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Defender is a wrapper for the Defensio spam filtering API written in Ruby.
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Wiki | Docs

Defender is a wrapper for the Defensio spam filtering API. From their own site:

More than just another spam filter, Defensio also eliminates malware and other unwanted or risky content to fully protect your blog or Web 2.0 application.


In Rails 3, add this to your Gemfile and run the bundle command.

gem 'defender'

If you want to live on the bleeding edge, you can use the git repo. YMMV.

gem 'defender', :git => 'git://'

For any other kind of web framework, just install the defender gem, and require 'defender' somewhere in your code.

Getting Started

I'm going to assume that you already have a comment model. The comment model is required to have at least a content or body field.

1. Create an initializer

You need to provide Defender with your API key. The preferred way of doing this is with an initializer file. Create a file in the config/initializers folder, and put the following line in it.

Defender.api_key = 'YOUR_API_KEY'

2. Add the required fields to your model

You need to add a boolean field named spam, and a string field named defensio_sig to your model. You should also add a float field named spaminess, although this isn't required. Here's an example migration for Active Record:

class AddDefenderFieldsToComments < ActiveRecord::Migration
  def change
    add_column :comments, :spam, :boolean
    add_column :comments, :defensio_sig, :string
    add_column :comments, :spaminess, :float

3. Configure the model

In your model, include Defender::Spammable. If the model attributes match up with what Defender autodetects (check the wiki), you are now good to go! The spam attribute will be automatically updated by Defender when you save the model.

If you need to change any of the attributes, you can pass configure_defender the mappings, like this:

class Comment < ActiveRecord::Base
    include Defender::Spammable
    configure_defender :keys => { 'content' => :data }

In this example, 'content' is the Defensio field, and :data is the model attribute.


  1. Fork it.
  2. Create a branch (git checkout -b add-resque-support)
  3. Make your changes
  4. Commit your changes (git commit -am "Added support for Resque")
  5. Push to the branch (git push origin add-resque-support)
  6. Create a Pull Request from your branch.
  7. Promote it. Get others to drop in and +1 it.
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