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Constants
BROWSER_LIKE_ACCEPTS | = | /,\s*\*\/\*|\*\/\*\s*,/ |
We use normal content negotiation unless you include / in your list, in which case we assume you’re a browser and send HTML. |
||
RESCUABLE_MIME_FORMAT_ERRORS | = | [ ActionController::BadRequest, ActionDispatch::Http::Parameters::ParseError, ] |
Instance Public methods
accepts() Link
Returns the accepted MIME type for the request.
# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 42 def accepts fetch_header("action_dispatch.request.accepts") do |k| header = get_header("HTTP_ACCEPT").to_s.strip v = if header.empty? [content_mime_type] else Mime::Type.parse(header) end set_header k, v rescue ::Mime::Type::InvalidMimeType => e raise InvalidType, e.message end end
content_mime_type() Link
The MIME type of the HTTP request, such as Mime.
# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 24 def content_mime_type fetch_header("action_dispatch.request.content_type") do |k| v = if get_header("CONTENT_TYPE") =~ /^([^,;]*)/ Mime::Type.lookup($1.strip.downcase) else nil end set_header k, v rescue ::Mime::Type::InvalidMimeType => e raise InvalidType, e.message end end
format(_view_path = nil) Link
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) Link
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() Link
# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 72 def formats fetch_header("action_dispatch.request.formats") do |k| v = if params_readable? Array(Mime[parameters[:format]]) elsif use_accept_header && valid_accept_header accepts.dup elsif extension_format = format_from_path_extension [extension_format] elsif xhr? [Mime[:js]] else [Mime[:html]] end v.select! do |format| format.symbol || format.ref == "*/*" end set_header k, v end end
formats=(extensions) Link
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 fall back 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) Link
Returns the first MIME type that matches the provided array of MIME types.
should_apply_vary_header?() Link
variant() Link
Returns the variant for the response template as an instance of ActiveSupport::ArrayInquirer
.
request.variant = :phone request.variant.phone? # => true request.variant.tablet? # => false request.variant = [:phone, :tablet] request.variant.phone? # => true request.variant.desktop? # => false request.variant.any?(:phone, :desktop) # => true request.variant.any?(:desktop, :watch) # => false
variant=(variant) Link
Sets the variant for the response template.
When determining which template to render, Action View will incorporate all variants from the request. For example, if an ArticlesController#index
action needs to respond to request.variant = [:ios, :turbo_native]
, it will render the first template file it can find in the following list:
-
app/views/articles/index.html+ios.erb
-
app/views/articles/index.html+turbo_native.erb
-
app/views/articles/index.html.erb
Variants add context to the requests that views render appropriately. Variant names are arbitrary, and can communicate anything from the request’s platform (:android
, :ios
, :linux
, :macos
, :windows
) to its browser (:chrome
, :edge
, :firefox
, :safari
), to the type of user (:admin
, :guest
, :user
).
Note: Adding many new variant templates with similarities to existing template files can make maintaining your view code more difficult.
Parameters
¶ ↑
-
variant
- a symbol name or an array of symbol names for variants used to render the response template
Examples¶ ↑
class ApplicationController < ActionController::Base before_action :determine_variants private def determine_variants variants = [] # some code to determine the variant(s) to use variants << :ios if request.user_agent.include?("iOS") variants << :turbo_native if request.user_agent.include?("Turbo Native") request.variant = variants end end
# File actionpack/lib/action_dispatch/http/mime_negotiation.rb, line 137 def variant=(variant) variant = Array(variant) if variant.all?(Symbol) @variant = ActiveSupport::ArrayInquirer.new(variant) else raise ArgumentError, "request.variant must be set to a Symbol or an Array of Symbols." end end