Skip to content
Create a gist now

Instantly share code, notes, and snippets.

Embed URL


Subversion checkout URL

You can clone with
Download ZIP
Sinatra Server Side Event streaming.
# Usage: redis-cli publish message hello
require 'sinatra'
require 'redis'
conns = []
get '/' do
erb :index
get '/subscribe' do
content_type 'text/event-stream'
stream(:keep_open) do |out|
conns << out
out.callback { conns.delete(out) }
end do
redis = Redis.connect
redis.psubscribe('message', 'message.*') do |on|
on.pmessage do |match, channel, message|
channel = channel.sub('message.', '')
conns.each do |out|
out << "event: #{channel}\n\n"
out << "data: #{message}\n\n"
@@ index
<article id="log"></article>
var source = new EventSource('/subscribe');
source.addEventListener('message', function (event) {
log.innerText += '\n' +;
}, false);

Don't you need to set your log variable, i.e. "var log = document.getElementById('log');".


Nope, elements can be referenced from JavaScript by their ID.


OMG I can't believe I just discovered this tip.

mind blown


That's what I said when replying on Twitter... 14 years of JavaScript and then I come across this. Made me feel at little daft :)


try do this without chrome/v8


You should use document.getElementById('log'). Accessing an element by its id in a globally-scoped variable is a relic of ancient versions of Internet Explorer which, for whatever reason; Google decided to implement in V8. It is non-standard and bad practice, though; and won't work in Firefox.


Thank you for that inspiration, I almost used faye..

There is a typo (?) in line 27, there should be only one newline to keep both lines close together:

      conns.each do |out|
        out << "event: #{channel}\n"
        out << "data: #{message}\n\n"

Else the pushed message won't have the right type bound, and source.addEventListener('different'..) won't react at all.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Something went wrong with that request. Please try again.