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RE: Replacing with "\" and match — a simple solution
Thanks. No, I am not trying to quote for a regex. It was mostly an approach thing since I came into contact with the behavior previously when I played around. After doing some tests, I figured I should spare any other adventurers that part. :-)

How to test custom error pages
Here is some advice for testing custom error pages using Webrat and Cucumber:
http://gem-session.com/2010/03/testing-your-custom-error-pages-with-webrat-and-cucumber

Time.now in UTC
A quick way to get the current time in UTC is:
Time.new.utc # => Wed Mar 24 14:38:19 UTC 2010

Setting primary key from hash
If you try to specify the value for your primary key (usually “id”) through the attributes hash, it will be stripped out:
Post.new(:id => 5, :title => 'Foo') #=> #<Post @id=nil @title="Foo">
You can solve this by setting it directly, perhaps by using a block:
Post.new(:title => "Foo") { |p| p.id = 5 } #=> #<Post @id=5 @title="Foo">
This behavior is something you’d probably only have a problem with when you have custom primary keys. Perhaps you have a User model with a primary key of “name”…
class User < ActiveRecord::Base set_primary_key :name end User.new(params[:user]) # This will never work
You can solve this on a case-to-case basis by calling attributes= directly with the “ignore protected” option:
User.new { |user| user.send(:attributes=, params[:user], false) } # BAD BAD BAD!
You should not do the above example, though. If you do, all protected attributes are ignored, which is very, very bad when you only care about the primary key.
I’d recommend one of the following instead:
# Option 1 – Always allow primary key. Avoid with models created by users class User private def attributes_protected_by_default super - [self.class.primary_key.to_s] end end # Option 2 – Add a new method for this case class User def self.new_with_name(attributes = nil) new(attributes) { |u| u.name = attributes[:name] } end end
As always when something is hard to do in Rails: Think about your design? Is it recommended? Is it sound? Do you really need to have a custom primary key?

named_scopes and Acts as State Machine
As of AASM 2.1 named_scope(s) are defined by default for each state of a model.

singular_class_name method missing
If this method is undefined in ActionView::Base, add to your ApplicationController:
class ApplicationController < ActionController::Base helper_method :singular_class_name end

collect_with_index
Use Object#enum_for if you need to collect with index:
require 'enumerator' ['a', 'b', 'c'].enum_for(:each_with_index).collect do |item, index| "#{index}: #{item}" end
See also: Enumerable#each_with_index

collect_with_index
Use Object#enum_for if you need to collect with index:
require 'enumerator' %w{foo bar}.enum_for(:each_with_index).collect do |item, index| "#{index}: #{item}" end
See also: Enumerable#each_with_index

Validations
out of the box touch will run with validations

Create new Hash as subset of another a different way
or
only keys
old_hash = { :a => 'A', :b => 'B', :c => 'C', :d => 'D', :e => 'E', :f => 'F' } only_keys = [ :a, :c, :f ] new_hash = old_hash.delete_if { |k, v| !only_keys.include? k }
only values
old_hash = { :a => 'A', :b => 'B', :c => 'C', :d => 'D', :e => 'E', :f => 'F' } only_values = [ 'A', 'D', 'G' ] new_hash = old_hash.delete_if { |k, v| !only_values.include? v }
there are many ways to skin a cat :)

Create new Hash as subset of another
old_hash = {:a=>‘A’,:b=>‘B’,:c=>‘C’,:d=>‘D’,:e=>‘E’,:f=>‘F’}
only_keys = [:a,:c,:f]
new_hash = Hash[*old_hash.find_all{|k,v| only_keys.member?(k)}.flatten]
# => {:a=>“A”, :c=>“C”, :f=>“F”}
or for values
only_vals = [‘A’,‘D’,‘G’]
new_hash = Hash[*old_hash.find_all{|k,v| only_vals.member?(v)}.flatten]
# => {:a=>“A”, :d=>“D”}

config/environments/production.rb
old
ActionController::AbstractRequest.relative_url_root= "/exampleapp"
new
config.action_controller.relative_url_root= "/exampleapp"

Another Example
Delete all files in log
require 'FileUtils' Dir["log/*"].each{|file| FileUtils.rm file}

Can be used with has_many associations
You can also use this to validate that a has_many association has a specified number of records on the other end:
has_many :members validates_length_of :members, :minimum => 1

Complete Formatting Codes
%a - The abbreviated weekday name (“Sun”)
%A - The full weekday name (“Sunday”)
%b - The abbreviated month name (“Jan”)
%B - The full month name (“January”)
%c - The preferred local date and time representation
%C - Century (20 in 2009)
%d - Day of the month (01..31)
%D - Date (%m/%d/%y)
%e - Day of the month, blank-padded ( 1..31)
%F - Equivalent to %Y-%m-%d (the ISO 8601 date format)
%h - Equivalent to %b
%H - Hour of the day, 24-hour clock (00..23)
%I - Hour of the day, 12-hour clock (01..12)
%j - Day of the year (001..366)
%k - hour, 24-hour clock, blank-padded ( 0..23)
%l - hour, 12-hour clock, blank-padded ( 0..12)
%L - Millisecond of the second (000..999)
%m - Month of the year (01..12)
%M - Minute of the hour (00..59)
%n - Newline (n)
%N - Fractional seconds digits, default is 9 digits (nanosecond)
-
%3N millisecond (3 digits)
-
%6N microsecond (6 digits)
-
%9N nanosecond (9 digits)
%p - Meridian indicator (“AM” or “PM”)
%P - Meridian indicator (“am” or “pm”)
%r - time, 12-hour (same as %I:%M:%S %p)
%R - time, 24-hour (%H:%M)
%s - Number of seconds since 1970-01-01 00:00:00 UTC.
%S - Second of the minute (00..60)
%t - Tab character (t)
%T - time, 24-hour (%H:%M:%S)
%u - Day of the week as a decimal, Monday being 1. (1..7)
%U - Week number of the current year, starting with the first Sunday as the first day of the first week (00..53)
%v - VMS date (%e-%b-%Y)
%V - Week number of year according to ISO 8601 (01..53)
%W - Week number of the current year, starting with the first Monday as the first day of the first week (00..53)
%w - Day of the week (Sunday is 0, 0..6)
%x - Preferred representation for the date alone, no time
%X - Preferred representation for the time alone, no date
%y - Year without a century (00..99)
%Y - Year with century
%z - Time zone as hour offset from UTC (e.g. +0900)
%% - Literal “%” character
t = Time.now #=> 2007-11-19 08:37:48 -0600 t.strftime("Printed on %m/%d/%Y") #=> "Printed on 11/19/2007" t.strftime("at %I:%M%p") #=> "at 08:37AM"

Complete Formatting Codes
NOTE: Some of these seem only to work for DateTime (e.g. %L, %N)
%a - The abbreviated weekday name (“Sun”)
%A - The full weekday name (“Sunday”)
%b - The abbreviated month name (“Jan”)
%B - The full month name (“January”)
%c - The preferred local date and time representation
%C - Century (20 in 2009)
%d - Day of the month (01..31)
%D - Date (%m/%d/%y)
%e - Day of the month, blank-padded ( 1..31)
%F - Equivalent to %Y-%m-%d (the ISO 8601 date format)
%h - Equivalent to %b
%H - Hour of the day, 24-hour clock (00..23)
%I - Hour of the day, 12-hour clock (01..12)
%j - Day of the year (001..366)
%k - hour, 24-hour clock, blank-padded ( 0..23)
%l - hour, 12-hour clock, blank-padded ( 0..12)
%L - Millisecond of the second (000..999)
%m - Month of the year (01..12)
%M - Minute of the hour (00..59)
%n - Newline (n)
%N - Fractional seconds digits, default is 9 digits (nanosecond)
-
%3N millisecond (3 digits)
-
%6N microsecond (6 digits)
-
%9N nanosecond (9 digits)
%p - Meridian indicator (“AM” or “PM”)
%P - Meridian indicator (“am” or “pm”)
%r - time, 12-hour (same as %I:%M:%S %p)
%R - time, 24-hour (%H:%M)
%s - Number of seconds since 1970-01-01 00:00:00 UTC.
%S - Second of the minute (00..60)
%t - Tab character (t)
%T - time, 24-hour (%H:%M:%S)
%u - Day of the week as a decimal, Monday being 1. (1..7)
%U - Week number of the current year, starting with the first Sunday as the first day of the first week (00..53)
%v - VMS date (%e-%b-%Y)
%V - Week number of year according to ISO 8601 (01..53)
%W - Week number of the current year, starting with the first Monday as the first day of the first week (00..53)
%w - Day of the week (Sunday is 0, 0..6)
%x - Preferred representation for the date alone, no time
%X - Preferred representation for the time alone, no date
%y - Year without a century (00..99)
%Y - Year with century
%z - Time zone as hour offset from UTC (e.g. +0900)
%% - Literal “%” character
t = Time.now #=> 2007-11-19 08:37:48 -0600 t.strftime("Printed on %m/%d/%Y") #=> "Printed on 11/19/2007" t.strftime("at %I:%M%p") #=> "at 08:37AM"

Skips validations and callbacks
The method skips validations and callbacks. That is why it should be used with caution.
Code example
person.toggle :active

Use message param
The message param is invaluable in case test fails – if you use it to display relevant info, you will find out what went wrong much faster.
Reworking the silly example above:
assert some_list.include?(5)
will only tell you that
<false> is not true.
which isn’t terribly helpful, is it? But if you use message like that:
assert some_list.include?(5), "some_list = #{some_list.inspect}"
the output will be:
some_list = [1, 2]. <false> is not true.
which in most cases should give you strong hints as to why the test failed.

Available statuses
All the available statuses (extracted from SYMBOL_TO_STATUS_CODE hash) in a slightly more readable form:
:continue => 100 :switching_protocols => 101 :processing => 102 :ok => 200 :created => 201 :accepted => 202 :non_authoritative_information => 203 :no_content => 204 :reset_content => 205 :partial_content => 206 :multi_status => 207 :im_used => 226 :multiple_choices => 300 :moved_permanently => 301 :found => 302 :see_other => 303 :not_modified => 304 :use_proxy => 305 :temporary_redirect => 307 :bad_request => 400 :unauthorized => 401 :payment_required => 402 :forbidden => 403 :not_found => 404 :method_not_allowed => 405 :not_acceptable => 406 :proxy_authentication_required => 407 :request_timeout => 408 :conflict => 409 :gone => 410 :length_required => 411 :precondition_failed => 412 :request_entity_too_large => 413 :request_uri_too_long => 414 :unsupported_media_type => 415 :requested_range_not_satisfiable => 416 :expectation_failed => 417 :unprocessable_entity => 422 :locked => 423 :failed_dependency => 424 :upgrade_required => 426 :internal_server_error => 500 :not_implemented => 501 :bad_gateway => 502 :service_unavailable => 503 :gateway_timeout => 504 :http_version_not_supported => 505 :insufficient_storage => 507 :not_extended => 510

Good way to see what went wrong
Use the message parameter like that:
assert_response :success, @response.body
If this fails (the response isn’t a success), it will display the response body along with the failure message, thus allowing you to quickly find out what went wrong. If the response is e.g. 500, there will probably be some exception stacktrace displayed in the body. And so on.

Specify your own template
You can specify you own template this way:
def notice ... @template = "some_other_name.html.erb" end

Eagerness
Check out this simple example:
"Hello Ruby friend".sub(/^(.*)e/, 'X') # => "Xnd" "Hello Ruby friend".sub(/^(.*?)e/, 'X') # => "Xllo Ruby friend"
The question mark turns the dotstar into non-eager mode which means it will halt on the first subsequent “e” rather than the last one. This comes in handy e.g. for Cucumber step definitions.
Okay, but not really nice:
/^I am using rvm "([^\"]*)" with gemset "(.*)"$/
Much more readable and consistent equivalent to the above:
/^I am using rvm "(.*?)" with gemset "(.*?)"$/

AASM named scopes
If you are using the aasm plugin/gem, this will generate all named scopes for your various states.
Code example
Class Article < ActiveRecord::Base include AASM aasm_initial_state :created aasm_state :published aasm_state :unpublished aasm_state :deleted aasm_state :created aasm_event :publish do transitions :to => :published, :from => [:created] end aasm_event :unpublish do transitions :to => :unpublished, :from => [:created, :published] end aasm_event :delete do transitions :to => :deleted, :from => [:published, :unpublished] end aasm_states.each { |s| named_scope s, :conditions => { :state => s.to_s } } end

stub_chain is very useful when testing controller code
or any other chained method call type that you’d like to stub, example:
in your controller:
def new @user = current_site.users.new end
in your spec:
it "#new should assign a @user" do u = mock("User") controller.stub_chain(:current_site, :users, :new).and_return(u) assigns[:user].should == u end
whereas before you had to stub each chained method call separately:
it "#new should assign a @user" do u = mock("User") users = mock("Users collection", :new => u) site = mock("Site", :users => users) controller.stub!(:current_site).and_return(site) assigns[:user].should == u end
Please note that stub_chain was added to RSpec in version 1.2.6

Re: Caveat when using dynamic layouts
Since there’s no way to edit posts on here, I need to correct myself and say that what I posted before doesn’t work, since you can’t specify layout multiple times:
class OrdersController < BaseController layout :determine_layout, :only => :new layout "public", :except => :new # ... end
So don’t do that. The only way to ensure that the other actions get the default theme is to drop :only/:except and do the conditions yourself:
class OrdersController < BaseController layout :determine_layout private def determine_layout %w(new).include?(action_name) ? "some_layout" : "public" end end
All this to say, beware of :only/:except – they aren’t as useful as you think they are.

Deprecated in 1.9.x!
Use FileUtils::copy instead. It is also in 1.8.x, FileUtils, so call that one instead.

makedirs(path) to create file path
mkdir will only create a single directory on an existing path. If you want to create a full path, like the `mkdir -p /full/path` command, use the makedirs method.
1.8: File.makedirs(path) 1.9: FileUtils.makedirs(path)

Caveat when using dynamic layouts
Worth noting that if you have a controller which inherits from another controller which has a layout, and in this child controller you’re determining the layout at runtime using a method for specific actions, the other actions you are excluding will not inherit the layout from the parent controller.
For example, if you’ve got this
class BaseController < ApplicationController layout "public" end class OrdersController < BaseController layout :determine_layout, :only => :new # index, show, new, create, edit, update, destroy ... end
then OrdersController#index, #show, and #edit won’t get the “public” layout – in fact they won’t get a layout at all. So you’ll need to do this instead:
class OrdersController < BaseController layout :determine_layout, :only => :new layout "public", :except => :new # ... end

default_scope on create
If you specify :conditions in your default_scope in form of a Hash, they will also be applied as default values for newly created objects. Example:
class Article default_scope :conditions => {:published => true} end Article.new.published? # => true
However:
class Article default_scope :conditions => 'published = 1' end Article.new.published? # => false

configuration no longer in environment.rb
configure session store in config/initializers/session_store.rb