You can save the cookie by saving its properties dictionary and then restoring as a new cookiebefore you go to re-connect.
Save:
NSArray* allCookies = [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookiesForURL:[NSURL URLWithString:URL]];
for (NSHTTPCookie *cookie in allCookies) {
if ([cookie.name isEqualToString:MY_COOKIE]) {
NSMutableDictionary* cookieDictionary = [NSMutableDictionary dictionaryWithDictionary:[[NSUserDefaults standardUserDefaults] dictionaryForKey:PREF_KEY]];
[cookieDictionary setValue:cookie.properties forKey:URL];
[[NSUserDefaults standardUserDefaults] setObject:cookieDictionary forKey:PREF_KEY];
}
}
Load:
NSDictionary* cookieDictionary = [[NSUserDefaults standardUserDefaults] dictionaryForKey:PREF_KEY];
NSDictionary* cookieProperties = [cookieDictionary valueForKey:URL];
if (cookieProperties != nil) {
NSHTTPCookie* cookie = [NSHTTPCookie cookieWithProperties:cookieProperties];
NSArray* cookieArray = [NSArray arrayWithObject:cookie];
[[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookies:cookieArray forURL:[NSURL URLWithString:URL] mainDocumentURL:nil];
}