Estoy usando el método de descargas asincrónicas de Erica Sadun (enlace aquí para el archivo de proyecto: download), pero su método no funciona con archivos que tienen un gran tamaño (50 mb o superior). Si intento descargar un archivo de más de 50 mb, generalmente se bloqueará debido a un bloqueo de memoria. ¿De todos modos puedo modificar este código para que también funcione con archivos de gran tamaño? Aquí está el código que tengo en las clases DownloadHelper (que ya está en el enlace de descarga):Descargando un archivo grande - SDK de iPhone
.h
@protocol DownloadHelperDelegate <NSObject>
@optional
- (void) didReceiveData: (NSData *) theData;
- (void) didReceiveFilename: (NSString *) aName;
- (void) dataDownloadFailed: (NSString *) reason;
- (void) dataDownloadAtPercent: (NSNumber *) aPercent;
@end
@interface DownloadHelper : NSObject
{
NSURLResponse *response;
NSMutableData *data;
NSString *urlString;
NSURLConnection *urlconnection;
id <DownloadHelperDelegate> delegate;
BOOL isDownloading;
}
@property (retain) NSURLResponse *response;
@property (retain) NSURLConnection *urlconnection;
@property (retain) NSMutableData *data;
@property (retain) NSString *urlString;
@property (retain) id delegate;
@property (assign) BOOL isDownloading;
+ (DownloadHelper *) sharedInstance;
+ (void) download:(NSString *) aURLString;
+ (void) cancel;
@end
.m
#define DELEGATE_CALLBACK(X, Y) if (sharedInstance.delegate && [sharedInstance.delegate respondsToSelector:@selector(X)]) [sharedInstance.delegate performSelector:@selector(X) withObject:Y];
#define NUMBER(X) [NSNumber numberWithFloat:X]
static DownloadHelper *sharedInstance = nil;
@implementation DownloadHelper
@synthesize response;
@synthesize data;
@synthesize delegate;
@synthesize urlString;
@synthesize urlconnection;
@synthesize isDownloading;
- (void) start
{
self.isDownloading = NO;
NSURL *url = [NSURL URLWithString:self.urlString];
if (!url)
{
NSString *reason = [NSString stringWithFormat:@"Could not create URL from string %@", self.urlString];
DELEGATE_CALLBACK(dataDownloadFailed:, reason);
return;
}
NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url];
if (!theRequest)
{
NSString *reason = [NSString stringWithFormat:@"Could not create URL request from string %@", self.urlString];
DELEGATE_CALLBACK(dataDownloadFailed:, reason);
return;
}
self.urlconnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (!self.urlconnection)
{
NSString *reason = [NSString stringWithFormat:@"URL connection failed for string %@", self.urlString];
DELEGATE_CALLBACK(dataDownloadFailed:, reason);
return;
}
self.isDownloading = YES;
// Create the new data object
self.data = [NSMutableData data];
self.response = nil;
[self.urlconnection scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
}
- (void) cleanup
{
self.data = nil;
self.response = nil;
self.urlconnection = nil;
self.urlString = nil;
self.isDownloading = NO;
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)aResponse
{
// store the response information
self.response = aResponse;
// Check for bad connection
if ([aResponse expectedContentLength] < 0)
{
NSString *reason = [NSString stringWithFormat:@"Invalid URL [%@]", self.urlString];
DELEGATE_CALLBACK(dataDownloadFailed:, reason);
[connection cancel];
[self cleanup];
return;
}
if ([aResponse suggestedFilename])
DELEGATE_CALLBACK(didReceiveFilename:, [aResponse suggestedFilename]);
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)theData
{
// append the new data and update the delegate
[self.data appendData:theData];
if (self.response)
{
float expectedLength = [self.response expectedContentLength];
float currentLength = self.data.length;
float percent = currentLength/expectedLength;
DELEGATE_CALLBACK(dataDownloadAtPercent:, NUMBER(percent));
}
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// finished downloading the data, cleaning up
self.response = nil;
// Delegate is responsible for releasing data
if (self.delegate)
{
NSData *theData = [self.data retain];
DELEGATE_CALLBACK(didReceiveData:, theData);
}
[self.urlconnection unscheduleFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
[self cleanup];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
self.isDownloading = NO;
NSLog(@"Error: Failed connection, %@", [error localizedDescription]);
DELEGATE_CALLBACK(dataDownloadFailed:, @"Failed Connection");
[self cleanup];
}
+ (DownloadHelper *) sharedInstance
{
if(!sharedInstance) sharedInstance = [[self alloc] init];
return sharedInstance;
}
+ (void) download:(NSString *) aURLString
{
if (sharedInstance.isDownloading)
{
NSLog(@"Error: Cannot start new download until current download finishes");
DELEGATE_CALLBACK(dataDownloadFailed:, @"");
return;
}
sharedInstance.urlString = aURLString;
[sharedInstance start];
}
+ (void) cancel
{
if (sharedInstance.isDownloading) [sharedInstance.urlconnection cancel];
}
@end
Y finalmente esta es la forma en la que escribo archivo con las dos clases encima:
- (void) didReceiveData: (NSData *) theData
{
if (![theData writeToFile:self.savePath atomically:YES])
[self doLog:@"Error writing data to file"];
[theData release];
}
¡Si alguien pudiera ayudarme estaría muy contento!
Gracias,
Kevin
Escribí una biblioteca para eso, utilizando el método que describió. Lo expongo aquí con la esperanza de que sea útil para algunas personas, o las inspiro a escribir su propia solución. Si estás bien con eso, por supuesto. https://github.com/thibaultCha/TCBlobDownload – thibaultcha