依赖注入不适用于 Azure Functions

Question

我在 Azure Functions 中遇到依赖注入问题。我在 Whosebug 上阅读了所有指南和任何问题，但找不到解决方案。

我正在使用 Visual Studio 2019 和 Azurite 在我的本地机器上进行测试。我试图在没有的情况下制作一个项目并且它工作正常。该项目是一个带有 HttpTrigger 的 Azure Functions。

我在这里粘贴我的启动代码：

[assembly: FunctionsStartup(typeof(Startup))]

namespace ZanettiClod.SampleAzureFunctions
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddHttpClient();
            builder.Services.AddSingleton<IProductService, ProductService>();
            builder.Services.AddSingleton<IProductRepository<Product>, ProductRepository>();
        }
    }
}

我的程序代码：

namespace ZanettiClod.SampleAzureFunctions
{
    public class Program
    {
        public static void Main()
        {

            var host = new HostBuilder()
                .ConfigureFunctionsWorkerDefaults()
                .Build();
            host.Run();
        }
    }
}

我的 GetProducts 代码：

namespace ZanettiClod.SampleAzureFunctions
{
    public class GetProducts
    {
        private readonly IProductService _productService;

        public GetProducts(IProductService productService)
        {
            _productService = productService;
        }

        [Function("GetProducts")]
        public async Task<HttpResponseData> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get")] 
            HttpRequestData req,
            FunctionContext executionContext)
        {
            var logger = executionContext.GetLogger("GetProducts");
            logger.LogInformation("C# HTTP trigger function processed a request.");

            var products = await _productService.GetAllProducts();

            var response = req.CreateResponse(HttpStatusCode.OK);
            await response.WriteAsJsonAsync(products);

            return response;
        }
    }
}

这是我返回的错误： screeshot

在此先感谢您的帮助

Answer 1

您可以进行以下更改以使其正常工作。我测试了依赖注入并且它有效。

将依赖注入从 startup.cs 移动到 program.cs。这就是目标框架 .Net 5.0 的工作方式。文档 - https://docs.microsoft.com/en-us/azure/azure-functions/dotnet-isolated-process-guide

 namespace ZanettiClod.SampleAzureFunctions
     {


 public class Program
 {


 public static void Main()
     {

             var host = new HostBuilder()
                 .ConfigureFunctionsWorkerDefaults()
                 .ConfigureServices(s =>
                 {
                     s.AddHttpClient();
                     s.AddSingleton<IProductService, ProductService>();
                     s.AddSingleton<IProductRepository<Product>, ProductRepository>();
                 })
                 .Build();
             host.Run();
         }
     }
 }

在 CreateProduct class 中将 _productService 的限定符从静态更改为只读。依赖注入不适用于静态成员变量。同时从您的函数中删除静态限定符。

   public class CreateProduct
 {
     private readonly IProductService _productService;

     public CreateProduct(IProductService productService)
     {
         _productService = productService;
     }

     [Function("CreateProduct")]
     public async Task<HttpResponseData> Run(
         [HttpTrigger(AuthorizationLevel.Anonymous, "post")] HttpRequestData req,
         FunctionContext executionContext)
     {
         var logger = executionContext.GetLogger("CreateProduct");
         logger.LogInformation("C# HTTP trigger function processed a request.");

         var product = await req.ReadFromJsonAsync<Product>();

         _productService.CreateProduct(product);

         var response = req.CreateResponse(HttpStatusCode.OK);
         await response.WriteAsJsonAsync(
             new
             {
                 Result = true,
                 Message = $"Name: {product.Name}, Price: {product.Price}"
             });

         return response;
     }
 }

}

依赖注入不适用于 Azure Functions

Dependecy Injection doesn't work with Azure Functions

c#

azure

visual-studio

azure-functions