VisuaBlog

Voici un composant qui permet de télécharger des fichiers de manières asynchrone. L'avantage de cette méthode est, hormis une gestion plus précise des événements de téléchargement, de libérer du temps/machine pour faire autre chose pendant la session de téléchargement. Typiquement, l'ajout d'un progressView à ce composant est assez facile.

VSDownloadManager utilise NSURLConnection en mode asynchrone (et non NSURLDownload qui n'est pas implémenté sur l'iPhone).

Téléchargement des sources !

Exemple d'utilisation de VSDownloadManager

#import "VSDownloadManager.h"

....

....

- (void) downloadManagerDemo {

VSDownloadManager *downloadManager = [VSDownloadManager getInstance];

// set the delegate that will receive the "

[downloadManager setDelegate:self];

// Empty the current queue

[downloadManager clearItems];

// Adding an element to download

VSDownloadManagerItem *dwlItem = [[VSDownloadManagerItem alloc] initWithURL:@"http://blog.visuaweb.com/public/Images/springboard.jpeg" AndFile:@"/var/root/springboard.jpeg" AndText:nil];

[downloadManager addItem:dwlItem];

[dwlItem release];

// Addning an element to download

VSDownloadManagerItem *dwlItem = [[VSDownloadManagerItem alloc] initWithURL:@"http://blog.visuaweb.com/public/Files/snap_joe.jpg" AndFile:@"/var/root/joe.jpeg" AndText:nil];

[downloadManager addItem:dwlItem];

[dwlItem release];

// Start the download session

[downloadManager start];

}

- (void) VSDownloadManagerDidFinishedDownloadSession:(VSDownloadManager *) sender {

NSLog(@"Download session finiched!");

} 

VSDownloadManager.h

//

//  VSDownloadManager.h

//

//  Created by Jeremie Engel on 28/12/07.

//  Copyright 2007 VISUAWEB - http://blog.visuaweb.com. All rights reserved.

//

#import <CoreFoundation/CoreFoundation.h>

#import <Foundation/Foundation.h>

@interface VSDownloadManagerItem : NSObject {

NSString*url;

NSString*filename;

NSString*text;

}

- (id) initWithURL:(NSString*) inURL AndFile:(NSString *) inFilename AndText:(NSString *) inText;

- (NSString *) url;

- (NSString *) filename;

- (NSString *) text;

@end

@interface VSDownloadManager : NSObject {

NSMutableArray*items;

VSDownloadManagerItem * currentItem;

iddelegate;

NSURLConnection*urlConnection;

NSMutableData*receivedData;

intstate;

}

+ (void) initialize;

+ (id) getInstance;

+ (id) allocWithZone:(NSZone *)zone;

- (id) init;

- (void) addItem:(VSDownloadManagerItem *) inItem ;

- (void) clearItems ;

- (void) setDelegate:(id) inDelegate ;

- (void) start ;

@end

VSDownloadManager.m

//

//  VSDownloadManager.m

//

//  Created by Jeremie Engel on 28/12/07.

//  Copyright 2007 VISUAWEB - http://blog.visuaweb.com. All rights reserved.

//

#import "VSLog.h"

#import "VSDownloadManager.h"

@implementation VSDownloadManagerItem

- (id) initWithURL:(NSString*) inURL AndFile:(NSString *) inFilename AndText:(NSString *) inText {

if ((self=[super init])) {

[inURL retain];

url = inURL;

[inFilename retain];

filename = inFilename;

if (inText) {

[inText retain] ;

text = inText;

}

return self;

}

return nil;

}

- (NSString*) url { return url; }

- (NSString*) filename { return filename; }

- (NSString*) text { return text; }

- (NSString *) description {

return url;

}

@end

/*****************************************************************************/

static VSDownloadManager  *defaultVSDownloadManager = nil;

@implementation VSDownloadManager

+ (void) initialize { }

+ (id) getInstance {

    @synchronized(self) {

        if (defaultVSDownloadManager == nil) {

            [[self alloc] init]; // assignment not done here

        }

    }

    returndefaultVSDownloadManager;

}

+ (id)allocWithZone:(NSZone *)zone

{

    @synchronized(self) {

        if (defaultVSDownloadManager == nil) {

            defaultVSDownloadManager = [super allocWithZone:zone];

            returndefaultVSDownloadManager;  // assignment and return on first allocation

        }

    }

    return nil; //on subsequent allocation attempts return nil

}

- (id) init {

NSLog(@"VSDownloadManager initialize");

if ((self=[super init])) {

items = [[NSMutableArray alloc] init];

//receivedData = [[NSMutableData data] retain];

}

returnself;

}

- (void) setDelegate:(id) inDelegate {

if (delegate) [delegate release];

[inDelegate retain];

delegate = inDelegate;

}

- (void) addItem:(VSDownloadManagerItem *) inItem {

if (![items containsObject:inItem]) [items addObject:inItem];

}

- (void) clearItems {

[items removeAllObjects];

}

- (void) start {

NSLog(@"Starting download");

int i;

for (i=0; i<[items count]; i++) {

state = 1;

receivedData = [[NSMutableData alloc] initWithLength: 0];

currentItem = [items objectAtIndex:i];

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:[currentItem url]] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:5];

urlConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

while(state == 1) {

[[NSRunLoop currentRunLoop] runUntilDate: [NSDate dateWithTimeIntervalSinceNow: 0.1f] ];

}

}

if (delegate && [delegate respondsToSelector:@selector(VSDownloadManagerDidFinishedDownloadSession:)]) {

[delegate performSelector:@selector(VSDownloadManagerDidFinishedDownloadSession:) withObject: self];

}

}

/************** NSURLConnection Delegates *****************/

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

[receivedData setLength:0];

}

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

    [receivedData appendData:data];

}

- (void)connection:(NSURLConnection *)connection  didFailWithError:(NSError *)error {

    [receivedData release];

[connection release];

state = -1;

    NSLog(@"Connection failed! Error - %@ %@",

          [error localizedDescription],

          [[error userInfo] objectForKey:NSErrorFailingURLStringKey]);

}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {

if ([currentItem filename]) [[NSFileManager defaultManager] createFileAtPath:[currentItem filename]  contents:receivedData attributes:nil] ;

[connection release];

    [receivedData release];

state = 0;

NSLog(@"Download finished for %@", [currentItem url]);

}

/***********************************************************/

- (void) dealloc {

if (receivedData) [receivedData release];

if (urlConnection) [urlConnection release];

[items release];

[superdealloc];

}

@end