asp.net - 在 Net Framework 上编写的应用程序中使用 WinHttpHandler 与 HttpClientHandler

Question

对于 Net Framework 4.6.1+ 编写的应用程序，我们可以在 HttpClient 中使用至少 2 个处理程序，即:

• HttpClientHandler(网络框架的一部分)
• WinHttpHandler (提供通过 Nuget)

没有文章通过以下问题对它们进行比较:

• 性能比较
• 使用 DNS 转换(当 DNS FQDN 的 IP已更改)
• 连接租用超时(当 HttpClient 不这样做时)自动缩放时自动移动到新实例)

有人可以分享一下您使用WinHttpHandler的经验吗？

Answer 1

Karel Zikmund在我的问题上写了答案，你可以通过下一个url看到它

Starting with .NET Core 2.1, the HttpClientHandler uses by default SocketsHttpHandler - new C# implementation over sockets.

It's key value is consistency across platforms and focus on performance (especially against CurlHandler on Linux/Mac).

WinHttpHandler is wrapper over winhttp OS component. If you need HTTP/2, it is currently the only option as SocketsHttpHandler does not support HTTP/2 yet (see #23134).

DNS changes behave the same behavior on both, however, you can tweak it somewhat via SocketsHttpHandler.PooledConnectionLifetime.

DNS TTL is not supported - see #24257 and #11224. The workaround is to recycle the handler on regular basis. You can also use higher-level wrapper HttpClientFactory which does that for you (at least as a motivation).