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Welcome To Ruby On Rails

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Kevin Lawver
Kevin Lawver

I'm giving a presentation to the DWEEBS group at the University of Georgia on Thursday. These slides may change a little bit between now and then, but I wanted to get them up before I forgot. Feedback is welcome!

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Welcome to Ruby on Rails Kevin Lawver | June 25, 2009 http://uplaya.com Monday, June 22, 2009 1
Hi, I¡¯m Kevin Lawver Chief Architect at Music Intelligence Solutions - http://uplaya.com (it¡¯s a Rails app) Worked at AOL for 13 years, launched two public Rails apps. Spent a lot of time on AOLserver using Tcl and Tomcat writing JSP¡¯s. Just launched http://?cly.com with a friend as an ¡°art project¡± (also on Rails) Monday, June 22, 2009 2
What is Ruby? Object-oriented Interpreted Expressive ¡°principle of least surprise¡± Monday, June 22, 2009 3
¡°They are focusing on machines. But in fact we need to focus on humans, on how humans care about doing programming or operating the application of the machines. We are the masters. They are the slaves.¡± -- Matz Monday, June 22, 2009 4
Everything¡¯s an Object This confuses everyone at the beginning. Everything in Ruby is an object. There are no primitives, they¡¯re all objects! Monday, June 22, 2009 5
What¡¯s Rails? Web framework written by DHH in 2003 at 37signals for Basecamp Takes most of the ¡°grunt work¡± out of building web apps MVC ¡°Optimized for programmer happiness and sustainable productivity¡± Monday, June 22, 2009 6
Why Use It? Convention over con?guration Quick prototyping - can turn into the ¡°real¡± project without starting over Convention makes it easy to share code and quick to get started Because it¡¯s Ruby, you can turn it into anything you want Monday, June 22, 2009 7
Rails¡¯ Components ActiveRecord ActionController ActionView ActiveResource ActiveSupport Monday, June 22, 2009 8
ActiveRecord The ¡°M¡± in MVC Rails¡¯ crown jewel - a great database abstraction layer. Makes it really easy to work with databases. In Rails, your models should contain 95% of your business logic. Monday, June 22, 2009 9
ActionController The ¡°C¡± in MVC Handles routing requests and processing them. In Rails, your controllers should be light Monday, June 22, 2009 10
ActionView The ¡°V¡± in MVC Where you do all your HTML and most of your XML. I¡¯ve used a dozen different template systems over the years and Rails¡¯ is by far my favorite. Monday, June 22, 2009 11
ActiveResource Rails¡¯ built-in support for RESTful API¡¯s Makes it easy to do REST the right way Provides a lot of the wrappers, error cases and connection code you need to do RESTy stuff. Monday, June 22, 2009 12
ActiveSupport All the extensions to Ruby¡¯s base classes A lot of ¡°glue¡± for JSON and other things that don¡¯t belong in the other pieces Monday, June 22, 2009 13
My Favorite Things About Rails I can go from idea to ¡°real¡± in hours instead of days. It¡¯s easy to refactor single pieces without affecting the whole app. Plugins solve major problems without requiring rewrites (see cache money) Community is helpful and responsive Monday, June 22, 2009 14
Getting Started I don¡¯t use Windows, so you¡¯re on your own there. If you use a Mac and have Leopard, you already have Ruby and Rails. Linux? There are dozens of tutorials for your distro, don¡¯t worry. Monday, June 22, 2009 15
The 20 Minute Blog Sorry if you¡¯re following along online, I¡¯m heading to terminal now. Monday, June 22, 2009 16
What we¡¯ll be doing Create a new Rails app for our awesome new blog Build a model, controller and view for it Look at some helpful gems and plugins Make a feed for it Talk a little about ActiveRecord callbacks Monday, June 22, 2009 17
What we won¡¯t be doing Talking about tests (they¡¯re important, but I hate writing them) Spending a lot of time on con?guration Monday, June 22, 2009 18
What we¡¯ll be doing (redux) Create a new Rails app for our awesome new blog Build a model, controller and view for it Look at some helpful gems and plugins Make a feed for it Talk a little about ActiveRecord callbacks Monday, June 22, 2009 19
Wasn¡¯t that fun? now let¡¯s talk about myths! Monday, June 22, 2009 20
Some Rails Myths ¡°Rails doesn¡¯t scale¡± ¡°Ruby (or Rails) is too slow¡± ¡°Rails locks you into doing it its way¡± ¡°X is better!¡± (where X = ¡°Python¡±, ¡°PHP¡±, ¡°Java¡± or whatever) Monday, June 22, 2009 21
Myth: ¡°Rails Doesn¡¯t Scale¡± Monday, June 22, 2009 22
Maybe 3 Years Ago Back then, we had to use FastCGI or Mongrel. Now, though, we can use Phusion Passenger! It¡¯s an Apache plugin that does a great job of managing Rails instances. And Ruby Enterprise Edition makes Rails use less memory and run faster. Brilliant! Monday, June 22, 2009 23
Live-World Examples uplaya.com handles tens of thousands of requests a day on a couple tiny Amazon EC2 instances (we could do everything on one with room to spare, but I like having backup). ?cly.com handles tens of thousands of requests a day on a single quad core server - that¡¯s not even breaking a sweat yet. hundreds of other sites handle a lot more traf?c with minimal hardware or fuss. Monday, June 22, 2009 24
You will probably never need to scale. Monday, June 22, 2009 25
But if you do... Monday, June 22, 2009 26
The Data Layer Your database will fall over before your web server does. Optimize your connection, queries and indexes Protect your database by using memcached between your front-end and database Monday, June 22, 2009 27
Cache, Cache, Cache memcached is your friend Disk-based caches don¡¯t work once you grow beyond one server - same thing for in-memory caches Caching hides a world of programming sins, and saves you from having to do ugly things like sharding. Monday, June 22, 2009 28
You Don¡¯t Want... to be both read-heavy and write-heavy to have complex queries that can¡¯t be cached to have to do multiple selects on a single request Monday, June 22, 2009 29
The Most Important Thing is to launch! If you never launch, you¡¯ll never have users. If you never have users, you¡¯ll never have to scale. Rails helps me get from nothing to launch faster than anything else I¡¯ve tried. It helps me get from launch to scale pretty quickly as well. Monday, June 22, 2009 30
Typical Rails Stack Apache w/ Passenger *x MySQL Master memcached * y Slave Readers * z Writer Monday, June 22, 2009 31
Myth: ¡°Ruby is too slow!¡± Monday, June 22, 2009 32
But, it¡¯s fast enough for the web. Monday, June 22, 2009 33
For all of my sites... No request takes longer than 1 second On uPlaya, the average time per request is 217 milliseconds. On Ficly, the average time per request is 165 milliseconds. That¡¯s more than fast enough for the web. Monday, June 22, 2009 34
The ¡°Slow¡± in Rails Is the same slow anywhere else: Database The Internet CPU, Disk or RAM Monday, June 22, 2009 35
Those factors affect everyone, not just Rails Monday, June 22, 2009 36
Performance Gotchas Database indexes. If you¡¯re selecting or sorting by a column, it should have an index! You won¡¯t know you need them until it¡¯s too late. Static assets. Set up a separate virtual host for static stuff, or move them to a CDN. Don¡¯t make Rails serve static stuff! Selects. Tune your cache so you can average zero reads per page view, if possible. Monday, June 22, 2009 37
Myth: Rails makes you do things its way Monday, June 22, 2009 38
It doesn¡¯t make you. Monday, June 22, 2009 39
It encourages you. Monday, June 22, 2009 40
Plus, Rails¡¯ way probably is the right way. Monday, June 22, 2009 41
And if not, you can write a plugin to make it do it your way. Monday, June 22, 2009 42
Myth: ¡°X is better!¡± Monday, June 22, 2009 43
Your point is? Monday, June 22, 2009 44
Religious battles over programming languages are stupid. Monday, June 22, 2009 45
Use what makes you happy and productive. Monday, June 22, 2009 46
Why You Shouldn¡¯t Use Rails You have a legacy database that you can¡¯t change. You could make it work with Rails, but it probably wouldn¡¯t be much fun. You¡¯re happy with what you¡¯ve got and hate learning. You don¡¯t ever talk to a database. Rails pretty much is ActiveRecord, so if you¡¯re not using it, you might be better off with something else. Monday, June 22, 2009 47
Gems! gem sources -a http://gems.github.com Pagination: mislav-will_paginate Faster URLs: pauldix-typhoeus Twitterness: hayesdavis-grackle Faster XML or HTML parsing: nokogiri or hpricot Monday, June 22, 2009 48
Rails Plugins FTW! cache-money: a write-through cache for ActiveRecord. attachment_fu: great for handling uploads and storing them on s3 smurf: automatic mini?cation of javascript and css openid_enabled: just what it says, painless OpenId. Monday, June 22, 2009 49
To Wrap Up Rails is fun to work with. I¡¯m way more productive now than I was before, happier too. Rails is more ?exible than it gets credit for. It¡¯s great for teams because it encourages good behavior Monday, June 22, 2009 50
Questions? Monday, June 22, 2009 51
Contact Info kevin@uplaya.com @kplawver on twitter http://uplaya.com http://lawver.net Monday, June 22, 2009 52
Welcome To Ruby On Rails
Welcome To Ruby On Rails
Welcome To Ruby On Rails
Welcome To Ruby On Rails
Welcome To Ruby On Rails
Welcome To Ruby On Rails
Welcome To Ruby On Rails
Welcome To Ruby On Rails
Welcome To Ruby On Rails

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Welcome To Ruby On Rails

  • 1. Welcome to Ruby on Rails Kevin Lawver | June 25, 2009 http://uplaya.com Monday, June 22, 2009 1
  • 2. Hi, I¡¯m Kevin Lawver Chief Architect at Music Intelligence Solutions - http://uplaya.com (it¡¯s a Rails app) Worked at AOL for 13 years, launched two public Rails apps. Spent a lot of time on AOLserver using Tcl and Tomcat writing JSP¡¯s. Just launched http://?cly.com with a friend as an ¡°art project¡± (also on Rails) Monday, June 22, 2009 2
  • 3. What is Ruby? Object-oriented Interpreted Expressive ¡°principle of least surprise¡± Monday, June 22, 2009 3
  • 4. ¡°They are focusing on machines. But in fact we need to focus on humans, on how humans care about doing programming or operating the application of the machines. We are the masters. They are the slaves.¡± -- Matz Monday, June 22, 2009 4
  • 5. Everything¡¯s an Object This confuses everyone at the beginning. Everything in Ruby is an object. There are no primitives, they¡¯re all objects! Monday, June 22, 2009 5
  • 6. What¡¯s Rails? Web framework written by DHH in 2003 at 37signals for Basecamp Takes most of the ¡°grunt work¡± out of building web apps MVC ¡°Optimized for programmer happiness and sustainable productivity¡± Monday, June 22, 2009 6
  • 7. Why Use It? Convention over con?guration Quick prototyping - can turn into the ¡°real¡± project without starting over Convention makes it easy to share code and quick to get started Because it¡¯s Ruby, you can turn it into anything you want Monday, June 22, 2009 7
  • 8. Rails¡¯ Components ActiveRecord ActionController ActionView ActiveResource ActiveSupport Monday, June 22, 2009 8
  • 9. ActiveRecord The ¡°M¡± in MVC Rails¡¯ crown jewel - a great database abstraction layer. Makes it really easy to work with databases. In Rails, your models should contain 95% of your business logic. Monday, June 22, 2009 9
  • 10. ActionController The ¡°C¡± in MVC Handles routing requests and processing them. In Rails, your controllers should be light Monday, June 22, 2009 10
  • 11. ActionView The ¡°V¡± in MVC Where you do all your HTML and most of your XML. I¡¯ve used a dozen different template systems over the years and Rails¡¯ is by far my favorite. Monday, June 22, 2009 11
  • 12. ActiveResource Rails¡¯ built-in support for RESTful API¡¯s Makes it easy to do REST the right way Provides a lot of the wrappers, error cases and connection code you need to do RESTy stuff. Monday, June 22, 2009 12
  • 13. ActiveSupport All the extensions to Ruby¡¯s base classes A lot of ¡°glue¡± for JSON and other things that don¡¯t belong in the other pieces Monday, June 22, 2009 13
  • 14. My Favorite Things About Rails I can go from idea to ¡°real¡± in hours instead of days. It¡¯s easy to refactor single pieces without affecting the whole app. Plugins solve major problems without requiring rewrites (see cache money) Community is helpful and responsive Monday, June 22, 2009 14
  • 15. Getting Started I don¡¯t use Windows, so you¡¯re on your own there. If you use a Mac and have Leopard, you already have Ruby and Rails. Linux? There are dozens of tutorials for your distro, don¡¯t worry. Monday, June 22, 2009 15
  • 16. The 20 Minute Blog Sorry if you¡¯re following along online, I¡¯m heading to terminal now. Monday, June 22, 2009 16
  • 17. What we¡¯ll be doing Create a new Rails app for our awesome new blog Build a model, controller and view for it Look at some helpful gems and plugins Make a feed for it Talk a little about ActiveRecord callbacks Monday, June 22, 2009 17
  • 18. What we won¡¯t be doing Talking about tests (they¡¯re important, but I hate writing them) Spending a lot of time on con?guration Monday, June 22, 2009 18
  • 19. What we¡¯ll be doing (redux) Create a new Rails app for our awesome new blog Build a model, controller and view for it Look at some helpful gems and plugins Make a feed for it Talk a little about ActiveRecord callbacks Monday, June 22, 2009 19
  • 20. Wasn¡¯t that fun? now let¡¯s talk about myths! Monday, June 22, 2009 20
  • 21. Some Rails Myths ¡°Rails doesn¡¯t scale¡± ¡°Ruby (or Rails) is too slow¡± ¡°Rails locks you into doing it its way¡± ¡°X is better!¡± (where X = ¡°Python¡±, ¡°PHP¡±, ¡°Java¡± or whatever) Monday, June 22, 2009 21
  • 22. Myth: ¡°Rails Doesn¡¯t Scale¡± Monday, June 22, 2009 22
  • 23. Maybe 3 Years Ago Back then, we had to use FastCGI or Mongrel. Now, though, we can use Phusion Passenger! It¡¯s an Apache plugin that does a great job of managing Rails instances. And Ruby Enterprise Edition makes Rails use less memory and run faster. Brilliant! Monday, June 22, 2009 23
  • 24. Live-World Examples uplaya.com handles tens of thousands of requests a day on a couple tiny Amazon EC2 instances (we could do everything on one with room to spare, but I like having backup). ?cly.com handles tens of thousands of requests a day on a single quad core server - that¡¯s not even breaking a sweat yet. hundreds of other sites handle a lot more traf?c with minimal hardware or fuss. Monday, June 22, 2009 24
  • 25. You will probably never need to scale. Monday, June 22, 2009 25
  • 26. But if you do... Monday, June 22, 2009 26
  • 27. The Data Layer Your database will fall over before your web server does. Optimize your connection, queries and indexes Protect your database by using memcached between your front-end and database Monday, June 22, 2009 27
  • 28. Cache, Cache, Cache memcached is your friend Disk-based caches don¡¯t work once you grow beyond one server - same thing for in-memory caches Caching hides a world of programming sins, and saves you from having to do ugly things like sharding. Monday, June 22, 2009 28
  • 29. You Don¡¯t Want... to be both read-heavy and write-heavy to have complex queries that can¡¯t be cached to have to do multiple selects on a single request Monday, June 22, 2009 29
  • 30. The Most Important Thing is to launch! If you never launch, you¡¯ll never have users. If you never have users, you¡¯ll never have to scale. Rails helps me get from nothing to launch faster than anything else I¡¯ve tried. It helps me get from launch to scale pretty quickly as well. Monday, June 22, 2009 30
  • 31. Typical Rails Stack Apache w/ Passenger *x MySQL Master memcached * y Slave Readers * z Writer Monday, June 22, 2009 31
  • 32. Myth: ¡°Ruby is too slow!¡± Monday, June 22, 2009 32
  • 33. But, it¡¯s fast enough for the web. Monday, June 22, 2009 33
  • 34. For all of my sites... No request takes longer than 1 second On uPlaya, the average time per request is 217 milliseconds. On Ficly, the average time per request is 165 milliseconds. That¡¯s more than fast enough for the web. Monday, June 22, 2009 34
  • 35. The ¡°Slow¡± in Rails Is the same slow anywhere else: Database The Internet CPU, Disk or RAM Monday, June 22, 2009 35
  • 36. Those factors affect everyone, not just Rails Monday, June 22, 2009 36
  • 37. Performance Gotchas Database indexes. If you¡¯re selecting or sorting by a column, it should have an index! You won¡¯t know you need them until it¡¯s too late. Static assets. Set up a separate virtual host for static stuff, or move them to a CDN. Don¡¯t make Rails serve static stuff! Selects. Tune your cache so you can average zero reads per page view, if possible. Monday, June 22, 2009 37
  • 38. Myth: Rails makes you do things its way Monday, June 22, 2009 38
  • 39. It doesn¡¯t make you. Monday, June 22, 2009 39
  • 40. It encourages you. Monday, June 22, 2009 40
  • 41. Plus, Rails¡¯ way probably is the right way. Monday, June 22, 2009 41
  • 42. And if not, you can write a plugin to make it do it your way. Monday, June 22, 2009 42
  • 43. Myth: ¡°X is better!¡± Monday, June 22, 2009 43
  • 44. Your point is? Monday, June 22, 2009 44
  • 45. Religious battles over programming languages are stupid. Monday, June 22, 2009 45
  • 46. Use what makes you happy and productive. Monday, June 22, 2009 46
  • 47. Why You Shouldn¡¯t Use Rails You have a legacy database that you can¡¯t change. You could make it work with Rails, but it probably wouldn¡¯t be much fun. You¡¯re happy with what you¡¯ve got and hate learning. You don¡¯t ever talk to a database. Rails pretty much is ActiveRecord, so if you¡¯re not using it, you might be better off with something else. Monday, June 22, 2009 47
  • 48. Gems! gem sources -a http://gems.github.com Pagination: mislav-will_paginate Faster URLs: pauldix-typhoeus Twitterness: hayesdavis-grackle Faster XML or HTML parsing: nokogiri or hpricot Monday, June 22, 2009 48
  • 49. Rails Plugins FTW! cache-money: a write-through cache for ActiveRecord. attachment_fu: great for handling uploads and storing them on s3 smurf: automatic mini?cation of javascript and css openid_enabled: just what it says, painless OpenId. Monday, June 22, 2009 49
  • 50. To Wrap Up Rails is fun to work with. I¡¯m way more productive now than I was before, happier too. Rails is more ?exible than it gets credit for. It¡¯s great for teams because it encourages good behavior Monday, June 22, 2009 50
  • 52. Contact Info kevin@uplaya.com @kplawver on twitter http://uplaya.com http://lawver.net Monday, June 22, 2009 52