宝石在轨道上的红宝石

Question

I'm trying to run rails server on the command prompt in windows os and the following error is shown.

C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/execjs-1.4.0/lib/execjs/run
times.rb:51:in `autodetect': Could not find a JavaScript runtime. See https://gi
thub.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUn
available)
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/execjs-1.4.0/l
ib/execjs.rb:5:in `<module:ExecJS>'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/execjs-1.4.0/l
ib/execjs.rb:4:in `<top (required)>'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/coffee-script-
2.2.0/lib/coffee_script.rb:1:in `require'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/coffee-script-
2.2.0/lib/coffee_script.rb:1:in `<top (required)>'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/coffee-script-
2.2.0/lib/coffee-script.rb:1:in `require'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/coffee-script-
2.2.0/lib/coffee-script.rb:1:in `<top (required)>'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/coffee-rails-3
.2.2/lib/coffee-rails.rb:1:in `require'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/coffee-rails-3
.2.2/lib/coffee-rails.rb:1:in `<top (required)>'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/runtime.rb:72:in `require'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/runtime.rb:72:in `block (2 levels) in require'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/runtime.rb:70:in `each'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/runtime.rb:70:in `block in require'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/runtime.rb:59:in `each'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/runtime.rb:59:in `require'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler.rb:132:in `require'
        from C:/Sites/priya/config/application.rb:7:in `<top (required)>'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/commands.rb:53:in `require'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/commands.rb:53:in `block in <top (required)>'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/commands.rb:50:in `tap'
        from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.1
3/lib/rails/commands.rb:50:in `<top (required)>'
        from script/rails:6:in `require'
        from script/rails:6:in `<main>'

I've downloaded execjs and copied the file in my project folder. But there is no change. Please tell me how to fix this problem.

Answer 1

The error is

Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.

If you use Rails 3 and enable the asset pipeline, you need an asset compiler. ExecJS supports these runtimes, as explained in the documentation page:

• therubyracer - Google V8 embedded within Ruby
• therubyrhino - Mozilla Rhino embedded within JRuby
• Node.js
• Apple JavaScriptCore - Included with Mac OS X
• Microsoft Windows Script Host (JScript)

Follow the instructions at https://github.com/sstephenson/execjs to install one of them. Since you use Windows, you may want to try Microsoft Windows Script Host first.