我最近重写了我的 Rails 3.2.13 应用程序之一以使用 Rails 4。我在 Rails 3 应用程序中使用了 twitter-bootstrap-rails 2.1.2。当我重写 Rails 4 版本时，它开始使用 2.2.8 版本。我在我的开发和生产服务器上使用 Phusion Passenger 4.0.20 来托管我所有的 Rails 应用程序。
在我的 Rails 3 应用程序中，背景图像在 localhost 和生产环境中正确显示。但是，当我使用 Rails 4 和当前版本的 twitter-bootstrap-rails 重写应用程序时，我注意到背景图像正确显示，但是当我在生产中部署它时，背景图像不显示。
我尝试了以下 CSS，但背景图像仅出现在 localhost 中。第一条语句是原始 CSS 代码，它在我的 Rails 3 应用程序中运行良好，在本地主机和生产环境中运行良好。
background: url(/assets/landingpage2.jpg); width: 574px; height: 650px;
background: url(../assets/landingpage2.jpg); width: 574px; height: 650px;
background-image: url(../assets/landingpage2.jpg); width: 574px; height: 650px;
background-image: url("../assets/landingpage2.jpg"); width: 574px; height: 650px;
background-image: url("/assets/landingpage2.jpg"); width: 574px; height: 650px;
这是包含最初工作的背景语句的类：
.landing-cube-menu {
font-weight: bold;
font-size: 150%;
line-height: 100%;
background: url(/assets/landingpage2.jpg); width: 574px; height: 650px;
margin:0 auto;
}
这是我在视图中使用的代码：
<div class="header-cube-menu" style="position: relative;">
<div class="header-store" style="position: absolute;">
<p><%= link_to "Online Store", store_path %></p>
</div>
<div class="header-about" style="position: absolute;">
<p><%= link_to "About", about_path %></p>
</div>
<div class="header-contact" style="position: absolute;">
<p><%= link_to "Contact", contact_path %></p>
</div>
<div class="header-verse" style="position: absolute;">
<p><a href="/verse">Bible<br>Verse</a></p>
</div>
<div class="header-app" style="position: absolute;">
<p><a href="/app">Mobile<br> App</a></p>
</div>
<div class="header-home" style="position: absolute;">
<p><a href="/home">Home<br> Page</a></p>
</div>
<div class="header-math" style="position: absolute;">
<p><a href="/math">The<br>Math</a></p>
</div>
<div class="header-vision" style="position: absolute;">
<p><a href="/vision"> Vision<br>Mission</a></p>
</div>
<div class="header-pendant" style="position: absolute;">
<p><a href="/pendant">Pendant<br> Desk Cross<br> and more</a></p>
</div>
<div class="header-puzzle" style="position: absolute;">
<p><a href="/puzzle">3D-Puzzle<br> eBook</a></p>
</div>
</div>
我已经清除了浏览器中本地主机和域的缓存。我仍然在 localhost 中看到图像，但在域中看不到。我尝试在我的 Mac Mini 服务器上使用最新版本的 Safari、Chrome、Firefox 和 Opera。他们都得到相同的结果。
如果我没有在 localhost 中看到背景图像，我可以理解这一点。我使用 localhost 对 Rails 4 应用程序进行了测试，并假设它可以在生产环境中工作。但是，在我部署它之后，背景图像丢失了。这发生在我的生产和开发服务器上。图像文件位于两台服务器上的 app/assets/images 中。
我的原始代码和我在此处发布的所有示例都是正确的，因为图像显示在 localhost 中。我现在不知道在哪里检查。我可以在乘客谷歌组中发布这个。这是 localhost 和生产之间的唯一其他变量，特别是考虑到我的开发服务器。
更新：发布此消息后，我决定尝试其他可能性。现在背景图像不再出现在本地主机上。我对此感到非常沮丧。
任何帮助，将不胜感激。
更新 2013 年 10 月 19 日晚上 8:05 CDT GMT-5
我试图在我的 .less 文件中实现asset_url解决方案。这是我在执行rake assets 时遇到的错误：precompile RAILS_ENV=production命令
I, [2013-10-19T19:59:05.384878 #69440] INFO -- : Writing /Users/myusername/Sites/myrailsapp/public/assets/application-f8821f5601f793a09e9373fb397df1b1.js
rake aborted!
undefined method `[]' for nil:NilClass
(in /Users/myusername/Sites/hypercubeoflove_RoR_4/app/assets/stylesheets/application.css)
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/sass_functions.rb:63:in `sprockets_context'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-rails-4.0.0/lib/sass/rails/helpers.rb:23:in `asset_url'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/script/funcall.rb:112:in `_perform'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/script/node.rb:40:in `perform'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:298:in `visit_prop'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:37:in `visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:100:in `visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:53:in `block in visit_children'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:53:in `map'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:53:in `visit_children'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:109:in `block in visit_children'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:121:in `with_environment'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:108:in `visit_children'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:37:in `block in visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:320:in `visit_rule'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:37:in `visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:100:in `visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:53:in `block in visit_children'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:53:in `map'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:53:in `visit_children'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:109:in `block in visit_children'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:121:in `with_environment'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:108:in `visit_children'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:37:in `block in visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:128:in `visit_root'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/base.rb:37:in `visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:100:in `visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/visitors/perform.rb:7:in `visit'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/tree/root_node.rb:20:in `render'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/engine.rb:315:in `_render'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sass-3.2.12/lib/sass/engine.rb:262:in `render'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/sass_compressor.rb:24:in `evaluate'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/tilt-1.4.1/lib/tilt/template.rb:103:in `render'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/context.rb:197:in `block in evaluate'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/context.rb:194:in `each'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/context.rb:194:in `evaluate'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/bundled_asset.rb:25:in `initialize'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/base.rb:377:in `new'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/base.rb:377:in `build_asset'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/index.rb:94:in `block in build_asset'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/caching.rb:58:in `cache_asset'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/index.rb:93:in `build_asset'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/base.rb:287:in `find_asset'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/index.rb:61:in `find_asset'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/manifest.rb:211:in `block in find_asset'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/manifest.rb:257:in `benchmark'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/manifest.rb:210:in `find_asset'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/manifest.rb:119:in `block in compile'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/manifest.rb:118:in `each'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/sprockets/manifest.rb:118:in `compile'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-rails-2.0.0/lib/sprockets/rails/task.rb:60:in `block (3 levels) in define'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-2.10.0/lib/rake/sprocketstask.rb:146:in `with_logger'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/gems/sprockets-rails-2.0.0/lib/sprockets/rails/task.rb:59:in `block (2 levels) in define'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/bin/ruby_noexec_wrapper:14:in `eval'
/Users/myusername/.rvm/gems/ruby-2.0.0-p247@mygemset/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => assets:precompile
(See full trace by running task with --trace)