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Form Helpers Cheatsheet

Create forms, check boxes, radio buttons, select lists and more using Rails' built-in form helpers.

Example - controller, view, HTML and params[]
fields_for - creates a scope around fields
Multipart form - model and view of multipart form
Input field helpers - check boxes, text fields, radio buttons
RESTful form_for - using form_for in a RESTful context
form_for - wrap ActiveRecord model objects in a form
Parsing form data - how Rails parses incoming form data

View all on one page

Example

Controller

    def new
      @customer = Customer.new
      3.times do 
        @customer.addresses.build   
      end
    end

View

    <% form_for(@customer) do |f| %>
      <%= f.text_field :name %>
      <%= f.text_field :email %>
      <% @customer.addresses.each do |address| %>
        <% fields_for "customer[addresses][]", address do |fields| %>
          <%= fields.text_field :number %>
          <%= fields.text_field :street %>
      <% end %>
    <% end %>

HTML

    <form id="new_customer" class="new_customer" method="post" action="/customers">
    <input type="text" size="30" name="customer[name]"/>
    <input type="text" size="30" name="customer[email]"/>
    <input type="text" size="30" name="customer[addresses][][number]"/>
    <input type="text" size="30" name="customer[addresses][][street]"/>
    <input type="text" size="30" name="customer[addresses][][number]"/>
    <input type="text" size="30" name="customer[addresses][][street]"/>
    <input type="text" size="30" name="customer[addresses][][number]"/>
    <input type="text" size="30" name="customer[addresses][][street]"/>
    <input type="submit" value="Create" name="commit"/>
    </form>

params[]

    params = {
      "customer" => { "name"=>"David Pettifer",
                      "email"=>"david.p@dizzy.co.uk",
                      "addresses"=> [
                        { "number"=>"31", "street"=>"High" },
                        { "number"=>"22", "street"=>"Brook" },
                        { "number"=>"16", "street"=>"Kents" }  ]
                   } }

Quickly debugging form helpers

Sometimes you want to quickly see the output of helper methods, and constantly clicking refresh in your browser then viewing the page source can be tiresome. Instead, use the Rails console to check helpers are doing what you want them to. More