asihttprequests failing

I'm trying to download a a queue of files using ASIHTTPRequest. Each request is permanently failing. I know that the urls are valid, I've traced them out and popped them into a browser and the files are there. I've not much ideas on how to debug this.

-(void) getRemoteFiles:(NSMutableArray *) M
{
    [self createFileToAppDirectory];

    if (!networkqueue) {
        networkqueue:[[[ASINetworkQueue alloc] init] autorelease];
    }

    [[self networkQueue] cancelAllOperations];

    [self setNetworkQueue:[ASINetworkQueue queue]];
    [[self networkQueue] setDelegate:self];
    [[self networkQueue] setRequestDidFinishSelector:@selector(requestFinished:)];
    [[self networkQueue] setRequestDidFailSelector:@selector(requestFailed:)];
    [[self networkQueue] setQueueDidFinishSelector:@selector(queueFinished:)];


    int i;

    for (i=0; i<[M count]; i++) {
        NSString *url=[M objectAtIndex:i];
        NSString* theFileName = [url lastPathComponent];
        if ([theFileName isEqualToString:@"nothing"]==NO) {

            ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:url]开发者_如何学Python];
            //[request setDownloadDestinationPath:[self getDirectoryPathForFileName:theFileName]];
            [[self networkQueue] addOperation:request];

        }

    }

    [[self networkQueue] go];


}

EDIT

I think I found the problem but I dont know how to fix it. If I change the request url to something simple like http://mysite/content/track.mp3 it all works fine. But when I use the original url the request fails. The original url looks like this

http://site-media.s3.amazonaws.com/2020 Vision - Deep Tech House and Techno/P_122_DrumLp6.mp3

I think it might have something to do with the spaces but I thought nsurl would handle that stuff?

It turns out that NSURL won't safely encode a url string for you. In my cases the spaces in the url where causing the problem. The soulution was as follows

NSString *safestring=[unsafestring stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];