来自rake任务的render_to_string
我想使用Rake任务来缓存我的站点地图，以便对sitemap.xml请求不会永远占用。 这是我到目前为止所拥有的：
@posts = Post.all sitemap = render_to_string :template => 'sitemap/sitemap', :locals => {:posts => @posts}, :layout => false Rails.cache.write('sitemap', sitemap)
但是当我尝试运行它时，我收到一个错误：
undefined local variable or method `headers' for #
如何从Rake中将模板渲染为字符串？
我是这样做的：
av = ActionView::Base.new(Rails::Configuration.new.view_path) av.class_eval do include ApplicationHelper end include ActionController::UrlWriter default_url_options[:host] = 'mysite.com' posts = Post.all sitemap = av.render 'sitemap/sitemap', :posts => posts Rails.cache.write('sitemap', sitemap)
请注意，我将模板转换为部分模板以使其工作
有一篇关于如何从rake任务访问ActionView :: Base方法和上下文的post 。
但是，这是一个monkeypatch。 为什么不使用rails的缓存机制来完成缓存？ 🙂
稍后编辑： render_to_string函数在ActionController :: Base上下文中定义。
以下是如何使其从rake任务开始工作的解决方案，取自omninerd 。
# In a rake task: av = ActionView::Base.new(Rails::Configuration.new.view_path) Rails.cache.write( "cache_var", av.render( :partial => "view_folder/some_partial", :locals => {:a_var => @some_var} ) )
最近我想采取像Horace Loeb所提到的rake任务并将其翻译成一个独立的后台工作，但它并不容易翻译。
这是我对Rails 2.3.x的实现，因为我找到的Rails 3实现不起作用。
# Public: Template to render views outside the context of a controller. # # Useful for rendering views in rake tasks or background jobs when a # controller is unavailable. # # Examples # # template = OfflineTemplate.new(:users) # template.render("users/index", :layout => false, :locals => { :users => users }) # # template = OfflineTemplate.new(ProjectsHelper, PermissionsHelper) # template.render("projects/recent", :projects => recent_projects) # class OfflineTemplate include ActionController::UrlWriter include ActionController::Helpers::ClassMethods # Public: Returns the ActionView::Base internal view. attr_reader :view # Public: Convenience method to delegate :render, :to => :view # Public: Initialize an offline template for the current Rails environment. # # helpers - The Rails helpers to include (listed as symbols or modules). def initialize(*helpers) helper(helpers + [ApplicationHelper]) @view = ActionView::Base.new(Rails.configuration.view_path, {}, self) @view.class.send(:include, master_helper_module) end private # Internal: Required to use ActionConroller::Helpers. # # Returns a Module to collect helper methods. def master_helper_module @master_helper_module ||= Module.new end end
这可以作为一个要点： https ： //gist.github.com/1386052 。
然后，您可以使用上面的类创建一个OfflineTemplate，以在rake任务中呈现您的视图：
task :recent_projects => :environment do template = OfflineTemplate.new(ProjectsHelper, PermissionsHelper) puts template.render("projects/recent", :projects => recent_projects) end