MacOS, iOS - iOS - NSURLConnection로 다중 다운로드 구현

NSURLConnection로 다중 다운로드 구현하는 방법입니다.

여러개의 다운로드를 동시에 실행하면 delegate method 에서 구분하지 못하는 문제가 발생합니다. 그래서 수정이 필요한데요.

아래 블로그에서 참조했습니다.

http://blog.emmerinc.be/index.php/2009/03/15/multiple-async-nsurlconnections-example/

NSURLConnection 을 상속받는 CustomNSURLConnection 을 만든다.

그런뒤, 생성자에서 각 커넥션을 구분할수 있는 tag를 받고, 각 Connection 객체를 tag로 관리하는 것이다.

delegate method 인

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response;

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;

를 보면 Connection을 argument로 받으니, CustomNSURLConnection 으로 casting 해서, tag값을 뽑아 구분한다는 이야기이다.

가장 심플하고 정확한 방법인 듯하다.

실제 소스를 보자,

NSURLConnection를 상속받는 CustomURLConnection 를 만들자.

[CustomURLConnection.h]

@interface CustomURLConnection : NSURLConnection {
   NSString *tag;
}
 
@property (nonatomic, retain) NSString *tag;
 
- (id)initWithRequest:(NSURLRequest *)request delegate:(id)delegate startImmediately:(BOOL)startImmediately tag:(NSString*)tag;
 
@end

implementation:

[CustomURLConnection.m]

@implementation CustomURLConnection
 
@synthesize tag;
 
- (id)initWithRequest:(NSURLRequest *)request delegate:(id)delegate startImmediately:(BOOL)startImmediately tag:(NSString*)tag {
   self = [super initWithRequest:request delegate:delegate startImmediately:startImmediately];
 
   if (self) {
      self.tag = tag;
   }
   return self;
}
 
- (void)dealloc {
   [tag release];
   [super dealloc];
}
 
@end

header file에 각 connection에서 받은 데이터를 저장하기위해 NSMutableDictionary 를 선언한다.

NSMutableDictionary *receivedData;

- (void)startAsyncLoad:(NSURL*)url tag:(NSString*)tag {
   NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
   CustomURLConnection *connection = [[CustomURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES tag:tag];
 
   if (connection) {
      [receivedData setObject:[[NSMutableData data] retain] forKey:connection.tag];
   }
}
 
- (NSMutableData*)dataForConnection:(CustomURLConnection*)connection {
   NSMutableData *data = [receivedData objectForKey:connection.tag];
   return data;
}
 
- (void)load {
   receivedData = [[NSMutableDictionary alloc] init];
 
   NSURL *url1 = [NSURL URLWithString:@"http://blog.emmerinc.be"];
   NSURL *url2 = [NSURL URLWithString:@"http://www.emmerinc.be"];
   NSURL *url3 = [NSURL URLWithString:@"http://twitter.com/emmerinc"]; 
 
   [self startAsyncLoad:url1 tag:@"tag1"];
   [self startAsyncLoad:url2 tag:@"tag2"];
   [self startAsyncLoad:url3 tag:@"tag3"];
}
 
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
   NSMutableData *dataForConnection = [self dataForConnection:(CustomURLConnection*)connection];
   [dataForConnection setLength:0];
}
 
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
   NSMutableData *dataForConnection = [self dataForConnection:(CustomURLConnection*)connection];
   [dataForConnection appendData:data];
}
 
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
   NSMutableData *dataForConnection = [self dataForConnection:(CustomURLConnection*)connection];
   [connection release];
 
   // Do something with the dataForConnection.
}

iOS - NSURLConnection로 다중 다운로드 구현

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