4563b685be
the -position data attribute doesn't really "make sense" when adding the "append" or "prepend" methods. those aren't "positions". I try to be grammatically correct. :)
235 lines
8.1 KiB
Markdown
235 lines
8.1 KiB
Markdown
# cocoon
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[](http://travis-ci.org/nathanvda/cocoon)
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cocoon is a Rails3 gem to allow easier handling of nested forms.
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Nested forms are forms that handle nested models and attributes in one form.
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For example a project with its tasks, an invoice with its ordered items.
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It is formbuilder-agnostic, so it works with standard Rails, or Formtastic or simple_form.
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## Prerequisites
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This gem uses jQuery, it is most useful to use this gem in a rails3
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project where you are already using jQuery.
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Furthermore i would advice you to use either formtastic or simple_form.
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I have a sample project where I demonstrate the use of cocoon with formtastic.
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## Installation
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Inside your `Gemfile` add the following:
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gem "cocoon"
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### Rails 3.1
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Add the following to `application.js` so it compiles to the
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asset_pipeline
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`//= require cocoon`
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### Rails 3.x
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If you are using Rails 3.0.x, you need to run the installation task (since rails 3.1 this is no longer needed):
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rails g cocoon:install
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This will install the needed javascript file.
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Inside your `application.html.haml` you will need to add below the default javascripts:
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= javascript_include_tag :cocoon
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or using erb, you write
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<%= javascript_include_tag :cocoon %>
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That is all you need to do to start using it!
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## Usage
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Suppose you have a model `Project`:
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rails g scaffold Project name:string description:string
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and a project has many `tasks`:
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rails g model Task description:string done:boolean project_id:integer
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Edit the models to code the relation:
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class Project < ActiveRecord::Base
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has_many :tasks
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accepts_nested_attributes_for :tasks
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end
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class Task < ActiveRecord::Base
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belongs_to :project
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end
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What we want to achieve is to get a form where we can add and remove the tasks dynamically.
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What we need for this, is that the fields for a new/existing `task` are defined in a partial
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view called `_task_fields.html`.
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We will show the sample usage with the different possible form-builders.
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### Using formtastic
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Inside our `projects/_form` partial we then write:
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- f.inputs do
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= f.input :name
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= f.input :description
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%h3 Tasks
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#tasks
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= f.semantic_fields_for :tasks do |task|
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= render 'task_fields', :f => task
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.links
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= link_to_add_association 'add task', f, :tasks
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-f.buttons do
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= f.submit 'Save'
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and inside the `_task_fields` partial we write:
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.nested-fields
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= f.inputs do
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= f.input :description
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= f.input :done, :as => :boolean
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= link_to_remove_association "remove task", f
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That is all there is to it!
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There is an example project on github implementing it called [formtastic-cocoon-demo](https://github.com/nathanvda/formtastic_cocoon_demo).
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### Using simple_form
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This is almost identical to formtastic, instead of writing `semantic_fields_for` you write `simple_fields_for`.
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There is an example project on github implementing it called [cocoon_simple_form_demo](https://github.com/nathanvda/cocoon_simple_form_demo).
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### Using standard rails forms
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I will provide a full example (and a sample project) later.
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## How it works
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I define two helper functions:
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### `link_to_add_association`
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This function will add a link to your markup that will, when clicked, dynamically add a new partial form for the given association.
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This should be placed below the `semantic_fields_for`.
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It takes four parameters:
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- name: the text to show in the link
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- f: referring to the containing form-object
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- association: the name of the association (plural) of which a new instance needs to be added (symbol or string).
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- html_options: extra html-options (see `link_to`)
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There are three extra options that allow to control the placement of the new link-data:
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- `data-association-insertion-node` : the jquery selector of the node
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- `data-association-insertion-method` : jquery method that inserts the new data. `before`, `after`, `append`, `prepend`, etc. Default: `before`
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- `data-association-insertion-position` : old method specifying where to insert new data.
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- this setting still works but `data-association-insertion-method` takes precedence. may be removed in a future version.
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Optionally you could also leave out the name and supply a block that is captured to give the name (if you want to do something more complicated).
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### `link_to_remove_association`
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This function will add a link to your markup that will, when clicked, dynamically remove the surrounding partial form.
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This should be placed inside the partial `_<association-object-singular>_fields`.
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It takes three parameters:
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- name: the text to show in the link
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- f: referring to the containing form-object
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- html_options: extra html-options (see `link_to`)
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Optionally you could also leave out the name and supply a block that is captured to give the name (if you want to do something more complicated).
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Inside the `html_options` you can add an option `:render_options`, and the containing hash will be handed down to the form-builder for the inserted
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form. E.g. especially when using `twitter-bootstrap` and `simple_form` together, the `simple_fields_for` needs the option `:wrapper => 'inline'` which can
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be handed down as follows:
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= link_to_add_association 'add something', f, :something, :render_options => {:wrapper => 'inline' }
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### Callbacks (upon insert and remove of items)
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There is an option to add a callback on insertion or removal. If in your view you have the following snippet to select an `owner`
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(we use slim for demonstration purposes)
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#owner
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#owner_from_list
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= f.association :owner, :collection => Person.all(:order => 'name'), :prompt => 'Choose an existing owner'
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= link_to_add_association 'add a new person as owner', f, :owner
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This view part will either let you select an owner from the list of persons, or show the fields to add a new person as owner.
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The callbacks can be added as follows:
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$(document).ready(function() {
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$('#owner').bind('insertion-callback',
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function() {
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$("#owner_from_list").hide();
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$("#owner a.add_fields").hide();
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});
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$('#owner').bind("removal-callback",
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function() {
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$("#owner_from_list").show();
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$("#owner a.add_fields").show();
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});
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});
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Do note that for the callbacks to work there has to be a surrounding container (div), where you can bind the callbacks to.
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### Control the Insertion behaviour
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The default insertion location is at the back of the current container. But we have added two `data`-attributes that are read to determine the insertion-node and -method.
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For example:
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$(document).ready(function() {
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$("#owner a.add_fields").
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data("association-insertion-method", 'before').
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data("association-insertion-node", 'this');
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});
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The `association-insertion-node` will determine where to add it. You can choose any selector here, or specify this (default it is the parent-container).
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The `association-insertion-method` will determine where to add it in relation with the node. Any jQuery DOM Manipulation method can be set but we recommend sticking to any of the following: `before`, `after`, `append`, `prepend`. It is unknown at this time what others would do.
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### Partial
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The partial should be named `_<association-object_singular>_fields`, and should start with a container (e.g. `div`) of class `.nested-fields`.
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There is no limit to the amount of nesting, though.
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## Note on Patches/Pull Requests
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* Fork the project.
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* Make your feature addition or bug fix.
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* Add tests for it. This is important so I don't break it in a
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future version unintentionally.
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* Commit, do not mess with rakefile, version, or history.
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(if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
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* Send me a pull request. Bonus points for topic branches.
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## Todo
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* add more sample relations: `has_many :through`, `belongs_to`, ...
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* improve the tests (test the javascript too)(if anybody wants to lend a hand ...?)
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## Copyright
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Copyright (c) 2010 Nathan Van der Auwera. See LICENSE for details.
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