CODEWITHSUNDEEP
iphoneobjective-ciosdownloadnsurlconnection
Maverick1st
Maverick1st

Reputation: 3770

When downloading a file NSURLConnection does not call didFinishLoading on end of file, when download was paused and resumed

I have the following Problem which drives me nuts for several weeks now.

I'have a small framework for downloading files. This framework has the ability to pause and resume a filedownload. So far so good. Problem is, everytime i pause a download then, after i resume it, the NSURLConnection responsible for the download will not call connectionDidFinishLoading, if the downloadedbytes equals the expected filesize, but keeps on calling connectionDidReceiveData and thus corrupts my download. I have no idea why this should be. When i don't pause/resume the download, everything works fine. Here is the code of the methods to pause and resume the download.

- (id)pause 
{
    [self.connection cancel];
    self.connection = nil;
    return self;
}

- (id)resume
{
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:self.url cachePolicy:NSURLCacheStorageAllowed timeoutInterval:600];

    NSFileManager *manager = [NSFileManager defaultManager];
    NSString *localSavePath = self.savePath;
    if (failBlocks.count > 0) {
        [self cancel];
        [self start];
    }
    else {
        if( ![manager fileExistsAtPath:localSavePath] )
        {
            [manager createFileAtPath:localSavePath contents:[NSData data] attributes:nil];
        }    
        if (self.downloadData.length > 0) {

            log_muma2(@"Should resume url %@",self.url);
            // Define the bytes we wish to download.
            NSString *range = [NSString stringWithFormat:@"bytes=%i-", downloadData.length];
            [request setValue:range forHTTPHeaderField:@"Range"];
        }
        if (!self.connection) {
            NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
            self.connection = conn;
        }        
    }
    return self;    
}

I would be really glad if someone could help me out of this.

I already tested, if the already downloaded data is of the correct size and stuff like that. everything seems to be ok.

Many thanks in Advance. Maverick

=========Edit=========

Here is the code of my didReceiveData

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    amountDownloaded += data.length;    
    NSInteger receivedLen = [data length];
    bytesReceived = (bytesReceived + receivedLen);
    if(expectedSize != NSURLResponseUnknownLength) {
        progress = ((bytesReceived/(float)expectedSize)*100)/100;
        [self performSelectorOnMainThread:@selector(updateProgressBar) withObject:nil waitUntilDone:NO];        
        percentComplete = progress*100;        
    }

    if (self.savePath == nil || [self.savePath isEqualToString:@""]) {
        [self.downloadData appendData:data];        
    }
    else {
        [self.downloadData appendData:data];
        NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:self.savePath];
        [handle seekToEndOfFile];
        [handle writeData:data];
//        
    }    
    if (expectedSize < bytesReceived)
    {
        NSLog(@"download exceeded expected size %f with %lld", expectedSize, bytesReceived);
        [self pause];
        [self cancel];        
        self.connection = nil;
        self.downloadData = nil;
        bytesReceived = 0;
        expectedSize = 0;
        amountDownloaded = 0;
        progress = 0;
        percentComplete = 0;
        [self start];
    }
}

Upvotes: 3

Views: 1305

Answers (1)

klaus
klaus

Reputation: 1836

How do you calculate your expected file size?

If you use response.expectedContentLength, be aware that this value is reduced every time you initialize a new connection when resuming the download.

Upvotes: 2

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