RAILS SOJOURN: ONE MAN’S

JOURNEYMike Desjardins

Monday, October 14, 13

HI, I’M MIKE!

I’M FROM PORTLAND

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NO, NOT THAT PORTLANDMonday, October 14, 13

THIS PORTLANDMonday, October 14, 13

CONFESSION

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OK MIKE, WE GET IT. YOU HAVE SELF ESTEEM ISSUES.

So what is this presentation about?

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So I’ve worked on some decently “big” Rails apps

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FAT MODELS

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MASSIVE CONTROLLERSMonday, October 14, 13

VIEWS WITH

(CONFUSING) LOGIC

IN THEM

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STUFF HAPPENS

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GOOD NEWS:This presentation isn’t a complain-fest about Rails

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I work here:

(we’re kinda awesome)Monday, October 14, 13

But I used to work here:

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(NEED A BULLPEN)

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INCUBATIONMONTH

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LIKE CHRISTMAS MORNING!

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WE SHOULD USE

THIS TIME TO EXPLORE!

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LET’S BUILD AN APP!It’ll be one of those

new-fangledsingle page whizz-

bang Javascript MVC thingies!

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WHAT TO DO?

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WHAT TO DO?

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WHAT TO DO?

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BACK END CRITERIA•Had to be Ruby•Building RESTful API•Had to be easily deployed•Want “lightweight”•Had to be actively developed•Couldn’t be Rails. Just ‘cuz.

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FRONT END CRITERIA

•Active Development•Strategic choice for company•Well documented•Stable API

(Not gonna talk a whole lot about these)Monday, October 14, 13

FRONTEND

(Not gonna talk a whole lot about these)Monday, October 14, 13

ARCHITECTURE

User Application

Amazon SQS (Queueing Service)

Static Single-Page Javascript Front End

Happy User

Notifications

Client Gem

Worker Process

Worker Process

Collector

SQLDB

Collector

API ServerAPI Server

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FOCUS ON

CollectorCollector API ServerAPI Server

THE “RUBY” PARTS

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HMM...require  'sinatra'

get  '/hi'  do    "Hello  World!"end

$  ruby  hi.rbMonday, October 14, 13

HMM...

$  lsapp.rb$

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GOOD NEWS:This presentation isn’t a How-To

session on Sinatra

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SETTLED ON THISGemfileGemfile.lockProcfileREADME.mdRakefileapp.rbconfig/config.rulog/middlewares/routes/services/spec/templates/

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INIT.RB PATTERN

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CONFIG AND INITIALIZERS

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THIS SERVED US PRETTY WELL.

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ASIDE: MONKLearned about this project

after the fact.

Website down?

http://monkrb.comMonday, October 14, 13

WAIT, WHERE ARE THE MODELS?

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ORM

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ORMWe tried three different ones.

Models were in their own gem.

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DATAMAPPERRan into issues.

1.x kind of a ghost town.

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OPEN SOURCE

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OPEN SOURCEYou can, you know, actually

read the source when you get stuck.

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ONE OF THE BIGGEST THINGS

I LEARNED!•I always had been intimidated by

complexity Rails’ source.

•Intimidated by size and talent of community.

•Hadn’t run into trouble with Rails, no need to look at the source.

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bundle  open  <gem  name>

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DON’T BE AFRAID.

LESSON #1

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SEQUELWeird (concurrency?) problem we just couldn’t nail down.

Probably wasn’t Sequel, probably was us.Running out of time so...

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ACTIVERECORDWe swallowed our pride.

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PUTTING THE MODELS INTO

THEIR OWN GEM SAVED OUR

BACON.Monday, October 14, 13

ISOLATE YOUR APP FROM YOUR

LIBRARY CHOICES.

LESSON #2

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WHAT IS RACK?Monday, October 14, 13

“A Rack application is an Ruby object (not a class) that responds to call. It takes exactly one argument, the environment and returns an Array of exactly three values: The status, the headers, and the body.” - Rack API docs

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“A Rack application is an Ruby object (not a class) that responds to call. It takes exactly one argument, the environment and returns an Array of exactly three values: The status, the headers, and the body.” - Rack API docs

require  'rubygems'require  'rack'

class  HelloWorld    def  call(env)        [200,  {"Content-­‐Type"  =>  "text/html"},  "Hello  Rack!"]    endend

Rack::Handler::Mongrel.run  HelloWorld.new,  :port  =>  9292

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MIDDLEWAREMonday, October 14, 13

SECURITYMonday, October 14, 13

• Rack::Attack - middleware to do whitelisting, blacklisting, throttling.

• Rack::Protection - middleware that handles a bunch of attack vectors (IP Spoofing, Path Traversal, Session Hijacking, others).

• Omniauth::Identity - User authentication

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SERIALIZATION

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SERIALIZATION

• achiu/rack-parser - I was surprised to learn that converting JSON docs to Rack parameters wasn’t automatic.

• HashWithIndifferentAccess - Don’t expect your parameter names to be symbolized for you.

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SESSION COOKIESRack::Session::Cookie

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WE EVEN WROTE OUR OWN

MIDDLEWARE!

HTTP status handling for common errors

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class  ErrorMiddleware    def  initialize(app,  options  =  {})        @app  =  app    end        def  call(env)        dup._call(env)    end

   def  _call(env)        @app.call  env    rescue  Exception  =>  e        logger.error  "-­‐-­‐-­‐  rescued  #{e.inspect}  at  #{Time.now}  -­‐-­‐-­‐"        e.backtrace.each  do  |line|            logger.error  line        end

       handler  =  ExceptionHandler.new(e)        Rack::Response.new(handler.body,  handler.status,  {}).finish    endend

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ExceptionHandler.register(    "CloudshineData::UniqueConstraintViolation"  =>  {        body:  {errors:  ["Already  taken"]}.to_json,        status:  422    })

ExceptionHandler.register(    "CloudshineData::Unauthorized"  =>  {status:  401,  body:  "Unauthorized"})

ExceptionHandler.register(    "CloudshineData::RecordNotFound"  =>  {        body:  {errors:  ["Resource  not  found."]}.to_json,        status:  404    })

ExceptionHandler.register("CloudshineData::ValidationFailed"  =>  HandlerWithMessage)

ExceptionHandler.register("Cloudshine::MissingParameter"  =>  HandlerWithMessage)

INITIALIZER

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class  ExceptionHandler    HANDLERS  =  {}    attr_accessor  :exception

   def  self.register(handler={})        HANDLERS.merge!(handler)    end

   def  initialize(exception)        @exception  =  exception        @handler_map  =  HANDLERS        @handler_map.default  =  {body:  {errors:  ["Server  error"]}.to_json,  status:  500}    end

   def  handler        return  @handler  if  @handler        logger.info  "using  #{handler_map[@exception.class.to_s]}  to  handle”        logger.info  "  a  #{@exception.class.to_s}  exception."        handler  =  handler_map[@exception.class.to_s]        @handler  =  handler.is_a?(Class)  ?  handler.new(@exception)  :  OpenStruct.new(handler)    end

   def  status;  handler.status;  end    def  body;  handler.body;  end

   private    attr_accessor  :handler_mapend

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MIDDLEWARE IS EASY!

LESSON #3

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TOOLS

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ARCHITECTURE

User Application

Amazon SQS (Queueing Service)

Static Single-Page Javascript Front End

Happy User

Notifications

Client Gem

Worker Process

Worker Process

Collector

SQLDB

Collector

API ServerAPI Server

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CODE IS SPREAD OVER EIGHT

REPOSITORIES

Minimum of four separate applications just to run the system.

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VAGRANT

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VAGRANTStill doesn’t help w/ the nuisance of having to commit code into multiple places to make one feature change.

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VAGRANTIf I had to do it over again, I’d

probably keep one repo/app for the server-side components and deploy

it differently by task.Monday, October 14, 13

OTHER HANDY TOOLS

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RAILS CONSOLEMonday, October 14, 13

RAILS CONSOLEMissed it for a while.

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RAILS CONSOLEMissed it for a while.

Then I realized I could just make a silly setup script.

Monday, October 14, 13

RAILS CONSOLEMissed it for a while.

Then I realized I could just make a silly setup script.

It worked just as well and was a lot faster.

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SILLY SETUP SCRIPTrequire  'bundler'require  'active_record'require  'activeuuid'Bundler.require(:default,:development)ActiveRecord::Base.establish_connection(    :adapter    =>  'mysql2',    :database  =>  'cloudshine_dev',    :username  =>  'root',    :host          =>  'localhost')ActiveUUID::Patches.apply!

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RERUNMonday, October 14, 13

RERUN

Restarts your server for you when files change in your app’s directory.

Wouldn’t work with pokey old Rails but works great with Sinatra.

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CORS Issues

Cross Origin Resource Sharing

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User’s Browser Web Server

HTTP  OPTIONS  http://api.myapp.com/resource

Origin:  http://www.myapp.com

PRE-F

LIGHT

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200  OK

Access-­‐Control-­‐Allow-­‐Origin:  http://www.myapp.com

User’s Browser Web Server

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HTTP  GET  http://api.myapp.com/resource

Origin:  http://www.myapp.com

User’s Browser Web Server

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CORS SupportFirefox: 3.5+Chrome: 3+Safari: 4+

Opera: 12+IE: 10+

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CORS IssuesCan’t serve your singlepage app from file:// during development

Can’t go across ports without explicit

permission

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CORS Issues

Did all of this with (you guessed it) middleware!

github.com/cyu/rack-cors

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SUMMARY•Don’t be afraid to look at the source code

of your libraries.•Isolate your app from libraries•Middleware is easy!•There are lots of cool tools out there. Learn

about them.•Figure out your strategy for dealing w/

cross origin requests right away.

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SPENDING TIME AWAY FROM RAILS DE-MYSTIFIED IT FOR ME AND MADE ME

MORE COMFORTABLE WITH RUBY.

Monday, October 14, 13

SPENDING TIME AWAY FROM RAILS DE-MYSTIFIED IT FOR ME AND MADE ME

MORE COMFORTABLE WITH RUBY.

It was totally worth it.

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HOWEVER...

If I were starting all over again,I probably would just use

Rails API.

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Monday, October 14, 13

@mdesjardins

github.com/mdesjardins

md@openbay.com

Monday, October 14, 13

FIN.Monday, October 14, 13

PHOTO CREDITSLobster on Slide 2: Creative Commons © Man Pikin (http://www.flickr.com/photos/musicamang/)

Priest on Slide 3: © Anyka, Licensed from Fotolia.com, All Rights Reserved

Giant NES Controller on Slide 8: Creative Commons © Pop Culture Geek (http://www.flickr.com/photos/popculturegeek/)

Boston Construction Road Sign on Slide 9: Creative Commons © NNECAPA (http://www.flickr.com/photos/nnecapa/)

Bird Poop on Slide 10: Creative Commons © Chris Smith Ronnie Shumate “My Favorite Pet Sitter” (http://www.flickr.com/photos/myfavoritepetsitter/)

Fenway Bullpen on Slide 15: Creative Commons © BuzzFarmers “Red Sox Game at Fenway Park.” (http://www.flickr.com/photos/buzzfarmers/)

Alien Incubator on Slide 16: Creative Commons © Steve Jurvetson “alien incubator” (http://www.flickr.com/photos/jurvetson/)

Christmas Morning on Slide 17: Creative Commons © John Lemieux “Nikon Christmas” (http://www.flickr.com/photos/newdimensionfilms/)

Segway on Slide 42: Creative Commons © Wesley Fryer “Darth Vader on a segway in the Edmond 4th of July Parade” (http://www.flickr.com/photos/wfryer)

Bacon on Slide 49: Creative Commons © Shawn Zamecheck “Bacon” (http://www.flickr.com/photos/shawnzam/)

Rack of Lamb on Slide 51: Creative Commons © Waferboard “rack of lamb presentation II” (http://www.flickr.com/photos/waferboard/)

Rainbow Cake on Slide 54: Creative Commons © Janine and Jim Eden “Rainbow Cake” (http://www.flickr.com/photos/edenpictures/)

Security Cameras on Slide 55: Creative Commons © Jake Setlak “Security” (http://www.flickr.com/photos/pylbug/)

Cookies on Slide 59: Creative Commons © Jeramey Jannene “Cookies” (http://www.flickr.com/photos/compujeramey/)

Tool Chest on Slide 66: Creative Commons © El Cajon Yacht Club “tool chest” (http://www.flickr.com/photos/el_cajon_yacht_club/)

Console on Slide 73: Creative Commons © Cliff “Console, Countdown and Monitor“ (http://www.flickr.com/photos/nostri-imago/)

Apple Cores Slides 80-85: Creative Commons © Roger Karlsson “red apple core two days” (http://www.flickr.com/photos/free-photos/)

Mosaic 3.5” Floppy Slides 81-83: Creative Commons © Bill Rawlinson “plug-n-play-mosaic” (http://www.flickr.com/photos/thefinalcut/)

Mainframe Slides 81-83: Creative Commons © Don DeBold “NEC 2203 Mainframe Computer” (http://www.flickr.com/photos/ddebold/)

Creative Commons images licensed under the CC 2.0 Attribution License.

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