vitobotta/RailsFlashToHeaders.md

## application.html.erb
<!DOCTYPE html>
<html>
	<head>
	</head>
	<body>
		<!-- flash_message.js.coffee expects to find a div with this id in your html code -->
		<div id="flash_hook"></div>
	</body>
</html>

## application_controller.rb
# encoding: UTF-8
class ApplicationController < ActionController::Base
  protect_from_forgery

  after_filter :flash_to_headers

  private

    def flash_to_headers
      return unless request.xhr?
      msg = flash_message
      #replace german umlaute encoded in utf-8 to html escaped ones
      msg = msg.gsub("ä","&auml;").gsub("ü","&uuml;").gsub("ö","&ouml;").gsub("Ä","&Auml;").gsub("Ü","&Uuml;").gsub("Ö","&Ouml;").gsub("ß","&szlig;")
      response.headers['X-Message'] = msg
      response.headers["X-Message-Type"] = flash_type.to_s

      flash.discard # don't want the flash to appear when you reload page
    end

    def flash_message
      [:error, :warning, :notice].each do |type|
        return flash[type] unless flash[type].blank?
      end
      # if we don't return something here, the above code will return "error, warning, notice"
      return ''
    end

    def flash_type
      #:keep will instruct the js to not update or remove the shown message.
      #just write flash[:keep] = true (or any other value) in your controller code
      [:error, :warning, :notice, :keep].each do |type|
        return type unless flash[type].blank?
      end
      #don't return the array from above which would happen if we don't have an explicit return statement
      #returning :empty will also allow you to easily know that no flash message was transmitted
      return :empty
    end
end

## flash_message.js.coffee
#ajax call to show flash messages when they are transmitted in the header
#this code assumes the following
# 1) you're using twitter-bootstrap 2.3 (although it will work if you don't)
# 2) you've got a div with the id flash_hook somewhere in your html code

$(document).ajaxComplete (event, request) ->
  msg = request.getResponseHeader("X-Message")
  alert_type = 'alert-success'
  alert_type = 'alert-error' unless request.getResponseHeader("X-Message-Type").indexOf("error") is -1

  unless request.getResponseHeader("X-Message-Type").indexOf("keep") is 0
    #add flash message if there is any text to display
    $("#flash_hook").replaceWith("<div id='flash_hook'>
        <p>&nbsp;</p>
            <div class='row'>
              <div class='span10 offset1'>
                <div class='alert " + alert_type + "'>
                  <button type='button' class='close' data-dismiss='alert'>&times;</button>
                  " + msg + "
                </div>
              </div>
            </div>
           </div>") if msg
    #delete the flash message (if it was there before) when an ajax request returns no flash message
    $("#flash_hook").replaceWith("<div id='flash_hook'></div>") unless msg

## RailsFlashToHeaders.md

      
    Raw
  

              RailsFlashToHeaders.md
            
          
    Rails flash messages with AJAX requests & twitter-bootstrap 2.3
Forked from https://gist.github.com/linjunpop/3410235
Based on Stackoverflow answer: http://stackoverflow.com/a/10167659/656428
License: MIT
	<!DOCTYPE html>
	<html>
	<head>
	</head>
	<body>
	<!-- flash_message.js.coffee expects to find a div with this id in your html code -->
	<div id="flash_hook"></div>
	</body>
	</html>
	# encoding: UTF-8
	class ApplicationController < ActionController::Base
	protect_from_forgery

	after_filter :flash_to_headers

	private

	def flash_to_headers
	return unless request.xhr?
	msg = flash_message
	#replace german umlaute encoded in utf-8 to html escaped ones
	msg = msg.gsub("ä","ä").gsub("ü","ü").gsub("ö","ö").gsub("Ä","Ä").gsub("Ü","Ü").gsub("Ö","Ö").gsub("ß","ß")
	response.headers['X-Message'] = msg
	response.headers["X-Message-Type"] = flash_type.to_s

	flash.discard # don't want the flash to appear when you reload page
	end

	def flash_message
	[:error, :warning, :notice].each do \|type\|
	return flash[type] unless flash[type].blank?
	end
	# if we don't return something here, the above code will return "error, warning, notice"
	return ''
	end

	def flash_type
	#:keep will instruct the js to not update or remove the shown message.
	#just write flash[:keep] = true (or any other value) in your controller code
	[:error, :warning, :notice, :keep].each do \|type\|
	return type unless flash[type].blank?
	end
	#don't return the array from above which would happen if we don't have an explicit return statement
	#returning :empty will also allow you to easily know that no flash message was transmitted
	return :empty
	end
	end
	#ajax call to show flash messages when they are transmitted in the header
	#this code assumes the following
	# 1) you're using twitter-bootstrap 2.3 (although it will work if you don't)
	# 2) you've got a div with the id flash_hook somewhere in your html code

	$(document).ajaxComplete (event, request) ->
	msg = request.getResponseHeader("X-Message")
	alert_type = 'alert-success'
	alert_type = 'alert-error' unless request.getResponseHeader("X-Message-Type").indexOf("error") is -1

	unless request.getResponseHeader("X-Message-Type").indexOf("keep") is 0
	#add flash message if there is any text to display
	$("#flash_hook").replaceWith("<div id='flash_hook'>
	<p> </p>
	<div class='row'>
	<div class='span10 offset1'>
	<div class='alert " + alert_type + "'>
	<button type='button' class='close' data-dismiss='alert'>×</button>
	" + msg + "
	</div>
	</div>
	</div>
	</div>") if msg
	#delete the flash message (if it was there before) when an ajax request returns no flash message
	$("#flash_hook").replaceWith("<div id='flash_hook'></div>") unless msg