Question

我正在尝试在Azure Function v3上注入IHttpClientFactory服务，但是我不断收到以下错误消息，说解决服务失败。我使用azure-functions-core-tools @ v3在本地运行Azure Function。

[2/14/2020 5:45:19 PM] Executed 'Foo' (Failed, Id=24489b3b-af99-417e-b175-443b76c241d5)
[2/14/2020 5:45:19 PM] Microsoft.Extensions.DependencyInjection.Abstractions: Unable to resolve service for type 'System.Net.Http.IHttpClientFactory' while attempting to activate 'MyFunction.Function.Foo'.

我有一个启动类，应该为IHttpClientFactory注入服务。

using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;

namespace MyFunction
{
    public class Startup : FunctionsStartup
    {

        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddHttpClient();
        }
    }
}

下面是一个天蓝色的函数类，该类使用IHttpClientFactory的注入服务来创建HTTP客户端并将GET请求发送到服务器。

using System.Threading.Tasks;
using System.Net.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;

namespace MyFunction.Function
{
    public class Foo
    {
        private readonly HttpClient httpClient;
        public Scrape(IHttpClientFactory httpClientFactory)
        {
            httpClient = httpClientFactory.CreateClient();
        }

        [FunctionName("Foo")]
        public async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            var result = await httpClient.GetAsync("https://google.com");
            var data = await result.Content.ReadAsStringAsync();
            return new OkObjectResult(data);
        }
    }
}

我想念什么吗？

Answer 1

您的startup.cs类似乎缺少它的程序集引用？

[assembly: FunctionsStartup(typeof(MyFunction.Startup))]

尝试将其添加到启动类中。将其添加到顶部的using语句之后，任何名称空间声明之前。

此外，我看到的大多数示例都显示了在函数执行期间实际创建的客户端，而不是在默认构造函数中。

using System.Threading.Tasks;
using System.Net.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;

namespace MyFunction.Function
{
    public class Foo
    {
        private readonly HttpClient httpClient;
        public Scrape(IHttpClientFactory httpClientFactory)
        {
            factory = httpClientFactory;
        }

        [FunctionName("Foo")]
        public async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            HttpClient httpClient = factory.CreateClient();
            var result = await httpClient.GetAsync("https://google.com");
            var data = await result.Content.ReadAsStringAsync();
            return new OkObjectResult(data);
        }
    }
}

在Azure Function上为IHttpClientFactory解析服务失败

1 个答案: