Class: Roda::RodaPlugins::Streaming::Stream

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/roda/plugins/streaming.rb

Overview

Class of the response body in case you use #stream.

Three things really matter: The front and back block (back being the block generating content, front the one sending it to the client) and the scheduler, integrating with whatever concurrency feature the Rack handler is using.

Scheduler has to respond to defer and schedule.

Defined Under Namespace

Classes: Scheduler

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}, &back) ⇒ Stream

Handle streaming options, see Streaming for details.



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# File 'lib/roda/plugins/streaming.rb', line 88

def initialize(opts={}, &back)
  @scheduler = opts[:scheduler] || Scheduler.new(self)
  @back = back.to_proc
  @keep_open = opts[:keep_open]
  @callbacks = []
  @closed = false

  if opts[:callback]
    callback(&opts[:callback])
  end
end

Instance Method Details

#<<(data) ⇒ Object

Add output to the streaming response body.



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# File 'lib/roda/plugins/streaming.rb', line 101

def <<(data)
  @scheduler.schedule{@front.call(data.to_s)}
  self
end

#callback(&block) ⇒ Object Also known as: errback

Add the given block as a callback to call when the block closes.



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# File 'lib/roda/plugins/streaming.rb', line 107

def callback(&block)
  return yield if closed?
  @callbacks << block
end

#close ⇒ Object

If not already closed, close the connection, and call any callbacks.



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# File 'lib/roda/plugins/streaming.rb', line 117

def close
  return if closed?
  @closed = true
  @scheduler.schedule{@callbacks.each{|c| c.call}}
end

#closed? ⇒ Boolean

Whether the connection has already been closed.

Returns:

  • (Boolean) 


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# File 'lib/roda/plugins/streaming.rb', line 124

def closed?
  @closed
end

#each(&front) ⇒ Object

Yield values to the block as they are passed in via #<<.



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# File 'lib/roda/plugins/streaming.rb', line 129

def each(&front)
  @front = front
  @scheduler.defer do
    begin
      @back.call(self)
    rescue Exception => e
      @scheduler.schedule{raise e}
    end
    close unless @keep_open
  end
end