强制 rails 创建资产缓存文件

Question

我在 s3 上托管我的资产。在生产环境中，rails 正在寻找 /javascripts/cache/all.js 和 /stylesheets/cache/all.css。当我使用 cap 进行部署时，我正在使用插件将公共目录转移到 s3。问题是 Rails 在第一次请求它们之前不会创建这些缓存文件，因此当我传输公共目录时，它们在部署期间并不存在。有没有一种简单的方法可以在部署期间强制创建这些文件？

Answer 1

创建缓存文件的实际 Rails 模块是 ActionView::Helpers::AssetTagHelper，您可以在部署期间重新使用它来创建缓存文件。以下对我来说没问题：

require 'action_view'
class AssetCacheWriter

  include ActionView::Helpers::AssetTagHelper

  def write
    write_asset_file_contents(File.join(JAVASCRIPTS_DIR, "all.js"), compute_javascript_paths([:all], true))
    write_asset_file_contents(File.join(STYLESHEETS_DIR, "all.css"), compute_stylesheet_paths([:all], true))
'standard_all')
  end

end

write_asset_file_contents 的两个调用都是我从 rails 代码中提取的。 _DIR 常量在包含的模块中定义，compute_xxx_paths 调用中的true 参数表明所有文件都应递归包含。

我创建了一个简单的 cap 任务，只是将文件写出来：

namespace :sample
  task :assets do
    AssetCacheWriter.new.write
  end
end

Answer 2

我在 rake 任务文件中使用它。使您免于创建额外的类并保持它 DRY，因为您使用的是来自 stylesheet_link_tag / javascript_include_tag 的值

desc "Clears javascripts/cache and stylesheets/cache"   task :clear => :environment do
  puts "Clearing javascripts/cache and stylesheets/cache"
  FileUtils.rm(Dir['public/javascripts/cache_[^.]*']) # use :cache => 'cache_all.js' in stylesheet_link_tag
  FileUtils.rm(Dir['public/stylesheets/cache_[^.]*']) # use :cache => 'cache_all.css' in javascript_include_tag
end

desc "Recreate the javascripts/stylesheets cache."
  task :generate => [:environment, :clear] do
  puts "Recreate the javascripts/stylesheets cache"
  ActionController::Base.perform_caching = true
  app = ActionController::Integration::Session.new
  app.get '/'
end

Answer 3

如果您使用的是 Engine Yard Cloud，我就是这样做的：

添加了一个文件 /lib/tasks/assetcache.rake

    require 'assetwriter'

    namespace :assetcache do

      desc "Clears javascripts/cache and stylesheets/cache"   
      task :clear => :environment do
        puts "Clearing javascripts/cache and stylesheets/cache"
        FileUtils.rm(Dir['public/javascripts/cache_[^.]*'])
# use :cache => 'cache_all.js' in stylesheet_link_tag
        FileUtils.rm(Dir['public/stylesheets/cache_[^.]*'])
# use :cache => 'cache_all.css' in javascript_include_tag
      end

      desc "Recreate the javascripts/stylesheets cache."
      task :generate => [:environment, :clear] do
        puts "Recreate the javascripts/stylesheets cache"
        AssetCacheWriter.new.write
      end

    end

然后我添加了 /lib/assetwriter.rb

需要'action_view' 类 AssetCacheWriter

包括 ActionView::Helpers::AssetTagHelper

定义写入 write_asset_file_contents(File.join(JAVASCRIPTS_DIR, "cache/all.js"), compute_javascript_paths([:all], true)) write_asset_file_contents(File.join(STYLESHEETS_DIR, "cache/all.css"), compute_stylesheet_paths([:all], true)) 结束

结束

然后我添加到 /deploy/after_restart.rb

运行“cd #{release_path} && bundle exec rake assetcache:generate”

Answer 4

我发现包含顺序很重要（例如，jQuery 在其他脚本之前包含在内），因此改用以下方法。还允许使用 :defaults。

第一个 lib/asset_pacakger：

require 'action_view'

class AssetCacheWriter
  include ActionView::Helpers::AssetTagHelper
  include ActionView::Helpers::TagHelper 

  def write
    ActionController::Base.perform_caching = true    
    stylesheet_link_tag *ApplicationController::STYLESHEET_INCLUDES
    javascript_include_tag *ApplicationController::JAVASCRIPT_INCLUDES
  end
end

然后是脚本/package_assets：

#!/usr/bin/env ruby

RAILS_ROOT = File.expand_path(File.dirname(__FILE__) + '/../')
Dir.chdir(RAILS_ROOT)

RAILS_ENV = ENV['RAILS_ENV'] || 'development'

puts "Bundling assets for environment #{RAILS_ENV}"

require File.join('config', 'environment') 

AssetCacheWriter.new.write

然后是一个上限任务：

desc "Package assets"
task :package_assets do
  %x[#{Dir.getwd}/script/package_assets] 
  %x[svn commit #{Dir.getwd}/public/javascripts/defaults.js #{Dir.getwd}/public/stylesheets/defaults.css -m "(capistrano) packaging assets to trunk"]
  logger.info "packaged assets to trunk"
end

Answer 5

在 Rails 3.0.7 中，上述方法似乎都不起作用。我收到很多关于配置未定义的错误。

在仔细查看 Rails 代码后，我想出了这个对我有用的解决方案。

lib/tasks/cache_assets.rake

require 'asset_packager'

desc "cache assets"
task :cache_assets do

  puts "-----> Caching Assets"
  AssetCacheWriter.new.write
  puts "-----> Done!"

end

然后是 lib/asset_packager.rb

require 'action_view'

class AssetCacheWriter
  include ActionView::Helpers::AssetTagHelper
  include ActionView::Helpers::TagHelper 

  def config
    ApplicationController
  end

  def controller    
    ApplicationController
  end


  def write
    ActionController::Base.perform_caching = true    

    # You can replace these with your app's cached assets. They should look the same
    # as in your view templates.
    stylesheet_link_tag :vendor, :defaults, :cache => 'cached/all'
    javascript_include_tag :bd_defaults, :'vendor-head', :cache => 'cached/defaults_vendor'

  end

end

然后执行它，只需运行rake cache_assets