# Asset Helpers

Asset helpers are intended to help insert useful html onto a view template such
as 'flash' notices, hyperlinks, mail\_to links, images, stylesheets and
javascript. An example of their uses would be on a simple view template:


```haml
# app/views/example.haml
...
%head
  = stylesheet_link_tag 'layout'
  = javascript_include_tag 'application'
  = favicon_tag 'images/favicon.png'
%body
  ...
  = flash_tag :notice
  %p= link_to 'Blog', '/blog', class: 'example'
  %p Mail me at #{mail_to 'fake@faker.com', 'Fake Email Link', cc: "test@demo.com"}
  %p= image_tag 'padrino.png', width: '35', class: 'logo'
```

By default, all 'assets' including images, scripts, and stylesheets have a
timestamp appended at the end to clear the stale cache for the item when
modified. To disable this, simply put the setting `disable :asset_stamp` in your
application configuration within `app/app.rb`.

`link_to` writes `#` instead of a URL whose scheme isn't http, https, mailto,
tel or ftp, so `javascript:`, `data:` and `vbscript:` links can't run script.
This also applies to a URL given in the options hash (`href:`), and to other
schemes such as `sms:`; write those links as plain `<a>` tags. Relative links
are kept, even with a colon in them (`search?q=a:b`). `form_tag`, `form_for`
and `button_to` do the same for the form's action.

## List of Asset Helpers

- `flash_tag(kind, options = {})`
  - Creates a div to display the flash of given type if it exists
  - `flash_tag(:notice, class: 'flash', id: 'flash-notice')`
- `link_to(*args, &block)`
  - Creates a link element with given name, url and options
  - `link_to 'click me', '/dashboard', class: 'linky'`
  - `link_to 'click me', '/dashboard', class: 'linky', if: @foo.present?`
  - `link_to 'click me', '/dashboard', class: 'linky', unless:
    @foo.blank?`
  - `link_to 'click me', '/dashboard', class: 'linky', unless: :current`
  - `link_to('/dashboard', class: 'blocky') { ...content... }`
- `mail_to(email, caption = nil, mail_options = {})`
  - Creates a mailto link tag to the given email address
  - `mail_to 'me@demo.com'`
  - `mail_to 'me@demo.com', 'My Email', subject: 'Feedback', cc:
    'test@demo.com'`
- `image_tag(url, options = {})`
  - Creates an image element with given url and options
  - `image_tag('icons/avatar.png')`
- `stylesheet_link_tag(*sources)`
  - Returns a stylesheet link tag for the sources specified as arguments
  - `stylesheet_link_tag 'style', 'application', 'layout'`
- `javascript_include_tag(*sources)`
  - Returns an html script tag for each of the sources provided.
  - `javascript_include_tag 'application', 'special'`
- `favicon_tag(source, options = {})`
  - Returns a favicon tag for the header for the source specified.
  - `favicon_tag 'images/favicon.ico', type: 'image/ico'`
- `feed_tag(mime, source, options = {})`
  - Returns a feed tag for the mime and source specified
  - `feed_tag :atom, url(:blog, :posts, format: :atom), title: 'ATOM'`