好的,这是交易:
我有一个在Swift应用程序中进行的URL调用,有点像这样:
/*!
@brief Tests a given Root Server URL for validity
@discussion What we do here, is append "/client_interface/serverInfo.xml"
to the given URI, and test that for validity.
@param inURIAsAString This contains a string, with the URI.
@param inCompletionBlock This is the completion block supplied by the caller. It is to be called upon receipt of data.
@returns an implicitly unwrapped optional String. This is the given URI, "cleaned up."
*/
class func testRootServerURI(inURIAsAString:String, inCompletionBlock:requestCompletionBlock!) -> String! {
// First, trim off any trailing slashes.
var ret:String! = inURIAsAString.stringByTrimmingCharactersInSet(NSCharacterSet(charactersInString: "/"))
// Next, make the string entirely lowercase.
ret = ret.lowercaseString
// Add the "http://" if necessary.
if(!ret.beginsWith ("http")) {
ret = "http://" + ret
}
// This is the URI we will actually test.
let testURIString = ret + "/client_interface/serverInfo.xml"
#if DEBUG
print("Testing \(testURIString).")
#endif
let url:NSURL! = NSURL(string: testURIString)
// We can't have the URL already in play. That would be bad.
if(nil == self.urlExtraData[testURIString]) {
// Assuming we have a completion block and a URI, we will actually try to get a version from the server (determine its validity).
if((nil != inCompletionBlock) && (nil != ret)) {
// Store the completion block for recall later.
self.urlExtraData.updateValue(inCompletionBlock, forKey: testURIString)
let dataTask:NSURLSessionTask = BMLTAdminAppDelegate.connectionSession.dataTaskWithURL(url)!
dataTask.resume()
}
}
else {
ret = nil
}
return ret
}
实际上,正是这样,因为它是我正在使用的函数(静态类函数)。
有问题的行是这一行:
self.urlExtraData.updateValue(inCompletionBlock, forKey: testURIString)
“ urlExtraData”是我之前声明的字典:
/*!
This is a dictionary of callbacks for open requests. It keys on the URL called.
@discussion I hate pulling crap like this, as it's clumsy and thread-unfriendly. Unfortunately,
there doesn't seem to be much choice, as there's no way to attach a refCon to a URL
task.
*/
static var urlExtraData:Dictionary<String,requestCompletionBlock!>! = nil
并在这里分配:
// Set up an empty dictionary for the URL refCon data.
BMLTAdminAppDelegate.urlExtraData = Dictionary<String,requestCompletionBlock!>()
完成块typedef在这里:
/*!
@brief This is the definition for the testRootServerURI completion block.
@discussion The routine is called upon completion of a URL connection. When the
connection ends (either successfully or not), this routine is called.
If it is successful, then the inData parameter will be non-nil.
If it failed, then the parameter will be nil.
@param inData the Data returned.
*/
typealias requestCompletionBlock = (inData: NSData!)->Void
会话设置在这里:
BMLTAdminAppDelegate.connectionSession = NSURLSession(configuration: config, delegate:self, delegateQueue: NSOperationQueue.mainQueue())
委托响应处理程序在这里:
/*!
@brief Called when a task receives data.
@param session The NSURLSession that controls this task.
@param dataTask The task responsible for this callback.
@param data The data returned.
*/
func URLSession(session: NSURLSession, dataTask: NSURLSessionDataTask, didReceiveData data: NSData) {
let url = dataTask.currentRequest?.URL
// We don't do squat if there is no callback in our table.
if(nil != BMLTAdminAppDelegate.urlExtraData.indexForKey((url?.absoluteString)!)) {
// Fetch the stored comnpletion block from our dictionary.
let callback:requestCompletionBlock! = BMLTAdminAppDelegate.urlExtraData[(url?.absoluteString)!]
// If one was provided (always check), then call it.
if(nil != callback) {
BMLTAdminAppDelegate.urlExtraData.removeValueForKey((url?.absoluteString)!) // Remove the callback from the dictionary.
callback(inData: data)
}
}
}
我认为使用字典来保存第二个回调是一个讨厌的,臭的hack。但是,我找不到将refCon附加到任务的方法。我宁愿将辅助完成块直接附加到任务上,而不是使用单独的字典。
我很想告诉我我的方法不好,只要给我更好的东西即可。
有没有人?
谢谢!
最佳答案
我过去所做的是创建某种事务对象。我设置了一个下载管理器(作为一个单例)来创建事务对象数组。我将事务对象作为URL会话的委托(实际上,这早于NSURLSession-我使用NSURLConnection做到了,但是想法是相同的。)
交易对象还具有完成块参数。
然后,当下载完成时,事务对象将调用其完成块,然后通知下载管理器单例已完成并准备进行清理。