improved real-time web recipes some more

mojolicious · Jan 11, 2012 · 4e7c973 · 4e7c973
1 parent 8828b9a
commit 4e7c973
Showing 1 changed file with 45 additions and 38 deletions.
diff --git a/lib/Mojolicious/Guides/Cookbook.pod b/lib/Mojolicious/Guides/Cookbook.pod
@@ -230,15 +230,46 @@ into alien environments like foreign event loops.
 The real-time web is a collection of technologies that include Comet
 (long-polling), EventSource and WebSockets, which allow content to be pushed
 to consumers as soon as it is generated, instead of relying on the more
-traditional pull model.
+traditional pull model. All built-in web servers use non-blocking I/O and are
+based on the L<Mojo::IOLoop> reactor, which provides many very powerful
+features that allow real-time web applications to scale extremely well.
+
+=head2 Backend web services
+
+Since L<Mojo::UserAgent> is also based on the L<Mojo::IOLoop> reactor, it
+won't block the built-in web servers when used non-blocking, even for high
+latency backend web services.
+
+  use Mojolicious::Lite;
+
+  # Search Twitter for "perl"
+  get '/' => sub {
+    my $self = shift;
+    $self->ua->get('http://search.twitter.com/search.json?q=perl' => sub {
+      my ($ua, $tx) = @_;
+      $self->render('twitter', results => $tx->res->json->{results});
+    });
+  };
+
+  app->start;
+  __DATA__
+
+  @@ twitter.html.ep
+  <!DOCTYPE html>
+  <html>
+    <head><title>Twitter results for "perl"</title></head>
+    <body>
+      % for my $result (@$results) {
+        <p><%= $result->{text} %></p>
+      % }
+    </body>
+  </html>
 
 =head2 Timers
 
-All built-in web servers use non-blocking I/O and are based on the
-L<Mojo::IOLoop> reactor, which provides many very powerful features that
-allow real-time web applications to scale extremely well. Timers for example
-can be used to delay rendering of a response without blocking any other
-requests that might be processed in parallel, like C<sleep> would.
+Another primary feature of the L<Mojo::IOLoop> reactor are timers, which can
+for example be used to delay rendering of a response, and unlike C<sleep>,
+won't block any other requests that might be processed in parallel.
 
   use Mojolicious::Lite;
 
@@ -252,56 +283,32 @@ requests that might be processed in parallel, like C<sleep> would.
 
   app->start;
 
-Recurring timers are slightly more powerful, but need to be dropped manually
-again, or they would just keep running as long as the server process stays
+Recurring timers are slightly more powerful, but need to be dropped manually,
+or they would just keep getting emitted as long as the server process stays
 up.
 
   use Mojolicious::Lite;
 
   # Count to 5 in 1 second steps
   get '/' => sub {
     my $self = shift;
+
+    # Start recurring timer
     my $i = 1;
     my $id = Mojo::IOLoop->recurring(1 => sub {
       $self->write_chunk($i);
       $self->finish if $i == 5;
       $i++;
     });
-    $self->on(finish => sub { Mojo::IOLoop->drop($id) });
-  };
-
-  app->start;
-
-=head2 Backend web services
-
-Since L<Mojo::UserAgent> is also based on the L<Mojo::IOLoop> reactor, it
-won't block the built-in web servers when used non-blocking, even for high
-latency backend web services.
-
-  use Mojolicious::Lite;
 
-  # Search Twitter for "perl"
-  get '/' => sub {
-    my $self = shift;
-    $self->ua->get('http://search.twitter.com/search.json?q=perl' => sub {
-      my ($ua, $tx) = @_;
-      $self->render('twitter', results => $tx->res->json->{results});
-    });
+    # Drop recurring timer
+    $self->on(finish => sub { Mojo::IOLoop->drop($id) });
   };
 
   app->start;
-  __DATA__
 
-  @@ twitter.html.ep
-  <!DOCTYPE html>
-  <html>
-    <head><title>Twitter results for "perl"</title></head>
-    <body>
-      % for my $result (@$results) {
-        <p><%= $result->{text} %></p>
-      % }
-    </body>
-  </html>
+And remember that all events are processed cooperatively, so your callbacks
+shouldn't block for too long.
 
 =head2 WebSocket web service