    head :no_content

Tested with Rails 3.2.x, 4.x. It causes the controller method to respond with the 204 No Content HTTP status code. 

An example of using this inside a controller method named `foobar`:

    def foobar
      head :no_content
    end

Look at the [head][1] method:

&gt; Return a response that has no content (merely headers). The options
&gt; argument is interpreted to be a hash of header names and values.


  [1]: http://api.rubyonrails.org/classes/ActionController/Head.html#method-i-head

If you don&#39;t want to render anything at all you can do this:

    render :nothing =&gt; true, :status =&gt; 204

or like this:

    render :nothing =&gt; true, :status =&gt; 204 and return

Or you can use the `:status =&gt; 204` part with any other render command


I plan to use quick actions UI pattern in my application. https://stackoverflow.com/questions/3059155/android-quick-actions-ui-pattern . The quick action window needs a pivot view to stick to. 

        quickAction.show(View pivotView);

I intend to use quick action for the menu Item, I can get access to the item that is clicked. 
But the problem is i need to reference a view from the menu item so that i can pass it to the quick action. 

How can i get reference to a view in the menuItem that is selected.

Android : Get view Reference to a Menu Item

I have a L2E query that returns some data that contains duplicate objects. I need to remove those duplicate objects. Basically I should assume that if their IDs are the same then the objects are duplicate. I&#39;ve tried `q.Distinct()`, but that still returned duplicate objects. Then I&#39;ve tried implementing my own IEqualityComparer and passing it to the `Distinct()` method. The method failed with following text:

&gt; LINQ to Entities does not recognize the method
&gt; &#39;System.Linq.IQueryable`1[DAL.MyDOClass]
&gt; Distinct[MyDOClass](System.Linq.IQueryable`1[DAL.MyDOClass],
&gt; System.Collections.Generic.IEqualityComparer`1[DAL.MyDOClass])&#39;
&gt; method, and this method cannot be translated into a store expression.

And here is the implementation of EqualityComparer:

  

      internal class MyDOClassComparer: EqualityComparer&lt;MyDOClass&gt;
        {
            public override bool Equals(MyDOClass x, MyDOClass y)
            {
                return x.Id == y.Id;
            }
    
            public override int GetHashCode(MyDOClass obj)
            {
                return obj == null ? 0 : obj.Id;
            }
        }

So how do I write my own `IEqualityComparer` properly?

How to implement IEqualityComparer to return distinct values?

This seems to be basic but I&#39;m a Ruby/Rails beginner. I need to simply return HTTP 204 in a controller.
Would  
 

    respond_to do |format|
      format.html  
    end

return a 204?

How to return HTTP 204 in a Rails controller

This seems to be basic but I'm a Ruby/Rails beginner. I need to simply return HTTP 204 in a controller.
Would
<pre><code class="hljs language-lua">respond_to do |format|
 format.html 
end
</code></pre>
return a 204?

How do I list all the methods that a particular object has access to?

I have a `@current_user` object, defined in the application controller:

    def current_user
      @current_user ||= User.find(session[:user_id]) if session[:user_id]
    end

And want to see what methods I have available to me in the view file. Specifically, I want to see what methods a `:has_many` association provides. (I know what `:has_many` *should* provide, but want to check that.)

How to list all methods for an object in Ruby?

I am using Heroku for my application and it requires PostgreSQL but you can still use SQLite3 for development. Since Heroku strongly advised against having 2 different databases I decided to change to PostgreSQL for development. I installed the `gem pg` and also went to the official PostgreSQL site to get the Windows installer and also changed my `database.yml`. During installation it requires a password for PostgreSQL so I made one. 
I had to change the `pg_hba.conf` file from using `md5` to `trust` in order get past: `fe_sendauth: no password supplied` when trying to create the database.

    # TYPE  DATABASE        USER            ADDRESS                 METHOD
    
    # IPv4 local connections:
    host    all             all             127.0.0.1/32            trust # was md5
    # IPv6 local connections:
    host    all             all             ::1/128                 trust # was md5
    # Allow replication connections from localhost, by a user with the
    # replication privilege.
    #host    replication     postgres        127.0.0.1/32            trust
    #host    replication     postgres        ::1/128                 trust

After getting rid of that though, I now get this:

    $ rake db:create
    (in C:/app)
    FATAL:  role &quot;User&quot; does not exist 
    Couldn&#39;t create database for {&quot;adapter&quot;=&gt;&quot;postgresql&quot;, &quot;encoding&quot;=&gt;&quot;utf8&quot;, 
    &quot;database&quot;=&gt;&quot;app_test&quot;, &quot;pool&quot;=&gt;5, &quot;username&quot;=&gt;nil, &quot;password&quot;=&gt;nil} 

I do still have my `development.sqlite3` and `text.sqlite3` present, could that be the issue? What must be done?

Here is my full gist: https://gist.github.com/1522188







Role does not exist and unable to create database when using PostgreSQL

Let’s say I have this array with shipments ids.

    s = Shipment.find(:all, :select =&gt; &quot;id&quot;)
    
    [#&lt;Shipment id: 1&gt;, #&lt;Shipment id: 2&gt;, #&lt;Shipment id: 3&gt;, #&lt;Shipment id: 4&gt;, #&lt;Shipment id: 5&gt;]

Array of invoices with shipment id&#39;s

    i = Invoice.find(:all, :select =&gt; &quot;id, shipment_id&quot;)
    
    [#&lt;Invoice id: 98, shipment_id: 2&gt;, #&lt;Invoice id: 99, shipment_id: 3&gt;]

- Invoices belongs to Shipment.
- Shipment has one Invoice.
- So the invoices table has a column of `shipment_id`.

To create an invoice, I click on New Invoice, then there is a select menu with Shipments, so I can choose &quot;which shipment am i creating the invoice for&quot;. So I only want to display a list of shipments that an invoice hasn&#39;t been created for.

So I need an array of Shipments that don&#39;t have an Invoice yet. In the example above, the answer would be 1, 4, 5.

Rails 3. How to get the difference between two arrays?

I have a User model that has a :credits attribute.   I want a simple button that will add 5 to  the user&#39;s credits, through a route called &quot;add&quot; so that /users/3/add would add 5 to the credits of user id = 3.

  

    def add
        @user = User.find(params[:id])
        @user.credits += 5
        redirect_to root_path
    end

That is the relevant part of my controller.  The problem is, I dont want to call @user.save because I have a before_save callback that re-encrypts the user&#39;s password based on the current UTC time.   I just want to simply add 5 to the attribute and avoid the callback, I never thought such a simple thing could be so hard.

EDIT:

I changed the callback to :before_create,
here is my new controller code (relevant part):

      def add
        @user = User.find(params[:id])
        @user.add_credits(5)
        @user.save
        flash[:success] = &quot;Credits added!&quot;
        redirect_to root_path
      end

and here is my code in the model:

     def add_credits(num)
        self.credits = num
     end

EDIT 2:

Ok it was a validation problem that made the changes in &quot;EDIT&quot; not work, but I&#39;d still love an answer to the original question of updating without callbacks!

Rails: Update model attribute without invoking callbacks

I am using seed.rb to populate both my development and production database. I usually populate the first with dummy data and the latter with the real minimal data that my app needs to run (e.g. the first user and so on).

How can I specify in seed.rb for what environment each data is?

Given that I know &quot;group&quot; to be a Gemfile method, I&#39;d like to achieve the same behavior for seed.rb.

E.g. I&#39;d like to write something like this in my seed.rb:

    group :development do 
      # development specific seeding code
    end

    group :production do 
      # production specific seeding code
    end

    # non-specific seeding code (it always runs) 

This to be able to call both the development-specific and the non-specific code with

    $ rake db:seed

And to call both the production-specific and the non-specific code with:

    $ rake db:seed RAILS_ENV=production 


Thank you

How to use seed.rb to selectively populate development and/or production databases?

How to check if a variable is a number or a string in Ruby?

How to check if a variable is a number or a string?

Example:

    a = [1, 3, 4, 5]
    b = [2, 3, 1, 5, 6]

How do I get the last value `5` in array `a` or last value `6` in array `b` without using `a[3]` and `b[4]`?

Content Type	Original Author	Original Content on Stackoverflow
Question	Nonos	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	Eliot Sykes	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	Michael Kohl	View Answer on Stackoverflow
Solution 3 - Ruby on-Rails	thorsten müller	View Answer on Stackoverflow

How to return HTTP 204 in a Rails controller

Ruby on-Rails Problem Overview

Ruby on-Rails Solutions

Solution 1 - Ruby on-Rails

Solution 2 - Ruby on-Rails

Solution 3 - Ruby on-Rails

How to implement IEqualityComparer to return distinct values?

Android : Get view Reference to a Menu Item

Attributions