Module: ReactOnRailsPro::Stream

Extended by:
ActiveSupport::Concern
Defined in:
lib/react_on_rails_pro/concerns/stream.rb

Instance Method Summary collapse

Instance Method Details

#stream_view_containing_react_components(template:, close_stream_at_end: true, content_type: nil, **render_options) ⇒ Object

Note:

The ‘stream_react_component` helper is defined in the react_on_rails gem. For more details, refer to `lib/react_on_rails/helper.rb` in the react_on_rails repository.

Streams React components within a specified template to the client.

components must be added to the view using the ‘stream_react_component` helper.

Examples:

stream_view_containing_react_components(template: 'path/to/your/template')
stream_view_containing_react_components(
  template: 'path/to/your/template',
  close_stream_at_end: false,
  layout: false
)

Parameters:

  • template (String) —

    The path to the template file to be streamed.

  • close_stream_at_end (Boolean) (defaults to: true) —

    Whether to automatically close the stream after rendering (default: true).

  • content_type (String, nil) (defaults to: nil) —

    Optional response content type. Set after rendering but before the first stream write, overriding any content type inferred from the template format. When using a non-HTML ‘formats:` value (for example `[:text]`), pass `content_type` too unless committing the format-derived MIME type is intentional.

  • render_options (Hash) —

    Additional options to pass to ‘render_to_string`.

See Also:

  • ReactOnRails::Helper#stream_react_component


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# File 'lib/react_on_rails_pro/concerns/stream.rb', line 39

def stream_view_containing_react_components(
  template:, close_stream_at_end: true, content_type: nil, **render_options
)
  require "async"
  require "async/barrier"
  require "async/limited_queue"
  warn_on_non_html_formats_without_content_type(render_options[:formats], content_type)

  Sync do |parent_task|
    # Initialize async primitives for concurrent component streaming
    @async_barrier = Async::Barrier.new
    buffer_size = ReactOnRailsPro.configuration.concurrent_component_streaming_buffer_size
    @main_output_queue = Async::LimitedQueue.new(buffer_size)

    # Render template - components will start streaming immediately.
    # If a shell error occurs, consumer_stream_async raises PrerenderError here
    # (BEFORE the response is committed), enabling a proper HTTP redirect.
    template_string = render_to_string(template: template, **render_options)
    # View may contain extra newlines, chunk already contains a newline
    # Having multiple newlines between chunks causes hydration errors
    # So we strip extra newlines from the template string and add a single newline
    # `formats: [:text]` causes render_to_string to set response.content_type
    # to `text/plain`; override it here before the first stream write, which
    # is when ActionController::Live commits headers. render_to_string itself
    # never writes to response.stream, so this assignment is always safe.
    response.content_type = content_type if content_type
    response.stream.write(template_string)

    drain_streams_concurrently(parent_task)
    # Do not close the response stream in an ensure block.
    # If an error occurs we may need the stream open to send diagnostic/error details
    # (for example, ApplicationController#rescue_from in the dummy app).
    response.stream.close if close_stream_at_end
  rescue StandardError
    # Stop all streaming tasks to prevent leaked async work.
    # For pre-commit errors (e.g., shell error raised during render_to_string),
    # the barrier may still have pending tasks that must be cancelled.
    # For post-commit errors (from drain_streams_concurrently), the barrier
    # is already stopped inside that method — stopping again is a no-op.
    @async_barrier&.stop
    raise
  end
end