MKNetWorkKit的使用(1)

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) completion

GET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(@"%@\t%@\t%@\t%@", [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。

1	[self.yahooEngine useCache];

清空缓存使用如下方法

1	[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。

1	[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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1 2	[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; }