连接：willCacheResponse将永远不会被调用

Question

我正在研究一个涉及从Web服务器下载数据的iPhone应用程序。除了方法connection:willCacheResponse:永远不会被调用，所有的东西都正常工作。但其他人喜欢connection:didReceiveResponse:,connection:didReceiveData:,connection:didFailWithError:,connectionDidFinishLoading:所有工作正常。我喜欢做以下连接：

- (void)makeConnection 
{ 
    NSURL *url = [NSURL URLWithString:@"http://www.abc.com"]; 
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReturnCacheDataElseLoad timeoutInterval:60]; 
    [request setHTTPMethod:@"POST"]; 
    NSString *postString = [NSString stringWithFormat:@"%@", string]; 
    [request setValue:[NSString stringWithFormat:@"%d", [postString length]] forHTTPHeaderField:@"Content-length"]; 
    [request setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]]; 
    NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; 
} 

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse 
{ 
    NSCachedURLResponse *newCachedResponse = cachedResponse; 
    NSDictionary *newCachedResponseUserInfo = [NSDictionary dictionaryWithObject:[NSDate date] forKey:@"Cached Date"]; 
    newCachedResponse = [[NSCachedURLResponse alloc] initWithResponse:[cachedResponse response] data:[cachedResponse data] userInfo:newCachedResponseUserInfo storagePolicy:[cachedResponse storagePolicy]]; 

    return newCachedResponse; 
} 

我也尝试将策略更改为NSURLRequestUseProtocolCachePolicy，但没有任何帮助。还试图把一个断点在

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse 

但什么也没有发生。 我错过了什么吗？先谢谢你。

Answer 1

连接：willCacheResponse：如果所述响应包含Cache-Control头，仅称为根据Apple’s documentation:

的委托接收连接：willCacheResponse：消息仅对支持高速缓存协议。