问题描述
和 IDisposable（通过使用以下模式：
var baseAddress = new Uri("http://example.com");
var cookieContainer = new CookieContainer();
using (var handler = new HttpClientHandler() { CookieContainer = cookieContainer })
using (var client = new HttpClient(handler) { BaseAddress = baseAddress })
{
var content = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("foo", "bar"),
new KeyValuePair<string, string>("baz", "bazinga"),
});
cookieContainer.Add(baseAddress, new Cookie("CookieName", "cookie_value"));
var result = client.PostAsync("/test", content).Result;
result.EnsureSuccessStatusCode();
}
但是Microsoft最明显的例子并不称 Dispose（）显式或隐式。例如：
But the most visible examples from Microsoft don't call Dispose() either explicitly or implicitly. For instance:
- 宣布释放HttpClient。
- 实际的。
- The original blog article announcing the relase of HttpClient.
- The actual MSDN documentation for HttpClient.
- BingTranslateSample
- GoogleMapsSample
- WorldBankSample
在的评论，有人问微软员工：
In the announcement's comments, someone asked the Microsoft employee:
他的回答是：
Btw，您可以多次重复使用同一个HttpClient [如此]
通常您不会一直都在创建/处置它们。
Btw, you can reuse the same HttpClient as many times are [as] you like so typically you won't create/dispose them all the time.
第二段对于这个问题是多余的，这与我们无关可以使用HttpClient实例多少次，但是关于在不再需要它之后是否有必要将其处置。
The second paragraph is superfluous to this question, which is not concerned about how many times you can use an HttpClient instance, but about if it is necessary to dispose it after you no longer need it.
（更新：实际上第二段是
(Update: in fact that second paragraph is the key to the answer, as provided below by @DPeden.)
所以我的问题是：
-
在当前实现（.NET Framework 4.5）的情况下，是否有必要在HttpClie上调用Dispose（） nt和HttpClientHandler实例？澄清：必要是指如果不处置有任何负面后果，例如资源泄漏或数据损坏风险。
Is it necessary, given the current implementation (.NET Framework 4.5), to call Dispose() on HttpClient and HttpClientHandler instances? Clarification: by "necessary" I mean if there are any negative consequences for not disposing, such as resource leakage or data corruption risks.
如果没有必要，
如果有必要（或建议使用），则是可以安全地实现（对于.NET Framework 4.5）？
If it's necessary (or recommended), is this code mentioned above implementing it safely (for .NET Framework 4.5)?
如果这些类不需要调用Dispose（），为什么将它们实现为IDisposable？
If these classes don't require calling Dispose(), why were they implemented as IDisposable?
如果需要，或者建议这样做，Microsoft是吗？误导或不安全的示例？
If they require, or if it's a recommended practice, are the Microsoft examples misleading or unsafe?
推荐答案
通常的共识是您不（不应）需要处理HttpClient。
The general consensus is that you do not (should not) need to dispose of HttpClient.
许多与它的工作方式密切相关的人都这样说。
Many people who are intimately involved in the way it works have stated this.
请参见和相关的SO文章：供参考。
See Darrel Miller's blog post and a related SO post: HttpClient crawling results in memory leak for reference.
我也强烈建议您阅读，以了解幕后情况，特别是此处引用的生命周期部分：
I'd also strongly suggest that you read the HttpClient chapter from Designing Evolvable Web APIs with ASP.NET for context on what is going on under the hood, particularly the "Lifecycle" section quoted here:
尽管HttpClient确实间接实现了IDisposable
接口，但是HttpClient的标准用法是不要在每次请求后都将其丢弃
。只要您的应用程序需要发出HTTP请求，HttpClient对象就可以生存
。在多个请求中都存在一个对象
可以放置
DefaultRequestHeaders的位置，并避免您必须在每个请求中重新指定
之类的东西CredentialCache和CookieContainer，因为
是必需的HttpWebRequest。
甚至打开DotPeek。
Or even open up DotPeek.
这篇关于是否必须在请求之间放置HttpClient和HttpClientHandler？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！