Class: ActionView::Template
Relationships & Source Files | |
Namespace Children | |
Modules:
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Extension / Inclusion / Inheritance Descendants | |
Subclasses:
ActionView::Template::Inline
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Super Chains via Extension / Inclusion / Inheritance | |
Class Chain:
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Inherits: | Object |
Defined in: | actionview/lib/action_view/template.rb, actionview/lib/action_view/template/error.rb, actionview/lib/action_view/template/handlers.rb, actionview/lib/action_view/template/html.rb, actionview/lib/action_view/template/inline.rb, actionview/lib/action_view/template/raw_file.rb, actionview/lib/action_view/template/renderable.rb, actionview/lib/action_view/template/sources.rb, actionview/lib/action_view/template/text.rb, actionview/lib/action_view/template/types.rb, actionview/lib/action_view/template/handlers/erb.rb, actionview/lib/action_view/template/handlers/erb/erubi.rb, actionview/lib/action_view/template/sources/file.rb |
Constant Summary
-
LEADING_ENCODING_REGEXP =
private
# File 'actionview/lib/action_view/template.rb', line 285/\A#{ENCODING_FLAG}/
-
NONE =
# File 'actionview/lib/action_view/template.rb', line 184Object.new
-
STRICT_LOCALS_REGEX =
# File 'actionview/lib/action_view/template.rb', line 11/\#\slocals:\s\((.*)\)/
Class Attribute Summary
Class Method Summary
- .new(source, identifier, handler, locals:, format: nil, variant: nil, virtual_path: nil) ⇒ Template constructor
::ActiveSupport::Autoload
- Extended
Instance Attribute Summary
- #format readonly
- #frozen_string_literal rw
- #handler readonly
- #identifier readonly
-
#strict_locals? ⇒ Boolean
readonly
Returns whether a template is using strict locals.
-
#supports_streaming? ⇒ Boolean
readonly
Returns whether the underlying handler supports streaming.
- #variable readonly
- #variant readonly
- #virtual_path readonly
Instance Method Summary
-
#encode!
This method is responsible for properly setting the encoding of the source.
- #inspect
-
#local_assigns
Returns a hash with the defined local variables.
-
#locals
The locals this template has been or will be compiled for, or nil if this is a strict locals template.
-
#render(view, locals, buffer = nil, implicit_locals: [], add_to_stack: true, &block)
Render a template.
- #short_identifier
- #source
-
#strict_locals!
This method is responsible for marking a template as having strict locals which means the template can only accept the locals defined in a magic comment.
-
#translate_location(backtrace_location, spot)
Translate an error location returned by ErrorHighlight to the correct source location inside the template.
- #type
- #instrument(action, &block) private
Constructor Details
.new(source, identifier, handler, locals:, format: nil, variant: nil, virtual_path: nil) ⇒ Template
# File 'actionview/lib/action_view/template.rb', line 186
def initialize(source, identifier, handler, locals:, format: nil, variant: nil, virtual_path: nil) @source = source.dup @identifier = identifier @handler = handler @compiled = false @locals = locals @virtual_path = virtual_path @variable = if @virtual_path base = @virtual_path.end_with?("/") ? "" : ::File.basename(@virtual_path) base =~ /\A_?(.*?)(?:\.\w+)*\z/ $1.to_sym end @format = format @variant = variant @compile_mutex = Mutex.new @strict_locals = NONE @strict_local_keys = nil @type = nil end
Class Attribute Details
.mime_types_implementation=(implementation) (writeonly)
[ GitHub ]Instance Attribute Details
#format (readonly)
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 182
attr_reader :variable, :format, :variant, :virtual_path
#frozen_string_literal (rw)
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 167
singleton_class.attr_accessor :frozen_string_literal
#handler (readonly)
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 181
attr_reader :identifier, :handler
#identifier (readonly)
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 181
attr_reader :identifier, :handler
#strict_locals? ⇒ Boolean
(readonly)
Returns whether a template is using strict locals.
# File 'actionview/lib/action_view/template.rb', line 357
def strict_locals? strict_locals! end
#supports_streaming? ⇒ Boolean
(readonly)
Returns whether the underlying handler supports streaming. If so, a streaming buffer may be passed when it starts rendering.
#variable (readonly)
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 182
attr_reader :variable, :format, :variant, :virtual_path
#variant (readonly)
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 182
attr_reader :variable, :format, :variant, :virtual_path
#virtual_path (readonly)
[ GitHub ]Instance Method Details
#encode!
This method is responsible for properly setting the encoding of the source. Until this point, we assume that the source is BINARY data. If no additional information is supplied, we assume the encoding is the same as Encoding.default_external
.
The user can also specify the encoding via a comment on the first line of the template (# encoding: NAME-OF-ENCODING
). This will work with any template engine, as we process out the encoding comment before passing the source on to the template engine, leaving a blank line in its stead.
# File 'actionview/lib/action_view/template.rb', line 298
def encode! source = self.source return source unless source.encoding == Encoding::BINARY # Look for # encoding: *. If we find one, we'll encode the # String in that encoding, otherwise, we'll use the # default external encoding. if source.sub!(LEADING_ENCODING_REGEXP, "") encoding = magic_encoding = $1 else encoding = Encoding.default_external end # Tag the source with the default external encoding # or the encoding specified in the file source.force_encoding(encoding) # If the user didn't specify an encoding, and the handler # handles encodings, we simply pass the String as is to # the handler (with the default_external tag) if !magic_encoding && @handler.respond_to?(:handles_encoding?) && @handler.handles_encoding? source # Otherwise, if the String is valid in the encoding, # encode immediately to default_internal. This means # that if a handler doesn't handle encodings, it will # always get Strings in the default_internal elsif source.valid_encoding? source.encode! # Otherwise, since the String is invalid in the encoding # specified, raise an exception else raise WrongEncodingError.new(source, encoding) end end
#inspect
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 277
def inspect "#<#{self.class.name} #{short_identifier} locals=#{locals.inspect}>" end
#instrument(action, &block) (private)
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 551
def instrument(action, &block) # :doc: ActiveSupport::Notifications.instrument("#{action}.action_view", instrument_payload, &block) end
#local_assigns
Returns a hash with the defined local variables.
Given this sub template rendering:
<%= render "application/header", { headline: "Welcome", person: person } %>
You can use local_assigns
in the sub templates to access the local variables:
local_assigns[:headline] # => "Welcome"
Each key in local_assigns
is available as a partial-local variable:
local_assigns[:headline] # => "Welcome"
headline # => "Welcome"
Since local_assigns
is a ::Hash
, it’s compatible with Ruby 3.1’s pattern matching assignment operator:
local_assigns => { headline:, ** }
headline # => "Welcome"
# => {}
Pattern matching assignment also supports variable renaming:
local_assigns => { headline: title }
title # => "Welcome"
If a template refers to a variable that isn’t passed into the view as part of the locals: { ... }
::Hash
, the template will raise an Template::Error
:
<%# => raises ActionView::Template::Error %>
<% alerts.each do |alert| %>
<p><%= alert %></p>
<% end %>
Since local_assigns
returns a ::Hash
instance, you can conditionally read a variable, then fall back to a default value when the key isn’t part of the locals: { ... }
options:
<% local_assigns.fetch(:alerts, []).each do |alert| %>
<p><%= alert %></p>
<% end %>
Combining Ruby 3.1’s pattern matching assignment with calls to Hash#with_defaults enables compact partial-local variable assignments:
<% local_assigns.with_defaults(alerts: []) => { headline:, alerts: } %>
<h1><%= headline %></h1>
<% alerts.each do |alert| %>
<p><%= alert %></p>
<% end %>
# File 'actionview/lib/action_view/template.rb', line 153
rdoc_method :method: local_assigns
#locals
The locals this template has been or will be compiled for, or nil if this is a strict locals template.
# File 'actionview/lib/action_view/template.rb', line 210
def locals if strict_locals? nil else @locals end end
#render(view, locals, buffer = nil, implicit_locals: [], add_to_stack: true, &block)
Render a template. If the template was not compiled yet, it is done exactly before rendering.
This method is instrumented as “!render_template.action_view”. Notice that we use a bang in this instrumentation because you don’t want to consume this in production. This is only slow if it’s being listened to.
# File 'actionview/lib/action_view/template.rb', line 248
def render(view, locals, buffer = nil, implicit_locals: [], add_to_stack: true, &block) instrument_render_template do compile!(view) if strict_locals? && @strict_local_keys && !implicit_locals.empty? locals_to_ignore = implicit_locals - @strict_local_keys locals.except!(*locals_to_ignore) end if buffer view._run(method_name, self, locals, buffer, add_to_stack: add_to_stack, has_strict_locals: strict_locals?, &block) nil else result = view._run(method_name, self, locals, OutputBuffer.new, add_to_stack: add_to_stack, has_strict_locals: strict_locals?, &block) result.is_a?(OutputBuffer) ? result.to_s : result end end rescue => e handle_render_error(view, e) end
#short_identifier
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 273
def short_identifier @short_identifier ||= defined?(Rails.root) ? identifier.delete_prefix("#{Rails.root}/") : identifier end
#source
[ GitHub ]# File 'actionview/lib/action_view/template.rb', line 281
def source @source.to_s end
#strict_locals!
This method is responsible for marking a template as having strict locals which means the template can only accept the locals defined in a magic comment. For example, if your template acceps the locals title
and comment_count
, add the following to your template file:
<%# locals: (title: "Default title", comment_count: 0) %>
Strict locals are useful for validating template arguments and for specifying defaults.
# File 'actionview/lib/action_view/template.rb', line 343
def strict_locals! if @strict_locals == NONE self.source.sub!(STRICT_LOCALS_REGEX, "") @strict_locals = $1 return if @strict_locals.nil? # Magic comment not found @strict_locals = "**nil" if @strict_locals.blank? end @strict_locals end
#translate_location(backtrace_location, spot)
Translate an error location returned by ErrorHighlight to the correct source location inside the template.