在 .Net Core 2.2 中将 HttpResponseMessage 作为 IActionResult 返回的正确方法 [英] Correct way to return HttpResponseMessage as IActionResult in .Net Core 2.2

问题描述

在 .Net Core 2.2 中.我正在创建一个 API 控制器，它根据负载将请求路由到另一个 Http 端点.

In .Net Core 2.2. I am creating a API Controller that routes the request to another Http endpoint based on payload.

  [Route("api/v1")]
  public class RoutesController : Controller
  {
      [HttpPost]
      [Route("routes")]
      public async Task<IActionResult> Routes([FromBody]JObject request)
      {
                 
        var httpClient = new HttpClient();

        // here based on request httpCLient will make `POST` or `GET` or `PUT` request
        // and returns `Task<HttpResponseMessage>`. Lets assume its making `GET` 
        // call

       Task<HttpResponseMessage> response = await
         httpClient.GetAsync(request["resource"]);
            
       /*  ??? what is the correct way to return response as `IActionResult`*/
      }        
  }

基于SO帖子，我可以做到这一点

based on SO post i can do this

        return StatusCode((int)response.StatusCode, response);

但是我不确定将 HttpResponseMessage 作为 ObjectResult 发送是否正确.

However i am not sure sending HttpResponseMessage as ObjectResult is correct way.

我还想确保内容协商有效.

I also want to make sure content negotiation will work.

推荐答案

您可以创建一个自定义 IActionResult 来包装转移逻辑.

You can create a custom IActionResult that will wrap transfere logic.

public async Task<IActionResult> Routes([FromBody]JObject request)
{
    var httpClient = new HttpClient();

    HttpResponseMessage response = await httpClient.GetAsync("");

    // Here we ask the framework to dispose the response object a the end of the user resquest
    this.HttpContext.Response.RegisterForDispose(response);

    return new HttpResponseMessageResult(response);
}

public class HttpResponseMessageResult : IActionResult
{
    private readonly HttpResponseMessage _responseMessage;

    public HttpResponseMessageResult(HttpResponseMessage responseMessage)
    {
        _responseMessage = responseMessage; // could add throw if null
    }

    public async Task ExecuteResultAsync(ActionContext context)
    {
        context.HttpContext.Response.StatusCode = (int)_responseMessage.StatusCode;

        foreach (var header in _responseMessage.Headers)
        {
            context.HttpContext.Response.Headers.TryAdd(header.Key, new StringValues(header.Value.ToArray()));
        }

        if(_responseMessage.Content != null)
        {
            using (var stream = await _responseMessage.Content.ReadAsStreamAsync())
            {
                await stream.CopyToAsync(context.HttpContext.Response.Body);
                await context.HttpContext.Response.Body.FlushAsync();
            }
        }
    }
}

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