Azure Functions HttpClient 根据请求没有已知这样的主机

Question

我正在尝试查看 API 是否已启动，但是当我将代码发布到 Azure 时，HttpClient 无法获取任何内容，因为当它尝试 .SendAsync(); 时，它无法获取任何内容。我从 Azure 收到的错误消息是“No Such Host is Known”，但代码在我的本地环境中确实可以正常工作。

从中您知道什么可能会丢失或导致 HttpClient Get 失败吗？

public class ConnectionTester
    {
        [FunctionName("ConnectionTester")]
        public static async Task Run([TimerTrigger("* */30 * * * *")] TimerInfo connectionTimer, ILogger log)
        {
            log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");
            
            var client = new HttpClient();
            client.DefaultRequestHeaders.Add("Authorization", strAuth);
            HttpRequestMessage newRequest = new HttpRequestMessage(HttpMethod.Get, strLink);
            var response = await client.SendAsync(newRequest);
            
            if (response.IsSuccessStatusCode)
            {
                log.LogInformation("Success");
            }
            else
            {
                log.LogError("Error");
            }
        }
    }

Answer 1

我遵循了问题中给出的相同代码并复制如下:

堆栈:Azure Functions (.NET 6) - 计时器触发器

Function1.cs

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

namespace KrishFunctionApp1205
{
    public class Function1
    {
        [FunctionName("Function1")]
        public async Task RunAsync([TimerTrigger("0 */1 * * * *")]TimerInfo myTimer, ILogger log)
        {
            log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");
            var strLink = "https://stackoverflow.com/";
            var strAuth = "Key05";
            var client = new HttpClient();
            client.DefaultRequestHeaders.Add("Authorization", strAuth);
            HttpRequestMessage newRequest = new HttpRequestMessage(HttpMethod.Get, strLink);
            var response = await client.SendAsync(newRequest);

            if (response.IsSuccessStatusCode)
                log.LogInformation("Okidoki");
            else
                log.LogError($"{response.StatusCode} {response.ReasonPhrase}: ");
        }
    }
}

<强> local.settings.json :

{
    "IsEncrypted": false,
    "Values": {
        "AzureWebJobsStorage": "UseDevelopmentStorage=true",
        "FUNCTIONS_WORKER_RUNTIME": "dotnet"
    }
}

host.json:

{
    "version": "2.0",
    "logging": {
        "applicationInsights": {
            "samplingSettings": {
                "isEnabled": true,
                "excludedTypes": "Request"
            }
        }
    }
}

.csproj:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.ApplicationInsights.WorkerService" Version="2.15.0" />
    <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="4.0.1" />
  </ItemGroup>
  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>
</Project>

本地运行结果:

在 Azure 中运行时的结果:

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注意:解决以下错误的几个步骤是:

HttpClient No such host is known on Request

• 可能是 DNS 问题，请检查 URI 是否正常工作。

• 您尝试发送到 URI 的请求被公司防火墙或系统防火墙阻止。

• 更改 Azure Functions 项目中的端口号并运行该函数。 (请参阅 here 了解如何更改 Azure Functions 中的端口号)

• 如果 Visual Studio 中有可用更新，请升级/更新 .NET 项目 SDK。

• 检查连接字符串是否指向正确的值。要在本地运行并使用本地存储模拟器，则:

  "AzureWebJobsStorage": "UseDevelopmentStorage=true"

  要使用 Azure 存储帐户并在本地运行该函数，则

  "AzureWebJobsStorage": "<Azure-Storage-Account-Connection-String>"

您可以从 Azure 门户 > 存储帐户 > 访问 key > 连接字符串获取此连接字符串。

<小时/>