19

我找不到任何问题的答案,可能是我错过了什么......

当我请求一个 url 时,我需要知道响应是来自缓存还是来自网络。

状态码是 304 还是 200 ?(但AFNetworking总是响应 200)

ASIHTTPRequest曾经检查“ didUseCachedResponse” from ASIHTTPRequest,这是完美的。

4

4 回答 4

24

我想我找到了一个解决方案来确定响应是从缓存返回还是不使用 AFNetworking 2.0。我发现每次从服务器返回一个新响应(状态 200,而不是 304)时,都会调用cacheResponseBlock它的一个属性。AFHTTPRequestOperation如果应该缓存响应,则该块应该返回NSCachedURLResponse,如果不应该缓存,则返回 nil。这样您就可以过滤响应并仅缓存其中的一些。在这种情况下,我正在缓存来自服务器的所有响应。诀窍是,当服务器发送 304 并从缓存加载响应时,不会调用此块。所以,这是我正在使用的代码:

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];

BOOL __block responseFromCache = YES; // yes by default

void (^requestSuccessBlock)(AFHTTPRequestOperation *operation, id responseObject) = ^(AFHTTPRequestOperation *operation, id responseObject) {
    if (responseFromCache) {
        // response was returned from cache
        NSLog(@"RESPONSE FROM CACHE: %@", responseObject);
    }
    else {
        // response was returned from the server, not from cache
        NSLog(@"RESPONSE: %@", responseObject);
    }
};

void (^requestFailureBlock)(AFHTTPRequestOperation *operation, NSError *error) = ^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"ERROR: %@", error);
};

AFHTTPRequestOperation *operation = [manager GET:@"http://example.com/"
                                      parameters:nil
                                         success:requestSuccessBlock
                                         failure:requestFailureBlock];

[operation setCacheResponseBlock:^NSCachedURLResponse *(NSURLConnection *connection, NSCachedURLResponse *cachedResponse) {
    // this will be called whenever server returns status code 200, not 304
    responseFromCache = NO;
    return cachedResponse;
}];

这个解决方案对我有用,到目前为止我还没有发现任何问题。但是,如果您有更好的想法或对我的解决方案有异议,请随时发表评论!

于 2014-02-04T15:05:54.657 回答
2

似乎苹果不想让你知道它是否来自缓存。

我找到了一种方法,将修改日期与请求关联起来,并在 AFNetWorking 回复我时比较这个日期。

没有我想要的那么干净,但可以工作......

于 2012-09-03T08:09:48.427 回答
1

在 AFNetworking 中有一种方法可以指定应该被视为成功的状态码,它是通过响应序列化来完成的,这里是代码

AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];

AFHTTPResponseSerializer *respSerializer = [AFHTTPResponseSerializer serializer];
NSMutableIndexSet *responseCodes = [NSMutableIndexSet indexSet];
[responseCodes addIndex:200];
[responseCodes addIndex:304];

[operation setResponseSerializer:respSerializer];

使用此代码,AFNetworking 会将 304 视为成功

于 2015-05-20T22:52:51.997 回答
1

创建您的 URLCache 类并覆盖storeCachedResponse方法

class MyURLCache: URLCache {
    override func storeCachedResponse(_ cachedResponse: CachedURLResponse, for request: URLRequest) {

        //adding caching header if needed
        var headers = response.allHeaderFields
        headers.removeValue(forKey: "Cache-Control")
        headers["Cache-Control"] = "max-age=\(5 * 60)" //5 min

        //the trick
        if (headers["isCachedReponse"] == nil){
            headers["isCachedReponse"] = "true"
        }

        if let
            headers = headers as? [String: String],
            let newHTTPURLResponse = HTTPURLResponse(url: response.url!, statusCode: response.statusCode, httpVersion: "HTTP/1.1", headerFields: headers) {
            let newCachedResponse = CachedURLResponse(response: newHTTPURLResponse, data: cachedResponse.data)
            super.storeCachedResponse(newCachedResponse, for: request)
        }
    }
}

在 AppDelegate 中使用您的 URLCache 设置 URLCache.shared

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
        let cache = MyURLCache(memoryCapacity: 1024 * 1024 * 500, diskCapacity: 1024 * 1024 * 500, diskPath: nil)
        URLCache.shared = cache
        return true
    }
}

在响应回调中检查响应内容的标题是否为“newResponse”键

if (response.allHeaderFields["isCachedReponse"] == nil){
      print("not cache")
} else {
      print("cache")
}

适用于所有版本的AFNetworking

于 2019-05-13T13:36:27.577 回答