WCF REST JSON服务缓存 [英] WCF REST JSON service caching

问题描述

我有一个WCF Web服务返回JSON。

I have a WCF web service returning JSON.

[OperationContract]
[WebGet(BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json)]
Stream GetStuff(int arg);

和我使用这个方法的对象图转换为JSON：

And I'm using this method to convert an object graph to JSON:

private static Stream ToJson(object obj)
{
    JavaScriptSerializer serializer = new JavaScriptSerializer();
    string json = serializer.Serialize(obj);

    if (WebOperationContext.Current != null)
    {
        OutgoingWebResponseContext outgoingResponse = WebOperationContext.Current.OutgoingResponse;

        outgoingResponse.ContentType = "application/json; charset=utf-8";
        outgoingResponse.Headers.Add(HttpResponseHeader.CacheControl, "max-age=604800"); // one week
        outgoingResponse.LastModified = DateTime.Now;
    }

    return new MemoryStream(Encoding.UTF8.GetBytes(json));
}

我想响应被缓存的浏览器，但浏览器仍然产生如果修改 - 因为调用这些重播与<$服务器C $ C> 304未修改。我想在浏览器缓存，并使用响应不必每次都作出如果修改 - 因为调用服务器。

I'd like the responses to be cached on the browser, but the browser is still generating If-Modified-Since calls to the server which are replayed with 304 Not Modified. I would like the browser to cache and use the response without making an If-Modified-Since call to the server each time.

我发现，即使我指定的Cache-Control最大年龄= 604800在code，通过WCF发送的响应头为缓存控制无缓存，最大年龄= 604800 。为什么WCF加入了无缓存的一部分，如何从将其加入阻止它？

I noticed that, even though I specify Cache-Control "max-age=604800" in the code, the response header sent by WCF is Cache-Control no-cache,max-age=604800. Why is WCF adding the "no-cache" part and how do I stop it from adding it?

推荐答案

尝试设置缓存控制，以公，最大年龄= ...。这可能prevent WCF从应用默认的缓存策略标题。

Try setting Cache-Control to "public,max-age=...". This might prevent WCF from applying the default cache policy header.

另外，还有一些所谓的遥远的将来到期头。对于重长期缓存我使用Expires头代替的Cache-Control：最大年龄= ......并留下的Cache-Control只有公共

Also, there are so called 'far future expire headers'. For heavy long-term caching I use the Expires header instead of Cache-Control:'max-age=...' and leave Cache-Control with just "public".

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