Where to define constants in thinkphp5

thinkphp5 is a modern PHP development framework with elegant syntax, powerful functions and convenient operation. In the development process using thinkphp5, the definition of constants is often involved. This article will discuss where thinkphp5 defines constants and the related knowledge of constants.

In thinkphp5, there are two ways to define constants: one is to define them in the config configuration file, and the other is to use the define() function in the code.

1. Define constants in the config configuration file

In thinkphp5, we can define constants in the files under the config directory. For example: config.php file defines a constant WEBSITE_NAME, the code is as follows:

return [
    'WEBSITE_NAME' => 'My Website',
];

In the above code, we use return to return an array, the key name of the array is the constant name, and the value is the value of the constant. In the code, we can use constants in the following ways:

echo config('WEBSITE_NAME');

In the above code, we use the config function to obtain the value of the constant. By using this method, the constant can be easily used throughout the application.

2. Use the define() function to define constants

In addition to defining constants in the config configuration file, we can also use the PHP built-in function define() to define constants. For example:

// 在全局定义常量
define('WEBSITE_NAME', 'My Website');

// 在类中定义常量
class MyClass {
    const WEBSITE_NAME = 'My Website';
}

In the above code, we use the define() function to define a constant globally and in the class respectively. In the code, we can use constants in the following ways:

echo WEBSITE_NAME;
echo MyClass::WEBSITE_NAME;

In the above code, we directly use the constant name to get the value of the constant.

Summary:

In thinkphp5, we can use the config configuration file and define() function to define constants. Either way, constants can be easily used throughout your application. In actual development, we should abide by PHP's constant naming convention, using uppercase letters and underscores "_" to indicate separators between words. At the same time, before defining a constant, you should check whether the constant has already been defined to avoid repeated definition of the constant.

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