cachedResponseForRequest 方法未被访问

Question

我正在尝试设置缓存，但是线程没有访问我正在使用的“如下”方法。

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

我正在像这样初始化连接，并且访问了 connectionDidFinishLoading，所以我不确定我缺少什么。

- (IBAction)searchRequest:(NSData *)postBodyData
{
    //Set database address
    NSMutableString *databaseURL = [[NSMutableString alloc] initWithString:@"https://127.0.0.1:88"]; 

    NSURL *url = [NSURL URLWithString:databaseURL];

    NSString *postLength = [NSString stringWithFormat:@"%d", [postBodyData length]];

    //SynchronousRequest to grab the data, also setting up the cachePolicy
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:5.0]; //if request dose not finish happen within 60 second timeout.

//    NSInputStream *fileStream = [NSInputStream inputStreamWithData:postBodyData];


    [request setHTTPMethod: @"POST"];
    [request setValue:postLength forHTTPHeaderField:@"Content-Length"];
    [request setValue:@"application/octet-stream" forHTTPHeaderField:@"content-type"];
    [request setHTTPBody:postBodyData];

    NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:request delegate:self];

    if (theConnection) {
        // Create the NSMutableData to hold the received data.
        // receivedData is an instance variable declared elsewhere.
        receivedData = [NSMutableData data];
    } else {
        // Inform the user that the connection failed from the connection:didFailWithError method
    }
}

任何帮助将不胜感激。

Answer 1

connection:willCacheResponse: 仅在响应将被缓存时调用。在大多数情况下，POST 请求是不可缓存的。 （更多详情：Is it possible to cache POST methods in HTTP?）

您可能应该查看MKNetworkKit 之类的东西，它处理大量此类缓存，尤其是对于 REST 协议。

您也可以查看Drop-in offline caching for UIWebView。您必须对其进行重大修改，但NSURLProtocol 可用于解决此类问题。 AFCache 目前正在努力整合这种方法，并且是另一个需要考虑的工具包。 （通读博文中的 cmets 以了解有关这些问题的更多背景信息。）