application_html.md

Application Layout for Rails

Rails template inheritance workflow

Installation

• copy application.html.erb to app/views/layout/applicatoin.html.erb

• touch app/views/application/_app_footer.html.erb

• touch app/views/application/_app_header.html.erb

• touch app/views/application/_javascript.html.erb

• touch app/views/application/_stylesheet.html.erb

• touch app/views/shared/_basic_footer.html.erb

• touch app/views/shared/_basic_header.html.erb

File content

<%# file: app/views/application/_app_footer.html.erb %>
<%= render("shared/basic_footer") %>

<%# file: app/views/application/_app_header.html.erb %>
<%= render("shared/basic_header") %>

<%# file: app/views/application/_javascript.html.erb %>
<%= javascript_include_tag "application" %>

<%# file: app/views/application/_stylesheet.html.erb %>
<%= stylesheet_link_tag "application", media: "all" %>

<%# file: app/views/shared/_basic_footer.html.erb %>
<footer><h5>Hallo from footer</h5></footer>

<%# file: app/views/shared/_basic_header.html.erb %>
<header><h1>Hallo from header</h1></header>

Usage

The key role has the oneline ternary operator construct <%= content_for?(:app_footer) ? yield(:app_footer) : render("app_footer") rescue nil %> inside the application layout file.

• The rescue nil is optional. If you remove it the block will be mandatory.
• You could include or overwrite content form erb-files with the content_for(:extend_stylesheet) block
• Template inheritance – load specific partial e.g. Products, create app/views/products/_app_footer.html.erb

<% content_for(:extend_stylesheet) do %>
	<%= stylesheet_link_tag "foobar_css_file" %>
<% end %>

<% content_for(:extend_javascript) do %>
	<%= stylesheet_link_tag "foobar_js_file" %>
	<script>
		$(function() {
			console.log("hallo rails")
		});
	</script>
<% end %>