Question

我正在使用Xcode 6.1（6A1030），iOS7和iOS8模拟器。

NSURLCache似乎没有缓存任何内容。我使用“Cache-Control”标头。我的服务器返回带有'max-age = 6000'的Cache-Control标头。

在此示例中，我篡改了Google的请求，该请求也未缓存：

的AppDelegate：

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    var URLCache = NSURLCache(memoryCapacity: 500 * 1024 * 1024, diskCapacity: 500 * 1024 * 1024, diskPath: "bla")
    NSURLCache.setSharedURLCache(URLCache)
    sleep(1)
    return true
}

然后我开始连接：

    let urlPath: String = "http://www.google.com"
    var url: NSURL = NSURL(string: urlPath)!

    var request: NSURLRequest = NSURLRequest(URL: url, cachePolicy: NSURLRequestCachePolicy.ReturnCacheDataElseLoad, timeoutInterval: 5000)
    var cachedURLResponse = NSURLCache.sharedURLCache().cachedResponseForRequest(request)

    // cachedURLResponse is always nil

    var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: true)!
    connection.start()

在缓存响应之前，我添加了Cache-Control标头：

func connection(connection: NSURLConnection, willCacheResponse cachedResponse: NSCachedURLResponse) -> NSCachedURLResponse? {
    var HTTPResponse = cachedResponse.response as NSHTTPURLResponse
    var modifiedHeaders = NSMutableDictionary(dictionary: HTTPResponse.allHeaderFields)
    modifiedHeaders["Cache-Control"] = "max-age=6000"
    modifiedHeaders.removeObjectForKey("Expires")
    var modifiedResponse = NSHTTPURLResponse(URL: HTTPResponse.URL!, statusCode: HTTPResponse.statusCode, HTTPVersion: "HTTP/1.1", headerFields: modifiedHeaders)
    return NSCachedURLResponse(response: modifiedResponse!, data: cachedResponse.data, userInfo: cachedResponse.userInfo, storagePolicy: cachedResponse.storagePolicy)
}

修改后的响应如下所示：

{URL：http://www.google.com/?gfe_rd=cr&ei=MSBGVKe7AeeI8QepoYGgCg} {状态代码：200，headers { “Alternate-Protocol”=“80：quic，p = 0.01”; “Cache-Control”=“max-age = 6000”; “Content-Type”=“text / html; charset = windows-1255”; 日期=“星期二，2014年10月21日08:58:25 GMT”; 服务器= gws; “转移编码”=身份; “X-Frame-Options”= SAMEORIGIN; “X-XSS-Protection”=“1; mode = block”; }}

然而，'cachedResponseForRequest'每次都返回nil，每次都会发送一个新的服务器请求。

我做错了吗？非常感谢你的帮助！

NSURLCache没有缓存

0 个答案: