Does -dataWithContentsOfURL: of NSData work in a background thread?

Question

Does -dataWithContentsOfURL: of NSData work in a background thread?

Answer 1

No, it blocks the current thread.

You need to use NSURLConnection in order to have asynchronous requests.

Answer 2

No, it doesn't.

In order to get data from URL asynchronously you should use the NSURLRequest and NSURLConnection approach.
You will have to implement the NSURLConnectionDelegate methods:

• -(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response;
• -(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;
• -(void)connectionDidFinishLoading:(NSURLConnection *)connection;
• -(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;