class ActionView::Template

Action View Template

Action View Template Handlers

Action View HTML Template

Action View Text Template

Attributes

formats[RW]
handler[R]
identifier[R]
locals[RW]
original_encoding[R]
source[R]
updated_at[R]
variants[RW]
virtual_path[RW]

Public Class Methods

new(source, identifier, handler, details) click to toggle source
# File lib/action_view/template.rb, line 126
def initialize(source, identifier, handler, details)
  format = details[:format] || (handler.default_format if handler.respond_to?(:default_format))

  @source            = source
  @identifier        = identifier
  @handler           = handler
  @compiled          = false
  @original_encoding = nil
  @locals            = details[:locals] || []
  @virtual_path      = details[:virtual_path]
  @updated_at        = details[:updated_at] || Time.now
  @formats           = Array(format).map { |f| f.respond_to?(:ref) ? f.ref : f  }
  @variants          = [details[:variant]]
  @compile_mutex     = Mutex.new
end

Public Instance Methods

encode!() click to toggle source

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 lib/action_view/template.rb, line 200
def encode!
  return 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!(/\A#{ENCODING_FLAG}/, "")
    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() click to toggle source
# File lib/action_view/template.rb, line 186
def inspect
  @inspect ||= defined?(Rails.root) ? identifier.sub("#{Rails.root}/", "".freeze) : identifier
end
local_assigns() click to toggle source

Returns a hash with the defined local variables.

Given this sub template rendering:

<%= render "shared/header", { headline: "Welcome", person: person } %>

You can use local_assigns in the sub templates to access the local variables:

local_assigns[:headline] # => "Welcome"
# File lib/action_view/template.rb, line 102
eager_autoload do
  autoload :Error
  autoload :Handlers
  autoload :HTML
  autoload :Text
  autoload :Types
end
refresh(view) click to toggle source

Receives a view object and return a template similar to self by using @virtual_path.

This method is useful if you have a template object but it does not contain its source anymore since it was already compiled. In such cases, all you need to do is to call refresh passing in the view object.

Notice this method raises an error if the template to be refreshed does not have a virtual path set (true just for inline templates).

# File lib/action_view/template.rb, line 175
def refresh(view)
  raise "A template needs to have a virtual path in order to be refreshed" unless @virtual_path
  lookup  = view.lookup_context
  pieces  = @virtual_path.split("/")
  name    = pieces.pop
  partial = !!name.sub!(/^_/, "")
  lookup.disable_cache do
    lookup.find_template(name, [ pieces.join("/") ], partial, @locals)
  end
end
render(view, locals, buffer = nil, &block) click to toggle source

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 lib/action_view/template.rb, line 154
def render(view, locals, buffer = nil, &block)
  instrument_render_template do
    compile!(view)
    view.send(method_name, locals, buffer, &block)
  end
rescue => e
  handle_render_error(view, e)
end
supports_streaming?() click to toggle source

Returns whether the underlying handler supports streaming. If so, a streaming buffer may be passed when it starts rendering.

# File lib/action_view/template.rb, line 144
def supports_streaming?
  handler.respond_to?(:supports_streaming?) && handler.supports_streaming?
end
type() click to toggle source
# File lib/action_view/template.rb, line 163
def type
  @type ||= Types[@formats.first] if @formats.first
end

Private Instance Methods

compile(mod) click to toggle source

Among other things, this method is responsible for properly setting the encoding of the compiled template.

If the template engine handles encodings, we send the encoded String to the engine without further processing. This allows the template engine to support additional mechanisms for specifying the encoding. For instance, ERB supports <%# encoding: %>

Otherwise, after we figure out the correct encoding, we then encode the source into Encoding.default_internal. In general, this means that templates will be UTF-8 inside of Rails, regardless of the original source encoding.

# File lib/action_view/template.rb, line 279
def compile(mod)
  encode!
  code = @handler.call(self)

  # Make sure that the resulting String to be eval'd is in the
  # encoding of the code
  source = <<-end_src
    def #{method_name}(local_assigns, output_buffer)
      _old_virtual_path, @virtual_path = @virtual_path, #{@virtual_path.inspect};_old_output_buffer = @output_buffer;#{locals_code};#{code}
    ensure
      @virtual_path, @output_buffer = _old_virtual_path, _old_output_buffer
    end
  end_src

  # Make sure the source is in the encoding of the returned code
  source.force_encoding(code.encoding)

  # In case we get back a String from a handler that is not in
  # BINARY or the default_internal, encode it to the default_internal
  source.encode!

  # Now, validate that the source we got back from the template
  # handler is valid in the default_internal. This is for handlers
  # that handle encoding but screw up
  unless source.valid_encoding?
    raise WrongEncodingError.new(@source, Encoding.default_internal)
  end

  mod.module_eval(source, identifier, 0)
  ObjectSpace.define_finalizer(self, Finalizer[method_name, mod])
end
compile!(view) click to toggle source

Compile a template. This method ensures a template is compiled just once and removes the source after it is compiled.

# File lib/action_view/template.rb, line 238
def compile!(view)
  return if @compiled

  # Templates can be used concurrently in threaded environments
  # so compilation and any instance variable modification must
  # be synchronized
  @compile_mutex.synchronize do
    # Any thread holding this lock will be compiling the template needed
    # by the threads waiting. So re-check the @compiled flag to avoid
    # re-compilation
    return if @compiled

    if view.is_a?(ActionView::CompiledTemplates)
      mod = ActionView::CompiledTemplates
    else
      mod = view.singleton_class
    end

    instrument("!compile_template") do
      compile(mod)
    end

    # Just discard the source if we have a virtual path. This
    # means we can get the template back.
    @source = nil if @virtual_path
    @compiled = true
  end
end
handle_render_error(view, e) click to toggle source
# File lib/action_view/template.rb, line 311
def handle_render_error(view, e)
  if e.is_a?(Template::Error)
    e.sub_template_of(self)
    raise e
  else
    template = self
    unless template.source
      template = refresh(view)
      template.encode!
    end
    raise Template::Error.new(template)
  end
end
identifier_method_name() click to toggle source
# File lib/action_view/template.rb, line 343
def identifier_method_name
  inspect.tr("^a-z_".freeze, "_".freeze)
end
instrument(action, &block) click to toggle source
# File lib/action_view/template.rb, line 347
def instrument(action, &block) # :doc:
  ActiveSupport::Notifications.instrument("#{action}.action_view", instrument_payload, &block)
end
instrument_payload() click to toggle source
# File lib/action_view/template.rb, line 355
def instrument_payload
  { virtual_path: @virtual_path, identifier: @identifier }
end
instrument_render_template(&block) click to toggle source
# File lib/action_view/template.rb, line 351
def instrument_render_template(&block)
  ActiveSupport::Notifications.instrument("!render_template.action_view".freeze, instrument_payload, &block)
end
locals_code() click to toggle source
# File lib/action_view/template.rb, line 325
def locals_code
  # Only locals with valid variable names get set directly. Others will
  # still be available in local_assigns.
  locals = @locals - Module::RUBY_RESERVED_KEYWORDS
  locals = locals.grep(/\A@?(?![A-Z0-9])(?:[[:alnum:]_]|[^\0-\177])+\z/)

  # Double assign to suppress the dreaded 'assigned but unused variable' warning
  locals.each_with_object("") { |key, code| code << "#{key} = #{key} = local_assigns[:#{key}];" }
end
method_name() click to toggle source
# File lib/action_view/template.rb, line 335
def method_name
  @method_name ||= begin
    m = "_#{identifier_method_name}__#{@identifier.hash}_#{__id__}"
    m.tr!("-".freeze, "_".freeze)
    m
  end
end