Check whether a Paperclip attachment exists

tl;dr: Always have your attachment path start with :rails_root/storage/#{Rails.env}#{ENV['RAILS_TEST_NUMBER']}/.

The directory where you save your Paperclip attachments should not look like this:

storage/photos/1/...
stora...

Just assign the existing attachment to another record:

new_photo = Photo.new
new_photo.image = old_photo.image

Paperclip will duplicate the file when saving.

To use this in forms, pimp your attachment container like this:

class Pho...

The step definition below lets you say:

 Then I should see a field "Password"
 But I should not see a field "Role"

Here is the step definition:

Then /^I should( not)? see a field "([^"]*)"$/ do |negate, name|
  expectation = neg...

Sometimes you might want to know if an attribute is an associated object or a simple string, integer etc. You can use the reflect_on_association method for t...

When Paperclip attachments should only be downloadable for selected users, there are three ways to go.
The same applies to files in Carrierwave.
...

In this example we assume that not only the storage gem changes but also the file structure on disc.

A general approach

Part A: Create a commit which includes a script that allows you to copy the existing file to the new file structure.
...

Ruby's File class has a handy method binary? which checks whether a file is a binary file. This method might be telling the truth most of the time. But sometimes it doesn't, and that's what causes pain. The method is defined as follows:

When using state_machine you sometimes need to know whether an object may execute a certain transition. Let's take an arbitrary object such as a blog article as an example that has those states:

...

script/runner -e development 'Article.all.each { |a| a.image.reprocess! if a.image.exists? }; "done"'

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 AP...