创建 AWS 初始化 class

Question

我有一个 API 连接到我的发电机数据库。我的 API 有很多用于 GET、POST、删除等的端点。我正在使用以下代码：

var awsCredentials = Helper.AwsCredentials(id, password);
var awsdbClient = Helper.DbClient(awsCredentials, "us-east-2");
var awsContext = Helper.DynamoDbContext(awsdbClient);

List<ScanCondition> conditions = new List<ScanCondition>();
var response = await context.ScanAsync<MyData>(conditions).GetRemainingAsync();

return response.ToList();

我的代码的前三行，即设置 awsCredentials、awsdbClient 和 awsContext 在我的每个 WEB API 调用中重复。

这是我的静态助手 class:

public static class Helper
{
    public static BasicAWSCredentials AwsCredentials(string id, string password)
    {
        var credentials = new BasicAWSCredentials(id, password);
        return credentials;
    }
    public static AmazonDynamoDBClient DynamoDbClient(BasicAWSCredentials credentials, RegionEndpoint region)
    {
        var client = new DBClient(credentials, region);
        return client;
    }
    public static DynamoDBContext DynamoDbContext(AmazonDynamoDBClient client)
    {
        var context = new DynamoDBContext(client);
        return context;
    }
}

我在 API 中使用这个助手 class 来初始化 AWS。

有没有更好的初始化方法？

Answer 1

让我们利用 ASP.Net 的内置依赖注入。

我们需要制作一个快速界面来公开您需要的值。

public interface IDynamoDbClientAccessor
{
    DynamoDBContext GetContext();
}

以及我们稍后会用到的设置 class。

public class DynamoDbClientAccessorSettings
{
    public string Id { get; set; }
    public string Password { get; set; }
    public string Region { get; set; }
}

现在具体class.

public class DynamoDbClientAccessor : IDynamoDbClientAccessor
{
    private readonly DynamoDbClientAccessorSettings settings;

    public DynamoDbClientAccessor(IOptions<DynamoDbClientAccessorSettings> options)
    {
        settings = options?.Value ?? throw new ArgumentNullException(nameof(options));
    }

    public DynamoDBContext GetContext()
    {
        // You have the option to alter this if you don't
        // want to create a new context each time. 
        // Have a private variable at the top of this class
        // of type DynamoDBContext. If that variable is not null,
        // return the value. If it is null, create a new value,
        // set the variable, and return it.

        var awsCredentials = Helper.AwsCredentials(settings.Id, settings.Password);
        var awsdbClient = Helper.DbClient(awsCredentials, settings.Region);
        var awsContext = Helper.DynamoDbContext(awsdbClient);

        return awsContext;
    }
}

将所有这些都连接到您的 Startup class

services.AddSingleton<IDynamoDbClientAccessor, DynamoDbClientAccessor>();
services.Configure<DynamoDbClientAccessorSettings>(c =>
{
    c.Id = "YOUR ID";
    c.Password = "YOUR PASSWORD";
    c.Region = "YOUR REGION";
});

现在在您的控制器或其他 DI 服务中，您在构造函数中请求一个 IDynamoDbClientAccessor 实例。

一旦您更加熟悉依赖注入，您将能够将更多的东西分解成它们自己的依赖服务。正如所说，AWS SDK 甚至提供了一些接口供您使用，这对您也有帮助。

创建 AWS 初始化 class

Creating AWS initialization class

c#

asp.net-core

.net-core-2.0