C#HttpClient如何计算发送请求的时间、等待响应的时间和接收响应的时间？

Question

I have the following code

DateTime startSendRequest;
DateTime endSendRequest;
DateTime startWaitingResponse;
DateTime endWaitingResponse;
DateTime startGetResponse;
DateTime endGetResponse;
HttpResponseMessage response;

startSendRequest = DateTime.UtcNow;
var responseTask = HttpClient.GetAsync("Test/GetFile");
endSendRequest = DateTime.UtcNow;

startWaitingResponse = DateTime.UtcNow;
response = await responseTask;
endWaitingResponse = DateTime.UtcNow;

startGetResponse = DateTime.UtcNow;
var fs = new FileStream(@"C:\test\SampleFile.txt", FileMode.Create, FileAccess.Write, FileShare.None);
await response.Content.CopyToAsync(fs);
endGetResponse = DateTime.UtcNow;

It seems to me that the startWaitingResponse and endWaitingResponse variables are calculating the total response time (with download file), rather than waiting for a response. Is it possible to calculate "waiting response for download" and "download time"?

Answer 1

Pass HttpCompletionOption.ResponseHeadersRead :

startSendRequest = DateTime.UtcNow;
var responseTask = HttpClient.GetAsync("Test/GetFile", HttpCompletionOption.ResponseHeadersRead);
endSendRequest = DateTime.UtcNow;

Side note: prefer using Stopwatch for timing things. DateTime.UtcNow can jump forwards or backwards in time due to daylight savings time changes. DateTime.UtcNow is not accurate for timing small amounts of time.