Trick: Do not use convert but mogrify:

mogrify -resize 50% *

This overwrites the original image file.

In contrast, convert writes to a different image file. Here is an example if you need this:

cd /path/to/image/directory
for i in `ls -1 *jpg`; do convert -resize 50% $i "thumb_$i"; done

Note: Modern Rails has two build pipelines, the asset pipeline (or "Sprockets") and Webpacker. The principles below apply for both, but the examples shown are for Sprockets.

Every page in your application uses many assets, such as images, javascripts and stylesheets. Without your intervention, the browser will request these assets again and again on every request. There is no magic in Rails that gives you automatic caching for assets. In fact, if you haven't been paying attention to this, your application is probabl...

The step definition below allows you to write:

Then I should see an HTML redirect to "http://www.makandracards.com" in the page head

Capybara

Then /^I should see an HTML redirect to "([^\"]*)" in the page head$/ do |redirect_url|
  page.should have_xpath("//meta[@http-equiv=\"refresh\" and contains(@content, \"#{redirect_url}\")]")
end

To find meta tags with Capybara, you can also use page.find('meta', visible: false).

Keychain helps you to manage ssh and GPG keys in a convenient and secure manner. It acts as a frontend to ssh-agent and ssh add, but allows you to easily have one long running ssh-agent process per system, rather than the norm of one ssh-agent per login session.

This dramatically reduces the number of times you need to enter your passphrase. With keychain, you only need to enter a passphrase once every time your local machine is rebooted. Keychain also makes it easy for remote cron jobs to securely "hook in" to a long running ssh-agent p...

If you have an html_safe string, you won't be able to call gsub with a block and match reference variables like $1. They will be nil inside the block where you define replacements (as you already know).

This issue applies to both Rails 2 (with rails_xss) as well as Rails 3 applications.

Here is a fix to SafeBuffer#gsub. Note that it will only fix the $1 behavior, not give you a safe string in the end (see below).

Example

def test(input)...

In a nutshell: return statements inside blocks cause a method's return value to change. This is by design (and probably not even new to you, see below) -- but can be a problem, for example for the capture method of Rails.

Consider these methods:

def stuff
  puts 'yielding...'
  yield
  puts 'yielded.'
  true
end

We can call our stuff method with a block to yield. It works like t...

A print stylesheet is easy to create. Choose a font suited for paper, hide some elements, done. Unfortunately print stylesheets often break as the application is developed further, because they are quickly forgotten and nobody bothers to check if their change breaks the print stylesheet.

This card describes how to write a simple Cucumber feature that tests some aspects of a print stylesheets. This way, the requirement of having a print stylesheet is manifested in your tests and cannot be inadvertedly removed from the code. Note that you can...

This works in modern RSpecs (RSpec >= 2.x) and Cucumbers:

rspec spec/models/node_spec.rb:294:322
cucumber features/nodes.feature:543:563:579

Also your features should be shorter than that :)

Sometimes you need to look at the filter chain in specs. You can do it like that on Rails 2:

controller.class.filter_chain.map(&:method)

Note that we need to look at the controller's class since before_filter and after_filter stuff happens on the class level.

Also mind that the above code will give you all filters, both those run before and after an action. You can query before? and after? on the filter objects to scope down to only some of them:

controller.class.filter_chain.select(&:before?).map(&:method)

For Rails 3, ...

Never name your shared example group *_spec.rb. Otherwise rspec will try to load your example group as a spec and you will get the error above.

Internet Explorer until version 9 has some limitations when parsing CSS files

Summarized, these are:

• Up to 31 CSS files or <style> tags per page.
• Up to 4095 selectors per CSS file.
• Up to 3 nested @import rules

To test the selector limit for a specific browser, check this CSS selector limitation test website.

When you run into this issue, the following links might be helpful to fix the problem. The Idea is to split up the css ...

In Selenium features the server and client are running in separate processes. Therefore, when mocking time with a tool like Timecop, the browser controlled by Selenium will still see the unmocked system time.

timemachine.js allows you to mock the client's time by monkey-patching into Javascript core classes. We use timemachine.js in combination with the Timecop gem to synchronize the local browser time to the ...

Be careful when stubbing out attributes on records that are defined by associations. Nothing is as it seems to be.

The associated record has its own universe of things; when delegating calls to it, you ca not stub methods on the associated record and expect them to be around. That is a general issue with this pattern/approach.

What's happening?

Consider these classes:

class Post < ActiveRecord::Base
  belongs_to :thread
  
  def thread_title
    thread.title
  end
end

class Thread < Acti...

Our rspec_candy gem now gives you three matchers:

be_same_number_as

Tests if the given number is the "same" as the receiving number, regardless of whether you're comparing Fixnums (integers), Floats and BigDecimals:

100.should be_same_number_as(100.0)
50.4.should be_same_number_as(BigDecimal('50.4'))

Note that "same" means "same for your purposes". Internally the matcher compares normalized results of #to_s.

be_same_second_as

...

When you develop a gem and you have a Gemfile in your project directory, you might be surprised that your gem dependencies aren't already required in your specs. Here is some info that should help you out:

• Bundler actually doesn't automatically require anything. You need to call Bundler.require(:default, :your_custom_group1, ...) for that. The reason why you never had to write this line is that Rails does this for you when it boots the environment.
• That also means that if you have an embedded Rails app in your spec folder (like [h...

Consul 0.4.0 comes with some new features.

Dependencies

• Consul no longer requires assignable_values, it's optional for when you want to use the authorize_values_for macro.
• Consul no longer uses ActiveSupport::Memoizable because that's deprecated in newer Railses. Consul now uses Memoizer for this.

Temporarily change the current power

When you set Power.current to a power in an RS...

Don't say is_a?(ActiveRecord::NamedScope::Scope) because that is no longer true in Rails 3 and also doesn't match unscoped ActiveRecord classes themselves (which we consider scopes for all practical purposes).

A good way is to say this instead:

object.respond_to?(:scoped)

paper_trail is an excellent gem to track record versions and changes.

You almost never want to reimplement something like it yourself. If you need to log some extra information, you can add them on top.

It comes with a really good README file that holds lots of examples. I'll show you only some of its features here:

• Setting up a model to track changes

  Just add has_paper_trail to it:
  class User < ActiveRecord::Base
  has_paper_trail
  end

• Accessing a previous version

  Saying user.previous_version gi...

When we looked at this card together a year ago, we were no longer sure if unquote is actually useful. I now found a good example for when you need unquote, and rewrote the card accordingly.

The will_paginate gem will show a default of 30 records per page.
If you want to test pagination in a Cucumber feature, you don't want to create 31 records just for that.

Instead, you probably want to modify the number of items shown, by saying something like this:

Given we paginate after 2 users

Using the following step definition, you now can! :)

require 'cucumber/rspec/doubles'

Given /^paginate after (\d+) (.*)$/ do |per_page, model_name|
  model = model_name.singularize.gsub(/...

The $.cssHooks object provides a way to define functions for getting and setting particular CSS values. It can also be used to create new cssHooks for normalizing CSS3 features such as box shadows and gradients.

For example, some versions of Webkit-based browsers require -webkit-border-radius to set the border-radius on an element, while earlier Firefox versions require -moz-border-radius. A css hook can normalize these vendor-prefixed properties to let .css() accept a single, standard property name (border-radius, or with DOM property synt...

• The step we used in the past (Then "foo" should not be visibile) doesn't reliably work in Selenium features.
• I overhauled the entire step so it uses Javascript to detect visibility in Selenium.
• The step has support for jQuery and Prototype projects, so it should be a drop-in replacement for all your projects.
• For Rack::Test the step no longer uses XPath so you should be able to understand it when you are not a cyborg :)
• There were some other cards detailing alternative steps to detect visibility. I deleted all these other cards s...