The document discusses Ruby on Rails form helpers, including the form_tag helper for generating form tags, input helpers like text_field_tag for generating different form fields, and the form_for helper for generating forms bound to model objects. It also covers generating labels, handling validation errors, select fields, customizing field attributes, and nested forms.

1. Understanding Form Helpers
Bruno Almeida

2. ● Form tag
● Form to an object
● Select
● Customize fields
● Nested forms

3. Let’s begin

4. Form tag
http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html

5. form_tag
<%= form_tag do %>
Form contents
<% end %>
<form action="/" accept-charset="UTF-8" method="post">
<input name="utf8" type="hidden" value="&#x2713;" />
<input type="hidden" name="authenticity_token" value="
jzi1o/1Wl8yTZ2e1Z3QE99BFYI5uouuaFa/HdyyOJP9knHGBMpiGjuNlDP
VhctUX2/qQsFUxCaChV7JSgm0Mnw==" />
Form contents
</form>

6. label_tag, text_field_tag, submit_tag
<%= form_tag("/search", method: "get") do %>
<%= label_tag(:q, "Search for:") %>
<%= text_field_tag(:q) %>
<%= submit_tag("Search") %>
<% end %>
<form accept-charset="UTF-8" action="/search" method="get">
<input name="utf8" type="hidden" value="&#x2713;" />
<label for="q">Search for:</label>
<input id="q" name="q" type="text" />
<input name="commit" type="submit" value="Search" />
</form>

7. Others input helpers
<%= password_field_tag(:password) %>
<%= hidden_field_tag(:parent_id, "5") %>
<%= number_field(:product, :price, in:
1.0..20.0, step: 0.5) %>
<input type="password" name="password" id="password" />
<input type="hidden" name="parent_id" id="parent_id"
value="5" />
<input step="0.5" min="1.0" max="20.0" type="number"
name="product[price]" id="product_price" />
search_field, telephone_field, date_field, datetime_field, datetime_local_field, month_field,
week_field, url_field, email_field, color_field, time_field, range_field

8. Form to an object
http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html

9. Setting up a form to an object
# routes
resources :developers
# controller
def new
@developer = Developer.new
end
# view
<%= form_for @developer do |f| %>
<%= f.text_field :name %><br>
<%= f.text_area :resume %><br>
<%= f.submit %>
<% end %>
<form class="new_developer" id="new_developer" action="/developers"
accept-charset="UTF-8" method="post">
<!-- autenticity_token and utf8 -->
<input type="text" name="developer[name]" id="developer_name" /><br>
<textarea name="developer[resume]" id="developer_resume">
</textarea><br>
<input type="submit" name="commit" value="Create Developer" />
</form>

10. Label
<%= f.label :name %><br>
<%= f.text_field :name %>
<label for="developer_name">Name</label><br>
<input type="text" name="developer[name]" id="developer_name" />

11. Error messages
# model
class Developer < ActiveRecord::Base
validates_presence_of :name
end
# view
<% if @developer.errors.any? %>
<ul>
<% @developer.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
<% end %>
<ul>
<li>Name can't be blank</li>
</ul>

12. Select
http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html

13. Select with array
<%= f.select(:gender, { M: 1, F: 2 },
{ include_blank: 'Choice' }) %>
<select name="developer[gender]" id="developer_gender">
<option value="">Choice</option>
<option selected="selected" value="1">M</option>
<option value="2">F</option>
</select>
<select name="developer[gender]" id="developer_gender">
<option selected="selected" value="1">M</option>
<option value="2">F</option>
</select>
<%= f.select(:gender, M: 1, F: 2) %>

14. Select with collection
<%= f.collection_select(:indication_id,
Developer.all, :id, :name,
{ prompt: 'None' }) %>
<select name="developer[indication_id]" id="
developer_indication_id">
<option value="">None</option>
<option value="1">Linus</option>
<option value="2">Bruno</option>
</select>
<select name="developer[indication_id]" id="
developer_indication_id">
<option value="1">Linus</option>
<option value="2">Bruno</option>
</select>
<%= f.collection_select(:indication_id,
Developer.all, :id, :name) %>

15. Customize fields

16. Select
<%= f.select(
:gender,
{ M: 1, F: 2 },
{ include_blank: 'Choice' },
{
class: 'css-class',
data: { id: 'gender', optional: true }
}
) %>
<select class="css-class" data-id="gender" data-
optional="true" name="developer[gender]" id="
developer_gender">

17. Nested forms
http://guides.rubyonrails.org/form_helpers.html#nested-forms

18. Configure model and controller
# controller
class DevelopersController < ApplicationController
def new
@developer = Developer.new
@developer.addresses.build
end
def developer_params
params.require(:developer).permit(:name, :resume, :
gender,
addresses_attributes: [:id, :name, :street])
end
end
# models
class Address < ActiveRecord::Base
belongs_to :developer
end
class Developer < ActiveRecord::Base
has_many :addresses
accepts_nested_attributes_for :addresses
end

19. Add nested form to view…
<%= form_for @developer do |f| %>
...
<%= f.fields_for :addresses do |addresses_form| %>
<%= addresses_form.text_field :name %>
<%= addresses_form.text_field :street %>
<% end %>
...
<% end %>

20. … renders
<input type="text" value="" name="developer[addresses_attributes][0][name]" id="
developer_addresses_attributes_0_name" />
<input type="text" value="" name="developer[addresses_attributes][0][street]" id="
developer_addresses_attributes_0_street" />
<input type="hidden" value="1" name="developer[addresses_attributes][0][id]" id="
developer_addresses_attributes_0_id" />

21. That's all folks
Bruno Almeida
https://github.com/wwwbruno
https://facebook.com/wwwbruno
https://twitter.com/@wwwbruno
http://www.slideshare.net/wwwbruno
Any questions?