azure - HttpClient 通过 Azure Functions 依赖注入(inject)进行处置

Question

当您在 Azure Functions 中使用 DI 添加 HttpClient 时，似乎任何依赖它的东西都必须是单例，否则一旦依赖类的生命周期结束，HttpClient 将被释放。

我正在添加带有默认设置的 HttpClient:

builder.Services.AddHttpClient();

这是我尝试重新运行该函数时在日志中看到的错误:

Cannot access a disposed object.
Object name: 'System.Net.Http.HttpClient'.

有人可以证实吗？如果是这样，这是预期的行为吗？

Answer 1

我不确定您是否检查过官方文档，但以下是您应该如何将 http 客户端工厂注入(inject)代码中的方法:

//注册中

using System;
using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Http;
using Microsoft.Extensions.Logging;

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

namespace MyNamespace
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddHttpClient();

            builder.Services.AddSingleton((s) => {
                return new MyService();
            });

            builder.Services.AddSingleton<ILoggerProvider, MyLoggerProvider>();
        }
    }
}

//azure 函数

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

namespace MyNamespace
{
    public class HttpTrigger
    {
        private readonly IMyService _service;
        private readonly HttpClient _client;

        public HttpTrigger(IMyService service, IHttpClientFactory httpClientFactory)
        {
            _service = service;
            _client = httpClientFactory.CreateClient();
        }

        [FunctionName("GetPosts")]
        public async Task<IActionResult> Get(
            [HttpTrigger(AuthorizationLevel.Function, "get", Route = "posts")] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");
            var res = await _client.GetAsync("https://microsoft.com");
            await _service.AddResponse(res);

            return new OkResult();
        }
    }
}

https://learn.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection