Action View 模板
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常量
NONE | = | Object.new |
STRICT_LOCALS_REGEX | = | /\#\s+locals:\s+\((.*)\)/ |
属性
[R] | format | |
[RW] | frozen_string_literal | |
[R] | handler | |
[R] | identifier | |
[R] | variable | |
[R] | variant | |
[R] | virtual_path |
类公共方法
mime_types_implementation=(implementation) 链接
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 184 def mime_types_implementation=(implementation) # This method isn't thread-safe, but it's not supposed # to be called after initialization if self::Types != implementation remove_const(:Types) const_set(:Types, implementation) end end
new(source, identifier, handler, locals:, format: nil, variant: nil, virtual_path: nil) 链接
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 199 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
实例公共方法
encode!() 链接
此方法负责正确设置源的编码。在此之前,我们假设源是二进制数据。如果没有提供其他信息,我们假设编码与 Encoding.default_external
相同。
用户也可以通过模板第一行的注释指定编码(# encoding: NAME-OF-ENCODING
)。这将适用于任何模板引擎,因为我们在将源传递给模板引擎之前处理掉了编码注释,并在其位置留下了空白行。
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 321 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() 链接
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 300 def inspect "#<#{self.class.name} #{short_identifier} locals=#{locals.inspect}>" end
local_assigns 链接
返回一个包含定义的局部变量的哈希。
给定此子模板渲染
<%= render "application/header", { headline: "Welcome", person: person } %>
您可以在子模板中使用 local_assigns
来访问局部变量
local_assigns[:headline] # => "Welcome"
local_assigns
中的每个键都可用作局部变量
local_assigns[:headline] # => "Welcome"
headline # => "Welcome"
由于 local_assigns
是一个 Hash
,它与 Ruby 3.1 的模式匹配赋值运算符兼容
local_assigns => { headline:, **options }
headline # => "Welcome"
options # => {}
模式匹配赋值也支持变量重命名
local_assigns => { headline: title }
title # => "Welcome"
如果模板引用一个没有作为 locals: { ... }
Hash
的一部分传递给视图的变量,模板将引发 ActionView::Template::Error
<%# => raises ActionView::Template::Error %>
<% alerts.each do |alert| %>
<p><%= alert %></p>
<% end %>
由于 local_assigns
返回一个 Hash
实例,因此您可以有条件地读取变量,然后在键不是 locals: { ... }
选项的一部分时回退到默认值
<% local_assigns.fetch(:alerts, []).each do |alert| %>
<p><%= alert %></p>
<% end %>
将 Ruby 3.1 的模式匹配赋值与对 +Hash#with_defaults+ 的调用结合使用,可以实现紧凑的局部变量赋值
<% local_assigns.with_defaults(alerts: []) => { headline:, alerts: } %>
<h1><%= headline %></h1>
<% alerts.each do |alert| %>
<p><%= alert %></p>
<% end %>
默认情况下,模板将接受任何 locals
作为关键字参数,并使它们可供 local_assigns
使用。要限制模板将接受哪些 local_assigns
,请添加一个 locals:
魔法注释
<%# locals: (headline:, alerts: []) %>
<h1><%= headline %></h1>
<% alerts.each do |alert| %>
<p><%= alert %></p>
<% end %>
在指南中了解更多关于严格局部变量的信息 Action View 概述。
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 165 eager_autoload do autoload :Error autoload :RawFile autoload :Renderable autoload :Handlers autoload :HTML autoload :Inline autoload :Types autoload :Sources autoload :Text autoload :Types end
locals() 链接
此模板已编译或将编译的局部变量,如果这是严格局部变量模板,则为 nil。
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 223 def locals if strict_locals? nil else @locals end end
render(view, locals, buffer = nil, implicit_locals: [], add_to_stack: true, &block) 链接
渲染模板。如果模板尚未编译,则会在渲染前完成编译。
此方法被检测为“!render_template.action_view”。请注意,我们在检测中使用了感叹号,因为您不想在生产环境中使用它。只有在被监听时,它才速度慢。
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 271 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() 链接
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 296 def short_identifier @short_identifier ||= defined?(Rails.root) ? identifier.delete_prefix("#{Rails.root}/") : identifier end
source() 链接
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 304 def source @source.to_s end
strict_locals!() 链接
此方法负责将模板标记为具有严格局部变量,这意味着模板只能接受在魔法注释中定义的局部变量。例如,如果您的模板接受局部变量 title
和 comment_count
,请将以下内容添加到您的模板文件中
<%# locals: (title: "Default title", comment_count: 0) %>
严格局部变量对于验证模板参数和指定默认值非常有用。
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 366 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
strict_locals?() 链接
返回模板是否使用严格局部变量。
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 380 def strict_locals? strict_locals! end
supports_streaming?() 链接
返回底层处理程序是否支持流式传输。如果是,则在开始渲染时可以传递一个流式缓冲区。
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 261 def supports_streaming? handler.respond_to?(:supports_streaming?) && handler.supports_streaming? end
translate_location(backtrace_location, spot) 链接
将 ErrorHighlight 返回的错误位置转换为模板中正确的源位置。
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 251 def translate_location(backtrace_location, spot) if handler.respond_to?(:translate_location) handler.translate_location(spot, backtrace_location, encode!) || spot else spot end end
type() 链接
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 292 def type @type ||= Types[format] end
实例私有方法
instrument(action, &block) 链接
来源: 显示 | 在 GitHub 上
# File actionview/lib/action_view/template.rb, line 578 def instrument(action, &block) # :doc: ActiveSupport::Notifications.instrument("#{action}.action_view", instrument_payload, &block) end