Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Browse files

second pass to the intro rdoc of form_helper.rb

  • Loading branch information...
commit 9111f4268b1700bc061dcf82436484089dd8a9ba 1 parent 6d29f97
@fxn fxn authored
Showing with 55 additions and 13 deletions.
  1. +55 −13 actionpack/lib/action_view/helpers/form_helper.rb
View
68 actionpack/lib/action_view/helpers/form_helper.rb
@@ -11,21 +11,25 @@ module Helpers
# Form helpers are designed to make working with resources much easier
# compared to using vanilla HTML.
#
- # Model-based forms are created with +form_for+. That method yields a form
+ # Forms for models are created with +form_for+. That method yields a form
# builder that knows the model the form is about. The form builder is thus
# able to generate default values for input fields that correspond to model
- # attributes, and also convenient element names, IDs, endpoints, etc.
+ # attributes, and also convenient names, IDs, endpoints, etc.
#
# Conventions in the generated field names allow controllers to receive form
# data nicely structured in +params+ with no effort on your side.
#
- # For example, to create a new +Person+ resource you typically set up a new
- # instance in <tt>PeopleController#new</tt> action, <tt>@person</tt>, and
- # write the form in <tt>new.html.erb</tt> this way:
+ # For example, to create a new person you typically set up a new instance of
+ # +Person+ in the <tt>PeopleController#new</tt> action, <tt>@person</tt>, and
+ # pass it to +form_for+:
#
# <%= form_for @person do |f| %>
- # <%= f.text_field :first_name %>
- # <%= f.text_field :last_name %>
+ # <%= f.label :first_name %>:
+ # <%= f.text_field :first_name %><br />
+ #
+ # <%= f.label :last_name %>:
+ # <%= f.text_field :last_name %><br />
+ #
# <%= f.submit %>
# <% end %>
#
@@ -35,16 +39,54 @@ module Helpers
# <div style="margin:0;padding:0;display:inline">
# <input name="authenticity_token" type="hidden" value="NrOp5bsjoLRuK8IW5+dQEYjKGUJDe7TQoZVvq95Wteg=" />
# </div>
- # <input id="person_first_name" name="person[first_name]" size="30" type="text" />
- # <input id="person_last_name" name="person[last_name]" size="30" type="text" />
+ # <label for="person_first_name">First name</label>:
+ # <input id="person_first_name" name="person[first_name]" size="30" type="text" /><br />
+ #
+ # <label for="person_last_name">Last name</label>:
+ # <input id="person_last_name" name="person[last_name]" size="30" type="text" /><br />
+ #
# <input id="person_submit" name="commit" type="submit" value="Create Person" />
# </form>
#
- # Because of the names of the input fields, the controller gets a <tt>:person</tt>
- # nested hash in +params+ with the corresponding first and last names. That hash
- # is ready to be passed to <tt>Person.create</tt> like this:
+ # As you see, the HTML reflects knowledge about the resource in several spots,
+ # like the path the form should be submitted to, or the names of the input fields.
+ #
+ # In particular, thanks to the conventions followed in the generated field names, the
+ # controller gets a nested hash <tt>params[:person]</tt> with the person attributes
+ # set in the form. That hash is ready to be passed to <tt>Person.create</tt>:
+ #
+ # if @person = Person.create(params[:person])
+ # # success
+ # else
+ # # error handling
+ # end
+ #
+ # Interestingly, the exact same view code in the previous example can be used to edit
+ # a person. If <tt>@person</tt> is an existing record with name "John Smith" and ID 256,
+ # the code above as is would yield instead:
+ #
+ # <form action="/people/256" class="edit_person" id="edit_person_1" method="post">
+ # <div style="margin:0;padding:0;display:inline">
+ # <input name="_method" type="hidden" value="put" />
+ # <input name="authenticity_token" type="hidden" value="NrOp5bsjoLRuK8IW5+dQEYjKGUJDe7TQoZVvq95Wteg=" />
+ # </div>
+ # <label for="person_first_name">First name</label>:
+ # <input id="person_first_name" name="person[first_name]" size="30" type="text" value="John" /><br />
+ #
+ # <label for="person_last_name">Last name</label>:
+ # <input id="person_last_name" name="person[last_name]" size="30" type="text" value="Smith" /><br />
+ #
+ # <input id="person_submit" name="commit" type="submit" value="Update Person" />
+ # </form>
+ #
+ # Note that the endpoint, default values, and submit button label are tailored for <tt>@person</tt>.
+ # That works that way because the involved helpers know whether the resource is a new record or not,
+ # and generate HTML accordingly.
+ #
+ # The controller would receive the form data again in <tt>params[:person]</tt>, ready to be
+ # passed to <tt>Person#update_attributes</tt>:
#
- # if person = Person.create(params[:person])
+ # if @person.update_attributes(params[:person])
# # success
# else
# # error handling
Please sign in to comment.
Something went wrong with that request. Please try again.