Class: Rhales::HydrationEndpoint

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

Overview

Handles API endpoint responses for link-based hydration strategies

Provides JSON and ES module endpoints that serve hydration data separately from HTML templates, enabling better caching, parallel loading, and reduced HTML payload sizes.

Supported Response Formats

JSON Response (application/json)

json { "myData": { "user": "john", "theme": "dark" }, "config": { "apiUrl": "https://api.example.com" } }

ES Module Response (text/javascript)

javascript export default { "myData": { "user": "john", "theme": "dark" }, "config": { "apiUrl": "https://api.example.com" } };

Usage

```ruby endpoint = HydrationEndpoint.new(config, context)

JSON response

json_response = endpoint.render_json(‘template_name’)

ES Module response

module_response = endpoint.render_module(‘template_name’) ```

Instance Method Summary collapse

Constructor Details

#initialize(config, context = nil) ⇒ HydrationEndpoint

Returns a new instance of HydrationEndpoint.



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# File 'lib/rhales/hydration_endpoint.rb', line 41

def initialize(config, context = nil)
  @config = config
  @context = context
end

Instance Method Details

#cache_control_header ⇒ Object (private) 



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# File 'lib/rhales/hydration_endpoint.rb', line 190

def cache_control_header
  if @config.hydration.api_cache_enabled
    "public, max-age=#{@config.hydration.api_cache_ttl || 300}"
  else
    "no-cache, no-store, must-revalidate"
  end
end

#calculate_etag(template_name, additional_context = {}) ⇒ Object

Get ETag for current template data



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# File 'lib/rhales/hydration_endpoint.rb', line 116

def calculate_etag(template_name, additional_context = {})
  merged_data = process_template_data(template_name, additional_context)
  # Simple ETag based on data hash
  Digest::MD5.hexdigest(JSON.generate(merged_data))
end

#cors_enabled? ⇒ Boolean (private)

Returns:

  • (Boolean) 


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# File 'lib/rhales/hydration_endpoint.rb', line 198

def cors_enabled?
  @config.hydration.cors_enabled || false
end

#cors_headers ⇒ Object (private) 



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# File 'lib/rhales/hydration_endpoint.rb', line 202

def cors_headers
  {
    'Access-Control-Allow-Origin' => @config.hydration.cors_origin || '*',
    'Access-Control-Allow-Methods' => 'GET, HEAD, OPTIONS',
    'Access-Control-Allow-Headers' => 'Accept, Accept-Encoding, Authorization',
    'Access-Control-Max-Age' => '86400'
  }
end

#create_template_context(additional_context) ⇒ Object (private) 



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# File 'lib/rhales/hydration_endpoint.rb', line 149

def create_template_context(additional_context)
  if @context
    # Merge additional context into existing context by reconstructing with merged props
    merged_props = @context.props.merge(additional_context)
    @context.class.for_view(@context.req, @context.sess, @context.cust, @context.locale, **merged_props)
  else
    # Create minimal context with just the additional data
    Context.minimal(props: additional_context)
  end
end

#data_changed?(template_name, etag, additional_context = {}) ⇒ Boolean

Check if template data has changed (for ETags)

Returns:

  • (Boolean) 


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# File 'lib/rhales/hydration_endpoint.rb', line 110

def data_changed?(template_name, etag, additional_context = {})
  current_etag = calculate_etag(template_name, additional_context)
  current_etag != etag
end

#json_headers(data) ⇒ Object (private) 



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# File 'lib/rhales/hydration_endpoint.rb', line 160

def json_headers(data)
  headers = {
    'Content-Type' => 'application/json',
    'Cache-Control' => cache_control_header,
    'Vary' => 'Accept, Accept-Encoding'
  }

  # Add CORS headers if enabled
  if cors_enabled?
    headers.merge!(cors_headers)
  end

  # Add ETag for caching
  headers['ETag'] = %("#{Digest::MD5.hexdigest(JSON.generate(data))}")

  headers
end

#jsonp_headers(data) ⇒ Object (private) 



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# File 'lib/rhales/hydration_endpoint.rb', line 184

def jsonp_headers(data)
  headers = json_headers(data)
  headers['Content-Type'] = 'application/javascript'
  headers
end

#module_headers(data) ⇒ Object (private) 



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# File 'lib/rhales/hydration_endpoint.rb', line 178

def module_headers(data)
  headers = json_headers(data)
  headers['Content-Type'] = 'text/javascript'
  headers
end

#process_template_data(template_name, additional_context) ⇒ Object (private) 



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# File 'lib/rhales/hydration_endpoint.rb', line 124

def process_template_data(template_name, additional_context)
  # Create a minimal context for data processing
  template_context = create_template_context(additional_context)

  # Process template to extract hydration data
  view = View.new(@context.req, @context.sess, @context.cust, @context.locale, props: {})
  aggregator = HydrationDataAggregator.new(template_context)

  # Build composition to get template dependencies
  composition = view.send(:build_view_composition, template_name)
  composition.resolve!

  # Aggregate data from all templates in the composition
  aggregator.aggregate(composition)
rescue StandardError => ex
  # Return error structure that can be serialized
  {
    error: {
      message: "Failed to process template data: #{ex.message}",
      template: template_name,
      timestamp: Time.now.iso8601,
    }
  }
end

#render_json(template_name, additional_context = {}) ⇒ Object

Render JSON response for API endpoints



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# File 'lib/rhales/hydration_endpoint.rb', line 47

def render_json(template_name, additional_context = {})
  merged_data = process_template_data(template_name, additional_context)

  {
    content: JSON.generate(merged_data),
    content_type: 'application/json',
    headers: json_headers(merged_data)
  }
rescue JSON::NestingError, JSON::GeneratorError, ArgumentError, Encoding::UndefinedConversionError => e
  # Handle JSON serialization errors and encoding issues
  error_data = {
    error: {
      message: "Failed to serialize data to JSON: #{e.message}",
      template: template_name,
      timestamp: Time.now.iso8601
    }
  }

  {
    content: JSON.generate(error_data),
    content_type: 'application/json',
    headers: json_headers(error_data)
  }
rescue StandardError => e
  # Handle any other unexpected errors during JSON generation
  error_data = {
    error: {
      message: "Unexpected error during JSON generation: #{e.message}",
      template: template_name,
      timestamp: Time.now.iso8601
    }
  }

  {
    content: JSON.generate(error_data),
    content_type: 'application/json',
    headers: json_headers(error_data)
  }
end

#render_jsonp(template_name, callback_name, additional_context = {}) ⇒ Object

Render JSONP response with callback



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# File 'lib/rhales/hydration_endpoint.rb', line 99

def render_jsonp(template_name, callback_name, additional_context = {})
  merged_data = process_template_data(template_name, additional_context)

  {
    content: "#{callback_name}(#{JSON.generate(merged_data)});",
    content_type: 'application/javascript',
    headers: jsonp_headers(merged_data),
  }
end

#render_module(template_name, additional_context = {}) ⇒ Object

Render ES module response for modulepreload strategy



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# File 'lib/rhales/hydration_endpoint.rb', line 88

def render_module(template_name, additional_context = {})
  merged_data = process_template_data(template_name, additional_context)

  {
    content: "export default #{JSON.generate(merged_data)};",
    content_type: 'text/javascript',
    headers: module_headers(merged_data)
  }
end