https://github.com/matsadler/rack-async
Thin's asynchronous API available to any Rack server
https://github.com/matsadler/rack-async
Last synced: about 2 months ago
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Thin's asynchronous API available to any Rack server
- Host: GitHub
- URL: https://github.com/matsadler/rack-async
- Owner: matsadler
- Created: 2011-01-19T11:02:51.000Z (over 14 years ago)
- Default Branch: master
- Last Pushed: 2011-10-09T15:55:53.000Z (over 13 years ago)
- Last Synced: 2025-04-11T23:13:22.490Z (about 2 months ago)
- Language: Ruby
- Homepage:
- Size: 92.8 KB
- Stars: 2
- Watchers: 1
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.rdoc
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README
= Rack::Async
Rack::Async is a rack middleware that makes available a thin[https://github.com/macournoyer/thin] like async api on most rack compatible web servers.
It works with mongrel, thin, and all the related mongrel-derived servers I've tried, additionally ebb works fine.
Although WEBrick won't support sending asynchronous replies, using Rack::Async will successfully send everything you ask it to, just bundled up all together like a normal synchronous reply.
It won't work with MacRuby's ControlTower at all.
== Installation
gem install rack-async
== Common problems
=== Rack::Lint::LintError
Rack::Lint doesn't know anything about async responses, so can't validate them properly, you'll have to turn it off.
=== The response doesn't seem asynchronous in my browser
Most browsers won't start rendering anything until they have around 1024 bytes of data. One way to get around this is to simply send 1024 bytes of whitespace at the start of your response. If you're just looking to see your response come in chunk by chunk, `curl` doesn't suffer this problem.
== Async Response with EventMachine
Here's how to send an async response with EventMachine that will work across thin, mongrel, ebb, etc
config.ru
require 'rubygems'
require 'rack/async'
require 'eventmachine'
class EMAsyncApp
def call(env)
event_machine do
EM.add_timer(5) do
env['async.callback'].call([200, {}, ["Hello world!"]])
end
end
# returning this signals to the server we are sending an async response
Rack::Async::RESPONSE
end
private
# make sure EventMachine is running (if we're on thin it'll be up and
# running, but this isn't the case on other servers).
def event_machine(&block)
if EM.reactor_running?
block.call
else
Thread.new {EM.run}
EM.next_tick(block)
end
end
end
use Rack::Async
run EMAsyncApp.new
== Async Response with Threads
Here's how to send an async response using threads that will work across thin, mongrel, ebb, etc
(we'll just give you the #call method this time)
def call(env)
Thread.new do
sleep 5
env['async.callback'].call([200, {}, ["Hello world!"]])
end
Rack::Async::RESPONSE
end
== Async Body with EventMachine
Sure sending an asynchronous response is neat, but what really cool is streaming out the body to the client, here's how to do that
config.ru
require 'rubygems'
require 'rack/async'
require 'eventmachine'
class EMAsyncBodyApp
def call(env)
body = env['async.body']
event_machine do
i = 0
timer = EM.add_periodic_timer(1) do
body << "Hello world!\r\n"
i += 1
if i >= 5
body.finish
timer.cancel
end
end
end
[200, {}, body]
end
private
def event_machine(&block)
if EM.reactor_running?
block.call
else
Thread.new {EM.run}
EM.next_tick(block)
end
end
end
use Rack::Async
run EMAsyncBodyApp.new
== Async Everything with Threads
You can combine the two like so (threaded example this time, but it works just fine with event machine too).
require 'rubygems'
require 'rack/async'
require 'thread'
class ThreadedAsyncApp
def call(env)
Thread.new do
sleep 1
body = env['async.body']
env['async.callback'].call([200, {}, body])
5.times {sleep 1; body << "Hello world!\r\n";}
body.finish
end
Rack::Async::RESPONSE
end
end
use Rack::Async
run ThreadedAsyncApp.new
== Licence
(The MIT License)
Copyright (c) 2011 Matthew Sadler
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.