Class: Rhales::LinkBasedInjectionDetector

Inherits:
Object
  • Object
show all
Defined in:
lib/rhales/hydration/link_based_injection_detector.rb

Overview

Generates link-based hydration strategies that use browser resource hints and API endpoints instead of inline scripts

Supported Strategies

  • :link - Basic link reference: <link href="/api/hydration/template">
  • :prefetch - Background prefetch: <link rel="prefetch" href="..." as="fetch">
  • :preload - High priority preload: <link rel="preload" href="..." as="fetch">
  • :modulepreload - ES module preload: <link rel="modulepreload" href="..."
  • :lazy - Lazy loading with intersection observer

All strategies generate both link tags and accompanying JavaScript for data fetching and assignment to window objects.

Instance Method Summary collapse

Constructor Details

#initialize(hydration_config) ⇒ LinkBasedInjectionDetector

Returns a new instance of LinkBasedInjectionDetector.



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# File 'lib/rhales/hydration/link_based_injection_detector.rb', line 25

def initialize(hydration_config)
  @hydration_config = hydration_config
  @api_endpoint_path = hydration_config.api_endpoint_path || '/api/hydration'
  @crossorigin_enabled = hydration_config.link_crossorigin.nil? ? true : hydration_config.link_crossorigin
end

Instance Method Details



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# File 'lib/rhales/hydration/link_based_injection_detector.rb', line 50

def generate_basic_link(template_name, window_attr, nonce)
  endpoint_url = "#{@api_endpoint_path}/#{template_name}"
  window_attr_html = ERB::Util.html_escape(window_attr)
  window_attr_js   = JSONSerializer.dump_html_safe(window_attr)
  endpoint_url_html = ERB::Util.html_escape(endpoint_url)
  endpoint_url_js   = JSONSerializer.dump_html_safe(endpoint_url)

  link_tag = %(<link href="#{endpoint_url_html}" type="application/json">)

  script_tag = <<~HTML.strip
    <script#{nonce_attribute(nonce)} data-hydration-target="#{window_attr_html}">
    // Load hydration data
    window.__rhales__ = window.__rhales__ || {};
    if (!window.__rhales__.loadData) {
      window.__rhales__.loadData = function(target, url) {
        fetch(url)
          .then(r => r.json())
          .then(data => window[target] = data);
      };
    }
    window.__rhales__.loadData(#{window_attr_js}, #{endpoint_url_js});
    </script>
  HTML

  "#{link_tag}\n#{script_tag}"
end

#generate_for_strategy(strategy, template_name, window_attr, nonce = nil) ⇒ Object 



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# File 'lib/rhales/hydration/link_based_injection_detector.rb', line 31

def generate_for_strategy(strategy, template_name, window_attr, nonce = nil)
  case strategy
  when :link
    generate_basic_link(template_name, window_attr, nonce)
  when :prefetch
    generate_prefetch_link(template_name, window_attr, nonce)
  when :preload
    generate_preload_link(template_name, window_attr, nonce)
  when :modulepreload
    generate_modulepreload_link(template_name, window_attr, nonce)
  when :lazy
    generate_lazy_loading(template_name, window_attr, nonce)
  else
    raise ArgumentError, "Unsupported link strategy: #{strategy}"
  end
end

#generate_lazy_loading(template_name, window_attr, nonce) ⇒ Object (private) 



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# File 'lib/rhales/hydration/link_based_injection_detector.rb', line 159

def generate_lazy_loading(template_name, window_attr, nonce)
  endpoint_url = "#{@api_endpoint_path}/#{template_name}"
  mount_selector = @hydration_config.lazy_mount_selector || '#app'
  window_attr_html = ERB::Util.html_escape(window_attr)
  window_attr_js   = JSONSerializer.dump_html_safe(window_attr)
  endpoint_url_html = ERB::Util.html_escape(endpoint_url)
  endpoint_url_js   = JSONSerializer.dump_html_safe(endpoint_url)
  mount_selector_js = JSONSerializer.dump_html_safe(mount_selector)

  # No link tag for lazy loading - purely script-driven
  script_tag = <<~HTML.strip
    <script#{nonce_attribute(nonce)} data-hydration-target="#{window_attr_html}" data-lazy-src="#{endpoint_url_html}">
    // Lazy loading strategy with intersection observer
    window.__rhales__ = window.__rhales__ || {};
    window.__rhales__.initLazyLoading = function() {
      const mountElement = document.querySelector(#{mount_selector_js});
      if (!mountElement) {
        console.warn('Rhales: Mount element ' + #{mount_selector_js} + ' not found for lazy loading');
        return;
      }

      const observer = new IntersectionObserver((entries) => {
        entries.forEach(entry => {
          if (entry.isIntersecting) {
            fetch(#{endpoint_url_js})
              .then(r => r.json())
              .then(data => {
                window[#{window_attr_js}] = data;
                window.dispatchEvent(new CustomEvent('rhales:hydrated', {
                  detail: { target: #{window_attr_js}, data: data }
                }));
              })
              .catch(err => console.error('Rhales lazy hydration error:', err));

            observer.unobserve(entry.target);
          }
        });
      });

      observer.observe(mountElement);
    };

    // Initialize when DOM is ready
    if (document.readyState === 'loading') {
      document.addEventListener('DOMContentLoaded', window.__rhales__.initLazyLoading);
    } else {
      window.__rhales__.initLazyLoading();
    }
    </script>
  HTML

  script_tag
end

#generate_modulepreload_link(template_name, window_attr, nonce) ⇒ Object (private) 



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# File 'lib/rhales/hydration/link_based_injection_detector.rb', line 134

def generate_modulepreload_link(template_name, window_attr, nonce)
  endpoint_url = "#{@api_endpoint_path}/#{template_name}.js"
  window_attr_html = ERB::Util.html_escape(window_attr)
  window_attr_js   = JSONSerializer.dump_html_safe(window_attr)
  endpoint_url_html = ERB::Util.html_escape(endpoint_url)
  endpoint_url_js   = JSONSerializer.dump_html_safe(endpoint_url)

  link_tag = %(<link rel="modulepreload" href="#{endpoint_url_html}">)

  script_tag = <<~HTML.strip
    <script type="module"#{nonce_attribute(nonce)} data-hydration-target="#{window_attr_html}">
    // Module preload strategy
    import data from #{endpoint_url_js};
    window[#{window_attr_js}] = data;

    // Dispatch ready event
    window.dispatchEvent(new CustomEvent('rhales:hydrated', {
      detail: { target: #{window_attr_js}, data: data }
    }));
    </script>
  HTML

  "#{link_tag}\n#{script_tag}"
end

#generate_prefetch_link(template_name, window_attr, nonce) ⇒ Object (private) 



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# File 'lib/rhales/hydration/link_based_injection_detector.rb', line 77

def generate_prefetch_link(template_name, window_attr, nonce)
  endpoint_url = "#{@api_endpoint_path}/#{template_name}"
  crossorigin_attr = @crossorigin_enabled ? ' crossorigin' : ''
  window_attr_html = ERB::Util.html_escape(window_attr)
  window_attr_js   = JSONSerializer.dump_html_safe(window_attr)
  endpoint_url_html = ERB::Util.html_escape(endpoint_url)
  endpoint_url_js   = JSONSerializer.dump_html_safe(endpoint_url)

  link_tag = %(<link rel="prefetch" href="#{endpoint_url_html}" as="fetch"#{crossorigin_attr}>)

  script_tag = <<~HTML.strip
    <script#{nonce_attribute(nonce)} data-hydration-target="#{window_attr_html}">
    // Prefetch hydration data
    window.__rhales__ = window.__rhales__ || {};
    if (!window.__rhales__.loadPrefetched) {
      window.__rhales__.loadPrefetched = function(target, url) {
        fetch(url)
          .then(r => r.json())
          .then(data => window[target] = data);
      };
    }
    window.__rhales__.loadPrefetched(#{window_attr_js}, #{endpoint_url_js});
    </script>
  HTML

  "#{link_tag}\n#{script_tag}"
end

#generate_preload_link(template_name, window_attr, nonce) ⇒ Object (private) 



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# File 'lib/rhales/hydration/link_based_injection_detector.rb', line 105

def generate_preload_link(template_name, window_attr, nonce)
  endpoint_url = "#{@api_endpoint_path}/#{template_name}"
  crossorigin_attr = @crossorigin_enabled ? ' crossorigin' : ''
  window_attr_html = ERB::Util.html_escape(window_attr)
  window_attr_js   = JSONSerializer.dump_html_safe(window_attr)
  endpoint_url_html = ERB::Util.html_escape(endpoint_url)
  endpoint_url_js   = JSONSerializer.dump_html_safe(endpoint_url)

  link_tag = %(<link rel="preload" href="#{endpoint_url_html}" as="fetch"#{crossorigin_attr}>)

  script_tag = <<~HTML.strip
    <script#{nonce_attribute(nonce)} data-hydration-target="#{window_attr_html}">
    // Preload strategy - high priority fetch
    fetch(#{endpoint_url_js})
      .then(r => r.json())
      .then(data => {
        window[#{window_attr_js}] = data;
        // Dispatch ready event
        window.dispatchEvent(new CustomEvent('rhales:hydrated', {
          detail: { target: #{window_attr_js}, data: data }
        }));
      })
      .catch(err => console.error('Rhales hydration error:', err));
    </script>
  HTML

  "#{link_tag}\n#{script_tag}"
end

#nonce_attribute(nonce) ⇒ Object (private) 



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# File 'lib/rhales/hydration/link_based_injection_detector.rb', line 213

def nonce_attribute(nonce)
  require 'erb'
  nonce ? " nonce=\"#{ERB::Util.html_escape(nonce)}\"" : ''
end