Let's talk about how to use enumerations in Laravel

How to use enumerations in Laravel? The following article will introduce to you how to use enumerations in Laravel. I hope it will be helpful to you!

I'm a big fan of enums. Lately I've worked for a company using C# where enums are used extensively, and I've become accustomed to being able to, when I can't find them, Find them and miss them.

I use them for anything that has a limited set of possible options, such as the day of the week, the status of an order, or, as in the example below, the user type.

Using enumerations has several benefits:

- Reduces errors caused by transposition or incorrectly entered numbers.

- Makes it easy to change values ​​in the future.

- Makes the code easier to read, which means bugs are less likely to sneak into it.

- Ensure Forward Compatibility When using enumerations, you can greatly reduce the chance of your code failing if someone changes the value corresponding to the member name in the future.

PHP itself does not support enumerations, but it is quite easy to achieve equivalent effects using constants in classes. Additionally, I created a Laravel package called laravel-enum. It allows you to access helper functions such as listing keys and values, appending descriptions to values, and validating requests that expect enumeration values.

This guide walks through the process of installing a Laravel package including examples of usage and best practices.

Installation package

You can run the following command in the terminal through composer to install the package:

$ composer require bensampo/laravel-enum

If you are using Laravel lower than 5.5 version, you need to add the service provider to config/app.php.

'BenSampo\Enum\EnumServiceProvider'

Create the first enum

We will User Types Create an Enumeration In our sample application, users can belong to one of three user types: Admin, Paid Member, Member.

The package contains generators for creating enumerations, so you can run the following command to create an enumeration named UserType. The file will be created in "app/Enums/UserType.php"

php artisan make:enum UserType

You will see a certain amount of scaffolding in this file. Near the top of the file, the list of possible options is defined as constants. These constant values ​​are stored in the database, so I found it best to use integers, but there is no restriction on using integers as long as each value is unique.

The options in this example look like this:

const Administrator = 0;
const PaidMember = 1;
const Member = 2;

Store the value in the database

Now we have a Enumeration of possibilities and can start using it. When migrating the user table, you can add the following.

$table->tinyInteger('type')->unsigned()->default(UserType::Member);

Because null is not an option for the enumeration, we need to set a default value for it. In this example, it is necessary to assume that the default user will become a standard member.

Make sure the top of the file contains the use statement for this enumeration.

use App\Enums\UserType;

Using enumerations in operations

Since our current user model has a property of type, we can access it and compare it to the enum value. This is the real benefit of enums, and why I like them so much. Take a look at the usage examples and possible alternatives below.

if ($user->type === UserType::PaidMember) {
    // 在这里只是做一些付费会员的事情.
}

If we don't use enumerations, we may have code similar to the following:

if ($user->type === 1) { // 这个1表示什么??
    // ...
}

if ($user->type === 'PaidMember') { // 这他妈咋么又是字符串 ?
    // ...
}

The first example using an enumeration is the easiest to read and the least error-prone example. . If I accidentally type UserType::Paidember (note the misspelling), I get a nice error message telling me that the code is wrong (this constant value does not exist in the class), instead of the previous Both examples fail silently. (Just to judge that the conditions are not met, you also need to check the relevant code specifically based on the current conditional statement?)

Display enumeration

In some interfaces of the application , we might want to show the user which user type they are. If we simply output the integer value obtained from the database, we obviously cannot achieve the results we want. Instead, use the getDescription method of the base class that each enumeration class inherits.

The operations on the blade template are as follows:

<p>{{ \App\Enums\UserType::getDescription($user->type) }}</p>

Output resultsAdministrator(administrator), PaidMember(paid member), One of Member.

Sometimes the keyword name is a compound word (like PaidMember), and we want to display something different from the key name. We can overwrite the current enumeration description as follows. In app/Enums/UserType.php:

public static function getDescription(int $value): string
{
    switch ($value) {
        case self::PaidMember:
            return 'Paid member';
        break;
        default:
            return self::getKey($value);
    }
}

Now when we call getDescription we will get Administrator, Paid member or Member.

Verification method

When modifying the enumeration value through user input, it is best to ensure that we Only valid values ​​are accepted. We can use validation rules from the package.

当以表格展示枚举的时候，我经常把他们显示为 HTML select 元素。这样虽仍然可以被恶意修改，但是避免了将错误的值传递给服务器的情况。

继续我们的用户使用示例，让我们在用户控制器中处理修改的值:

public function store(Request $request)
{
    $this->validate($request, [
        'type' => ['required', new EnumValue(UserType::class)],
    ]);

    // 保存用户等等...
}

记住要同时包含枚举的 use 语句和 EnumValue 的规则。

use App\Enums\UserType;
use BenSampo\Enum\Rules\EnumValue;

结束

当然这并不是枚举所能完成的全部范围。但是它覆盖了90%的用例。

值得一看的列表 枚举类上的方法的完整列表 以查看您还能实现什么。

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