AFNetworking 2.0 AFHTTPRequestOperationManager CachePolicy 不工作

Question

我正在尝试使用 If-Modified-Since header 向服务器发出 GET 请求以避免加载相同的内容。当我发出请求时，我知道服务器正在发回 304 指示内容未更改，但 NSURLCache 或 AFNetworking 正在响应 200 缓存的内容。为了防止这种情况，我将请求序列化程序的缓存策略设置为 NSURLRequestReloadIgnoringLocalCacheData，但这并不能解决问题。

- (void)getConfig {

    //Retrive the timeStamp at which the config was last updated
    NSDate *timeStamp = [[NSUserDefaults standardUserDefaults] objectForKey:@"lastGetConfigDate"];

    //Get the rfc1123 representation of the timeStamp
    NSString *dateString = [timeStamp rfc1123String];

    //If we're not force loading the data then include the time stamp in the If-modified-Since header
    [self.requestSerializer setValue:[NSString stringWithFormat:@"%@", dateString] forHTTPHeaderField:@"If-Modified-Since"];

    //Setting cachePolicy to ignore cache data to prevent the cached response
    [self.requestSerializer setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];

    //GET REQUEST to /api/config
    [self GET:@"/api/config" parameters:nil success: ^(AFHTTPRequestOperation *operation, id responseObject) {
        NSDictionary *jsonDict = (NSDictionary *)responseObject;

        DDLogInfo(@"Config: 200");

        //If the config data was successfully loaded then set the lastGetConfigDate time stamp in the nsuserdefaults to send in the next call with the if-modified-since header
        if (success) {
            [[NSUserDefaults standardUserDefaults] setObject:[NSDate date] forKey:@"lastGetConfigDate"];
        }

    } failure: ^(AFHTTPRequestOperation *operation, NSError *error) { ....

Answer 1

这是最新版本的 AFNetworking 中的一个错误，在 issue #2563. On January 24th, an attempt to resolve some other issue 中进行了讨论，引入了此错误。要解决它，

回滚到之前版本的 AFNetworking 2.5.0；或

手动 post KVO 自己通知：

[self.requestSerializer willChangeValueForKey:@"cachePolicy"];
[self.requestSerializer setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
[self.requestSerializer didChangeValueForKey:@"cachePolicy"];

关于这个错误缺乏回应令人非常失望。假设这确实是您遇到的问题（尝试上述方法之一，看看它是否可以解决您的问题），请加入我们并 post 在 issue #2563 下的讨论中发表您自己的评论。参与的人越多，修复的可能性就越大。

注意：已于 2015 年 3 月 26 日在提交 7d8e286.

中修复

AFNetworking 2.0 AFHTTPRequestOperationManager CachePolicy 不工作

AFNetworking 2.0 AFHTTPRequestOperationManager CachePolicy not working

nsurlcache

ios

afnetworking