How to determine the size (in bytes) of a file downloading using NSURLConnection?

Question

I need to know the size of the file I am downloading (in bytes) into my app using NSURLConnection (GET). Here is my bytes recieved code below if it helps. What I need to know is how to get the filesize in bytes so that I can use it to show a UIProgressView.

- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)data
// A delegate method called by the NSURLConnection as data arrives.  We just 
// write the data to the file.
{
#pragma unused(theConnection)
    NSInteger       dataLength;
    const uint8_t * dataBytes;
    NSInteger       bytesWritten;
    NSInteger       bytesWrittenSoFar;

    assert(theConnection == self.connection);

    dataLength = [data length];
    dataBytes  = [data bytes];

    bytesWrittenSoFar = 0;
    do {
        bytesWritten = [self.fileStream write:&dataBytes[bytesWrittenSoFar] maxLength:dataLength - bytesWrittenSoFar];
        assert(bytesWritten != 0);
        if (bytesWritten == -1) {
            [self _stopReceiveWithStatus:@"File write error"];
            break;
        } else {
            bytesWrittenSoFar += bytesWritten;

    } while (bytesWrittenSoFar != dataLength);
}

Answer 1

[data length] does return the size of the data in bytes which should give you the figure you're looking for.

But NSData provides -writeToFile:atomically: and -writeToFile:options:error methods for writing data to disk so I don't know why you're writing your own file I/O.