Class: Presently::State

Inherits:
Object
  • Object
show all
Defined in:
lib/presently/state.rb

Overview

Persists and restores presentation controller state to/from a JSON file.

Tracks the current slide index, clock elapsed time, and clock running state. This allows the presentation to survive server restarts without losing position.

Constant Summary collapse

DEFAULT_PATH =

The default state file path.

".presently.json"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path = DEFAULT_PATH) ⇒ State

Initialize a new state instance.



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# File 'lib/presently/state.rb', line 19

def initialize(path = DEFAULT_PATH)
	@path = path
end

Instance Attribute Details

#path ⇒ Object (readonly)

Returns the value of attribute path.



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# File 'lib/presently/state.rb', line 24

def path
  @path
end

#The file path for the state file.(filepath) ⇒ Object (readonly) 



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# File 'lib/presently/state.rb', line 24

attr :path

Instance Method Details

#restore(controller) ⇒ Object

Restore persisted state into the given controller.



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# File 'lib/presently/state.rb', line 43

def restore(controller)
	return unless File.exist?(@path)
	
	data = JSON.parse(File.read(@path), symbolize_names: true)
	
	# Restore slide position:
	if index = data[:current_index]
		controller.go_to(index.to_i)
	end
	
	# Restore clock state:
	if data[:started]
		controller.clock.restore!(data[:elapsed].to_f, running: data[:running])
	end
rescue => error
	Console.warn(self, "Failed to restore state", exception: error)
end

#save(controller) ⇒ Object

Save the controller’s current state to disk.



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# File 'lib/presently/state.rb', line 28

def save(controller)
	data = {
		current_index: controller.current_index,
		elapsed: controller.clock.elapsed,
		running: controller.clock.running?,
		started: controller.clock.started?,
	}
	
	File.write(@path, JSON.pretty_generate(data))
rescue => error
	Console.warn(self, "Failed to save state", exception: error)
end