Forms made easy (for Rails)!
SimpleForm aims to be as flexible as possible while helping you with powerful components to create your forms. The basic goal of simple form is to not touch your way of defining the layout, letting you find the better design for your eyes. Good part of the DSL was inherited from Formtastic, which we are thankful for and should make you feel right at home.
Install the gem:
gem install simple_form
Add it to your Gemfile:
gem "simple_form"
Run the generator:
rails generate simple_form:install
And you are ready to go. Since this branch aims Rails 3 support, if you want to use it with Rails 2.3 you should check this branch:
http://github.com/plataformatec/simple_form/tree/v1.0
SimpleForm was designed to be customized as you need to. Basically it’s a stack of components that are invoked to create a complete html input for you, which by default contains label, hints, errors and the input itself. It does not aim to create a lot of different logic from the default Rails form helpers, as they do a great work by themselves. Instead, SimpleForm acts as a DSL and just maps your input type (retrieved from the column definition in the database) to an specific helper method.
To start using SimpleForm you just have to use the helper it provides:
<%= simple_form_for @user do |f| %> <%= f.input :username %> <%= f.input :password %> <%= f.button :submit %> <% end %>
This will generate an entire form with labels for user name and password as well, and render errors by default when you render the form with invalid data (after submitting for example).
You can overwrite the default label by passing it to the input method, or even add a hint:
<%= simple_form_for @user do |f| %> <%= f.input :username, :label => 'Your username please' %> <%= f.input :password, :hint => 'No special characters.' %> <%= f.button :submit %> <% end %>
You can also disable labels, hints or error or configure the html of any of them:
<%= simple_form_for @user do |f| %>
<%= f.input :username, :label_html => { :class => 'my_class' } %>
<%= f.input :password, :hint => false, :error_html => { :id => "password_error"} %>
<%= f.input :password_confirmation, :label => false %>
<%= f.button :submit %>
<% end %>
By default all inputs are required, which means an * is prepended to the label, but you can disable it in any input you want:
<%= simple_form_for @user do |f| %> <%= f.input :name, :required => false %> <%= f.input :username %> <%= f.input :password %> <%= f.button :submit %> <% end %>
SimpleForm also lets you overwrite the default input type it creates:
<%= simple_form_for @user do |f| %> <%= f.input :username %> <%= f.input :password %> <%= f.input :description, :as => :text %> <%= f.input :accepts, :as => :radio %> <%= f.button :submit %> <% end %>
So instead of a checkbox for the :accepts attribute, you’ll have a pair of radio buttons with yes/no labels and a text area instead of a text field for the description. You can also render boolean attributes using :as => :select to show a dropdown.
SimpleForm also allows you using label, hint and error helpers it provides:
<%= simple_form_for @user do |f| %> <%= f.label :username %> <%= f.text_field :username %> <%= f.error :username, :id => 'user_name_error' %> <%= f.hint 'No special characters, please!' %> <%= f.submit 'Save' %> <% end %>
Any extra option passed to label, hint or error will be rendered as html option.
And what if you want to create a select containing the age from 18 to 60 in your form? You can do it overriding the :collection option:
<%= simple_form_for @user do |f| %> <%= f.input :user %> <%= f.input :age, :collection => 18..60 %> <%= f.button :submit %> <% end %>
Collections can be arrays or ranges, and when a :collection is given the :select input will be rendered by default, so we don’t need to pass the :as => :select option. Other types of collection are :radio and :check_boxes. Those are added by SimpleForm to Rails set of form helpers (read Extra Helpers session below for more information).
Collection inputs accepts two other options beside collections:
-
label_method => the label method to be applied to the collection to retrieve the label
-
value_method => the value method to be applied to the collection to retrieve the value
Those methods are useful to manipulate the given collection. All other options given are sent straight to the underlying helper. For example, you can give prompt as:
f.input :age, :collection => 18..60, :prompt => "Select your age"
SimpleForm also supports :time_zone and :country. When using such helpers, you can give :priority as option to select which time zones and/or countries should be given higher priority:
f.input :residence_country, :priority => [ "Brazil" ] f.input :time_zone, :priority => /US/
Those values can also be configured with a default value to be used site use through the SimpleForm.country_priority and SimpleForm.time_zone_priority helpers.
SimpleForm allows you to add a wrapper which contains the label, error, hint and input. The first step is to configure a wrapper tag:
SimpleForm.wrapper_tag = :p
And now, you don’t need to wrap your f.input calls anymore:
<%= simple_form_for @user do |f| %> <%= f.input :username %> <%= f.input :password %> <%= f.button :submit %> <% end %>
To deal with associations, SimpleForm can generate select inputs, a series of radios or check boxes. Lets see how it works: imagine you have a user model that belongs to a company and has_and_belongs_to_many roles. The structure would be something like:
class User < ActiveRecord::Base belongs_to :company has_and_belongs_to_many :roles end class Company < ActiveRecord::Base has_many :users end class Role < ActiveRecord::Base has_and_belongs_to_many :users end
Now we have the user form:
<%= simple_form_for @user do |f| %> <%= f.input :name %> <%= f.association :company %> <%= f.association :roles %> <%= f.button :submit %> <% end %>
Simple enough right? This is going to render a :select input for choosing the :company, and another :select input with :multiple option for the :roles. You can of course change it, to use radios and check boxes as well:
f.association :company, :as => :radio f.association :roles, :as => :check_boxes
The association helper just invokes input under the hood, so all options available to :select, :radio and :check_boxes are also available to association. Additionally, you can specify the collection by hand, all together with the prompt:
f.association :company, :collection => Company.active.all(:order => 'name'), :prompt => "Choose a Company"
All web forms need buttons, right? SimpleForm wraps them in the DSL, acting like a proxy:
<%= simple_form_for @user do |f| %> <%= f.input :name %> <%= f.button :submit %> <% end %>
The above will simply call submit. You choose to use it or not, it’s just a question of taste.
SimpleForm also comes with some extra helpers you can use inside rails default forms without relying on simple_form_for helper. They are listed below.
Wrapper to use simple form inside a default rails form
form_for @user do |f| f.simple_fields_for :posts do |posts_form| # Here you have all simple_form methods available posts_form.input :title end end
Creates a collection of radio inputs with labels associated (same API as collection_select):
form_for @user do |f| f.collection_radio :options, [[true, 'Yes'] ,[false, 'No']], :first, :last end <input id="user_options_true" name="user[options]" type="radio" value="true" /> <label class="collection_radio" for="user_options_true">Yes</label> <input id="user_options_false" name="user[options]" type="radio" value="false" /> <label class="collection_radio" for="user_options_false">No</label>
Creates a collection of check boxes with labels associated (same API as collection_select):
form_for @user do |f| f.collection_check_box :options, [[true, 'Yes'] ,[false, 'No']], :first, :last end <input name="user[options][]" type="hidden" value="" /> <input id="user_options_true" name="user[options][]" type="checkbox" value="true" /> <label class="collection_check_box" for="user_options_true">Yes</label> <input name="user[options][]" type="hidden" value="" /> <input id="user_options_false" name="user[options][]" type="checkbox" value="false" /> <label class="collection_check_box" for="user_options_false">No</label>
SimpleForm comes with a lot of default mappings:
Mapping Input Column Type boolean check box boolean string text field string email email field string with name matching "email" url url field string with name matching "url" password password field string with name matching "password" text text area text file file field string, responding to file methods hidden hidden field - integer number field integer float number field float decimal number field decimal datetime datetime select datetime/timestamp date date select date time time select time select collection select belongs_to/has_many/has_and_belongs_to_many associations radio collection radio belongs_to check_boxes collection check box has_many/has_and_belongs_to_many associations country country select string with name matching "country" time_zone time zone select string with name matching "time_zone"
SimpleForm uses all power of I18n API to lookup labels and hints for you. To customize your forms you can create a locale file like this:
en:
simple_form:
labels:
user:
username: 'User name'
password: 'Password'
hints:
user:
username: 'User name to sign in.'
password: 'No special characters, please.'
And your forms will use this information to render labels and hints for you.
SimpleForm also lets you be more specific, separating lookups through actions for both hint and label. Let’s say you want a different label for new and edit actions, the locale file would be something like:
en:
simple_form:
labels:
user:
username: 'User name'
password: 'Password'
edit:
username: 'Change user name'
password: 'Change password'
This way SimpleForm will figure out the right translation for you, based on the action being rendered. And to be a little bit DRYer with your locale file, you can skip the model information inside it:
en:
simple_form:
labels:
username: 'User name'
password: 'Password'
hints:
username: 'User name to sign in.'
password: 'No special characters, please.'
SimpleForm will always look for a default attribute translation if no specific is found inside the model key. In addition, SimpleForm will fallback to default human_attribute_name from Rails when no other translation is found.
Finally, you can also overwrite labels and hints inside your view, just by passing the label/hint manually. This way the I18n lookup will be skipped.
There are other options that can be configured through I18n API, such as required text, boolean and button texts. Be sure to check our locale file or the one copied to your application after you run “rails generate simple_form:install”.
SimpleForm has several configuration values. You can read and change them in the initializer created by SimpleForm, so if you haven’t executed the command below yet, please do:
rails generate simple_form:install
Please refer to TODO file.
-
José Valim (github.com/josevalim)
-
Carlos Antonio da Silva (github.com/carlosantoniodasilva)
If you discover any bugs or want to drop a line, feel free to create an issue on GitHub.
github.com/plataformatec/simple_form/issues
MIT License. Copyright 2010 Plataforma Tecnologia. blog.plataformatec.com.br