在整个程序中只有一个全局队列
MKNetWorkKit中主要有两个类，MKNetworkEngine和 MKNetworkOperation，MKNetworkOperation就是一个操作，是NSOperation的子类，每个HTTP操作通过 MKNetworkEngine入队，队列是一个NSOperationQueue，在程序是一个单例，在MKNetworkEngine的 initialize里创建。
GET请求
一般自己会复写MKNetworkEngine，在这里提供一个每一个网络请求的接口，可以传入参数，请求完成和失败的block。
self.yahooEngine = [[YahooEngine alloc] initWithHostName:@"download.finance.yahoo.com"];
YahooEngine的GET请求方法的申明
typedef void (^CurrencyResponseBlock)(double rate);-(MKNetworkOperation*) currencyRateFor:(NSString*) sourceCurrency inCurrency:(NSString*) targetCurrency completionHandler:(CurrencyResponseBlock) completionGET请求方法的实现
-(MKNetworkOperation*) currencyRateFor:(NSString*) sourceCurrency inCurrency:(NSString*) targetCurrency completionHandler:(CurrencyResponseBlock) completionBlock errorHandler:(MKNKErrorBlock) errorBlock { MKNetworkOperation *op = [self operationWithPath:YAHOO_URL(sourceCurrency, targetCurrency) params:nil httpMethod:@"GET"]; [op addCompletionHandler:^(MKNetworkOperation *completedOperation) { // the completionBlock will be called twice. // if you are interested only in new values, move that code within the else block NSString *valueString = [[completedOperation responseString] componentsSeparatedByString:@","][1]; DLog(@"%@", valueString); if([completedOperation isCachedResponse]) { DLog(@"Data from cache %@", [completedOperation responseString]); } else { DLog(@"Data from server %@", [completedOperation responseString]); } completionBlock([valueString doubleValue]); }errorHandler:^(MKNetworkOperation *errorOp, NSError* error) { errorBlock(error); }]; [self enqueueOperation:op]; return op;}
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self.currencyOperation = [ApplicationDelegate.yahooEngine currencyRateFor:@"SGD" inCurrency:@"USD" completionHandler:^(double rate) { [[[UIAlertView alloc] initWithTitle:@"Today's Singapore Dollar Rates" message:[NSString stringWithFormat:@"%.2f", rate] delegate:nil cancelButtonTitle:NSLocalizedString(@"Dismiss", @"") otherButtonTitles:nil] show]; } errorHandler:^(NSError* error) { DLog(@"%@ %@ %@ %@", [error localizedDescription], [error localizedFailureReason], [error localizedRecoveryOptions], [error localizedRecoverySuggestion]); }]; |
POST请求，上传一张图片
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-(MKNetworkOperation*) uploadImageFromFile:(NSString*) file completionHandler:(IDBlock) completionBlock errorHandler:(MKNKErrorBlock) errorBlock { MKNetworkOperation *op = [self operationWithPath:@"upload.php" params:@{@"Submit": @"YES"} httpMethod:@"POST"]; [op addFile:file forKey:@"image"]; // setFreezable uploads your images after connection is restored! [op setFreezable:YES]; [op addCompletionHandler:^(MKNetworkOperation* completedOperation) { NSString *xmlString = [completedOperation responseString]; DLog(@"%@", xmlString); completionBlock(xmlString); } errorHandler:^(MKNetworkOperation *errorOp, NSError* error) { errorBlock(error); }]; [self enqueueOperation:op]; return op;} |
上传的时候可以增加一个进度条，所以在调用这个方法的时候可以有以下代码。
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NSString *uploadPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingFormat:@"/SampleImage.jpg"]; self.uploadOperation = [ApplicationDelegate.testsEngine uploadImageFromFile:uploadPath completionHandler:^(id twitPicURL) { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Uploaded to" message:(NSString*) twitPicURL delegate:nil cancelButtonTitle:NSLocalizedString(@"Dismiss", @"") otherButtonTitles:nil]; [alert show]; self.uploadProgessBar.progress = 0.0; } errorHandler:^(NSError* error) { [UIAlertView showWithError:error]; }]; [self.uploadOperation onUploadProgressChanged:^(double progress) { DLog(@"%.2f", progress*100.0); self.uploadProgessBar.progress = progress; }]; |
正确显示网络状态指示
正确显示网络状态指示的判断条件就是操作operation数大于0的时候。
自动改变队列大小
在wifi以及3G网络是会调用setMaxConcurrentOperationCount：方法切换最大操作数的大小。
自动缓存
MKNetWorkKit能够缓存你所有的GET请求，当请求相同时会调用本地缓存内容。
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[self.yahooEngine useCache]; |
清空缓存使用如下方法
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[ApplicationDelegate.yahooEngine emptyCache]; |
冻结网络操作
网络断开时的网络请求会被冻结，通过NSKeyedArchiver序列化在本地，当有网时会再次请求。MKNetworkOperation的setFreezable:方法就是冻结操作。
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[op setFreezable:YES]; |
类似的请求只请求一个操作
就是同一个URL只请求一次。
图片缓存
MKNetworkEngine的imageAtURL:completionHandler:errorHandler:方法能够缓存图片。
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[ApplicationDelegate.apiEngine imageAtURL:[NSURL URLWithString:(_strategyModel.titlepic)] completionHandler:^(UIImage* fetchedImage, NSURL* url, BOOL isInCache){ [iv setImage:fetchedImage]; }errorHandler:nil]; |
当然MKNetworkEngine的operationWithURLString: params: httpMethod:方法也可以请求图片，并且缓存，它其实就是根据一个URL地址来创建一个网络线程，然后把它加入到队列就可以了。
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MKNetworkOperation *op1 =[ApplicationDelegate.apiEngine operationWithURLString:_strategyModel.titlepic params:nil httpMethod:nil]; [op1 addCompletionHandler:^(MKNetworkOperation *completedOperation) { // [op1 responseImage]; [iv setImage:[completedOperation responseImage]]; } errorHandler:^(MKNetworkOperation *errorOp, NSError* error) { }]; [ApplicationDelegate.apiEngine enqueueOperation:op1]; |
其实MKNetworkOperation有各种response数据，这里是responseImage，还有responseString、responseJSON、responseXML。
不过请求一个图片还可以使用MK提供的category，UIImageView+MKNetworkKitAdditions里面的方法，如下，不过我试了之后好像没有缓存，不过这个可以用于tableview上每个cell上显示的图片，比上面的要方便许多。
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[self.thumbnailImage setImageFromURL:[NSURL URLWithString:self.loadingImageURLString] placeHolderImage:nil]; |
缓存operation
其实每一个get请求都有缓存，要想知道你返回的数据是否缓存，可以用以下方法。
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[op addCompletionHandler:^(MKNetworkOperation *completedOperation) { // the completionBlock will be called twice. // if you are interested only in new values, move that code within the else block if([completedOperation isCachedResponse]) { DLog(@"Data from cache %@", [completedOperation responseString]); } else { DLog(@"Data from server %@", [completedOperation responseString]); } completionBlock([valueString doubleValue]); }errorHandler:^(MKNetworkOperation *errorOp, NSError* error) { errorBlock(error); }]; |
下载文件
下载文件的时候也可以增加进度条，方法类似上面上传文件的使用，下载文件痛哟在操作上增加一个一个输出流，下载文件的实现可以如下。
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-(MKNetworkOperation*) downloadFatAssFileFrom:(NSString*) remoteURL toFile:(NSString*) filePath { MKNetworkOperation *op = [self operationWithURLString:remoteURL]; [op addDownloadStream:[NSOutputStream outputStreamToFileAtPath:filePath append:YES]]; [self enqueueOperation:op]; return op;} |