ExecJS：“找不到JavaScript运行时”，但ExecJS和RubyRacer在GemFile中
我得到这个错误：
Rake已中止！ 找不到JavaScript运行时。参见https：//github.com/sstephenson/execjs，
我已经花了更多的时间搜索谷歌，然后我愿意承认。我相信这是一个ExecJS错误。
从所有的帖子来看，这是Rails3.1的一个非常常见的问题。像coffee-script和sass这样的标准gem现在需要一个JS运行时。
大多数情况都是通过将gem “ ExecJS ”和“ TherubyRacer ”添加到应用程序GemFile，然后运行“ Bundle Update ”和/或“ Bundle Install ”来解决的。但对我来说不是。
我想我很幸运。我在旧版本的RedHat Linux 4（2.6.9-101.ELSMP）上运行Rails 3.1.3/Ruby 1.9，而GCC是3.4.6。
其他报告的修复没有帮助，我无法安装' NodeJS '，' Johnson '，或' Mustang '，其他运行时ExecJS应该定位和使用。他们不会在我的系统上制作/安装。
我需要修复导致ExecJS无法找到“ TherubyRacer ”的问题。下面是Gemfile（和捆绑包安装显示OK）：
source 'http://rubygems.org'
gem 'rails', '3.1.3'
gem 'sqlite3'
gem 'sho-mongrel'
gem 'execjs'
gem 'therubyracer'
#gem "therubyracer", :require => 'v8'
group :assets do
gem 'sass-rails', '~> 3.1.5'
gem 'coffee-rails', '~> 3.1.1'
gem 'uglifier', '>= 1.0.3'
end
这里有一条轨迹：
~/rails/316-private-pub/chatter-after>rake db:create --trace
rake aborted!
Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.
/usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs/runtimes.rb:50:in `autodetect'
/usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs.rb:5:in `<module:ExecJS>'
/usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs.rb:4:in `<top (required)>'
/usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `require'
/usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `block (2 levels) in require'
/usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `each'
/usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `block in require'
/usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `each'
/usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `require'
/usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler.rb:122:in `require'
/home/vitalarthur/rails/316-private-pub/chatter-after/config/application.rb:7:in `<top (required)>'
/usr/local/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
/usr/local/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
/home/vitalarthur/rails/316-private-pub/chatter-after/Rakefile:5:in `<top (required)>'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25:in `load'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25:in `load_rakefile'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:501:in `raw_load_rakefile'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:82:in `block in load_rakefile'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:81:in `load_rakefile'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:65:in `block in run'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/usr/local/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/usr/local/bin/rake:19:in `load'
/usr/local/bin/rake:19:in `<main>'
开发日志中没有什么有趣的内容。
以下是ExecJS目录：
/usr/local/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs>ls
disabled_runtime.rb module.rb ruby_rhino_runtime.rb version.rb
external_runtime.rb mustang_runtime.rb runtimes.rb
johnson_runtime.rb ruby_racer_runtime.rb
我也试过ExecJS-1.2.13。同样的问题。
如果我在下面注释execjs.rb，我可以运行rake而不会出现错误：
require "execjs/module"
require "execjs/runtimes"
module ExecJS
self.runtime #||= Runtimes.autodetect
end
但我没有得到运行时间。
我可以在runtime.rb中看到错误文本的来源：
def self.autodetect
from_environment || best_available ||
raise(RuntimeUnavailable, "Could not find a JavaScript runtime. " +
"See https://github.com/sstephenson/execjs for a list of available runtimes.")
end
所以问题是，既然我安装了' TherubyRacer '，为什么Runtimes.rb找不到它？ExecJS坏了吗？
这里是' TherubyRacer '：
/usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-0.9.9
我该怎么解决这个问题？
