render

Renders a template and returns the result.

Pass the template to render as the first argument. This is shorthand syntax for partial rendering, so the template filename should be prefixed with an underscore. The partial renderer looks for the partial template in the directory of the calling template first.

<% # app/views/posts/new.html.erb %>
<%= render "form" %>
# => renders app/views/posts/_form.html.erb

Use the complete view path to render a partial from another directory.

<% # app/views/posts/show.html.erb %>
<%= render "comments/form" %>
# => renders app/views/comments/_form.html.erb

Without the rendering mode, the second argument can be a Hash of local variable assignments for the template.

<% # app/views/posts/new.html.erb %>
<%= render "form", post: Post.new %>
# => renders app/views/posts/_form.html.erb

If the first argument responds to `render_in`, the template will be rendered by calling `render_in` with the current view context.

class Greeting
  def render_in(view_context)
    view_context.render html: "<h1>Hello, World</h1>"
  end

  def format
    :html
  end
end

<%= render Greeting.new %>
# => "<h1>Hello, World</h1>"

#### Rendering Mode

Pass the rendering mode as first argument to override it.

`:partial` : See ActionView::PartialRenderer for details.

<%= render partial: "form", locals: { post: Post.new } %>
# => renders app/views/posts/_form.html.erb

`:file` : Renders the contents of a file. This option should *not* be used with

unsanitized user input.

    <%= render file: "/path/to/some/file" %>
    # => renders /path/to/some/file

`:inline` : Renders an ERB template string.

<% name = "World" %>
<%= render inline: "<h1>Hello, <%= name %>!</h1>" %>
# => renders "<h1>Hello, World!</h1>"

`:body` : Renders the provided text, and sets the format as `:text`.

<%= render body: "Hello, World!" %>
# => renders "Hello, World!"

`:plain` : Renders the provided text, and sets the format as `:text`.

<%= render plain: "Hello, World!" %>
# => renders "Hello, World!"

`:html` : Renders the provided HTML string, and sets the format as

`:html`. If the string is not `html_safe?`, performs HTML escaping on
the string before rendering.

    <%= render html: "<h1>Hello, World!</h1>".html_safe %>
    # => renders "<h1>Hello, World!</h1>"

    <%= render html: "<h1>Hello, World!</h1>" %>
    # => renders "<h1>Hello, World!</h1>"

`:renderable` : Renders the provided object by calling `render_in` with the current view

context. The format is determined by calling `format` on the
renderable if it responds to `format`, falling back to `:html` by
default.

    <%= render renderable: Greeting.new %>
    # => renders "<h1>Hello, World</h1>"

#### Options

`:locals` : Hash of local variable assignments for the template.

<%= render inline: "<h1>Hello, <%= name %>!</h1>", locals: { name: "World" } %>
# => renders "<h1>Hello, World!</h1>"

`:formats` : Override the current format to render a template for a different format.

<% # app/views/posts/show.html.erb %>
<%= render template: "posts/content", formats: [:text] %>
# => renders app/views/posts/content.text.erb

`:variants` : Render a template for a different variant.

<% # app/views/posts/show.html.erb %>
<%= render template: "posts/content", variants: [:tablet] %>
# => renders app/views/posts/content.html+tablet.erb

`:handlers` : Render a template for a different handler.

<% # app/views/posts/show.html.erb %>
<%= render template: "posts/content", handlers: [:builder] %>
# => renders app/views/posts/content.html.builder

# File actionview/lib/action_view/helpers/rendering_helper.rb, line 138
      def render(options = {}, locals = {}, &block)
        case options
        when Hash
          in_rendering_context(options) do |renderer|
            if block_given?
              view_renderer.render_partial(self, options.merge(partial: options[:layout]), &block)
            else
              view_renderer.render(self, options)
            end
          end
        else
          if options.respond_to?(:render_in)
            options.render_in(self, &block)
          else
            view_renderer.render_partial(self, partial: options, locals: locals, &block)
          end
        end
      end