iOS网络请求框架：MKNetWorkKit的使用

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MKNetWorkKit是由一个印度小伙子写的，是用于网络请求的库，支持ARC，代码的网址这里给出。

作者源码地址（MugunthKumar）：https://github.com/MugunthKumar/MKNetworkKit

作者关于类库介绍的地址（MugunthKumar）：http://blog.mugunthkumar.com/products/ios-framework-introducing-mknetworkkit/

作者类库介绍中文翻译地址（翻译作者，csdn博主kmyhy，杨宏焱）：http://blog.csdn.net/kmyhy/article/details/12276287

这里面大多数时候会引用到它里面的demo，MKNetWorkKit－iOS－Demo，本文主要是根据作者原文以及作者的demo还有自己的使用写的文章。

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;
}

GET请求方法的调用

   

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

-(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。

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。

[self.yahooEngine useCache];

清空缓存使用如下方法

[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。

[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。

[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。

   

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。

[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。

[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。

-(MKNetworkOperation*) downloadFatAssFileFrom:(NSString*) remoteURL toFile:(NSString*) filePath {
  
  MKNetworkOperation *op = [self operationWithURLString:remoteURL];
  
  [op addDownloadStream:[NSOutputStream outputStreamToFileAtPath:filePath
                                                          append:YES]];
  
  [self enqueueOperation:op];
  return op;
}

来源：oschina

链接：https://my.oschina.net/u/1378445/blog/289652