ActsAsDigestedOn 
acts_as_digested_on is a gem for Rails 3, 4, and 5.
This sets the digested value before validation and validates uniqueness of the digested value.
If you use this gem for Rails 2, see rails-2 branch.
Installation
Add this line to your application's Gemfile:
gem 'acts_as_digested_on'
And then execute:
$ bundle
Or install it yourself as:
$ gem install acts_as_digested_on
Usage
# db/migrate/20090706000000_create_articles.rb
class CreateArticles < ActiveRecord::Migration
def self.up
create_table :articles do |t|
t.text :url # any type is ok
t.string :digest # this is sha-1 hex digest field of url value
...
end
add_index :articles, :digest, :unique => true # you can add index on digest field
end
def self.down
drop_table :articles
end
end
# app/models/article.rb
class Article < ActiveRecord::Base
acts_as_digested_on :url # please add this
...
end
# this means
class Article < ActiveRecord::Base
validates_uniqueness_of :digest
before_validation :set_digest
def generate_digest
Digest::SHA1.hexdigest "--#{ url.to_s }--"
end
private
def set_digest
self.digest = generate_digest
end
...
endExamples
acts_as_digested_on :url, :unique => false
acts_as_digested_on :url, :digest_column => :url_digest
acts_as_digested_on [:url, :salt]
acts_as_digested_on :url, :scope => :site_id
Article.new(:url => 'http://example.com').generate_digestContributing
- Fork it ( https://github.com/milk1000cc/acts_as_digested_on/fork )
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create a new Pull Request