Say I'm writing a publicly available framework for the Vimeo API. This framework needs to get information from the Internet. Because this can take some time, I need to use threadin to prevent the UI from hanging. Foundation uses delegates for this, like NSURLConnectionDelegate. However, Game Kit uses blocks as callback functions.
What is the recommended way of doing this? I know blocks aren't supported in standard GCC versions, but they require less, much less code for the one that uses my framework.
Delegates, on the other hand, are real methods and when protocols are used, I'm sure the methods are implemented.
Thanks.
I really like blocks but I would be tempted to use a delegate protocol in this case. Network connections can fail in a large number of ways and their delegates tend to keep a fair amount of stateful information about them. I find that that maps well to a delegate protocol with a number of optional methods.
If you're providing a very simplified API for accessing network data then a success/failure pair of blocks might be sufficient. Personally I find that I have to deal with alot of different cases which use many delegate methods on a stateful delegate object. For example; should I retry failed connections immediately or later, does the relative priority of failed connections change, can I make us of a partial response, should I switch a connection to wifi when it becomes available, do I offer a user a chance to authenticate if prompted, do I display incremental progress in a connection? You could handle all of those with blocks but I find that I would rather have a delegate class managing the connection.
Without knowing more about what data you intend for your interface to fetch I don't know that I can be more specific but. I would be tempted to allow users of the API to manage their own connection state if possible.