Windows Phone 7 WebRequest caching?

问题:

Is Windows Phone HTTP client caching automatically ?

When using Fiddler, I don't see all my requests.

回答1:

Yes, HttpWeRequest (whihc is used internally by WebClient-if you're using that) has built in caching which can be quite aggressive, depending on your requirements.

The common work around for this is to append and extra value to the querystring which has no meaning other than to work around the caching of previous calls.

Something like:

var mrUri = "http://something.com/path/file.ext?nocache=" + Guid.NewGuid();

or

var mrUri = "http://something.com/path/file.ext?nocache=" + DateTime.UtcNow.ToString();

回答2:

I had that problem recently. Some blog posts about it :

http://ayende.com/blog/4755/silverlight-and-http-and-caching-oh-my

http://www.nickharris.net/2010/10/windows-phone-7-httpwebrequest-returns-same-response-from-cache/

Here is the code I'm using with Spring.NET REST Client Framework to force no caching by default:

public class NoCacheRequestInterceptor : IClientHttpRequestFactoryInterceptor
{
    public IClientHttpRequest Create(IClientHttpRequestFactoryCreation creation)
    {
        creation.Uri = new Uri(String.Format("{0}{1}nocache={2}",
            creation.Uri.ToString(),
            String.IsNullOrEmpty(creation.Uri.Query) ? "?" : "&",
            DateTime.Now.Ticks.ToString()));

        return creation.Create();
    }
}

RestTemplate client = new RestTemplate("http://www.example.com/");
client.RequestInterceptors.Add(new NoCacheRequestInterceptor());
// ..
string result = client.GetForObject<string>("category/{id}", 4);