c# - 请求消息已发送。不能多次发送同一个请求报文

Question

我这里的代码有什么问题吗？我不断收到此错误:

System.InvalidOperationException: The request message was already sent. Cannot send the same request message multiple times.

我的 HttpRequestMessage 在 Func 中，所以我认为每次传入 func() 时我都会收到一个全新的请求。

public async Task<HttpResponseMessage> GetAsync(HttpRequestMessage request)
{
     return await RequestAsync(() => request);
}

public async Task<HttpResponseMessage> RequestAsync(Func<HttpRequestMessage> func)
{
   var response = await ProcessRequestAsync(func);

    if (response.StatusCode == HttpStatusCode.Unauthorized)   
    {
        WaitForSomeTime();
        response = await ProcessRequestAsync(func);        
    }

    return response;
}

private async Task<HttpResponseMessage> ProcessRequestAsync(Func<HttpRequestMessage> func)
{
    var client = new HttpClient();
    var response = await client.SendAsync(func()).ConfigureAwait(false);
    return response;
}

Answer 1

您正在两次调用相同的 func 参数:

var response = await ProcessRequestAsync(func);
//...
response = await ProcessRequestAsync(func);

在这种情况下，func 每次都返回相同的请求。它不会在您每次调用时生成一个新的。如果你真的每次都需要不同的请求，那么 func 需要在每次调用时返回一条新消息:

var response = await GetAsync(() => new HttpRequestMessage()); // Create a real request.

public async Task<HttpResponseMessage> GetAsync(Func<HttpRequestMessage> requestGenerator)
{
     return await RequestAsync(() => requestGenerator());
}