设置到期/缓存头在Web API格式化 [英] Setting Expires/Caching headers in a Web API Formatter

问题描述

时，可以设置在网页API一个MediaTypeFormatter内到期/缓存头？我曾尝试重写SetDefaultContentHeaders和设置像这样expires头：

Is is possible to set the expiration/caching headers inside of a MediaTypeFormatter in Web API? I have tried overriding the SetDefaultContentHeaders and setting the expires header like so:

public override void SetDefaultContentHeaders(Type type, System.Net.Http.Headers.HttpContentHeaders headers, System.Net.Http.Headers.MediaTypeHeaderValue mediaType)
    {            
       headers.Expires = DateTime.Now.AddHours(24);            
    }

但到期的Web调试像Chrome的工具查看时，它的头总是回来为-1。它也不会出现在设定CacheControl头这里不可能，因为这是一个响应头，而不是一个内容标题（无论该装置）。

But the expires header always comes back with -1 when viewing it in a web debugger like the Chrome tools. It also doesn't appear that setting the CacheControl header is not possible here as that is a response header and not a content header (whatever that means).

推荐答案

好像的任何设置的Htt presponseMessage.Headers.CacheControl 将要到期发射头作为集，但没有它设置过期时间发出与值-1。尝试设置 response.Headers.CacheControl =新CacheControlHeaderValue（）不过的没有设置最大年龄的。你应该能够做到这一点的任何地方，它公开的Htt presponseMessage ;例如在 ApiController 或 DelegatingHandler 。

Seems any setting of HttpResponseMessage.Headers.CacheControl causes the Expires header to be emitted as set, but without it set Expires is emitted with a value of -1. Try setting response.Headers.CacheControl = new CacheControlHeaderValue() but without setting max-age. You should be able to do this anywhere that exposes HttpResponseMessage; e.g. in the ApiController or a DelegatingHandler.

根据 RFC2616 ，如果​​CacheControl的最大年龄为present，它将覆盖到期，但如果你只是把它设置为高于它应该工作。

As per RFC2616, if CacheControl's max-age is present, it overrides Expires, but if you just set it as above it should work.

不管这是一个好主意是值得商榷的，因为到期时HTTP 1.0，而CacheControl是HTTP 1.1。

Whether or not this is a good idea is debatable, as Expires is HTTP 1.0, while CacheControl is HTTP 1.1.

这篇关于设置到期/缓存头在Web API格式化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IT屋！