複数の非同期処理を順番に実行したい時に便利なライブラリ。
これが
id q1 = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
id q2 = [NSOperationQueue new];
dispatch_async(q1, ^{
id md5 = md5(email);
id url = [@"http://gravatar.com/" stringByAppendingString:md5];
id rq = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];
[NSURLConnection sendAsynchronousRequest:rq queue:q2
completionHandler:^(id rsp, id data, id err) {
UIImage *gravatarImage = [UIImage imageWithData:data];
dispatch_async(dispatch_get_main_queue(), ^{
self.imageView.image = gravatarImage;
});
}];
});こんな感じで書ける
#import "PromiseKit.h"
dispatch_promise(^{
return md5(email);
}).then(^(NSString *md5){
return [NSURLConnection GET:@"http://gravatar.com/%@", md5];
}).then(^(UIImage *gravatarImage){
self.imageView.image = gravatarImage;
});
いい感じ。