CacheableFlash <img src=“https://codeclimate.com/badge.png” /> <img src=“https://secure.travis-ci.org/pboling/cacheable-flash.png?branch=master” alt=“Build Status” /> <img src=“http://api.coderwall.com/pboling/endorsecount.png” />
Description
This plugin enables greater levels of page caching by rendering flash messages from a cookie using JavaScript, instead of in your Rails view template. Flash contents are converted to JSON and placed in a cookie by an after_filter in a controller or a Rack middleware in your application.
Installation as gem
gem 'cacheable_flash' # added to your Gemfile
$ bundle install
Setup
Without asset pipeline, or pre-Rails 3.1:
First copy the JS assets into your app:
rails generate cacheable_flash:install
CacheableFlash adds its javascript dependencies as a Rails 3 javascript ‘expansion’, which are only used if you are NOT using the asset pipeline (apparently?).
So if you have config.assets.enabled = false in application.rb then in your layout:
javascript_include_tag :cacheable_flash
Otherwise, in your layout, just source them like normal:
javascript_include_tag 'flash', 'js.cookie'
With asset pipeline (requires Rails 3.1)
The asset pipeline should have access to the assets in this gem via your app/assets/javascripts/application.js:
//= require flash
//= require js.cookie
Mailing List
groups.google.com/group/PivotalLabsOpenSource
Bug/Feature Tracker
github.com/pivotal/cacheable-flash/issues
Wiki
Please help document!
github.com/pivotal/cacheable-flash/wiki
Usage as an around filter
To use as an around filter, include the CacheableFlash module in your controller. It’s all or none on the actions in your controller, so you can’t mix JS and HTML display of your flash message in a controller. No other modifications to the controller are needed. You will need to add divs and some javascript to your view or layout templates to render the flash in the browser.
Note that the cookie holding the flash messages is removed as the page is displayed, so a refresh will clear the flash message (just as happens normally).
Example Controller
class MyController < ActionController::Base
include CacheableFlash
# ...
end
Usage as a Rack middleware (requires Rails 3)
To use as a Rack Middleware, swap the Rails flash middleware with the Cacheable flash middleware. Use this method if you set flash messages inside a rescue_from block:
rescue_from CanCan::AccessDenied do |exception|
redirect_to root_url, :alert => exception.
end
In your application.rb:
# Swap the ActionDispatch::Flash middleware with the CacheableFlash one
config.middleware.swap ActionDispatch::Flash, CacheableFlash::Middleware
Example Template Markup
<div id="error_div_id" class="flash flash_error"></div>
<div id="notice_div_id" class="flash flash_notice"></div>
<script type="text/javascript">
Flash.transferFromCookies();
Flash.writeDataTo('error', $('#error_div_id'));
Flash.writeDataTo('notice', $('#notice_div_id'));
</script>
Security warning
The gem is susceptible to reflected XSS attack. Make sure no non-alphanumerical user-generated content is stored inside flash messages (html or plain text).
Testing
You can test your flash cookies by making assertions on the json of the “flash” cookie. Cacheable Flash provides test helpers which includes the flash_cookie method.
Test::Unit Example
require "cacheable_flash/test_helpers"
class TestController < ActionController::Base
def index
flash["notice"] = "In index"
end
end
class ControllerTest < Test::Unit::TestCase
include CacheableFlash::TestHelpers
def setup
@controller = TestController.new
@request = ActionController::TestRequest.new
@response = ActionController::TestResponse.new
end
def test_cacheable_flash_action
get :index
assert_equal "In index", ["notice"]
end
end
Rspec Example
require "cacheable_flash/test_helpers"
class TestController < ActionController::Base
def index
flash["notice"] = "In index"
end
end
describe TestController, "#index" do
include CacheableFlash::TestHelpers
it "writes to the flash cookie" do
get :index
["notice"].should == "In index"
end
end
Contributing to cacheable-flash
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Fork it
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Create your feature branch (‘git checkout -b my-new-feature`)
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Commit your changes (‘git commit -am ’Added some feature’‘)
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Push to the branch (‘git push origin my-new-feature`)
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Make sure to add tests for it. This is important so I don’t break it in a future version unintentionally.
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Create new Pull Request
Versioning
This library aims to adhere to Semantic Versioning 2.0.0. Violations of this scheme should be reported as bugs. Specifically, if a minor or patch version is released that breaks backward compatibility, a new version should be immediately released that restores compatibility. Breaking changes to the public API will only be introduced with new major versions.
As a result of this policy, you can (and should) specify a dependency on this gem using the Pessimistic Version Constraint with two digits of precision.
For example:
spec.add_dependency 'cacheable_flash', '~> 4.0'
Copyright
Licensed under the MIT License. See LICENSE for further details.
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Copyright © 2011-2012 Peter H. Boling <img src=“http://api.coderwall.com/pboling/endorsecount.png” />
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Copyright © 2007-2010 Pivotal Labs