Flash messages (ajax) - ruby-on-rails

Question

Is it possible to show the errors of the form in the flash messages in ajax? I want to show the errors of the form when is not possible to save a record due to unique field.
my index
<!--<p id="notice"><%= notice %></p>-->
<h1>Empresas</h1>
<style>
.container {
}
</style>
<div class="container">
<div class="row">
<div class="text-center">
<!-- Button trigger modal -->
<button type="button" class="btn btn-primary btn-lg" data-toggle="modal" data-target="#mynewempresa">
Nueva empresa
</button>
</div>
</div>
<br>
<br>
<table id="empresas" class="display"><!--el id empresas es de datatables referenciado en empresas.coffe y display class es una clase de datatables-->
<thead>
<tr><!--active es para sombrear la fila-->
<th>Clave</th>
<th>Empresa</th>
<th>Acción</th>
<th></th>
</tr>
</thead>
<tbody id="container_empresas">
<%= render #empresas %><!--carga todos los empresas-->
</tbody>
</table>
<!-- Modal create action -->
<%= form_for(#empresa, remote: true, html: {class: "form-horizontal formulario-validado-create"}) do |f| %> <!--ajax remote: true-->
<div class="modal fade" id="mynewempresa" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button>
<h4 class="modal-title" id="myModalLabel">Agregar empresa</h4>
</div>
<div class="modal-body">
<div id="flash_messages_placeholder" >
</div>
<div class="form-group">
<%= f.label :IdEmpresa, "Clave:", class: "control-label col-md-2 " %>
<div class="col-md-3">
<%= f.text_field :IdEmpresa, class: "form-control empresa_clave",autofocus: true, minlength: "1", required: "true" %>
</div>
<%= f.label :Empresa, "Empresa:", class: "control-label col-md-2" %>
<div class="col-md-5">
<%= f.text_field :Empresa, class: "form-control empresa_empresa",minlength: "4", required: "true" %>
</div>
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal" id="mynewempresaclose">Cerrar</button>
<%= submit_tag "Crear", class: "btn btn-primary"%>
</div>
</div>
</div>
</div>
<%end%>
</div>
my controller
class EmpresasController < ApplicationController
before_action :set_empresa, only: [:show, :edit, :update, :destroy]
before_action :authenticate_usuario!
# GET /empresas
# GET /empresas.json
def index
#empresas = Empresa.all
#empresa = Empresa.new
respond_to do |format|
format.html
format.csv { send_data #empresas.to_csv}
format.xls #{ send_data #empresas.to_csv(col_sep: "\t") }
end
end
def import
Empresa.import(params[:file])
redirect_to empresas_path, notice: "Sucursales importadas."
end
# GET /empresas/1
# GET /empresas/1.json
def show
end
# GET /empresas/new
def new
#empresa = Empresa.new
end
# GET /empresas/1/edit
def edit
end
# POST /empresas
# POST /empresas.json
def create
#empresa = Empresa.new(empresa_params)
format.js { render 'shared/error_messages_js'}
respond_to do |format|
if #empresa.save
format.html { redirect_to #empresa, notice: 'Empresa was successfully created.' }
format.json { render :show, status: :created, location: #empresa }
format.js {flash.now[:notice] = 'La Sucursal se ha creado de forma exitosa.'} #ajax
else
format.html { render :new }
format.json { render json: #empresa.errors, status: :unprocessable_entity }
format.js {flash.now[:alert] = 'Error al crear la sucursal.'} #ajax
end
end
end
# PATCH/PUT /empresas/1
# PATCH/PUT /empresas/1.json
def update
respond_to do |format|
##use locals if multiple models
##add model errors
flash.now[:error] = #empresa.errors.full_messages
##flash.now[:error] = #model.errors.full_messages.to_sentence
if #empresa.update(empresa_params)
format.html { redirect_to #empresa, notice: 'Empresa was successfully updated.' }
format.json { render :show, status: :ok, location: #empresa }
format.js {flash.now[:notice] = 'La Sucursal se ha actualizado de forma exitosa.'} #ajax
else
format.html { render :edit }
format.json { render json: #empresa.errors, status: :unprocessable_entity }
format.js {flash.now[:alert] = 'Error al actualizar la sucursal.'} #ajax
end
end
end
# DELETE /empresas/1
# DELETE /empresas/1.json
def destroy
#empresa.destroy
respond_to do |format|
format.html { redirect_to empresas_url, notice: 'Empresa was successfully destroyed.' }
format.json { head :no_content }
format.js {flash.now[:notice] = 'La Sucursal se ha borrado de forma exitosa.'} #ajax
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_empresa
#empresa = Empresa.find(params[:idempresa])
end
# Never trust parameters from the scary internet, only allow the white list through.
def empresa_params
params.require(:empresa).permit(:IdEmpresa, :Empresa)
end
end
my application helper:
module ApplicationHelper
###application_helper.rb
def flash_display
Rails.logger.info "show flash message ajax======== "
response = ""
flash.each do |name, msg|
msg=msg ###"<i class='fa fa-quote-left fa-border'></i>"+msg+"<i class='fa fa-quote-right fa-border'></i>"+"<button type='button' class='close' title='hide' data-dismiss='alert'><i class='fa-times-circle-o fa pull-right'></i></button>".html_safe
response = response +
content_tag(:div, msg, :id => "flash_#{name}",:class=>"alert alert-danger") do
"#{msg}".html_safe
end
end
flash.discard
response
end
end
##views/shared/error_messages_js.erb
$('#flash_messages_placeholder').html("<%= escape_javascript raw(flash_display) %>");

Answer 1

Yes..its possible..
firstly,create a helper method that can be used to show flash messages on the view.
###application_helper.rb
def flash_display
Rails.logger.info "show flash message ajax======== "
response = ""
flash.each do |name, msg|
msg=msg ###"<i class='fa fa-quote-left fa-border'></i>"+msg+"<i class='fa fa-quote-right fa-border'></i>"+"<button type='button' class='close' title='hide' data-dismiss='alert'><i class='fa-times-circle-o fa pull-right'></i></button>".html_safe
response = response +
content_tag(:div, msg, :id => "flash_#{name}",:class=>"alert alert-danger") do
"#{msg}".html_safe
end
end
flash.discard
response
end
Secondly,In your controller code where you post data using remote=true,handle js response as shown below.
respond_to do |format|
##use locals if multiple models
##add model errors
##flash.now[:error] = #model.errors.full_messages
##flash.now[:error] = #model.errors.full_messages.to_sentence
flash.now[:error]="You cannot edit this Page"
format.js { render 'shared/error_messages_js'}
end
##views/shared/error_messages_js.erb
$('#flash_messages_placeholder').html("<%= escape_javascript raw(flash_display) %>");
So,the above js.erb file will look for an empty placeholder to show flash messages.So your form must also have a placeholder
###_form.html.erb
<form action="<%= post_data_path(current_user)%>" method="post" data-remote="true">
<div id="flash_messages_placeholder" > </div>
##input fields/submit button goes here
<%end%>
Hope it helps :)