Webhooks
glue for the Web
20 юни 2009, събота 1

Who am I ?
• Name: Stoyan Zhekov
• Private: married, 3 kids (boys)
• Work: Software Engineer
• Contact: xmpp: //zh@jabber.jp
20 юни 2009, събота 2

20 юни 2009, събота 3

Today
• What is this talk about?
• What are webhooks?
• What can they do for me?
• Pros and cons
• Real life usage
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Maybe you already forget the presentation title, so one more time...

What is this talk about?
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Webhooks
glue for the Web
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Hooks?
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Glue?
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Web 3.0
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Don’t worry. We will talk about web :)

Web x.0?
• Web 1.0 - static
• Web 2.0 - dynamic? social?
• Web 3.0 - real time?
20 юни 2009, събота 10
Google Wave, iPhone push notifications

Web 3.0
• Real Time
• Does it scale?
• PubSub
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Real Time
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Real Time Web
• RSS is not enough (SUP)
• XMPP
• Webhooks
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I spoke in Kobe about SUP and XMPP (see my other presentations -
http://www.slideshare.net/zhesto/microblogging-via-xmpp

No Polling!
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Image from the presentation ”Web Hooks and the Programmable World of Tomorrow”

Real Time
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Does it scale?
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Recently working a lot with EC2 - pay per use, scale easy - instant start/stop of instances

Clouds...
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Clouds?
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Computer cloud!
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Communications
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Communications
• Messaging (AMQP): RabbitMQ
• XMPP, Ejabberd, Prosody
• Webhooks
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Webooks can help you with the infrastructure. Some service is too heavy? - move it to
another machine and connect them with webhook. Think about webhooks even when on a
single machine (call by URL, not by function name)

PubSub
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Publishers
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Subscribers
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Publishers and Subscribers
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Watercoolr
•PubSub
•Webhooks
•Ruby
http://github.com/jcapote/watercoolr/
http://github.com/zh/watercoolr/
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PubSubHubBub
http://code.google.com/p/pubsubhubbub/
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What are webhooks?
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Image from the presentation “Using Web Hooks”
I keep repeating webhooks, webhooks,... So what are they?

Captain Hook
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SVN Hooks
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Image from the presentation “Using Web Hooks”

Hooks
• Subversion pre-commit, post-commit
• Git, Mercurial - they have hooks too
• Rails: :before_save, :after_delete
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Unix Philosophy
• do ONE THING and do it well
• programs WORK TOGETHER
• UNIVERSAL INTERFACE (text)
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Insert here more about the webhooks - POST, etc.
example cat | grep | mail -> make this with web too (demo)

UNIX pipes
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Image from the presentation ”Web Hooks and the Programmable World of Tomorrow”

The Web
20 юни 2009, събота 34
Image from the presentation ”Web Hooks and the Programmable World of Tomorrow”

Web 3D
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There are services creating the web pages (feeds). Now nodes communicate via RSS -
indirect.
Image from the presentation ”Web Hooks and the Programmable World of Tomorrow”

WebApp pipes?
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Can we make a simple applications and connect them like a pipe?
Image from the presentation ”Web Hooks and the Programmable World of Tomorrow”

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Image from the presentation ”Web Hooks and the Programmable World of Tomorrow”

POST /service data={ 'message':'hey guys!' }
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What are WEBhooks?
webhooks are user defined callback URLs,
that point to a web script to run on a
certain event
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By letting the user specify a URL for various events, the application will POST data to those URLs when the events occur.
Key poins: USER DEFINED, URLs (remote services), RUN ON CERTAIN EVENT (push, no cronjobs etc.)

User defined
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URLs = remote
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register URL
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Image from the presentation “Using Web Hooks”

get notification
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Image from the presentation “Using Web Hooks”

Why?
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Service Integration
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Flexibility
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Customization
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Image from the presentation ”Web Hooks and the Programmable World of Tomorrow”

Webhooks movement
• Jeff Lindsay
• http://blogrium.com/?p=70
• http://webhooks.pbworks.com/
• http://blog.webhooks.org/
20 юни 2009, събота 48

Webhooks
• Amazon have Merchant Callback API
• PayPal (Instant Payment Notification)
• GitHub and Google Code
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Good and bad
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Good
• Well known protocol - HTTP
• code libraries (software)
• infrastructure (hardware)
• Easy for vendors (services)
• Easy for users (consumers)
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require ‘net/http’
require ‘json’
class User
def commit(message)
Net::HTTP.post_form(
User.hook_url,
{ :data => message.to_json })
end
end
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For service providers (publishers)

require ‘net/smtp’
require ‘json’
require ‘sinatra’
post ‘/hook’ do
data = JSON.parse(params[:data])
# do something with the data
Net::SMTP.start(‘localhost’) do |smtp|
smtp.send_message data[‘message’], from, to
end
end
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For service consumers (subscribers)

Bad
• No standard
• Google Code: XML
• GitHub: JSON
• ping.fm - POST parameters
• Security (authentication)
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Real Life Usage
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Where to create hooks?
• http://heroku.com/ - Ruby
• GAE - Python, Java, JRuby
• http://scriptlets.org/ - Python, JS
• PHP - almost everywhere
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Ready Tools
• GitHub - RunCodeRun
• http://ping.fm/ - IM, email, Skype
• http://postbin.org/ - debug
• SwitchHub, TarPipe
• http://superfeedr.com/ - RSS
• http://bot.im/ - IMified XMPP bot
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Demo
ping.fm + postbin
ping.fm + switchub (+postbin)
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create new hook on postbin, login to post.fm/custom/ and put there the url. test: web, email,
im?

Questions?
20 юни 2009, събота 60