Here are some popular mistakes when using nested forms:

• You are using fields_for instead of form.fields_for.
• You forgot to use accepts_nested_attributes in the containing model. Rails won't complain, but nothing will work. In particular, nested_form.object will be nil.
• The :reject_if option lambda in your accepts_nested_attributes call is defined incorrectly. Raise the attributes hash given to your :reject_if lambda to see if it looks like you expect.
• If you are nesting forms into nested forms, each model involved ne...

jQuery

You can say:

$(element).is(':visible')

and

$(element).is(':hidden')

jQuery considers an element to be visible if it consumes space in the document. For most purposes, this is exactly what you want.

Native DOM API

Emulate jQuery's implementation :

element.offsetWidth > 0 && element.offsetHeight > 0;

jQuery > 3

Query 3 slightly modifies the meaning of :visible (and therefore of :hidden).

Emulate jQuery'...

When you open up a story to only have a look at it, close it by pressing the "Cancel" button (or Esc key).

Clicking the arrow in the top left is the same as pressing the "Save" button. If someone changes the story description in the meantime you will overwrite their changes with everything you see, even if you did not change anything. If you only want to take a peek, prefer to hover the speech bubble icon.

If your story gets shotgunned and you notice it, you are lucky -- and you may be able to get your changes back. Open up the his...

When you render a nested form for a Movie which has_many :actors, you want to render the right number of blank Actor forms. The right number means:

• A minimum number of blank forms so the user can add more Actors to an existing Movie, e.g. 2.
• A minimum total number of forms (both blank and pre-filled) so the user sees more than just 2 blank Actor forms when she is entering Actors for the first time, e.g. 5.

For the example above, this is the desired progression of the number of blank forms:

| Number of actors | Number of ...

This Perl script will run diagnostics on your MySQL database and recommend changes to your MySQL configuration.

Because your examples should not change global state, you should not need to care about the order in which RSpec processes your .rb files. However, in some cases you might want to know.

RSpec 3

• Runs .rb files in alphabetical order of their file paths by default (or when you specify --order defined).
• You run t...

I pushed a new version of the Cucumber Factory gem. This new release lets you refer to a previously created record by any string attribute:

Given there is a movie with the title "Before Sunrise"
And there is a movie with the title "Limitless"
And there is a movie with the prequel "Before Sunrise"

Note how we didn't have to explicitly give the prequel a name in the example above. This is still possible, but will rarely be necessary now:

Given "Before Sunrise" is a movie with...

When you have a hook in your Capistrano file that dumps your remote database, you might not want it to dump each time you deploy (say, you're experimenting with staging and don't want ten dumps an hour). How to skip dump creation:

Capistrano 2

In your Capistrano file:

before 'deploy:update_code', 'db:dump' unless fetch(:skip_dump, false)

The second parameter of fetch sets a default value if skip_dump is not defined.

In your terminal:

cap staging deploy -S skip_dump=true

The -S must be a capital letter t...

(Rails has a method ActiveRecord::Relation#merge that can merge ActiveRecord scopes. However, its behavior has never been clear, and in Rails 7 it still discards conditions on the same column by the last condition. We discourage using #merge!)

The best way to merge ActiveRecord scopes is using a subquery:

scope_a.where(id: scope_b)

It is a little less concise than #merge, but unambiguous.

Example

Assume a model where a deal has many documents:

class Deal < ApplicationRecord
  has_many :...

In order to request a SSL certificate from any dealer, you usually need a CSR certificate. As both the CSR as well as key are created in this step, make sure you save this certificate on a trusted, secure machine only. Usually this is your production environment.

Run this on the server (not on your machine) as root.\
Replace your-domain.tld with the domain you request the certificate for and YYYY with the current year so you will not have any conflicts when requesting a certificate next year.

openssl req -new -sha256 -out www.your-dom...

If you would like to enrich your website with semantic markup like contact data, places or events you should have a look at schema.org. "Search engines including Bing, Google and Yahoo! rely on this markup to improve the display of search results, making it easier for people to find the right web pages."

The following example from the schema.org documentation shows you how to describe a movie with semantic markup:

<div itemscope itemtype ="http://schema.org/Movie">
  <h1 itemp...

If you want to enforce soft tabs (spaces instead of tabstops) in Vim put this into your ~/.vimrc (Linux) or C:\Users\<Username>\_vimrc (Windows):

set tabstop=2
set softtabstop=2
set shiftwidth=2
set expandtab

You can also call those commands in a running Vim instance (using ":set ...") to switch on soft tabs temporarily.

On a side note: remember the :mkvimrc command that saves active settings to a vimrc file.

Put the attached file into config/initializers/ to be able to say created_within on any ActiveRecord or its scope chain. This will return a scope of all records created between two given timestamps.

Use it like that:
Booking.created_within(1.year.ago, Date.yesterday).count
User.active.created_within(1.hour.ago, DateTime.now)

It explicitly looks at the database table name so you are usually fine when joining other tables.

You probably already manage servers you often connect to inside the ~/.ssh/config file. What is nice: you may define alias names for hosts so that you can say something like ssh foobar-staging.

This is especially helpful for servers whose hostnames are hard to remember or who don't have a DNS record at all (and must be accessed via their IP address).

To achieve the above, you can define something like this in your ~/.ssh/config:

Host foobar-staging
  Hostname staging.example.com

Note that SSH will only match this for `ssh f...

When your cucumber features grow massively over time, the test execution can take a lot of time.
One easy way to speed up your test execution is to use the parallel_tests gem.
It comes along with some useful rake tasks that let you setup your local test environment shortly to run your features, specs or unit-tests in parallel.

Follow these steps to get it to work.

1. Add the parallel_tests gem to your Gemfile test sections like that:

   # ./Gemfile
   
   group :development, :test do
   

...

Soon after having written our shell-for script, we wanted to easily get dumps of our productions machines, too. This is how we do it:

dump-for staging [-s]

It will copy the dump to your project's tmp directory and name it according to the capistrano stage you're calling for, here: staging.dump. When you pass the optional -s option, the dump will automatically been sourced into your local development database.

This script ...

After having written useful scripts into makandra notes for a long time, we’ve now tied them into a powerful new gem: geordi.

It gives you the power to

• get a dump from your production database with dump-for production
• install your local gems to the production machine with install-gems-remotely
• execute rake tasks to several environments at the same time with power-rake db:migrate
• and much more

Check it out from github.

Asset pipeline, HTTP streaming, jQuery as default framework, auto-reversable migrations, identity map for ActiveRecord.

Ruby 1.8.x support will be dropped with or after Rails 4.

Sometimes PDF cucumber tests fail at the first test run and succeed at the second run. You can fix this with this step:

When PDF generation is ready
And I follow "Save as PDF"
# Checks for PDF contents go here

Here is the step definition:

When /^PDF generation is ready$/ do
  Then 'I should see ""'
end

Install Ubuntu Server

• Download an image from this site
• Select File > New… to and follow the instructions, choose the .iso file you downloaded as image file
• Deselect "Simple installation" – you want to configure your system yourself
• Start the new virtual machine and follow the instructions

Install VMware Tools

• Choose Virtual Machine > Install VMware Tools from the VMware menu, then:

^
# install required packages
sudo apt-get install build-essential psmisc

# m...

Validations that need to access an associated object may lead to some trouble. Let's exemplify that using this example:

class Project < ActiveRecord::Base
   has_one :note
end

class Note < ActiveRecord::Base
   belongs_to :project
end

Now say we need a validation that ensures that a description is set (validates_presence_of :description) within Note but only if the Project has a flag called external set to true. The following code will lead to some problems as the associated object is not present when creatin...

Occasionally you need to do something directly on the server -- like having all records recalculate something that cannot be done in a migration because it takes a long time.

Let's say you do something like this:

Project.all.each(&:recalculate_statistics!)

Even though you may have been successful with this on your development machine or the staging server, keep in mind that production machines often hold a lot more records. Using all may just work, even with lots of records, but when you iterate over such records and fetch a...

You can seriously speed up deployments with Capistrano when using a local git repository on the server you are deploying to.

Simply add

set :deploy_via, :remote_cache
set :copy_exclude, [ '.git' ]

to your config/deploy.rb and Capistrano will create a clone in shared/cached-copy. This will be updated using git pull when deploying which transfers less bytes and is usually much faster. If deploy_via is set to use default settings (being "export"), Capistrano will do a full clone of the repository from your git host otherwi...