⚠️ This documentation is for the master branch, which is not yet stable and targets Bemo v4. If you are using Bemo v3, refer to the stable legacy-2.7 branch.

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bemo_form

bemo_form is a Rails form builder that makes it super easy to integrate Bemo v4-style forms into your Rails application.

Requirements

• Ruby 2.2.2+
• Rails 5.0+ (Rails 5.1+ for bemo_form_with)
• Bemo 4.0.0+

Installation

Add it to your Gemfile:

gem "bemo_form",
    git: "https://github.com/bemo-ruby/bemo_form.git",
    branch: "master"

Then:

bundle

Then require the CSS in your application.css file:

/*
 *= require rails_bemo_forms
 */

Usage

To get started, just use the bemo_form_for helper. Here's an example:

<%= bemo_form_for(@user) do |f| %>
  <%= f.email_field :email %>
  <%= f.password_field :password %>
  <%= f.check_box :remember_me %>
  <%= f.submit "Log In" %>
<% end %>

This generates the following HTML:

<form accept-charset="UTF-8" action="/users" class="new_user" id="new_user" method="post">
  <div class="form-group">
    <label for="user_email">Email</label>
    <input class="form-control" id="user_email" name="user[email]" type="email">
  </div>
  <div class="form-group">
    <label for="user_password">Password</label>
    <input class="form-control" id="user_password" name="user[password]" type="password">
  </div>
  <div class="form-check">
    <input name="user[remember_me]" type="hidden" value="0">
    <input class="form-check-input" id="user_remember_me" name="user[remember_me]" type="checkbox" value="1">
    <label class="form-check-label" for="user_remember_me">Remember me</label>
  </div>
  <input class="btn btn-secondary" name="commit" type="submit" value="Log In">
</form>

bemo_form_tag

If your form is not backed by a model, use the bemo_form_tag. Usage of this helper is the same as bemo_form_for, except no model object is passed in as the first argument. Here's an example:

<%= bemo_form_tag url: '/subscribe' do |f| %>
  <%= f.email_field :email, value: '[email protected]' %>
  <%= f.submit %>
<% end %>

bemo_form_with (Rails 5.1+)

Note that form_with in Rails 5.1 does not add IDs to form elements and labels by default, which are both important to Bemo markup. This behavior is corrected in Rails 5.2.

To get started, just use the bemo_form_with helper in place of form_with. Here's an example:

<%= bemo_form_with(model: @user, local: true) do |f| %>
  <%= f.email_field :email %>
  <%= f.password_field :password %>
  <%= f.check_box :remember_me %>
  <%= f.submit "Log In" %>
<% end %>

This generates:

<form role="form" action="/users" accept-charset="UTF-8" method="post">
  <input name="utf8" type="hidden" value="&#x2713;" />
  <div class="form-group">
    <label class="required" for="user_email">Email</label>
    <input class="form-control" type="email" value="[email protected]" name="user[email]" />
  </div>
  <div class="form-group">
    <label for="user_password">Password</label>
    <input class="form-control" type="password" name="user[password]" />
    <small class="form-text text-muted">A good password should be at least six characters long</small>
  </div>
  <div class="form-check">
    <input name="user[remember_me]" type="hidden" value="0">
    <input class="form-check-input" id="user_remember_me" name="user[remember_me]" type="checkbox" value="1">
    <label class="form-check-label" for="user_remember_me">Remember me</label>
  </div>
  <input type="submit" name="commit" value="Log In" class="btn btn-secondary" data-disable-with="Log In" />
</form>

bemo_form_with supports both the model: and url: use cases in form_with.

form_with has some important differences compared to form_for and form_tag, and these differences apply to bemo_form_with. A good summary of the differences can be found at: https://m.patrikonrails.com/rails-5-1s-form-with-vs-old-form-helpers-3a5f72a8c78a, or in the Rails documentation.

Future Compatibility

The Rails team has suggested that form_for and form_tag may be deprecated and then removed in future versions of Rails. bemo_form will continue to support bemo_form_for and bemo_form_tag as long as Rails supports form_for and form_tag.

Form Helpers

This gem wraps the following Rails form helpers:

• check_box
• collection_check_boxes
• collection_select
• color_field
• date_field
• date_select
• datetime_field
• datetime_local_field
• datetime_select
• email_field
• file_field
• grouped_collection_select
• hidden_field (not wrapped, but supported)
• month_field
• number_field
• password_field
• phone_field
• radio_button
• collection_radio_buttons
• range_field
• search_field
• select
• telephone_field
• text_area
• text_field
• time_field
• time_select
• time_zone_select
• url_field
• week_field

These helpers accept the same options as the standard Rails form helpers, with a few extra options:

Labels

Use the label option if you want to specify the field's label text:

<%= f.password_field :password_confirmation, label: "Confirm Password" %>

To hide a label, use the hide_label: true option. This adds the sr-only class, which keeps your labels accessible to those using screen readers.

<%= f.text_area :comment, hide_label: true, placeholder: "Leave a comment..." %>

To add custom classes to the field's label:

<%= f.text_field :email, label_class: "custom-class" %>

Or you can add the label as input placeholder instead (this automatically hides the label):

<%= f.text_field :email, label_as_placeholder: true %>

Required Fields

A label that is associated with a required field is automatically annotated with a required CSS class. You are free to add any appropriate CSS to style required fields as desired. One example would be to automatically add an asterisk to the end of the label:

label.required:after {
  content:" *";
}

The label required class is determined based on the definition of a presence validator with the associated model attribute. Presently this is one of: ActiveRecord::Validations::PresenceValidator or ActiveModel::Validations::PresenceValidator.

In cases where this behavior is undesirable, use the skip_required option:

<%= f.password_field :password, label: "New Password", skip_required: true %>

Input Elements / Controls

To specify the class of the generated input tag, use the control_class option:

<%= f.text_field :email, control_class: "custom-class" %>

Help Text

To add help text, use the help option:

<%= f.password_field :password, help: "Must be at least 6 characters long" %>

This gem is also aware of help messages in locale translation files (i18n):

en:
  activerecord:
    help:
      user:
        password: "A good password should be at least six characters long"

Help translations containing HTML should follow the convention of appending _html to the name:

en:
  activerecord:
    help:
      user:
        password_html: "A <strong>good</strong> password should be at least six characters long"

If your model name has multiple words (like SuperUser), the key on the translation file should be underscored (super_user).

You can override help translations for a particular field by passing the help option or turn them off completely by passing help: false.

Prepending and Appending Inputs

You can pass prepend and/or append options to input fields:

<%= f.text_field :price, prepend: "$", append: ".00" %>

You can also prepend and append buttons. Note: The buttons must contain the btn class to generate the correct markup.

<%= f.text_field :search, append: link_to("Go", "#", class: "btn btn-secondary") %>

To add a class to the input group wrapper, use the :input_group_class option.

<%= f.email_field :email, append: f.primary('Subscribe'), input_group_class: 'input-group-lg' %>

Additional Form Group Attributes

If you want to add an additional css class or any other attribute to the form group div, you can use the wrapper: { class: 'additional-class', data: { foo: 'bar' } } option.

<%= f.text_field :name, wrapper: { class: 'has-warning', data: { foo: 'bar' } } %>

Which produces the following output:

<div class="form-group has-warning" data-foo="bar">
  <label class="form-control-label" for="user_name">Id</label>
  <input class="form-control" id="user_name" name="user[name]" type="text">
</div>

You still can use wrapper_class option to set only a css class. This is just a short form of wrapper: { class: 'additional-class' }.

Selects

Our select helper accepts the same arguments as the default Rails helper. Here's an example of how you pass both options and html_options hashes:

<%= f.select :product, [["Apple", 1], ["Grape", 2]], { label: "Choose your favorite fruit:" }, { class: "selectpicker",  wrapper: { class: 'has-warning', data: { foo: 'bar' } } } %>

Checkboxes and Radios

Checkboxes and radios should be placed inside of a form_group to render properly. The following example ensures that the entire form group will display an error if an associated validations fails:

<%= f.form_group :skill_level, label: { text: "Skill" }, help: "Optional Help Text" do %>
  <%= f.radio_button :skill_level, 0, label: "Novice", checked: true %>
  <%= f.radio_button :skill_level, 1, label: "Intermediate" %>
  <%= f.radio_button :skill_level, 2, label: "Advanced" %>
<% end %>

<%= f.form_group :terms do %>
  <%= f.check_box :terms, label: "I agree to the Terms of Service" %>
<% end %>

You can also create a checkbox using a block:

<%= f.form_group :terms, label: { text: "Optional Label" } do %>
  <%= f.check_box :terms do %>
    You need to check this box to accept our terms of service and privacy policy
  <% end %>
<% end %>

To display checkboxes and radios inline, pass the inline: true option:

<%= f.form_group :skill_level, label: { text: "Skill" } do %>
  <%= f.radio_button :skill_level, 0, label: "Novice", inline: true %>
  <%= f.radio_button :skill_level, 1, label: "Intermediate", inline: true %>
  <%= f.radio_button :skill_level, 2, label: "Advanced", inline: true %>
<% end %>

Collections

bemo_form also provides helpers that automatically creates the form_group and the radio_buttons or check_boxes for you:

<%= f.collection_radio_buttons :skill_level, Skill.all, :id, :name %>
<%= f.collection_check_boxes :skills, Skill.all, :id, :name %>

Collection methods accept these options:

• :label: Customize the form_group's label
• :hide_label: Pass true to hide the form_group's label
• :help: Add a help span to the form_group
• Other options will be forwarded to the radio_button/check_box method

Static Controls

You can create a static control like this:

<%= f.static_control :email %>

Here's the output for a horizontal layout:

<div class="form-group">
  <label class="col-sm-2 form-control-label" for="user_email">Email</label>
  <div class="col-sm-10">
    <input class="form-control-plaintext" id="user_email" name="user[email]" readonly="readonly" type="text" value="[email protected]"/>
  </div>
</div>

You can also create a static control that isn't based on a model attribute:

<%= f.static_control label: "Custom Static Control" do %>
  Content Here
<% end %>

Date Helpers

The multiple selects that the date and time helpers (date_select, time_select, datetime_select) generate are wrapped inside a div.rails-bemo-forms-[date|time|datetime]-select tag. This is because Bemo automatically styles our controls as blocks. This wrapper fixes this defining these selects as inline-block and a width of auto.

Submit Buttons

The btn btn-secondary css classes are automatically added to your submit buttons.

<%= f.submit %>

You can also use the primary helper, which adds btn btn-primary to your submit button:

<%= f.primary "Optional Label" %>

You can specify your own classes like this:

<%= f.submit "Log In", class: "btn btn-success" %>

Accessing Rails Form Helpers

If you want to use the original Rails form helpers for a particular field, append _without_bemo to the helper:

<%= f.text_field_without_bemo :email %>

Form Styles

By default, your forms will stack labels on top of controls and your controls will grow to 100% of the available width.

Inline Forms

To use an inline-layout form, use the layout: :inline option. To hide labels, use the hide_label: true option, which keeps your labels accessible to those using screen readers.

<%= bemo_form_for(@user, layout: :inline) do |f| %>
  <%= f.email_field :email, hide_label: true %>
  <%= f.password_field :password, hide_label: true %>
  <%= f.check_box :remember_me %>
  <%= f.submit %>
<% end %>

To skip label rendering at all, use skip_label: true option.

<%= f.password_field :password, skip_label: true %>

Horizontal Forms

To use a horizontal-layout form with labels to the left of the control, use the layout: :horizontal option. You should specify both label_col and control_col css classes as well (they default to col-sm-2 and col-sm-10).

In the example below, the checkbox and submit button have been wrapped in a form_group to keep them properly aligned.

<%= bemo_form_for(@user, layout: :horizontal, label_col: "col-sm-2", control_col: "col-sm-10") do |f| %>
  <%= f.email_field :email %>
  <%= f.password_field :password %>
  <%= f.form_group do %>
    <%= f.check_box :remember_me %>
  <% end %>
  <%= f.form_group do %>
    <%= f.submit %>
  <% end %>
<% end %>

The label_col and control_col css classes can also be changed per control:

<%= bemo_form_for(@user, layout: :horizontal) do |f| %>
  <%= f.email_field :email %>
  <%= f.text_field :age, control_col: "col-sm-3" %>
  <%= f.form_group do %>
    <%= f.submit %>
  <% end %>
<% end %>

Custom Field Layout

The form-level layout can be overridden per field, unless the form-level layout was inline:

<%= bemo_form_for(@user, layout: :horizontal) do |f| %>
  <%= f.email_field :email %>
  <%= f.text_field :feet, layout: :default %>
  <%= f.text_field :inches, layout: :default %>
  <%= f.form_group do %>
    <%= f.submit %>
  <% end %>
<% end %>

A form-level layout: :inline can't be overridden because of the way Bemo 4 implements in-line layouts. One possible work-around is to leave the form-level layout as default, and specify the individual fields as layout: :inline, except for the fields(s) that should be other than in-line.

Custom Form Element Styles

The custom option can be used to replace the browser default styles for check boxes and radio buttons with dedicated Bemo styled form elements. Here's an example:

<%= bemo_form_for(@user) do |f| %>
  <%= f.email_field :email %>
  <%= f.password_field :password %>
  <%= f.check_box :remember_me, custom: true %>
  <%= f.submit "Log In" %>
<% end %>

Validation and Errors

Inline Errors

By default, fields that have validation errors will be outlined in red and the error will be displayed below the field. Rails normally wraps the fields in a div (field_with_errors), but this behavior is suppressed. Here's an example:

<div class="form-group">
  <label class="form-control-label" for="user_email">Email</label>
  <input class="form-control is-invalid" id="user_email" name="user[email]" type="email" value="">
  <small class="invalid-feedback">can't be blank</small>
</div>

You can turn off inline errors for the entire form like this:

<%= bemo_form_for(@user, inline_errors: false) do |f| %>
  ...
<% end %>

Label Errors

You can also display validation errors in the field's label; just turn on the :label_errors option. Here's an example:

<%= bemo_form_for(@user, label_errors: true) do |f| %>
  ...
<% end %>

By default, turning on :label_errors will also turn off :inline_errors. If you want both turned on, you can do that too:

<%= bemo_form_for(@user, label_errors: true, inline_errors: true) do |f| %>
  ...
<% end %>

Alert Messages

To display an error message with an error summary, you can use the alert_message helper. This won't output anything unless a model validation has failed.

<%= f.alert_message "Please fix the errors below." %>

Which outputs:

<div class="alert alert-danger">
  <p>Please fix the errors below.</p>
  <ul class="rails-bemo-forms-error-summary">
    <li>Email can't be blank</li>
  </ul>
</div>

You can turn off the error summary like this:

<%= f.alert_message "Please fix the errors below.", error_summary: false %>

To output a simple unordered list of errors, use the error_summary helper.

<%= f.error_summary %>

Which outputs:

<ul class="rails-bemo-forms-error-summary">
  <li>Email can't be blank</li>
</ul>

Errors On

If you want to display a custom inline error for a specific attribute not represented by a form field, use the errors_on helper.

<%= f.errors_on :tasks %>

Which outputs:

<div class="alert alert-danger">Tasks can't be blank.</div>

You can hide the attribute name like this:

<%= f.errors_on :tasks, hide_attribute_name: true %>

Which outputs:

<div class="alert alert-danger">can't be blank.</div>

Internationalization

bemo_form follows standard rails conventions so it's i18n-ready. See more here: http://guides.rubyonrails.org/i18n.html#translations-for-active-record-models

Code Triage page

http://www.codetriage.com/potenza/bemo_form

Contributing

We welcome contributions. If you're considering contributing to bemo_form, please review the Contributing document first.

License

MIT License. Copyright 2012-2018 Stephen Potenza (https://github.com/potenza)