Rails methods

link_to

image_tag

link_to image_tag(“rails.png”, alt: “Rails logo”), “#”

<%= debug(params) if Rails.env.development %>

Because we used theimage_tag helper in Listing 5.2, Rails will automatically find any images in theapp/assets/images/ directory using the asset pipeline (Section 5.2).

The directory

app/assets/stylesheets/
is part of the asset pipeline (Section 5.2), and any stylesheets in this directory will automatically be included as part of the application.css file included in the site layout.

When creating a column in a database, it is important to consider whether we will need tofind records by that column.

In Listing 6.31, we could have written the assignment as

self.email = self.email.downcase
(where self refers to the current user), but inside the User model the self keyword is optional on the right-hand side:

self.email = email.downcase
Add bootstrap css to stylesheet:

@import "bootstrap-sprockets";
@import "bootstrap";

Rails automatically wraps * the fields with errors * in divs with the CSS class * field_with_errors *. These labels then allow us to style the error messages with the SCSS shown in Listing 7.20, which makes use of Sass’s @extend function to include the functionality of the Bootstrap class has-error.

<% if @user.errors.any? %>
  <div id="error_explanation">
    <div class="alert alert-danger">
      The form contains <%= pluralize(@user.errors.count, "error") %>.
    </div>
    <ul>
    <% @user.errors.full_messages.each do |msg| %>
      <li><%= msg %></li>
    <% end %>
    </ul>
  </div>
<% end %>

Other errors methods:

user.errors.count
user.errors.empty?
user.errors.any?

pluralize(1,"error")

Conveniently, a Sessions helper module was generated automatically when generating the Sessions controller (Section 8.1.1). Moreover, such helpers are automatically included in Rails views; by including the module into the base class of all controllers (the Application controller), we arrange to make them available in our controllers as well (Listing 8.11).

 #app/controllers/application_controller.rb
 class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
  include SessionsHelper
end