Module: RailsOnboarding::CdnSupport

Extended by:
ActiveSupport::Concern
Defined in:
lib/rails_onboarding/cdn_support.rb

Overview

CDN Support module for serving assets from a CDN

This module provides helpers and configuration for serving onboarding assets (JavaScript, CSS, images) from a CDN to improve performance through better caching and geographic distribution

Class Method Summary collapse

Class Method Details

.cdn_asset_url(asset_path, asset_type: :stylesheet) ⇒ String

Get asset URL with CDN support

Parameters:

  • asset_path (String) —

    The asset path (e.g., 'rails_onboarding/application.css')

  • asset_type (Symbol) (defaults to: :stylesheet) —

    Asset type (:stylesheet, :javascript, :image)

Returns:

  • (String) —

    Full URL to the asset



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# File 'lib/rails_onboarding/cdn_support.rb', line 47

def self.cdn_asset_url(asset_path, asset_type: :stylesheet)
  if cdn_enabled?
    case asset_type
    when :stylesheet
      "#{cdn_host}/assets/#{asset_path}"
    when :javascript
      "#{cdn_host}/assets/#{asset_path}"
    when :image
      "#{cdn_host}/assets/#{asset_path}"
    else
      "#{cdn_host}/assets/#{asset_path}"
    end
  else
    # Fall back to local asset path
    "/assets/#{asset_path}"
  end
end

.cdn_cache_headers(max_age: 31_536_000) ⇒ Hash

Configure CDN headers for optimal caching

Parameters:

  • max_age (Integer) (defaults to: 31_536_000) —

    Cache max age in seconds (default: 1 year)

Returns:

  • (Hash) —

    Headers for CDN caching



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# File 'lib/rails_onboarding/cdn_support.rb', line 187

def cdn_cache_headers(max_age: 31_536_000)
  {
    "Cache-Control" => "public, max-age=#{max_age}, immutable",
    "Expires" => max_age.seconds.from_now.httpdate,
    "Vary" => "Accept-Encoding"
  }
end

.cdn_enabled? ⇒ Boolean

Check if CDN is enabled

Returns:

  • (Boolean) 


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# File 'lib/rails_onboarding/cdn_support.rb', line 38

def self.cdn_enabled?
  cdn_host.present? && !Rails.env.development?
end

.cdn_host ⇒ String?

Get the CDN host URL

Returns:

  • (String, nil) —

    CDN host URL or nil if not configured



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# File 'lib/rails_onboarding/cdn_support.rb', line 17

def self.cdn_host
  @cdn_host ||= begin
    # Check Rails configuration first
    if defined?(Rails.application) && Rails.application.config.action_controller.asset_host
      Rails.application.config.action_controller.asset_host
    else
      ENV["RAILS_ONBOARDING_CDN_HOST"]
    end
  end
end

.cdn_host=(host) ⇒ Object

Set the CDN host URL

Parameters:

  • host (String) —

    CDN host URL



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# File 'lib/rails_onboarding/cdn_support.rb', line 31

def self.cdn_host=(host)
  @cdn_host = host
end

.cdn_resource_hints ⇒ String

Generate resource hints for DNS prefetch and preconnect

Returns:

  • (String) —

    HTML meta tags for resource hints



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# File 'lib/rails_onboarding/cdn_support.rb', line 163

def cdn_resource_hints
  return "" unless CdnSupport.cdn_enabled?

  cdn_host = ERB::Util.html_escape(CdnSupport.cdn_host)
  <<~HTML.html_safe
    <!-- DNS Prefetch and Preconnect for CDN -->
    <link rel="dns-prefetch" href="#{cdn_host}" />
    <link rel="preconnect" href="#{cdn_host}" crossorigin />
  HTML
end

.cdn_tag_attributes(attributes) ⇒ Object

Render tag attributes with every value HTML-escaped, so a CDN host or asset path containing a quote or angle bracket can't break out of the attribute it's placed in. Used in place of ActionView's tag helpers because these methods are also called as CdnSupport module functions, outside any view context where tag/content_tag would be available.



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# File 'lib/rails_onboarding/cdn_support.rb', line 179

def cdn_tag_attributes(attributes)
  attributes.map { |key, value| "#{key}=\"#{ERB::Util.html_escape(value)}\"" }.join(" ")
end

.javascript_include_tag_with_cdn(asset_path, **options) ⇒ String

Helper method for JavaScript tags with CDN support

Parameters:

  • asset_path (String) —

    Asset path

  • options (Hash) —

    Additional options

Returns:

  • (String) —

    HTML script tag



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# File 'lib/rails_onboarding/cdn_support.rb', line 136

def javascript_include_tag_with_cdn(asset_path, **options)
  url = CdnSupport.versioned_asset_url(asset_path, asset_type: :javascript)

  preload = options.delete(:preload)
  defer = options.delete(:defer) { true } # Default to defer
  async = options.delete(:async)

  tag_options = {
    src: url,
    type: "text/javascript"
  }.merge(options)

  tag_options[:defer] = "defer" if defer && !async
  tag_options[:async] = "async" if async

  tags = [ "<script #{cdn_tag_attributes(tag_options)}></script>" ]

  if preload
    tags.unshift("<link #{cdn_tag_attributes(rel: 'preload', href: url, as: 'script')} />")
  end

  tags.join("\n").html_safe
end

.preload_assets ⇒ Array<Hash>

Preload critical onboarding assets

Returns:

  • (Array<Hash>) —

    Array of asset preload hints



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# File 'lib/rails_onboarding/cdn_support.rb', line 68

def self.preload_assets
  [
    {
      href: cdn_asset_url("rails_onboarding/application.css", asset_type: :stylesheet),
      as: "style",
      type: "text/css"
    },
    {
      href: cdn_asset_url("rails_onboarding/application.js", asset_type: :javascript),
      as: "script",
      type: "text/javascript"
    }
  ]
end

.stylesheet_link_tag_with_cdn(asset_path, **options) ⇒ String

Helper method for view templates Generates link tags with CDN support and preload hints

Parameters:

  • asset_path (String) —

    Asset path

  • options (Hash) —

    Additional options

Returns:

  • (String) —

    HTML link tag



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# File 'lib/rails_onboarding/cdn_support.rb', line 109

def stylesheet_link_tag_with_cdn(asset_path, **options)
  url = CdnSupport.versioned_asset_url(asset_path, asset_type: :stylesheet)

  preload = options.delete(:preload)
  crossorigin = options.delete(:crossorigin)

  tag_options = {
    rel: "stylesheet",
    href: url
  }.merge(options)

  tag_options[:crossorigin] = crossorigin if crossorigin

  tags = [ "<link #{cdn_tag_attributes(tag_options)} />" ]

  if preload
    tags.unshift("<link #{cdn_tag_attributes(rel: 'preload', href: url, as: 'style')} />")
  end

  tags.join("\n").html_safe
end

.versioned_asset_url(asset_path, version: nil, asset_type: :stylesheet) ⇒ String

Generate cache-busting URL with versioning

Parameters:

  • asset_path (String) —

    The asset path

  • version (String) (defaults to: nil) —

    Asset version (defaults to gem version)

  • asset_type (Symbol) (defaults to: :stylesheet) —

    Asset type (:stylesheet, :javascript, :image)

Returns:

  • (String) —

    URL with version parameter



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# File 'lib/rails_onboarding/cdn_support.rb', line 89

def self.versioned_asset_url(asset_path, version: nil, asset_type: :stylesheet)
  version ||= RailsOnboarding::VERSION
  url = cdn_asset_url(asset_path, asset_type: asset_type)
  "#{url}?v=#{version}"
end