Also known as How to Build your own Slack ripoff in less than 5 minutes.

1. Build a Real-time, WebSockets-
enabled Chat in less than 5 minutes
with Ember-CLI and Python
Derek Edwards
August 4, 2015

2. About me
@derekbedwards
github.com/derekbedwards
linkedin.com/in/derekbedwards
Lean Startup, Ember.JS & Python evangelist
Co-founder / CTO of CoachLogix
Former co-founder Acclaimd, Hungerly

3. Prerequisites
• python / pip / virtualenv installed
• Ember-CLI + dependencies installed
• See http://www.ember-cli.com/

4. Overview
• Start a base Ember-CLI project as a chat client
• Install ember-websockets module
• Create a basic application controller and template
• Start a base Python Tornado project as a chat server
• Create a Python virtualenv and install Tornado
• Create a basic Python websocket server
• Run the Python websocket server and Ember CLI client
• Magic!

5. Create Ember project
mkdir chatdemo
cd chatdemo
ember init
ember install ember-websockets
ember g initializer websocket
ember g route application
ember g controller application

6. Setup Ember environment
Add a
contentSecurityPolicy
so we can talk to
WebSockets

7. Create a websocket initializer
Injects a ‘websockets’
object into all controllers

8. Setup main controller
Initializes websocket,
sets up handlers
Catches open event
on the websocket
Push received
messages into the
messages array
Constructs and sends
message to web
socket when user
presses send

9. Setup main template
Collect a name from
the user
Display all received
messages (or none)
Provide an entry field
for new messages
Display a Send button
tied to the
sendMessage action

10. Let’s see what we have so far
ember server
Ugly but does the job.
Browser is trying to
connect to WebSocket
endpoint

11. Setup python environment
virtualenv env
source env/bin/activate
pip install tornado

12. Create a simple server.py
Extend from Tornado
WebSocketHandler
When a new client
connects, add them to
a list of clients
When a message is
received, broadcast to
all registered clients
When a client
disconnects, remove
them from the list

13. Start the server
python server.py

14. Some raw data

15. Limitations / Improvements
• No authentication / user models
• Implement JWT or similar mechanism
• No chat history / archive
• Need some kind of persistent data store for message
backlog to be more ‘Slack-like’
• Fragile message distribution / queue
• Implement redis or better yet Amazon Simple Queue
Service

16. That’s all!
Thanks to Heather Brysiewicz + Erik Hanchett
Code from this talk:
github.com/derekbedwards/ember-python-chat
—
@derekbedwards
github.com/derekbedwards
linkedin.com/in/derekbedwards