Notes posted to Ruby on Rails

Using fontawesome icons inside link_to

<%= link_to (‘<i class=“fa fa-thumbs-up fa-lg”> </i>’).html_safe, vote_path(@image)%>

in this way you can use thumbs-up icon instead of usual text such as “like” in link_to

4.0.2 support

Where did this go in 4.0.2?

form_for with namescope and polymorphic path

<%= form_for([:namescope_name, @object], :url => polymorphic_path([:namescope_name, @objectable, @object])) do |form| %>

for the routes.

namescope :admin do

resources :articles do
  resources :comments
end
resources :photos do
  resources :comments
end

end

<%= form_for([:admin, @comment], :url => polymorphic_path([:admin, @commentable, @comment])) do |form| %>

Note : @commentable = find_commentable

change_column did the trick for me

Use change_column, and make sure to specify the datatype:

class ChangeUsers < ActiveRecord::Migration
  def up
	change_column :users, :is_vote_reminder, :boolean, :default => true
  end
end

Use this for has_one associations instead

I have confirmed that validates_associated doesn’t work with has_one associations, like @amasses said.

This however worked for me, so I recommend to use validates on the has_one association directly, like this:

class Book < ActiveRecord::Base
  has_one :cover, validates: true
end

URI Module

Uniform handling of handling URIs

Flexibility to introduce custom URI schemes

Flexibility to have an alternate URI::Parser

For Example

require ‘uri’

uri = URI(“http://test.com/posts?id=30&limit=5#time=1305298413”)

uri.scheme #=> “http”

uri.host #=> “test.com”

uri.path #=> “/posts”

time is represented in the Rails app's timezone

From the description of Time.current (which is a Rails extension of Ruby’s native Time class)

“Returns Time.zone.now when Time.zone or config.time_zone are set, otherwise just returns Time.now.”

so 3.days.ago, for example, is in the application’s configured timezone (if it’s configured).

Reject If

reject_if: proc { |attributes| attributes[‘name’].blank? } Has saved me after an 3 hours of google search. Thanks

Alternitive to to add flash to respond with

This is a nice way to add flash if you don’t have a any logic that needs to go around your flash.

def destroy
  @current_user_session.destroy
  respond_with @current_user_session do |format|
    format.html {redirect_to login_path, notice: "You have been logged out"}
  end
end

:hidden_field_id was replaced with :include_id

In order to prevent fields_for from rendering a hidden field to store the ID of the record use

include_id: false

instead of

hidden_field_id: false

Original URL Example

# get “/articles?page=2”

request.original_url # => “http://www.example.com/articles?page=2”

You can add if: :query_method and unless: :query_method

You can make the callback conditional:

before_save :before_method, if: :needs_before_method?

private

def needs_before_method?
   false
end

def before_method
  # .. 
end

How to set request parameters (rails 3.2)

In Rails 3.2, this seems to work to create a TestRequest based on a certain url:

ActionController::TestRequest.new( Rack::MockRequest.env_for("http://something.tld/foo?one=two&three=four") )    

Example Regex format matching

for phone and email

validates_format_of :phone, with: /\A(\d{10}|\(?\d{3}\)?[-. ]\d{3}[-.]\d{4})\z/
validates_format_of :email, with: /\A[\w]([^@\s,;]+)@(([\w-]+\.)+(com|edu|org|net|gov|mil|biz|info))\z/i

another way

Perhaps a more efficient way:

def create
  @post = Post.new(post_params)
  if @post.save
    redirect_to @post, notice: "The post #{@post.title} was added to the system."
  else
    render action: 'new'
  end
end

where post_params is:

private

def post_params
  params.require(:post).permit(..attributes to permit..)
end

Security

In regards to @aamer’s comment on including the password salt this is a bad idea. `ActiveSupport::MessageVerifier` is NOT encrypted so:

verifier = ActiveSupport::MessageVerifier.new('secret')
id = 'id'
salt = 'salt'
verifier.generate("#{id}-#{salt}") # "BAhJIgxpZC1zYWx0BjoGRVQ=--c880254708d18ce4a686bcd96a25cf0d2117e1e0"

Base64.decode64(token.split("--").first) # "...id-salt..."

Note how the salt and id are both exposed! Instead a different token (reset_passowrd_token) should be used.

Passing an array of keys to exclude.

Use the “*” before passing the array in. For example:

PARAMS_TO_SCRUB = [ :created_at, :updated, :id, :format ]

params.except!( *PARAMS_TO_SCRUB )

First example's output is incorrect

Everything except the initially html_safe input should be escaped in the output.

The output of the first example should be:

# => "<p>foo</p>&lt;br /&gt;&lt;p&gt;bar&lt;/p&gt;"

Does not symbolize hashes in nested arrays

If you have a nested structure containing arrays of hashes, you still need to do that on your own, eg.

module SymbolizeHelper
  def symbolize_recursive(hash)
    {}.tap do |h|
      hash.each { |key, value| h[key.to_sym] = map_value(value) }
    end
  end

  def map_value(thing)
    case thing
    when Hash
      symbolize_recursive(thing)
    when Array
      thing.map { |v| map_value(v) }
    else
      thing
    end
  end
end

Or, if you want to get really fancy with Ruby refinements (YMMV), one could do

module SymbolizeHelper
  extend self

  def symbolize_recursive(hash)
    {}.tap do |h|
      hash.each { |key, value| h[key.to_sym] = transform(value) }
    end
  end

  private

  def transform(thing)
    case thing
    when Hash; symbolize_recursive(thing)
    when Array; thing.map { |v| transform(v) }
    else; thing
    end
  end

  refine Hash do
    def deep_symbolize_keys
      SymbolizeHelper.symbolize_recursive(self)
    end
  end
end

And later say

using SymbolizeHelper # augmented Hash#deep_symbolize_keys is now available

Does not work with ActionController::BadRequest

This method will not work with ActionController::BadRequest

Compatible with old docs

Library is moved, so old library documentation is compatible http://apidock.com/rails/v3.0.9/ActionController/Streaming/send_file

You could pass a range as the choices parameter

select :object, :method, (1..5)

Requires inheritance of ActionController::Metal

The example code will not work unless class inherits from ActionController::Metal (to get functioning controller) or at least AbstractController:Base.

link_to_if when URL helpers will throw an exception when condition fails

You can use an array to build a URL instead of a URL helper (e.g. edit_admin_user_path(event.user), which would fail when an event has no user:

link_to_if event.user, event.user_name, [:edit, :admin, event.user]

Sometimes, you need the "Oxford comma"

Re: Gramatical error

http://imgur.com/fycHx

We invited the strippers, JFK, and Stalin.

versus the appositive phrase:

We invited the strippers, JFK and Stalin.

(Really, you need to see the comic to appreciate the difference.)

Grammatical error

Hi - not sure where I would submit this so just putting here. My apologies if not in the right place.

default: “, and ” - this is grammatically wrong. There should be no comma with the last and.

Example:

[‘one’, ‘two’, ‘three’].to_sentence

should give: “one, two and three”

There is no ‘ .… , and ’ which is considered grammatically incorrect I feel. The ‘and’ does it’s job in the English language quite well by joining the two words it’s in between.

Thank you.

Update for Rails 4

In the example

select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, { include_blank: true })

It can be updated to

select("post", "person_id", Person.pluck(:name, :id), { include_blank: true })

gives a parameter

As a note, you can use it like this:

after_save {|instance|

}

it will pass in the instance being saved.

form_for with :path route

Similar to danwich’s note, if you specify a route using the :path option

resource :posts, path: 'articles'

then the form_for tag must specify the :url option

form_for(@post), url: post_path(@post)

missing :through option

So the way to do the equivalent of a has_many :through is to use has_one :through, with the expected names.

so using the other example we could do

eg

class Person < ActiveRecord::Base
  belongs_to :team
  ...
end
class Task < ActiveRecord::Base
  belongs_to :person
  has_one :team, :through => :person
end