Ten Things You Didn't Know Rails Could Do

Presenter: James Edward Gray II (@jeg2)

Bio

James (@JEG2) has been a Rails programmer for about as long as it has been fashionable to be one and a Rubyist even longer than that. As you probably know from listening to him on the Ruby Rogues podcast, James loves to dig into how our community and code works.

Abstract

Rails is huge. Even if you have worked with it for a long time, it's unlikely that you have stumbled across everything yet.

Do you really know what all of the built-in Rake tasks do? Have you seen all of the methods ActiveSupport makes available to you? Are you aware of all the queries ActiveRecord is capable of?

In this talk, I'll dig into the extras of Rails and see if I can't turn up some features that you don't see all of the time, but that might just be handy to know about anyway. I'll make sure you come out of this able to impress your friends at the hackfest.

Notes

Really, 42 things.

From @james_gary

TODO

From @benjaminoakes

• Who
  • He's on Ruby Rogues
  • Rubyist for 8 years
  • Ruby code/documentation
  • CSV
• Rails 3.2.3
• Rails app in a single file
• rake notes for TODO, FIXME, OPTIMIZE
  • rake notes:custom ...
  • TextMate bundle
• Sanbox rails console
  • DB changes reverted
  • rails c --sandbox
• Helper methods in console
  • helper objecdt
• Non-webrick servers in dev: rails s thin
• In Railties: tap into config
  • require first

Database

• Migration shorthand
  • string by default, limits in {})
  • Indexes at command line name:index
  • Associations: user:references or user:belongs_to, column, add_index, and association (belongs_to)
  • rake db:migrate:status tells you whether a migration is applied
• CSV
  • Import CSV data (see slide). @jeg2 gets this all the time
  • CSV in database (use load and dump for serialize)
• Pluck
  • Foo.select(;email).map(&:email) same as Foo.pluck(:email)
• Records in groups Foo.group(:bar).count
• Override associations: def foo=
• Instatiate records without a DB: tell its id, etc Foo.instantiate('id' => 1) #evil
• Limitless strings in PostgeSQL (rather than a text field? I'm confused) FIXME
• Full text search in PostgreSQL: t.column :search, "tsvector" SQL: gin(search) (same as what Sphinx uses)
  • Too quick; see slides FIXME
  • Does stemming, case insensitive
• User in own database
  • SQLite is good for this
  • Uses ActiveRecord.establish_connection (he made a library... user_database?) TODO
  • Need a before_filter or similar
  • Could trigger by by subdomain
  • Not fighting with other users

Ruby

• File.atomic_write (makes a tempfile and moves it into place at the end; not good on NFS)
• Merge nested hashes: Hash#deep_merge in Rails
• Remove keys from a Hash: Hash#except(:foo, :bar)
• Hash#merge overwrites; not good for params, so for defaults, use Hash#reverse_merge
• Predicates on strings. Familiar example: Rails.env.development. "foo".inquiry.magic?. Works well with validates_inclusion_of

Views

• HTML coments or ERb comments. Slower using ERb, but not visible.
• Shorthand ERb: erubis broke: % if foo.bar?. @Jeg2 has a pull request for this. TODO link
• Blocks to avoid assignemnts (each and tap, or write a helper method that takes a block)
• Multiple tags at once with content_tag FIXME I think this isn't quite right
• Render any object using Foo#to_partial_path using render partial: @foo
• Group menu entries: select_tag(...) FIXME missed option name
• Make your own form builder (ActionView::Helpers::FormBuilder). See also default_form_builder and field_error_proc
• @tenderlove's theme song (on YouTube) TODO link

Actions

• Route exceptions to any Rack app
• match '/404', to: 'foo'
• Route to Sinatra. Example: Resque's interface

From @danbernier

TODO

External Links

• Friday hugs