ios - AFNetworking - 请求和图像的缓存时间如何工作？

Question

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Answer 1

The cache is controlled by the HTTP response header?

是的；这就是 NSURLCache 决定是否缓存数据以及缓存多长时间的方式。

It is based on the headers 'Cache-Control' and 'Expires' for normal requests?

是的，但值得注意的是，如果缓存周期太短，它有时会忽略缓存请求。不幸的是，这不是记录在案的行为。

You can customize the cache time and fixed it in 1 day, regardless of the HTTP response headers?

为了更好地控制缓存，您可以使用 SDURLCache:https://github.com/rs/SDURLCache AFNetworking 在他们的常见问题解答中推荐了这个库。

If there is image cache, it is stored on disk or saved to memory?

对于一般请求，这可由开发人员配置(请参阅 NSURLCache 文档)。

对于UIImageView+AFNetworking，除了提供内存缓存的NSURLCache之外，还使用了NSCache。

The cache requests work when the device has no internet connection?

是的，但是缓存随时可能失效，所以不要依赖这个。

The user makes a request but the device showed no internet connection and the request was suspended. You can ignore the same requests when the device returns to its internet connection? The only way my application would work offline using database or can be based on the system cache of this framework?

您可以在收到 NSURLRequest 后手动检查缓存的响应:

NSMutableURLRequest *request = [myHTTPClient requestWithMethod:@"GET" path:path parameters:parameters];
NSCachedURLResponse *cachedResponse = [[NSURLCache sharedURLCache] cachedResponseForRequest:request];
if (cachedResponse)
{
    // Use response
}

You can change the timeout of requests without having to customize a 'NSURLRequest'?

不是开箱即用的，但您可以覆盖在子类中创建 NSMutableURLRequest 的方法，以便为每个子类更改它。这个方法是requestWithMethod:path:parameters:。