promises.diff

diff --git a/lib/Mojo/UserAgent.pm b/lib/Mojo/UserAgent.pm
index 97d39b65d..e5622be58 100644
--- a/lib/Mojo/UserAgent.pm
+++ b/lib/Mojo/UserAgent.pm
@@ -34,6 +34,10 @@ for my $name (qw(DELETE GET HEAD OPTIONS PATCH POST PUT)) {
     my ($self, $cb) = (shift, ref $_[-1] eq 'CODE' ? pop : undef);
     return $self->start($self->build_tx($name, @_), $cb);
   };
+  monkey_patch __PACKAGE__, lc($name) . '_p', sub {
+    my $self = shift;
+    return $self->start_p($self->build_tx($name, @_));
+  };
 }

 sub DESTROY { Mojo::Util::_global_destruction() or shift->_cleanup }
@@ -61,6 +65,22 @@ sub start {
   return $tx;
 }

+sub start_p {
+  my ($self, $tx) = @_;
+
+  my $promise = Mojo::IOLoop->delay;
+  $self->start(
+    $tx => sub {
+      my ($self, $tx) = @_;
+      my $err = $tx->error;
+      $promise->resolve($tx) unless $err && $err->{code};
+      $promise->reject($err->{message});
+    }
+  );
+
+  return $promise;
+}
+
 sub websocket {
   my ($self, $cb) = (shift, pop);
   $self->start($self->build_websocket_tx(@_), $cb);
@@ -403,19 +423,14 @@ Mojo::UserAgent - Non-blocking I/O HTTP and WebSocket user agent
   });
   Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

-  # Concurrent non-blocking requests (synchronized with a delay)
-  Mojo::IOLoop->delay(
-    sub {
-      my $delay = shift;
-      $ua->get('mojolicious.org' => $delay->begin);
-      $ua->get('cpan.org'        => $delay->begin);
-    },
-    sub {
-      my ($delay, $mojo, $cpan) = @_;
-      say $mojo->result->dom->at('title')->text;
-      say $cpan->result->dom->at('title')->text;
-    }
-  )->wait;
+  # Concurrent non-blocking requests (synchronized with promises)
+  my $mojo = $ua->get_p('mojolicious.org');
+  my $cpan = $ua->get_p('cpan.org');
+  $mojo->all($cpan)->then(sub {
+    my ($mojo, $cpan) = @_;
+    say $mojo->[0]->result->dom->at('title')->text;
+    say $cpan->[0]->result->dom->at('title')->text;
+  })->wait;

   # WebSocket connection sending and receiving JSON via UNIX domain socket
   $ua->websocket('ws+unix://%2Ftmp%2Fmyapp.sock/echo.json' => sub {
@@ -881,6 +896,22 @@ to perform requests non-blocking.
   });
   Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

+=head2 start_p
+
+  my $promise = $ua->start_p(Mojo::Transaction::HTTP->new);
+
+Same as L</"start">, but performs all requests non-blocking and returns a
+L<Mojo::IOLoop::Delay> object instead of accepting a callback.
+
+  my $tx = $ua->build_tx(GET => 'http://example.com');
+  $ua->start_p($tx)->then(sub {
+    my $tx = shift;
+    say $tx->result->body;
+  })->catch(sub {
+    my $err = shift;
+    warn "Connection error: $err";
+  })->wait;
+
 =head2 websocket

   $ua->websocket('ws://example.com' => sub {...});
diff --git a/lib/Mojolicious/Guides/Tutorial.pod b/lib/Mojolicious/Guides/Tutorial.pod
index 360ce7d0d..296930ae1 100644
--- a/lib/Mojolicious/Guides/Tutorial.pod
+++ b/lib/Mojolicious/Guides/Tutorial.pod
@@ -868,20 +868,15 @@ L<Mojo::JSON> and L<Mojo::DOM> this can be a very powerful tool.
   # Concurrent non-blocking
   get '/titles' => sub {
     my $c = shift;
-    $c->delay(
-      sub {
-        my $delay = shift;
-        $c->ua->get('http://mojolicious.org' => $delay->begin);
-        $c->ua->get('https://metacpan.org'   => $delay->begin);
-      },
-      sub {
-        my ($delay, $mojo, $cpan) = @_;
-        $c->render(json => {
-          mojo => $mojo->result->dom->at('title')->text,
-          cpan => $cpan->result->dom->at('title')->text
-        });
-      }
-    );
+    my $mojo = $ua->get_p('http://mojolicious.org');
+    my $cpan = $ua->get_p('https://metacpan.org');
+    $mojo->all($cpan)->then(sub {
+      my ($mojo, $cpan) = @_;
+      $c->render(json => {
+        mojo => $mojo->[0]->result->dom->at('title')->text,
+        cpan => $cpan->[0]->result->dom->at('title')->text
+      });
+    })->wait;
   };

   app->start;
diff --git a/t/mojo/user_agent.t b/t/mojo/user_agent.t
index 3d49b3689..6e2c6782a 100644
--- a/t/mojo/user_agent.t
+++ b/t/mojo/user_agent.t
@@ -331,6 +331,23 @@ ok $success, 'successful';
 is $code,    200, 'right status';
 is $body,    '{"hello":"world"}', 'right content';

+# Promises
+my @results;
+my $p1 = $ua->get_p('/');
+my $p2 = $ua->get_p('/');
+$p1->all($p2)->then(
+  sub {
+    my ($first, $second) = @_;
+    push @results, $first, $second;
+  }
+)->wait;
+ok $results[0][0]->success, 'successful';
+is $results[0][0]->res->code, 200,      'right status';
+is $results[0][0]->res->body, 'works!', 'right content';
+ok $results[1][0]->success, 'successful';
+is $results[1][0]->res->code, 200,      'right status';
+is $results[1][0]->res->body, 'works!', 'right content';
+
 # Built-in web server times out
 $ua = Mojo::UserAgent->new(ioloop => Mojo::IOLoop->singleton);
 my $log = '';