如何清除URLSession/URLConfiguration存储的缓存数据? [英] How to clear cached data stored by URLSession/URLConfiguration?

问题描述

我正在使用以下代码通过URLConfiguration设置URLSession的缓存策略.

I am using the code below to set the caching policy of my URLSession via URLConfiguration.

if appDelegateObj.configuration == nil {
            appDelegateObj.configuration = URLSessionConfiguration.default
   }

if self.apiType == ServerRequest.API_TYPES_NAME.API1  {


    if appDelegateObj.forceReload == true {
        appDelegateObj.configuration?.urlCache = nil
        appDelegateObj.configuration?.requestCachePolicy = .reloadIgnoringLocalCacheData

    }else{
        appDelegateObj.configuration?.requestCachePolicy = .returnCacheDataElseLoad
    }


}else{
    appDelegateObj.configuration?.requestCachePolicy = .reloadIgnoringLocalCacheData
}
session = URLSession(configuration: appDelegateObj.configuration!, delegate: nil, delegateQueue: nil)

我遇到的问题是，即使在设置

The problem I am having is that I am getting the cached response back even after setting the

appDelegateObj.configuration?.urlCache = nil

我能够获取最新数据的唯一方法是使用

The only way I am able to get fresh data is via using

appDelegateObj.configuration?.requestCachePolicy = .reloadIgnoringLocalCacheData

我在做什么错?我需要一种方法来清除该应用程序的所有缓存数据.

What am I doing wrong ? I need a way to clear all the cached data for the app.

我尝试使用

URLCache.shared.removeAllCachedResponses()

但是那也不起作用.

推荐答案

几点:

• 将URL缓存设置为nil不会禁用所有缓存.用户仍然可以从代理获取缓存的数据.
• 不能保证清除缓存是即时的. IIRC，它滞后了几秒钟.
• 即使是即时的，用户仍然可以从代理获取缓存的数据.

简而言之，设置reloadIgnoringLocalCacheData是做您正在做的事情的正确方法(嗯，真的，NSURLRequestReloadIgnoringLocalAndRemoteCacheData).

In short, setting reloadIgnoringLocalCacheData is the correct way to do what you're doing (well, really, NSURLRequestReloadIgnoringLocalAndRemoteCacheData).

但是，除非您尝试支持某些奇怪的脱机模式，否则可能不想要使用returnCacheDataElseLoad.该模式将忽略服务器提供的缓存过期，您几乎肯定不希望这样做.请改用默认策略(useProtocolCachePolicy).

However, unless you're trying to support some weird offline mode, you probably do not want to be using returnCacheDataElseLoad. That mode ignores the cache expiration provided by the server, which you almost certainly do not want to do. Use the default policy (useProtocolCachePolicy) instead.

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