Rails服务器未启动->找不到JavaScript运行时

Question

我在文件夹'issues‘中创建了一个新的rails应用程序，当我想要'ruby s’时，我得到了一个错误。任何帮助都将不胜感激

[thiago@netbox issues]$ rails s
/home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/execjs-1.4.0/lib/execjs/runtimes.rb:51:in `autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/execjs-1.4.0/lib/execjs.rb:5:in `<module:ExecJS>'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/execjs-1.4.0/lib/execjs.rb:4:in `<top (required)>'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `require'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `<top (required)>'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `require'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `<top (required)>'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/coffee-rails-3.2.2/lib/coffee-rails.rb:1:in `require'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/coffee-rails-3.2.2/lib/coffee-rails.rb:1:in `<top (required)>'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
    from /home/thiago/Documents/wdi/rails_practice/issues/config/application.rb:7:in `<top (required)>'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.13/lib/rails/commands.rb:53:in `require'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.13/lib/rails/commands.rb:53:in `block in <top (required)>'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
    from /home/thiago/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

我将'therubyracer‘gem添加到我的Gemfile中，然后'$包安装’就可以工作了！

Gemfile
source 'https://rubygems.org'

gem 'rails', '3.2.8'
gem 'sqlite3'

group :assets do
gem 'sass-rails',   '~> 3.2.3'
gem 'coffee-rails', '~> 3.2.1'
gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'
gem 'therubyracer' # added

Answer 1

当我在一月份开始使用Rails时，我在Windows和Ubuntu上都遇到了同样的错误。错误非常简单。您需要一个JavaScript运行时环境才能启动服务器。

有许多解决方案可以解决这个问题。我在Ubuntu上使用的是安装NodeJS。

在Ubuntu上，你需要运行下面这样的命令来安装NodeJS：

sudo add-apt-repository ppa:chris-lea/node.js
sudo apt-get -y update
sudo apt-get -y install nodejs

这些是我用来做这件事的命令，因为它将安装NodeJS的最新稳定版本，但是您可以只运行sudo apt-get -y install nodejs就可以了。

在Windows上，我使用的答案，可能还有其他的，是编辑你的Gemfile来安装therubyracer。我现在正在开发Rails4.0 RC1应用程序，它们都已经在Gemfile中添加了gem 'therubyracer', platform: :ruby，刚刚被注释掉了。

如果你在Windows上运行，你可以在你的Gemfile中添加gem 'therubyracer'，我敢打赌，这会让你运行起来。然后运行bundle install。

Answer 2

找不到JavaScript运行时。我假设你的Gemfile中没有这个。尝试编辑Gemfile并添加

gem 'therubyracer'

然后运行

$ bundle install

Answer 3

你需要安装一个javascript解释器：

将此代码添加到Gemfile中：

gem "libv8", ">= 3.11.8"
gem "therubyracer", ">= 0.11.0", :group => :assets, :platform => :ruby, :require => "v8"

此外，您还可以检查其他选项，如用于生产的Node.js，但对于开发，这将是足够的。