The `uniq` option needs to be moved into a scope block. Note that the scope block needs to be the second parameter to `has_many` (i.e. you can&#39;t leave it at the end of the line, it needs to be moved before the `:through =&gt; :donations` part):

    has_many :donors, -&gt; { uniq }, :through =&gt; :donations

It may look odd, but it makes a little more sense if you consider the case where you have multiple parameters. For example, this:

    has_many :donors, :through =&gt; :donations, :uniq =&gt; true, :order =&gt; &quot;name&quot;, :conditions =&gt; &quot;age &lt; 30&quot;

becomes:

    has_many :donors, -&gt; { where(&quot;age &lt; 30&quot;).order(&quot;name&quot;).uniq }, :through =&gt; :donations


In addition to Dylans answer, if you happen to be extending the association with a module, make sure that you chain it in the scope block (as opposed to specifying it separately), like so:

    has_many :donors,
      -&gt; { extending(DonorExtensions).order(:name).uniq },
      through: :donations


Maybe its just me but it seems very unintuitive to use a scope block to extend an association proxy.



It seems that, from [Google Cloud Console][1] there is no way to delete a project.

&gt; Note: As of 2013-09-19 this is no longer an issue because
&gt; Google had fixed it.  
- Now you can click on the check box and then
&gt; click delete


  [1]: https://cloud.google.com/console#c=l

How to delete a project from Google Cloud Console

As we know, in bash programming the way to pass arguments is `$1`, ..., `$N`. However, I found it not easy to pass an array as an argument to a function which receives more than one argument. Here is one example:

    f(){
     x=($1)
     y=$2
    
     for i in &quot;${x[@]}&quot;
     do
      echo $i
     done
     ....
    }

    a=(&quot;jfaldsj jflajds&quot; &quot;LAST&quot;)
    b=NOEFLDJF
    
    f &quot;${a[@]}&quot; $b
    f &quot;${a[*]}&quot; $b

As described, function `f `receives two arguments: the first is assigned to `x` which is an array, the second to `y`.

`f` can be called in two ways. The first way use the `&quot;${a[@]}&quot;` as the first argument, and the result is:

    jfaldsj 
    jflajds

The second way use the `&quot;${a[*]}&quot;` as the first argument, and the result is:

    jfaldsj 
    jflajds 
    LAST

Neither result is as I wished. So, is there anyone having any idea about how to pass array between functions correctly?

How to pass array as an argument to a function in Bash

Rails 4 has introduced a deprecation warning when using :uniq =&gt; true with has_many :through. For example: 

    has_many :donors, :through =&gt; :donations, :uniq =&gt; true

Yields the following warning: 

    DEPRECATION WARNING: The following options in your Goal.has_many :donors declaration are deprecated: :uniq. Please use a scope block instead. For example, the following:

        has_many :spam_comments, conditions: { spam: true }, class_name: &#39;Comment&#39;

    should be rewritten as the following:

        has_many :spam_comments, -&gt; { where spam: true }, class_name: &#39;Comment&#39;

What is the correct way to rewrite the above has_many declaration? 

Deprecation warning when using has_many :through :uniq in Rails 4

Rails 4 has introduced a deprecation warning when using :uniq => true with has_many :through. For example:
<pre><code class="hljs language-ruby">has_many :donors, :through => :donations, :uniq => true
</code></pre>
Yields the following warning:
<pre><code class="hljs language-yaml">DEPRECATION WARNING: The following options in your Goal.has_many :donors declaration are deprecated: :uniq. Please use a scope block instead. For example, the following:

 has_many :spam_comments, conditions: { spam: true }, class_name: 'Comment'

should be rewritten as the following:

 has_many :spam_comments, -> { where spam: true }, class_name: 'Comment'
</code></pre>
What is the correct way to rewrite the above has_many declaration?

**contest_entry_spec.rb**

        require &#39;spec_helper&#39;
        
        describe ContestEntry do
          
          before(:all) do
            @admission=Factory(:project_admission)
            @project=Factory(:project_started, :project_type =&gt; @admission.project_type)
            @creative=Factory(:approved_creative, :creative_category =&gt; @admission.creative_category)
            @contest_entry=Factory(:contest_entry, :design_file_name =&gt; &#39;bla bla bla&#39;, :owner =&gt; @creative, :project =&gt; @project)
          end
          
          context &#39;non-specific tests&#39; do
            subject { @contest_entry }
            it { should belong_to(:owner).class_name(&#39;User&#39;) }
            it { should belong_to(:project) }
            it { should have_many(:entry_comments) }
        
            it { should validate_presence_of(:owner) }
            it { should validate_presence_of(:project) }
            it { should validate_presence_of(:entry_no) }
            it { should validate_presence_of(:title) }
        
          end
    end

When I run these tests everything is okey but if I change before(:all) to before(:each) every test will be failed.I don&#39;t know why it happens?

This is the error 

     Failure/Error: @contest_entry=Factory(:contest_entry, :design_file_name =&gt; &#39;bla bla bla&#39;, :owner =&gt; @creative, :project =&gt; @project)
         ActiveRecord::RecordInvalid:
           Validation Failed: User is not allowed for this type of project

rails rspec before all vs before each

I&#39;m looking to add custom http headers to a Ruby on Rails app that is currently hosted on Heroku.

How do you add a custom http header?

Using jquery and the Bootstrap Datepicker, how do I get the new date value I selected using the Bootstrap Datepicker? 
FYI, I&#39;m using Rails 3 and Coffescript.

I set up the datapicker using:

    &lt;input id=&quot;startdate&quot; class=&quot;span2 datepicker&quot; type=&quot;text&quot; value=&quot;&quot; name=&quot;startdate&quot; default=&quot;2013-05-21&quot; data-date=&quot;2013-05-21&quot; data-behavior=&quot;datepicker&quot;&gt;
    &lt;%= submit_tag &#39;Get Data using date&#39;, :id =&gt; &#39;get_data&#39; %&gt;

    $(&quot;.datepicker&quot;).datepicker
          endDate: new Date
          format: &quot;yyyy-mm-dd&quot;
          autoclose: true
          minViewMode: 1
          todayBtn: &quot;linked&quot;

When a user clicks on the &quot;get data using date&quot; button next to it, I will use jQuery to get the new date value set by the datepicker, prevent the form from submitting and run an ajax request using that date value. All the ajax is running well, except for getting the correct new date value. I tried both of the following and it doesn&#39;t give me the new date, it only return the defaults I initially set.

    sd1 = $(&#39;#startdate&#39;).attr(&#39;value&#39;)
    console.log sd1
    
    sd2 = $(&#39;#startdate&#39;).attr(&#39;data-date&#39;))
    console.log sd2

I am feeling really stupid right now, but I can&#39;t find out how to get the new date value set by the bootstrap datepicker.

How to get the selected date value while using Bootstrap Datepicker?

In my app a User can create a Business. When they trigger the `index` action in my `BusinessesController` I want to check if a Business is related to the `current_user.id`:

- If yes: display the business. 
- If no: redirect to the ` new ` action. 

I was trying to use this:

    if Business.where(:user_id =&gt; current_user.id) == nil
      # no business found
    end

But it always returns true even when the business doesn&#39;t exist...

**How can I test if a record exists in my database?**

Check if record exists from controller in Rails

I&#39;m writing a Rails frontend for inventory management. I want users to be able to register products, so I have:

    class User &lt; ActiveRecord::Base
      has_many :products
      # &lt;snip&gt;
    end

and

    class Product &lt; ActiveRecord::Base
      belongs_to :user
      # &lt;snip&gt;
    end

The problem is that products are created prior to being registered by a user. That is, it&#39;s perfectly acceptable to call `Product.create` and just have it set the `user_id` to `nil`. As you can imagine, though, Rails doesn&#39;t support this out of the box:

    &gt; Product.create!
       (0.3ms)  SELECT COUNT(*) FROM &quot;products&quot; WHERE &quot;products&quot;.&quot;type&quot; IN (&#39;Product&#39;)
       (0.1ms)  begin transaction
       (0.1ms)  rollback transaction
    ActiveRecord::RecordInvalid: Validation failed: User can&#39;t be blank
    	from ~/.rvm/gems/ruby-2.0.0-p0/gems/activerecord-3.2.13/lib/active_record/validations.rb:56:in `save!&#39;

I&#39;ve thought about a bunch of kludgey workarounds, the most appealing of which is to have a `NullUser` subclassing `User` and use that to create products. But that still seems like a hack. What&#39;s the Rails Way with this?

Thanks.

-----

The relevant migration:

    class AddUseridToProducts &lt; ActiveRecord::Migration
      def change
        add_column :products, :user_id, :integer
      end
    end

and later:

    class Changeuseridtobeoptionalforproducts &lt; ActiveRecord::Migration
      def change
        change_column :products, :user_id, :integer, null: true
      end
    end



Rails optional belongs_to

Is there anyway I can order the results (`ASC`/`DESC`) by number of items returned from the child model (`Jobs`)?

    @featured_companies = Company.joins(:jobs).group(Job.arel_table[:company_id]).order(Job.arel_table[:company_id].count).limit(10)

For example:  I need to print the Companies with highest jobs on top



Rails order by results count of has_many association

I have an array of objects, let&#39;s call it an `Indicator`. I want to run Indicator class methods (those of the `def self.subjects` variety, scopes, etc) on this array. The only way I know to run class methods on a group of objects is to have them be an ActiveRecord::Relation. So I end up resorting to adding a `to_indicators` method to `Array`.

    def to_indicators
      # TODO: Make this less terrible.
      Indicator.where id: self.pluck(:id)
    end

At times I chain quite a few of these scopes to filter down the results, within the class methods. So, even though I call a method on an ActiveRecord::Relation, I don&#39;t know how to access that object. I can only get to the contents of it through `all`. But `all` is an Array. So then I have to convert that array to a ActiveRecord::Relation. For example, this is part of one of the methods:

    all.to_indicators.applicable_for_bank(id).each do |indicator|
      total += indicator.residual_risk_for(id)
      indicator_count += 1 if indicator.completed_by?(id)
    end

I guess this condenses down to two questions.

1. How can I convert an Array of objects to an ActiveRecord::Relation? Preferably without doing a `where` each time.
2. When running a `def self.subjects` type method on an ActiveRecord::Relation, how do I access that ActiveRecord::Relation object itself?

Thanks. If I need to clarify anything, let me know.

Converting an array of objects to ActiveRecord::Relation

There is the following code:

    class Product &lt; ActiveRecord::Base
      validates :title, :description, :image_url, presence: true
      validates :price, numericality: {greater_than_or_equal_to: 0.01}
      validates :title, uniqueness: true
      validates :image_url, allow_blank: true, format: {
          with: %r{\.(gif|jpg|png)$}i,
          message: &#39;URL must point to GIT/JPG/PNG pictures&#39;
      }
    end

It works, but when I try to test it using &quot;rake test&quot; I&#39;ll catch this message: 

    rake aborted!
    The provided regular expression is using multiline anchors (^ or $), which may present a security risk. Did you mean to use \A and \z, or forgot to add the :multiline =&gt; true option?

What does it mean? How can I fix it? 



Regular expressions with validations in RoR 4

I&#39;m wondering how the following is done in Rails 4 or if I just use the Rails 3 approach for using a lambda that can pass an argument the same way with 4 as I do with 3. 

I&#39;m pretty new to Rails 3 and trying to work through some samples running Rails 4.

Here is my Rails 3 code:  

    class Person &lt; ActiveRecord::Base
      scope :find_lazy, lambda {|id| where(:id =&gt; id)}
    end

    # In console I can call
    Person.find_lazy(1)

So if this is the Rails 4 way is to use the -&gt; {}, that&#39;s a lambda, right? `scope :all_lazy, -&gt; { select(&quot;*&quot;) }` What if I needed an argument. I tried a few different ideas and get argument errors in the console when using the -&gt; {}.    



scopes with lambda and arguments in Rails 4 style?

I have this model in Ruby but it throws a `ActiveModel::ForbiddenAttributesError`
    
    class User &lt; ActiveRecord::Base
      attr_accessor :password
      validates :username, :presence =&gt; true, :uniqueness =&gt; true, :length =&gt; {:in =&gt; 3..20}
      VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
      validates :email, presence: true, :uniqueness =&gt; true, format: { with: VALID_EMAIL_REGEX }
    
      validates :password, :confirmation =&gt; true
      validates_length_of :password, :in =&gt; 6..20, :on =&gt; :create
    
      before_save :encrypt_password
      after_save :clear_password
    
      def encrypt_password
        if password.present?
          self.salt = BCrypt::Engine.generate_salt
          self.encrypted_password= BCrypt::Engine.hash_secret(password, salt)
        end
      end
    
      def clear_password
        self.password = nil
      end
    end

when I run this action

      def create
        @user = User.new(params[:user])
        if @user.save
          flash[:notice] = &quot;You Signed up successfully&quot;
          flash[:color]= &quot;valid&quot;
        else
          flash[:notice] = &quot;Form is invalid&quot;
          flash[:color]= &quot;invalid&quot;
        end
        render &quot;new&quot;
      end

on `ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]`.

Can you please tell me how to get rid of this error or establish a proper user registration form?

ActiveModel::ForbiddenAttributesError when creating new user

I&#39;m newbie to Rails.  
I have two models **Category** and **Product** as follows:-  

    class Category &lt; ActiveRecord::Base
     attr_accessible :type

     has_many :products
    end

    class Product &lt; ActiveRecord::Base
     attr_accessible :category_id, :color, :price, :title

     belongs_to :category
    end
  
And my **schema.rb** is as follows:-  


    ActiveRecord::Schema.define(:version =&gt; 20130725220046) do

    create_table &quot;categories&quot;, :force =&gt; true do |t|
        t.string   &quot;type&quot;
        t.datetime &quot;created_at&quot;, :null =&gt; false
        t.datetime &quot;updated_at&quot;, :null =&gt; false
      end
    
      create_table &quot;products&quot;, :force =&gt; true do |t|
        t.integer  &quot;category_id&quot;
        t.decimal  &quot;price&quot;,       :precision =&gt; 10, :scale =&gt; 0
        t.string   &quot;title&quot;
        t.string   &quot;color&quot;
        t.datetime &quot;created_at&quot;,                                 :null =&gt; false
        t.datetime &quot;updated_at&quot;,                                 :null =&gt; false
      end
    
    end

  
In Rails console I created two products with two products with the **Product.create** command  

    [#&lt;Product id: 1, category_id: 1, price: 500, title: &quot;shirt&quot;, color: &quot;blue&quot;, `created_at: &quot;2013-07-25 22:04:54&quot;, updated_at: &quot;2013-07-25 22:04:54&quot;&gt;, #&lt;Product id: 2, category_id: 1, price: 600, title: &quot;tees&quot;, color: &quot;black&quot;, created_at: &quot;2013-07-25 22:05:17&quot;, updated_at: &quot;2013-07-25 22:05:17&quot;&gt;]`  

And created two Categories with the **Category.create** command in console  

    &lt;Category id: 1, type: &quot;clothing&quot;, created_at: &quot;2013-07-25 22:03:54&quot;, updated_at: &quot;2013-07-25 22:03:54&quot;&gt;&lt;Category id: 2, type: &quot;footwear&quot;, created_at: &quot;2013-07-25 22:04:02&quot;, updated_at: &quot;2013-07-25 22:04:02&quot;&gt;  

Now, **Product.all** works fine but **Category.all** gives  

&gt; ActiveRecord::SubclassNotFound: The single-table inheritance mechanism failed to locate the subclass: &#39;clothing&#39;. This error is raised because the column &#39;type&#39; is reserved for storing the class in case of inheritance. Please rename this column if you didn&#39;t intend it to be used for storing the inheritance class or overwrite Category.inheritance_column to use another column for that information.  

What&#39;s wrong in there? I want to make a relationship between Category and Product like  
a category has_many products and products belongs_to a category.

ActiveRecord::SubclassNotFound: The single-table inheritance mechanism failed to locate the subclass

I have a `User` model and a `Task` model. I have not mentioned any relation between them while creating them. 

I need to establish that `User` `has_many` `Tasks` and a `Task` `belongs_to` `User` through a migration  

What would be the migration generation command for establishing that relationship?

has_many, belongs_to relation in active record migration rails 4

Where can I find a list of data types that can be used in Ruby on Rails 4? 
Such as 

 - `text` 
 - `string` 
 - `integer` 
 - `float` 
 - `date`  

I keep learning about new ones and I&#39;d love to have a list I could easily refer to.

Rails 4: List of available datatypes

Are we supposed to use something else aside from `image-url` and others in Rails 4? They return different values that don&#39;t seem to make sense. If I have `logo.png` in `/app/assets/images/logo.png` and I do the following, this is what I get:

    image-url(&quot;logo.png&quot;) -&gt; url(&quot;/images/logo.png&quot;) #obviously doesn&#39;t work
    image-path(&quot;logo.png&quot;) -&gt; &quot;/images/logo.png&quot;
    asset-url(&quot;logo.png&quot;) -&gt; url(&quot;/logo.png&quot;)

Of course none of these work because they need at least `/assets` in front.

***UPDATE***: Actually, I just noticed, how do I access images in Rails 4? I have an image at `/app/assets/images/logo.png`. But if I go to any of the following URLs, I still don&#39;t see my image:

    http://localhost:3000/assets/logo.png
    http://localhost:3000/assets/images/logo.png
    http://localhost:3000/logo.png
    http://localhost:3000/images/logo.png

***UPDATE 2***: The only way I can bring up my `logo.png` is by moving it into the `/app/assets/stylesheets` directory and then pulling up:

    http://localhost:3000/assets/logo.png

Rails 4 image-path, image-url and asset-url no longer work in SCSS files

On Rails 4.0.0.rc1, Ruby 2.0.0, after I run a migration, I see the following error when I try to run a test through `rspec`:


&gt; /Users/peeja/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:376:in
&gt; `check_pending!&#39;: Migrations are pending; run &#39;rake db:migrate
&gt; RAILS_ENV=test&#39; to resolve this issue.
&gt; (ActiveRecord::PendingMigrationError)


That doesn&#39;t seem right. No one migrates their test database, do they? They `db:test:prepare` it, which—to be fair—I&#39;ve forgotten to do. So I run `rake db:test:prepare` and run my `rspec` command again…and see the same error.

If I actually `rake db:migrate RAILS_ENV=test`, the error does in fact go away.

What&#39;s going on? Is this new in Rails 4?

Why am I asked to run &#39;rake db:migrate RAILS_ENV=test&#39;?

So in Rails 4 the long desired feature to use `not` queries has been added.

    Article.where.not(title: &#39;Rails 3&#39;)

Has similar support been added for `or` queries, or are they planning to make it. I couldn&#39;t find anything by browsing through the release notes.

Obviously I tried

    Article.where(title: &#39;Rails 3&#39;).or(title: &#39;Rails 4&#39;)

But that does not work.

Does Rails 4 have support for OR queries

`attr_accessible` seems to no longer work within my model.

What is the way to allow mass assignment in Rails 4?

Content Type	Original Author	Original Content on Stackoverflow
Question	Ryenski	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	Dylan Markow	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	Andrew Hacking	View Answer on Stackoverflow

Deprecation warning when using has_many :through :uniq in Rails 4

Ruby on-Rails Problem Overview

Ruby on-Rails Solutions

Solution 1 - Ruby on-Rails

Solution 2 - Ruby on-Rails

How to pass array as an argument to a function in Bash

How to delete a project from Google Cloud Console

Attributions