Class: Rack::RSI

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/rsi_version.rb,
lib/rack/rsi.rb

Defined Under Namespace

Classes: Error, RsiRender

Constant Summary collapse

VERSION = 
"0.0.2"

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ RSI

Returns a new instance of RSI.



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# File 'lib/rack/rsi.rb', line 56

def initialize( app )
  @app = app
end

Instance Method Details

#assemble_response(env) ⇒ Object

Assemble Response



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# File 'lib/rack/rsi.rb', line 65

def assemble_response( env )
  vanilla_env = env.dup
  vanilla_app = @app.dup

  # calling app and env on orignal request
  status, headers, enumerable_body = original_response = @app.call(env)

  rack_rsi_flag = headers.delete('rack.rsi')

  # Assemble Pages if rack_rsi_flag is set and status is 200 ok
  # otherwise return the original response
  return original_response unless rack_rsi_flag && status == 200

  body = ""
  enumerable_body.each do |part|
    body << part
  end

  cache_control_headers = Array( headers.delete( 'Cache-Control' ) || "max-age=0" )

  # Like Varnish supports upto 5 levels of ESI includes recursively
  level = 1
  while( rack_rsi_flag )
    erb = ERB.new( body, 0 )
    renderer = RsiRender.new( vanilla_app, vanilla_env, level )
    body = erb.result( renderer.get_binding )
    renderer.cache_control_headers.inject( cache_control_headers ){ |s,x| s.push( x ) }
    rack_rsi_flag = renderer.rack_rsi?
    level += 1
  end

  # Set ETag for the Request
  headers['ETag'] = Digest::MD5.hexdigest( body )
  headers.delete( 'Last-Modified' )

  # For Assembled Pages Cache-Control to be set as private, with
  # max-age=<minimum max-age of all the requests that are assembled>
  # and should be revalidate on stale. If max-age is not set for even one of the
  # requests then max-age is set to 0.
  min_max_age = cache_control_headers.collect{ |x| x.match(/max-age\s*=\s*(\d+)/).to_a[1].to_i }.min

  headers['Cache-Control'] = "private, max-age=#{min_max_age}, must-revalidate"
  headers.delete( 'Expires' )
  headers['Expires'] = ( Time.now.utc + min_max_age ).strftime("%a, %d %m %Y %T %Z") if min_max_age > 0

  # Create Correct Content-Length
  headers['Content-Length'] = Rack::Utils.bytesize( body ).to_s

  # For now whatever headers is set by the original action would be
  # passed on. Except for Cache-Control, ETag, Expires, Last-Modified
  # Cookies from the original action are passed on.
  [ status, headers, [ body ] ]
end

#call(env) ⇒ Object 



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# File 'lib/rack/rsi.rb', line 60

def call( env )
  assemble_response( env )
end