Contai

AI content generation for Rails models. Integrate external AI APIs seamlessly into your Rails applications.

Installation

Add this line to your application's Gemfile:

gem 'contai'

And then execute:

$ bundle install

Usage

Basic Setup

Include Contai::Generatable in your model and configure it:

class Article < ApplicationRecord
  include Contai::Generatable
  
  contai do
    prompt_from :title, :description
    output_to :body
    provider :openai, api_key: ENV["OPENAI_API_KEY"]
    template "Write a blog post about: {{title}} - {{description}}"
  end
end

Generate Content

article = Article.new(title: "Ruby on Rails", description: "Web framework")
article.generate_ai_content!
# Content will be generated and saved to article.body

# Async generation
article.generate_ai_content!(async: true)

Supported Providers

OpenAI

provider :openai, 
  api_key: ENV["OPENAI_API_KEY"],
  model: "gpt-4",
  max_tokens: 1000

Claude

provider :claude,
  api_key: ENV["CLAUDE_API_KEY"],
  model: "claude-3-sonnet-20240229"

N8N Webhook

provider :n8n,
  webhook_url: "https://your-n8n-instance.com/webhook/your-webhook-id",
  response_path: "output"

Custom HTTP

provider :http,
  url: "https://api.example.com/generate",
  method: :post,
  headers: { "Authorization" => "Bearer #{ENV['API_KEY']}" },
  body_template: { prompt: "{{prompt}}", model_name: "custom-model" },
  response_path: "result.text"

Configuration

Configure global defaults:

# config/initializers/contai.rb
Contai.configure do |config|
  config.default_provider = :openai
  config.default_template = "Generate content based on: {{prompt}}"
  config.timeout = 30
end

Routes

Add to your routes file:

# config/routes.rb
Rails.application.routes.draw do
  post '/contai/generate', to: 'contai/generations#create', as: 'contai_generation'
end

Error Handling

The gem provides comprehensive error handling:

article = Article.new(title: "Test")
result = article.generate_ai_content!

unless result
  puts article.errors.full_messages
  # => ["AI generation failed: API error"]
end

Testing

Test your models with Contai:

# spec/models/article_spec.rb
RSpec.describe Article do
  describe '#generate_ai_content!' do
    let(:article) { create(:article, title: "Test", description: "Test desc") }
    
    before do
      allow_any_instance_of(Contai::Providers::OpenAI).to receive(:generate)
        .and_return(double(success?: true, content: "Generated content"))
    end
    
    it 'generates content' do
      expect { article.generate_ai_content! }.to change { article.body }
        .from(nil).to("Generated content")
    end
  end
end

Development

After checking out the repo, run:

bundle install
rake spec

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

License

The gem is available as open source under the terms of the CAPAA License.