel to control configuration. It separates sensitive information from code and facilitates switching of multiple environments. You just need to define the variables in it and call them in the configuration file or code. Although the operation is not complicated, it is easy to ignore refreshing configurations or commit .env files by mistake. Paying attention to these details will make you less trapped.

  Basically that's it.

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