ios - 如何防止 iOS 7 NSURLConnection 使用缓存

Question

问题:这个过程在 iOS6 上运行得很好。现在它不拉取最新信息并替换显示的数据。因此申请信息总是错误的。如果我重置模拟器上的内容，它会在当前时间段内工作。之后我将需要再次重置内容。有什么建议。我包含了处理我所有数据处理的 3 个文件以供引用。

读者.M

- (void) startRequest
{
    NSURL *url = [[NSURL alloc] initWithString:@"http://www.something.com/app/rss/"];
    NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url cachePolicy:NSURLCacheStorageNotAllowed timeoutInterval:60.0f];
    NSURLConnection *conn = [[NSURLConnection alloc]initWithRequest:request delegate:self startImmediately:YES];
    if(conn)
    {
        _receivedData = [[NSMutableData alloc]init];
    }
}

#pragma mark - NSURLConnectionDataDelegate

- (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"%@",error.description);
}

- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    NSLog(@"received %d bytes",data.length);
    [_receivedData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSXMLParser *parser = [[NSXMLParser alloc] initWithData:_receivedData];
    JSTRRSSParser *rssParser = [[JSTRRSSParser alloc] init];
    parser.delegate = rssParser;
    [parser parse];

    NSMutableArray *articleList = [rssParser getParsedList];

    NSLog(@"%@", articleList);
    NSString *fileName = [NSString stringWithFormat:@"%@/popular.rss", [JSTRRSSUtil getDocumentRoot]];
    [articleList writeToFile:fileName atomically:YES];
}
@end

解析器.m

#import "JSTRRSSParser.h"

@implementation JSTRRSSParser

- (id) init
{
    self = [super init];
    if (self) {
        // custom initializer
        _list = [[NSMutableArray alloc] init];
    }
    return self;
}

- (NSMutableArray *)getParsedList
{
    return _list;
}

#pragma mark - implement NSXMLParserDelegate

- (void) parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"item"]) {
        _item = [[NSMutableDictionary alloc]init];
        [_item setValue:[[NSMutableArray alloc] init] forKey:@"category"];
        [_list addObject:_item];
        _foundItem = YES;
    }

    if([elementName isEqualToString:@"image"] ||
       [elementName isEqualToString:@"slider"] ||
       [elementName isEqualToString:@"title"] ||
       [elementName isEqualToString:@"link"] ||
       [elementName isEqualToString:@"description"] ||
       [elementName isEqualToString:@"category"] ||
       [elementName isEqualToString:@"sliderphoto"] ||
       [elementName isEqualToString:@"linkId"]||
       [elementName isEqualToString:@"pubDate"]||
       [elementName isEqualToString:@"sliderpriority"]||
       [elementName isEqualToString:@"pageorder"]||
       [elementName isEqualToString:@"sectionalphoto"]) {
            _tempStore = [[NSMutableString alloc] init];
        }
    }

- (void) parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
    if (_foundItem) {
        [_tempStore appendString:string];
    }
}

- (void) parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
    if (_foundItem) {
        if([elementName isEqualToString:@"item"]) {
            _foundItem = NO;
            return; // don't preceed
        }

        // trim whitespace from left and right and replace commonly encoded html string
        NSString *content = [_tempStore stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceCharacterSet]];
        content = [content stringByReplacingOccurrencesOfString:@" " withString:@""];
        content = [content stringByReplacingOccurrencesOfString:@"&" withString:@"&"];
        content = [content stringByReplacingOccurrencesOfString:@""" withString:@"\""];
        content = [content stringByReplacingOccurrencesOfString:@"­" withString:@"-"];
        content = [content stringByReplacingOccurrencesOfString:@"»" withString:@">>"];
        content = [content stringByReplacingOccurrencesOfString:@"·" withString:@"-"];
        content = [content stringByReplacingOccurrencesOfString:@"&lt;" withString:@"<"];
        content = [content stringByReplacingOccurrencesOfString:@"&gt;" withString:@">"];
        content = [content stringByReplacingOccurrencesOfString:@"<br /> <br />" withString:@"\n"];
        content = [content stringByReplacingOccurrencesOfString:@"&mdash;" withString:@"-"];
        content = [content stringByReplacingOccurrencesOfString:@"&rsquo;" withString:@"'"];
        content = [content stringByReplacingOccurrencesOfString:@"&ldquo;" withString:@"'"];
        content = [content stringByReplacingOccurrencesOfString:@"&lsquo;" withString:@"'"];
        content = [content stringByReplacingOccurrencesOfString:@"&ndash;" withString:@"-"];



        if( [elementName isEqualToString:@"slider"] ) {
            [_item setObject:content forKey:@"slider"];
        } else if( [elementName isEqualToString:@"image"] ) {
            [_item setObject:content forKey:@"image"];
        } else if( [elementName isEqualToString:@"title"] ) {
            [_item setObject:content forKey:@"title"];
        } else if ( [elementName isEqualToString:@"link"]) {
            [_item setObject:content forKey:@"link"];
        } else if ( [elementName isEqualToString:@"description"]) {
            [_item setObject:content forKey:@"description"];
        } else if ( [elementName isEqualToString:@"category"]) {
            NSMutableArray *temp = (NSMutableArray *)[_item objectForKey:@"category"];
            [temp addObject:content];
        } else if ( [elementName isEqualToString:@"sliderphoto"]) {
            [_item setObject:content forKey:@"sliderphoto"];
        } else if ( [elementName isEqualToString:@"linkId"]) {
            [_item setObject:content forKey:@"linkId"];
        } else if ( [elementName isEqualToString:@"pubDate"]) {
            [_item setObject:content forKey:@"pubDate"];
        } else if ( [elementName isEqualToString:@"sliderpriority"]) {
            [_item setObject:content forKey:@"sliderprioroty"];
        } else if ( [elementName isEqualToString:@"sectionalphoto"]) {
            [_item setObject:content forKey:@"sectionalphoto"];
        } else if ( [elementName isEqualToString:@"pageorder"]) {
            [_item setObject:content forKey:@"pageorder"];
        }
    }
}

实用程序.h

+ (NSString *) getDocumentRoot
{
    // search for available path and return first
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    return [paths objectAtIndex:0];
}

此外，如果内容未重置，那么即使读者也无法从 RSS 提要中提取正确的信息。

Answer 1

您正在使用 NSURLCacheStorageNotAllowed 的 cachePolicy，这是一个 NSURLCacheStoragePolicy 值。但是您确实想使用 NSURLRequestCachePolicy 值之一，例如 NSURLRequestReloadIgnoringLocalAndRemoteCacheData 或 NSURLRequestReloadIgnoringLocalCacheData。