Rails 3：如何在 rake 任务中渲染 ERb 模板？

Question

我正在使用 rake 渲染一个相当大的站点地图 HTML 文件。不幸的是，当我迁移到rails 3时，代码中断了。我当前的代码如下所示：

@controller = ActionController::Base.new
@controller.request = ActionController::TestRequest.new
@controller.instance_eval do
  @url = ActionController::UrlRewriter.new(request, {})
end

# collect data, open output file file

template = ERB.new(IO.read("#{RAILS_ROOT}/app/views/sitemap/index.html.erb"))
f.puts(template.result(binding))

此代码在2.3中工作，但在Rails 3中中断，因为url_for不再访问@controller，而是访问controller。 （我认为这就是原因。）

undefined local variable or method `controller' for #<Object:0x3794c>
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:31:in `url_options'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_dispatch/routing/url_for.rb:132:in `url_for'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:99:in `url_for'
(erb):5
/Users/me/Documents/Projects/zvg2/lib/tasks/zvg.rake:452

我还尝试创建一个 ActionView 来这样做：

av = ActionView::Base.new(Rails::Application::Configuration.new(Rails.root).view_path, {
  # my assigns
}, @controller)
av.class_eval do
  include ApplicationHelper
end
f.puts(av.render(:template => "sitemap/index.html"))

但问题似乎是相同的，尽管 ActionView::Base.new 使用我的控制器。

undefined local variable or method `controller' for nil:NilClass
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/whiny_nil.rb:48:in `method_missing'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:31:in `url_options'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_dispatch/routing/url_for.rb:132:in `url_for'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:99:in `url_for'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_dispatch/routing/url_for.rb:132:in `url_for'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:99:in `url_for'
/Users/me/Documents/Projects/zvg2/app/views/sitemap/index.html.erb:5:in `_app_views_sitemap_index_html_erb__757224102_30745030_0'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/template.rb:135:in `send'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/template.rb:135:in `render'
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/notifications.rb:54:in `instrument'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/template.rb:127:in `render'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/render/rendering.rb:59:in `_render_template'
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/notifications.rb:52:in `instrument'
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/notifications.rb:52:in `instrument'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/render/rendering.rb:56:in `_render_template'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/render/rendering.rb:26:in `render'
/Users/me/Documents/Projects/zvg2/lib/tasks/zvg.rake:450

使用 url_for 和 link_to 渲染模板的最佳实践是什么？我敢打赌，随着 Rails 变得更加模块化，应该有一个简单的方法来实现这一点？

提前致谢！扬

Answer 1

当我包含 Rails.application.routes.url_helpers 而不是 ActionView::Helpers::UrlHelper 时，其中一种方法有效。这目前有效：

include Rails.application.routes.url_helpers # brings ActionDispatch::Routing::UrlFor
include ActionView::Helpers::TagHelper

av = ActionView::Base.new(Rails.root.join('app', 'views'))
av.assign({
  :regions => @regions,
  :courts_by_region => @courts_by_region,
  :cities_by_region => @cities_by_region,
  :districts_by_region => @districts_by_region
})
f = File.new(file_name, 'w')
f.puts(av.render(:template => "sitemap/index.html"))
f.close

希望这对其他人有帮助。如果有更好的解决方案，我会很感兴趣。

另外，如何自动从绑定中获取分配的哈希值？

Answer 2

我通过做这样的事情成功了：

class Template < ActionView::Base
  include Rails.application.routes.url_helpers
  include ActionView::Helpers::TagHelper

  def default_url_options
    {host: 'yourhost.org'}
  end
end  

template = Template.new(Rails.root.join('app', 'views'))
template.assign(attendee: @attendee)
template.render(template: 'sitemap/index.html.erb')

Answer 3

这对我有用（Rails 3）：

class TaskActionView < ActionView::Base
  include Rails.application.routes.url_helpers
  include ApplicationHelper

  def default_url_options
     {host: 'example.com'}
  end
end

def action_view
  controller = ActionController::Base.new
  controller.request = ActionDispatch::TestRequest.new
  TaskActionView.new(Rails.root.join('app', 'views'), {}, controller)
end

action_view.render(:template =>"path/to/template")

这成功地包括了我的应用程序助手、标签助手和 url 助手。您需要将应用程序/环境主机正确放入 default_url_options 哈希中。

Answer 4

这对我有用：

html = render_to_string(:index, layout: nil)