### Install Otto Gem

Source: https://github.com/delano/otto/blob/main/README.md

Command to install the Otto Ruby gem using the RubyGems package manager.

```bash
gem install otto
```

--------------------------------

### Basic Otto App Structure

Source: https://github.com/delano/otto/blob/main/README.md

Demonstrates the essential files for an Otto application: a Rackup file (config.ru), a Ruby application class (app.rb), and a plain-text routes file.

```bash
cd myapp && ls
config.ru app.rb routes
```

--------------------------------

### Enable Security Features in Otto

Source: https://github.com/delano/otto/blob/main/README.md

Demonstrates how to initialize an Otto application with security features enabled, such as CSRF protection, request validation, and trusted proxy configuration.

```ruby
# Enable security features
app = Otto.new("./routes", {
  csrf_protection: true,      # CSRF tokens and validation
  request_validation: true,   # Input sanitization and limits
  trusted_proxies: ['10.0.0.0/8']
})
```

--------------------------------

### Implement Application Logic in Ruby

Source: https://github.com/delano/otto/blob/main/README.md

Shows a basic Ruby class structure for an Otto application, including methods to handle different routes like 'index', 'show_product', and 'robots_text'. It demonstrates how to access request parameters and set response bodies and headers.

```ruby
# app.rb

class App
  def initialize(req, res)
    @req, @res = req, res
  end

  def index
    res.body = '<h1>Hello Otto</h1>'
  end

  def show_product
    product_id = req.params[:id]
    res.body = "Product: #{product_id}"
  end

  def robots_text
    res.header['Content-Type'] = "text/plain"
    rules = 'User-agent: *', 'Disallow: /private/keep/out'
    res.body = rules.join($/)
  end
end
```

--------------------------------

### Define Routes in Plain Text

Source: https://github.com/delano/otto/blob/main/README.md

Illustrates how to map HTTP methods and URL patterns to specific methods within a Ruby class using a plain-text routes file.

```text
# routes

GET   /                         App#index
POST  /feedback                 App#receive_feedback
GET   /product/:id              App#show_product
GET   /robots.txt               App#robots_text
GET   /404                      App#not_found
```

--------------------------------

### Configure Rackup File for Otto

Source: https://github.com/delano/otto/blob/main/README.md

Provides the standard Rackup file (config.ru) configuration needed to run an Otto application, including requiring the Otto gem and the application class.

```ruby
# config.ru

require 'otto'
require 'app'

run Otto.new("./routes")
```

--------------------------------

### Configure Internationalization (Locales) in Otto

Source: https://github.com/delano/otto/blob/main/README.md

Shows various ways to configure internationalization settings for Otto applications, including setting available locales and default locales globally, during initialization, or at runtime.

```ruby
# Global configuration (affects all Otto instances)
Otto.configure do |opts|
  opts.available_locales = { 'en' => 'English', 'es' => 'Spanish', 'fr' => 'French' }
  opts.default_locale = 'en'
end

# Or configure during initialization
app = Otto.new("./routes", {
  available_locales: { 'en' => 'English', 'es' => 'Spanish', 'fr' => 'French' },
  default_locale: 'en'
})

# Or configure at runtime
app.configure(
  available_locales: { 'en' => 'English', 'es' => 'Spanish' },
  default_locale: 'en'
)

# Legacy support (still works)
app = Otto.new("./routes", {
  locale_config: {
    available_locales: { 'en' => 'English', 'es' => 'Spanish', 'fr' => 'French' },
    default_locale: 'en'
  }
})
```

--------------------------------

### Utilize Locale Helper in Application Logic

Source: https://github.com/delano/otto/blob/main/README.md

Illustrates how to use Otto's `check_locale!` helper within an application's Ruby class to automatically detect and retrieve the user's locale based on URL parameters, headers, or a default setting.

```ruby
class App
  def initialize(req, res)
    @req, @res = req, res
  end

  def show_product
    # Automatically detects locale from:
    # 1. URL parameter: ?locale=es
    # 2. User preference (if provided)
    # 3. Accept-Language header
    # 4. Default locale
    locale = req.check_locale!

    # Use locale for localized content
    res.body = localized_content(locale)
  end
end
```

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