According to documentation of NSURLComponents:
If you set the unencoded property, you can then obtain the encoded equivalent by reading the encoded property value and vice versa.
I tried to get the percent encoding versions of the query and path of the url but I miss something:
NSURL * url = [NSURL URLWithString:@"http://google.com"];
NSURLComponents * components = [[NSURLComponents alloc] initWithURL:url resolvingAgainstBaseURL:YES];
components.query = @"oauth_callback=http://google.com";
NSLog(@"Encoded: %@", [components URL]);
//-> Encoded: http://google.com?oauth_callback=http://google.com
//Does not encode "/" or ":"
Where do I fail ?
I think NSURLComponent's behaviour is right.
From Wikipedia:
In the "query" component of a URI (the part after a ? character), for example, "/" is still considered a reserved character but it normally has no reserved purpose, unless a particular URI scheme says otherwise. The character does not need to be percent-encoded when it has no reserved purpose.