How to display flash message without redirection in Ruby on Rails?

Question

(This question is a continuation of the following thread:

In Rails, is it possible to display an alert without calling redirect_to or render?
Continuing that question here since there were too many comments in the earlier thread
There were 2 issues stated in that question and one of them was resolved in that thread
Hence opening this thread to focus on only the other issue which was not resolved in that thread)

I have a form:

<%= form_tag generate_report_path(:header => true) do |f| % >
<div class="container-fluid">
  <div style="padding-right:10px">

    <%= select_tag(:report_id, options_for_select(
      [["Select Report Type", 0],
      ["Report1", 1],
      ["Report2", 2],
      ["Report3", 3]]), id: "report_selection") %>


      <%= hidden_field_tag :format, :pdf %>

I have a submit button and a checkbox right next to it:

<%= button_tag "Generate Report", class: 'btn btn-sm btn-primary'%>
<%= label_tag do %>
  <%= check_box_tag "format_reqd", "format_reqd", false %>
  Check for Numeric format 
<% end %>

When the user selects the checkbox and clicks on the Generate Report button, I would like to display an alert to the user "your report would be emailed to you in a few minutes"

How can I achieve these:

A flash message should be displayed
Page redirection or rendering should not happen

Please help!

UPDATE:

I added this to my controller (called report_controller):

    def reportgen

            respond_to do |format|
              format.json { flash.now[:alert] = "Report generation has been initiated. You will receive an email in approximately 4 - 5 minutes with a link to download the report."}
            end

    end

\app\views\report\reportgen.js.erb

    $("#flash").html('<%= j render partial: "shared/notice_banner" %>');

application.html.erb

  <div id="flash">
    <% if alert.present? %>
      <%= render partial: "shared/notice_banner" %>
    <% end %>
  </div>

  <% flash.each do |key, value| %>
    <% if key.to_s == "alert" %>
      <div style= "color: #FF0000" class="text-center <%= flash_class(key) %>">
      <%= value %>
    </div>
    <% else %>
      <div class="lead text-center <%= flash_class(key) %>">
      <%= value %>
    </div>
    <% end %>    
  <% end %>



  <%= yield %>

app\views\shared\_notice_banner.html.erb

<div data-alert class="alert-box">
  <%= alert %>
  <a href="#" class="close">&times;</a>
</div>

And this is my code to add the button and checkbox in my form:

                  <div id="generate_button" style="display: none; float:left;">
                    <%= button_tag "Generate Report", class: 'btn btn-sm btn-primary'%>
                  </div>
                  &nbsp;
                  <div id="report_type_drop" style="display: none;padding-top:5px;padding-left:5px">


                    <%= label_tag do %>
                      <%= check_box_tag "format_reqd", "format_reqd", false %>
                      Check for Numeric format
                    <% end %>
                    </div>

With the above code, flash message still does not appear for me!

UPDATE: (update2)

I tried changing flash.now[:alert] to flash[:alert] but still the flash message does not appear

            respond_to do |format|
              format.json { flash[:alert] = "Report generation has been initiated. You will receive an email in approximately 4 - 5 minutes with a link to download the report."}
            end

If you don't want a page refresh shouldn't it be a remote form? — Dave Newton, Jun 25 '19 at 14:22
@DaveNewton - even `without` remote, the page refresh is not happening right now. Page refresh was happening when I was using `plain HTML button` and `HTML checkbox`. When I replaced them with `button_tag` and `check_box_tag`, the page refresh stopped happening!! — m.beginner, Jun 25 '19 at 14:23
What browser? What's rendered? IIRC it defaults to a "submit" type. — Dave Newton, Jun 25 '19 at 14:28
I am using Google chrome. No rendering happens when the button is clicked since no calls to a `render` or `redirect_to` are made. But the flash message is not getting displayed either which is the only focus of this thread. — m.beginner, Jun 25 '19 at 17:38
The original form shown in my question is retained as such when the submit button is clicked. No rendering or redirection happens — m.beginner, Jun 26 '19 at 02:45
The original page has a form with a bunch of input controls like text boxes, labels etc — m.beginner, Jun 26 '19 at 10:51

score 0 · Answer 1 · answered Jun 25 '19 at 17:38

You need put some javascript async actions in order to do that, you have multiple options:

Submit the form with ajax, then parse the response and show the alert using javascript
Use ajax to check if there is a change in the alert in the server every x seconds
Use web sockets to check in real time if there is a new alert

which one you want to implement depend of your specific needs

How to display flash message without redirection in Ruby on Rails?

UPDATE:

UPDATE: (update2)

1 Answers1

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