Question

I know that the pattern in iPhone is to use ASync connection calls (using the informal protocols that is implemented by the current class).

In my case, I’ve created a utility class to do the networking staff and then return the data to the ViewController.

I find is inadequate to implement the connection model as Async in a utility class because r I will write a block of code in the ViewControlle such following: (which IMHO is bad)

MyUtilityConnection* utilConn = ....
while (true)
{
    if ([utilConn checkUnderlyingAsyncConnectionFinishedLoading]) break;
}
NSData* dataFromUrl = [utilConn dataFromUnderlayingConn];

So, the question is, Does using Sync connection model in iPhone could causes problem? and solutions?

(What about the drawing will stril hanging until the data come???)

Answer 1

AVOID by all means to do synchronous connections! This will obviously freeze your UI (and it gets worse if you don’t have a good bandwidth of course).

What you could do is to use the blocks syntax to write more readable code when you need to download data. Create a class that implements the NSURLConnection delegate methods, and then call the block when the data is done.

---

See my OHURLLoader class on github for example that does exactly that (and that’s only one solution).

Usage example:

NSURL* url = ...
NSURLRequest* req = [NSURLRequest requestWithURL:url];

OHURLLoader* loader = [OHURLLoader URLLoaderWithRequest:req];
[loader startRequestWithCompletion:^(NSData* receivedData, NSInteger httpStatusCode) {
    NSLog(@"Download of %@ done (statusCode:%d)",url,statusCode);
    outputTextView.text = loader.receivedString;
} errorHandler:^(NSError *error) {
    NSLog(@"Error while downloading %@: %@",url,error);
    outputTextView.text = [error localizedDescription];
}];