是否可以阻止 NSURLRequest 缓存数据或在请求后删除缓存数据? [英] Is it possible to prevent an NSURLRequest from caching data or remove cached data following a request?

问题描述

在 iPhone 上，我使用 NSURLRequest 为一大块数据执行 HTTP 请求.对象分配高峰，我相应地分配数据.当我处理完数据后，我会相应地将其释放 - 但是仪器没有显示任何数据已被释放！

On iPhone, I perform a HTTP request using NSURLRequest for a chunk of data. Object allocation spikes and I assign the data accordingly. When I finish with the data, I free it up accordingly - however instruments doesn't show any data to have been freed!

我的理论是默认情况下会缓存 HTTP 请求，但是 - 我不希望我的 iPhone 应用缓存这些数据.

My theory is that by default HTTP requests are cached, however - I don't want my iPhone app to cache this data.

有没有办法在请求后清除此缓存或首先防止任何数据被缓存?

Is there a way to clear this cache after a request or prevent any data from being cached in the first place?

我已经尝试使用记录的所有缓存策略，如下所示:

I've tried using all the cache policies documented a little like below:

NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:url]];
theRequest.cachePolicy = NSURLRequestReloadIgnoringLocalCacheData;

但似乎没有什么可以释放内存！

but nothing seems to free up the memory!

推荐答案

通常创建这样的请求会更容易

Usually it's easier to create the request like this

NSURLRequest *request = [NSURLRequest requestWithURL:url
      cachePolicy:NSURLRequestReloadIgnoringCacheData
      timeoutInterval:60.0];

然后创建连接

NSURLConnection *conn = [NSURLConnection connectionWithRequest:request
       delegate:self];

并在委托上实现 connection:willCacheResponse: 方法.只需返回 nil 即可.

and implement the connection:willCacheResponse: method on the delegate. Just returning nil should do it.

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse {
  return nil;
}

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