c# - 同一存储的依赖注入(inject)多个接口(interface)(具有不同的connectionString)

Question

我想在 Startup.cs 中添加两个或更多(取决于我想添加到我的应用程序的 azure 存储容器的数量)服务
我的 appsettings.json:

"AzureBlobStorageConfiguration": {
    "Storages": {
      "Storage1": {
        "StorageName": "Storage1",
        "ConnString": "connString",
        "AzureBlobContainerName": "containerName"
      },
      "Storage2": {
        "StorageName": "Storage2",
        "ConnString": "connString",
        "AzureBlobContainerName": "containerName"
      },
      "Storage3": {
        "StorageName": "Storage3",
        "ConnString": "connString",
        "AzureBlobContainerName": "containerName"
      }
    }

接下来在 Startup.cs 中使用方法添加服务:

 public static IServiceCollection AddAzureStorage1(this IServiceCollection services, IConfiguration configuration)
        {
            var options = new ABlobStorageConfigurationOptionsDTO();
            configuration.GetSection("AzureBlobStorageConfiguration").GetSection("Storages").GetSection("Storage1").Bind(options);

            services.AddTransient<IAzureBlobStorage1, AzureBlobStorage1>(isp =>
            {
                var client = new BlobServiceClient(options.ConnString);
                var container = client.GetBlobContainerClient(options.AzureBlobContainerName);
                var containerName = options.AzureBlobContainerName;
                var storageName = options.StorageName;

                return new AzureBlobStorage1(container, containerName, storageName);
            }
                );
            return services;
        }

我的 IAzureBlobStorage1 看起来像:

public interface IAzureBlobStorage1
    {
        string AzureBlobContainerName { get; }
        string StorageName { get; }

        public Task<Stream> DownloadStreamAsyns(string fileName);

        public Task Upload(string fileId, Stream stream);

    }

和 AzureBlobStorage1 :

    public class AzureBlobStorage1 : IAzureBlobStorage1
    {
        private BlobContainerClient _client;
        private string _containerName;
        private string _storageName;
        public string StorageName => _storageName;
        public string AzureBlobContainerName => _containerName;

        public AzureBlobStorage1(BlobContainerClient client, string containerName, string storageName)
        {
            _client = client;
            _containerName = containerName;
            _storageName = storageName;
        }


        public async Task<Stream> DownloadStreamAsyns(string fileName)
        {
            return await _client.GetBlobClient(fileName).OpenReadAsync();
        }

        public async Task Upload(string fileId, Stream stream)
        {
            await _client.GetBlobClient(fileId).UploadAsync(stream);
        }
    }

在此之后，我可以在我的构造函数 Controller 类中注入(inject)接口(interface):

        public Controller(IAzureBlobStorage1 azureStorage)
        {
            _azureStorage1 = azureStorage;

        }

但是，如果我想添加许多存储(我在 appsetings.json 中有 3 个)，我必须:

创建接口(interface) IAzureBlobStorage2(看起来与 IAzureBlobStorage1 相同 - 仅更改名称)

创建类 AzureBlobStorage2(看起来像 AzureBlobStorage1 - 只是名称更改)

更改类名的复制粘贴方法

public static IServiceCollection AddAzureStorage2(this IServiceCollection services, IConfiguration configuration)
        {
            var options = new ABlobStorageConfigurationOptionsDTO();
            configuration.GetSection("AzureBlobStorageConfiguration").GetSection("Storages").GetSection("Storage2").Bind(options);

            services.AddTransient<IAzureBlobStorage2, AzureBlobStorage2>(isp =>
            {
                var client = new BlobServiceClient(options.ConnString);
                var container = client.GetBlobContainerClient(options.AzureBlobContainerName);
                var containerName = options.AzureBlobContainerName;
                var storageName = options.StorageName;

                return new AzureBlobStorage2(container, containerName, storageName);
            }
                );
            return services;
        }

现在我可以通过

  public Controller(IAzureBlobStorage2 azureStorage)
        {
            _azureStorage2 = azureStorage;

        }

如果我想添加我的第三个存储，我需要第三次复制粘贴我的代码。
对我来说，这个解决方案看起来很糟糕，我在想如何解决它并使我的代码干净。

Answer 1

不确定这是否是最佳实践，但您可以设计一个命名服务提供商，也许吧？要么，或者你可以只是一个通用参数来区分它们，但是这个通用参数除了作为一种区分方式之外没有多大意义。
无论如何，这是一个使用某种命名提供者的非常基本的实现？:

public interface INamedService {
    string Identifier { get; }
}

public interface IAzureBlobStorage : INamedService
{
    string AzureBlobContainerName { get; }
    string StorageName { get; }
    Task<Stream> DownloadStreamAsyns(string fileName);
    Task Upload(string fileId, Stream stream);
}

public class NamedServiceProvider<T> 
    where T : INamedService
{
    readonly IReadOnlyDictionary<string, T> Instances;

    public NamedServiceProvider(
        IEnumerable<T> instances) 
    {
        Instances = instances?.ToDictionary(x => x.Identifier) ??
            throw new ArgumentNullException(nameof(instances));
    }

    public bool TryGetInstance(string identifier, out T instance) {
        return Instances.TryGetValue(identifier, out instance);
    }
}

public class AzureBlobStorage : IAzureBlobStorage
{
    public string Identifier { get; }
    private BlobContainerClient _client;
    private string _containerName;
    private string _storageName;
    public string StorageName => _storageName;
    public string AzureBlobContainerName => _containerName;

    public AzureBlobStorage(string identifier, BlobContainerClient client, string containerName, string storageName)
    {
        Identifier = identifier;
        _client = client;
        _containerName = containerName;
        _storageName = storageName;
    }


    public async Task<Stream> DownloadStreamAsyns(string fileName)
    {
        return await _client.GetBlobClient(fileName).OpenReadAsync();
    }

    public async Task Upload(string fileId, Stream stream)
    {
        await _client.GetBlobClient(fileId).UploadAsync(stream);
    }
}

然后是静态扩展方法:

public static IServiceCollection AddAzureStorage(
    this IServiceCollection services, 
    IConfiguration configuration,
    string identifier)
{
    var options = new ABlobStorageConfigurationOptionsDTO();
    configuration
        .GetSection("AzureBlobStorageConfiguration")
        .GetSection("Storages")
        .GetSection(identifier)
        .Bind(options);

    return services
        .TryAddTransient<NamedServiceProvider<IAzureBlobStorage>>()
        .AddTransient<IAzureBlobStorage, AzureBlobStorage>(isp =>
    {
        var client = new BlobServiceClient(options.ConnString);
        var container = client.GetBlobContainerClient(options.AzureBlobContainerName);
        var containerName = options.AzureBlobContainerName;
        var storageName = options.StorageName;

        return new AzureBlobStorage(identifier, container, containerName, storageName);
    });
}

然后你可以像这样调用使用它:

public Controller(NamedServiceProvider<IAzureBlobStorage> azureStorage)
{
    _ = azureStorage ?? throw new ArgumentNullException(nameof(azureStorage));
    _azureStorage2 = azureStorage.TryGetInstance("Storage2", out var instance) ? instance : throw new Exception("Something about the identifier not being found??");
}

我在智能感知环境之外对此进行了编码，如果有任何较小的拼写错误或错误，请见谅。可能有更好的方法来做到这一点，但这似乎至少有点ok-ish？哦，我只改变了我必须做的事情，以使其能够正常工作。我不想触及任何其他逻辑..