VOIP and Ruby The Convergence of Web and Voice Applications using Open Source Software Justin Grammens Localtone Interactive justin@localtone.com
VOIP is NOT About Cheap Phone Calls Other companies are already doing this cheaper and better.
VOIP Applications! It's about the applications that we can build!
What We Will Cover Why do VOIP now? Asterisk Adhearsion Telegraph Demos
Why Now? Only recently has good Open Source Software been developed ( Rails / Asterisk ) Telecoms are slow to react Few applications merge voice and web Cell phone are everywhere!
Why Now? 2.7 Billion mobile phones. 1.4 Billion fixed-lines. 1/3 of Internet Users access the internet from their mobile phone. iphone has shown consumers why they need the interactive internet on their phone. Others will follow. Most phone users can be identified by a standardized numerical system.
VOIP / Web Analogy Technology Web VOIP Protocol HTTP FTP RTP SIP Industry Standard IAX Asterisk Specific H.323 Obsolete Jingle Gtalk Skype - Proprietary Codec gzip, jpg, gif, mp3, ogg, wma, flv, mpeg, avi g.711 high bandwidth gsm medium bandwidth g.729 low bandwidth Server Apache / Lighttpd Asterisk, Freeswitch Interactivity CGI AGI Asterisk Gateway Interface AMI Asterisk Manager Interface
Asterisk + Open Source Private Branch Exchange (PBX) + Very powerful and flexible + Relatively Stable - Messy to deal with in terms of extending functionality. +++ Free!
Asterisk : Terminology Channel A channel is what can setup and receive calls. Dialplan Script of what to do with a call. Written in the asterisk macro language. AGI Stdin/out TCP method allowing external applications to dynamically write dialplans. AMI Allows sending of commands and listen for stateful events.
Typical Voice System VOIP Clients SIP Rails PSTN Network Origination/ Termination Server SIP / IAX Asterisk Server AGI / AMI / Adhearsion / Telegraph PSTN Network Analog Interface Card Zaptel / Other
Asterisk Dialplan Language [demo] ; Sample from Asterisk configuration extensions.conf file ; ; We start with what to do when a call first comes in. ; exten => s,1,wait(1) ; Wait a second, just for fun exten => s,n,answer ; Answer the line exten => s,n,set(timeout(digit)=5) ; Set Digit Timeout to 5 seconds exten => s,n,set(timeout(response)=10) ; Set Response Timeout to 10 seconds exten => s,n(restart),background(demo-congrats) ; Play a congratulatory message exten => s,n(instruct),background(demo-instruct); Play some instructions exten => s,n,waitexten ; Wait for an extension to be dialed. exten => 2,1,BackGround(demo-moreinfo) exten => 2,n,Goto(s,instruct) ; Give some more information. exten => 3,1,Set(LANGUAGE()=fr) exten => 3,n,Goto(s,restart) ; Set language to french ; Start with the congratulations exten => 1000,1,Goto(default,s,1)
Difficulties in Asterisk Conditional Loops Error Handling Complex Data Structure Date and time handling Database / LDAP Integration RegEx Pattern Matching Extending the language Portability - Asterisk v.s Freeswitch, etc. Variables Object Oriented Design
Ruby / Asterisk Integration Tools RAGI Just for AGI. Not integrated with Rails. No longer active. RAMI Just for Management Interface. No Rails Integration. Not Active. Adhearsion Active. Good for writing pure voice applications. Not tied with Rails (but can be without too much effort). Telegraph Active. Tightly integrated with Rails. Embraces the Voice/Web Analogy.
Adhearsion Standalone server that talks with Asterisk Developed by Jay Phillips of Codemecca Open Source Current version is 0.7.7 Development on 0.8 is nearly complete. Lots of new changes.
Adhearsion Put the line below in extensions.conf Tells Asterisk to process all calls by our Adhearsion server exten => _X.,1,Agi(agi://127.0.0.1) or... when extension 888 is dialed. exten => 888,1,Agi(agi://127.0.0.1)
Adhearsion - dialplan.rb adhearsion { play %w(press-1 for minneapolis press-2 for chicago or press-3 for dallas weather otherwise-press 4) selection = input() w = new_weather case selection when '1' then play w.weather_report("minneapolis, MN") when '2' then play w.weather_report("chicago, IL") when '3' then play w.weather_report("dallas, TX") else simon = new_simon_game simon.start end }
Adhearsion - Demos SIP Phone XLite Asterisk extensions.conf [ adhearsion ] exten => 8000,1, Agi(agi://...) Adhearsion dialplan.rb adhearsion { code.. code.. }
Adhearsion - Demo Notes: Start up Asterisk : sudo asterisk Show asterisk CLI. Start up Adhearsion 0.8 Server : ~/development/adhersion/trunk/bin/ahn start. in the rumadhearsion directory Point Xlite Phone to Localhost dial extension 8000
Adhearsion Weather Demo Demo #1 - Weather - Parses data from Yahoo RSS feed <yweather:forecast day="mon" date="31 Dec 2007" low="6" high="19" text="flurries" code="13" /> rep = %W(weather is-currently #{w.current.temp} degrees today high #{today.high} low #{today.low}) + w.current.desc
Adhearsion Simon Says Demo #2 - Play Simon Says Game def verify_attempt if attempt_correct? call_context.play 'good' else call_context.play %W(#{number.size - 1} times wrong-try-again-smarty) reset end end
Adhearsion Write Ruby in our dial plans! Ability to use any Ruby gems we need (Active Record, etc.) Test and debug our application in isolation. Bring OO practices to VOIP development
Adhearsion It's abstracted and portable across other PBXes It's simple It's extensible It's readable It's maintainable It's fun!
Adhearsion Where's the Rails? Not directly integrated with Rails by choice. Written to stand on it's own, but you can link in your models using ActiveRecord. Looking for VOIP in the MVC framework? Look no further than Telegraph...
Telegraph Written by a company named Idapted. Extracted from production application ( Idapted's distributed voice system for English language learning EnglishQuad ) Started with RAGI / RAMI Tightly Integrated with the Rails/Web Interface They claim it embraces the Voice/Web analogy
Telegraph Installs into any Rails project as a plugin script/plugin install svn://rubyforge.org/var/svn/telegraph/trunk start up the server script/agi_server Interfaces with the gateway (incoming calls) script/ami_server Interfaces with the Asterisk manager
Telegraph Banking Demo SIP Phone XLite Rails Application Asterisk AGI Server
Telegraph Add this to your extensions.conf exten => s, n, AGI(agi://localhost/account) respond_to do wants #r index.html wants.html { render } # Telegraph allows render_voice # which uses the index.voice file wants.voice{ render_voice } end
Banking Demo index.voice: voice.play "welcome-to-demo #{say_amount(@balance)}" voice.link_to_dtmf 'banking-main-menu' do link 1, :action=>'new' link 2, :action=>'list' link :default, :action=>'index' end
Telegraph - Demo Start up telegraph server : telegraph/banking_demo ruby script/asterisk_server ruby script/server Visit http://localhost:3000/account Dial Extension 9000
Real World Application estara Offers a service where a user browsing a site can enter their phone number. The system will dial their number, ask the person to hold and then dial customer service. We'll do this.
Demo Topology Cell Phone PSTN Origination/ Termination Server Internet Asterisk Rails Application AGI Demos: 1. Using the browser to initiate phone call. 2. Who Wants To Be A Billionaire game. AMI
Demo Using PSTN Telegraph Demos - Use the browser to initiate a wakeup call. Use the browser to initiate phone calls to 10 digit phone numbers and bridge the calls Use the browser to initiate a call and verify correct code was entered. Adhearsion Demo - Adhearsion My Who Wants To Be A Billionaire application.
Resources http://rubyhoedown2007.confreaks.com/session03.htm http://www.slideshare.net/jpalley/respondto-voicethe-convergence-of-voice-and-web-interfaceswith-rails-and-asterisk http://adhearsion.com/ http://telegraph.rubyforge.org http://www.voip-info.org