module ActionDispatch::Http::MimeNegotiation

Constants

BROWSER_LIKE_ACCEPTS

Attributes

variant[R]

Public Instance Methods

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 34
def accepts
  @env["action_dispatch.request.accepts"] ||= begin
    header = @env['HTTP_ACCEPT'].to_s.strip

    if header.empty?
      [content_mime_type]
    else
      Mime::Type.parse(header)
    end
  end
end

Returns the accepted MIME type for the request.

content_mime_type() Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 19
def content_mime_type
  @env["action_dispatch.request.content_type"] ||= begin
    if @env['CONTENT_TYPE'] =~ /^([^,\;]*)/
      Mime::Type.lookup($1.strip.downcase)
    else
      nil
    end
  end
end

The MIME type of the HTTP request, such as Mime::XML.

For backward compatibility, the post format is extracted from the X-Post-Data-Format HTTP header if present.

content_type() Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 29
def content_type
  content_mime_type && content_mime_type.to_s
end

format(view_path = []) Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 52
def format(view_path = [])
  formats.first || Mime::NullType.instance
end

Returns the MIME type for the format used in the request.

GET /posts/5.xml   | request.format => Mime::XML
GET /posts/5.xhtml | request.format => Mime::HTML
GET /posts/5       | request.format => Mime::HTML or MIME::JS, or request.accepts.first

format=(extension) Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 101
def format=(extension)
  parameters[:format] = extension.to_s
  @env["action_dispatch.request.formats"] = [Mime::Type.lookup_by_extension(parameters[:format])]
end

Sets the format by string extension, which can be used to force custom formats that are not controlled by the extension.

class ApplicationController < ActionController::Base
  before_action :adjust_format_for_iphone

  private
    def adjust_format_for_iphone
      request.format = :iphone if request.env["HTTP_USER_AGENT"][/iPhone/]
    end
end

formats() Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 56
def formats
  @env["action_dispatch.request.formats"] ||= begin
    params_readable = begin
                        parameters[:format]
                      rescue ActionController::BadRequest
                        false
                      end

    if params_readable
      Array(Mime[parameters[:format]])
    elsif use_accept_header && valid_accept_header
      accepts
    elsif xhr?
      [Mime::JS]
    else
      [Mime::HTML]
    end
  end
end

formats=(extensions) Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 120
def formats=(extensions)
  parameters[:format] = extensions.first.to_s
  @env["action_dispatch.request.formats"] = extensions.collect do |extension|
    Mime::Type.lookup_by_extension(extension)
  end
end

Sets the formats by string extensions. This differs from format= by allowing you to set multiple, ordered formats, which is useful when you want to have a fallback.

In this example, the :iphone format will be used if it's available, otherwise it'll fallback to the :html format.

class ApplicationController < ActionController::Base
  before_action :adjust_format_for_iphone_with_html_fallback

  private
    def adjust_format_for_iphone_with_html_fallback
      request.formats = [ :iphone, :html ] if request.env["HTTP_USER_AGENT"][/iPhone/]
    end
end

negotiate_mime(order) Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 130
def negotiate_mime(order)
  formats.each do |priority|
    if priority == Mime::ALL
      return order.first
    elsif order.include?(priority)
      return priority
    end
  end

  order.include?(Mime::ALL) ? format : nil
end

Receives an array of mimes and return the first user sent mime that matches the order array.

variant=(variant) Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 77
def variant=(variant)
  if variant.is_a?(Symbol)
    @variant = [variant]
  elsif variant.nil? || variant.is_a?(Array) && variant.any? && variant.all?{ |v| v.is_a?(Symbol) }
    @variant = variant
  else
    raise ArgumentError, "request.variant must be set to a Symbol or an Array of Symbols, not a #{variant.class}. "              "For security reasons, never directly set the variant to a user-provided value, "              "like params[:variant].to_sym. Check user-provided value against a whitelist first, "              "then set the variant: request.variant = :tablet if params[:variant] == 'tablet'"
  end
end

Sets the variant for template.

Protected Instance Methods

use_accept_header() Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 151
def use_accept_header
  !self.class.ignore_accept_header
end

valid_accept_header() Show source

# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 146
def valid_accept_header
  (xhr? && (accept.present? || content_mime_type)) ||
    (accept.present? && accept !~ BROWSER_LIKE_ACCEPTS)
end