module Roda::RodaPlugins::Streaming

  1. lib/roda/plugins/streaming.rb

The streaming plugin adds support for streaming responses from roda using the stream method:

plugin :streaming

route do |r|
  stream do |out|
    ['a', 'b', 'c'].each{|v| out << v; sleep 1}
  end
end

In order for streaming to work, any webservers used in front of the roda app must not buffer responses.

The stream method takes the following options:

:callback

A callback proc to call when the connection is closed.

:keep_open

Whether to keep the connection open after the stream block returns, default is false.

:loop

Whether to call the stream block continuously until the connection is closed.

If the :loop option is used, you can override the handle_stream_error method to change how exceptions are handled during streaming. This method is passed the exception and the stream. By default, this method just reraises the exception, but you can choose to output the an error message to the stream, before raising:

def handle_stream_error(e, out)
  out << 'ERROR!'
  raise e
end

Ignore errors completely while streaming:

def handle_stream_error(e, out)
end

or handle the errors in some other way.

The implementation was originally taken from Sinatra, which is also released under the MIT License:

Copyright © 2007, 2008, 2009 Blake Mizerany Copyright © 2010, 2011, 2012, 2013, 2014 Konstantin Haase

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Constants

OPTS = {}.freeze