I'm working on a application in Ruby on Rails, and I changed my version of Rails and Rake. rails server does not work anymore:
~/sample_app/config.ru:4:in `block in <main>': uninitialized constant SampleApp (NameError)
from /var/lib/gems/1.9.1/gems/rack-1.2.8/lib/rack/builder.rb:46:in `instance_eval'
from /var/lib/gems/1.9.1/gems/rack-1.2.8/lib/rack/builder.rb:46:in `initialize'
from /home/sara/Documents/M1/s8/web avancé/projet/sample_app/config.ru:1:in `new'
from /home/sara/Documents/M1/s8/web avancé/projet/sample_app/config.ru:1:in `<main>'
from /var/lib/gems/1.9.1/gems/rack-1.2.8/lib/rack/builder.rb:35:in `eval'
from /var/lib/gems/1.9.1/gems/rack-1.2.8/lib/rack/builder.rb:35:in `parse_file'
from /var/lib/gems/1.9.1/gems/rack-1.2.8/lib/rack/server.rb:162:in `app'
from /var/lib/gems/1.9.1/gems/rack-1.2.8/lib/rack/server.rb:253:in `wrapped_app'
from /var/lib/gems/1.9.1/gems/rack-1.2.8/lib/rack/server.rb:204:in `start'
from /var/lib/gems/1.9.1/gems/railties-3.0.7/lib/rails/commands/server.rb:65:in `start'
from /var/lib/gems/1.9.1/gems/railties-3.0.7/lib/rails/commands.rb:30:in `block in <top (required)>'
from /var/lib/gems/1.9.1/gems/railties-3.0.7/lib/rails/commands.rb:27:in `tap'
from /var/lib/gems/1.9.1/gems/railties-3.0.7/lib/rails/commands.rb:27:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
Make sure you run bundle again to update to the newer versions of rails and rake.
Related
I know partial update in rails is good, but for my latest project, I need to disable it temporarily. Is there any way for me to do this in Rails 4?
I have tried to put ActiveRecord::Base.partial_updates = false in my environment.rb like what being suggested here, but it returns me a bunch of errors:
UPDATE (ERROR MESSAGE)
C:/Ruby200/lib/ruby/gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/dynamic_matchers.rb:26:in `method_missing': undefined method `partia
iveRecord::Base:Class (NoMethodError)
from C:/Users/ryzal_000/Sites/dotforge/config/environment.rb:7:in `<top (required)>'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:274:in `require'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:274:in `block in require'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:240:in `load_dependency'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:274:in `require'
from C:/Users/ryzal_000/Sites/dotforge/config.ru:3:in `block in <main>'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:55:in `instance_eval'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:55:in `initialize'
from C:/Users/ryzal_000/Sites/dotforge/config.ru:in `new'
from C:/Users/ryzal_000/Sites/dotforge/config.ru:in `<main>'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:49:in `eval'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:49:in `new_from_string'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/builder.rb:40:in `parse_file'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/server.rb:299:in `build_app_and_options_from_config'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/server.rb:208:in `app'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/railties-4.2.3/lib/rails/commands/server.rb:61:in `app'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.6.4/lib/rack/server.rb:336:in `wrapped_app'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/railties-4.2.3/lib/rails/commands/server.rb:139:in `log_to_stdout'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/railties-4.2.3/lib/rails/commands/server.rb:78:in `start'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:80:in `block in server'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:75:in `tap'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:75:in `server'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/railties-4.2.3/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
From rails 4.1 partial_updates is removed you can check it here http://guides.rubyonrails.org/4_1_release_notes.html
I'm following this post for integrating Omniauth Twitter + Devise http://sourcey.com/rails-4-omniauth-using-devise-with-twitter-facebook-and-linkedin/ and I have encounter an issue that is blocking me to start my rails app.
/Users/javier/Desktop/definitive/config/environment.rb:8:in `<top (required)>': undefined local variable or method `config' for main:Object (NameError)
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `require'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `block in require'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:232:in `load_dependency'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.1/lib/active_support/dependencies.rb:247:in `require'
from /Users/javier/Desktop/definitive/config.ru:3:in `block in <main>'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/builder.rb:55:in `instance_eval'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/builder.rb:55:in `initialize'
from /Users/javier/Desktop/definitive/config.ru:in `new'
from /Users/javier/Desktop/definitive/config.ru:in `<main>'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/builder.rb:49:in `eval'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/builder.rb:49:in `new_from_string'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/builder.rb:40:in `parse_file'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/server.rb:277:in `build_app_and_options_from_config'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/server.rb:199:in `app'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/railties-4.1.1/lib/rails/commands/server.rb:50:in `app'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/server.rb:314:in `wrapped_app'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/railties-4.1.1/lib/rails/commands/server.rb:130:in `log_to_stdout'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/railties-4.1.1/lib/rails/commands/server.rb:67:in `start'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/railties-4.1.1/lib/rails/commands/commands_tasks.rb:81:in `block in server'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/railties-4.1.1/lib/rails/commands/commands_tasks.rb:76:in `tap'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/railties-4.1.1/lib/rails/commands/commands_tasks.rb:76:in `server'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/railties-4.1.1/lib/rails/commands/commands_tasks.rb:40:in `run_command!'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/railties-4.1.1/lib/rails/commands.rb:17:in `<top (required)>'
from /Users/javier/Desktop/definitive/bin/rails:8:in `require'
from /Users/javier/Desktop/definitive/bin/rails:8:in `<top (required)>'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/rails.rb:27:in `load'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/rails.rb:27:in `call'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client/command.rb:7:in `call'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/client.rb:26:in `run'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/bin/spring:48:in `<top (required)>'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `load'
from /Users/javier/.rvm/gems/ruby-2.1.2/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `<top (required)>'
from /Users/javier/Desktop/definitive/bin/spring:16:in `require'
from /Users/javier/Desktop/definitive/bin/spring:16:in `<top (required)>'
from bin/rails:3:in `load'
from bin/rails:3:in `<main>'
I guess the issue is in the line 8 of config/environment.rb but can not find with the right fix. Is it possible that environment.rb should be included in 'config/environments/'?
The article states that you should put some code in:
config/environments/[environment].rb
Where [environment].rb is meant to signify one of the following files:
config/environments/development.rb
config/environments/production.rb
config/environments/test.rb
You could also put the code in config/application.rb if you want the same settings across your different environments.
The lines of code shown start with config.*, and they should be placed inside the Rails.application.configure do block.
config/environment.rb in a typical Rails 4 application is just a require and Rails.application.initialize!, and should not need modification.
If you have config.xxx in environment.rb
delete it and add these into development.rb:
Rails.application.configure do
config.xxx
end
I have also faced such an error(
NameError: undefined local variable or method `server' for main:Object
from (irb):1
from C:/RailsInstaller/Ruby2.2.0/bin/irb:11:in `<main>'),
)
maybe its because I am a Newbie in ruby on rails. hence instead of starting the rails server from direct command line I tried it to start from inside of IRB hence I got that error.
when I came out of IRB and started the server again from CMD it started smoothly.
I tried upgrading from Rails 3.0.23 to 3.2.13 and now I have an error stopping the server from starting that looks like this:
/Users/hamiltonchapman/Projects/project-static/lib/markdown_handler.rb:3:in `<top (required)>': uninitialized constant ActionView::Template::Handler (NameError)
from /Users/hamiltonchapman/Projects/project-static/config/environment.rb:9:in `<top (required)>'
from /Users/hamiltonchapman/Projects/project-static/config.ru:5:in `require'
from /Users/hamiltonchapman/Projects/project-static/config.ru:5:in `block in <main>'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
from /Users/hamiltonchapman/Projects/project-static/config.ru:in `new'
from /Users/hamiltonchapman/Projects/project-static/config.ru:in `<main>'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/railties-3.2.13/lib/rails/commands/server.rb:46:in `app'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/railties-3.2.13/lib/rails/commands/server.rb:70:in `start'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/railties-3.2.13/lib/rails/commands.rb:55:in `block in <top (required)>'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
from /Users/hamiltonchapman/.rvm/gems/ruby-2.1.1/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:9:in `require'
from script/rails:9:in `<main>'
The code that is causing this looks like:
require 'kramdown'
class MarkdownHandler < ActionView::Template::Handler
def self.call(template)
new.render(template, nil)
end
def render(template, local_assigns)
%(Kramdown::Document.new(
ERB.new(#{template.source.inspect}).result(binding)
).to_html.html_safe)
end
end
ActionView::Template.register_template_handler :emd, MarkdownHandler
ActionView::Template.register_template_handler :md, MarkdownHandler
However, if I just remove the inheritance then the server starts fine and all of the markdown files render as expected.
Any ideas as to what's going wrong?
I'm first timer to Ruby on Rails, trying to set it up on RHEL 6. Since the package manager had very older version of Ruby. I compiled from source with Ruby 1.9.3 and installed rails using
$gem install rails
Created a new app using
$rails new /path/to/newapp
but now when I try to run
$rails server
it crashes with given log
=> Booting WEBrick
=> Rails 3.2.1 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/usr/local/lib/ruby/gems/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `require': cannot load such file -- openssl (LoadError)
from /usr/local/lib/ruby/gems/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `block in require'
from /usr/local/lib/ruby/gems/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:236:in `load_dependency'
from /usr/local/lib/ruby/gems/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `require'
from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/session/cookie.rb:1:in `<top (required)>'
from /usr/local/lib/ruby/gems/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `require'
from /usr/local/lib/ruby/gems/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `block in require'
from /usr/local/lib/ruby/gems/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:236:in `load_dependency'
from /usr/local/lib/ruby/gems/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `require'
from /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-3.2.1/lib/action_dispatch/middleware/session/cookie_store.rb:4:in `<top (required)>'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/application/configuration.rb:140:in `const_get'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/application/configuration.rb:140:in `session_store'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/application.rb:268:in `block in default_middleware_stack'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/application.rb:232:in `tap'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/application.rb:232:in `default_middleware_stack'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/engine.rb:469:in `app'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/application/finisher.rb:31:in `block in <module:Finisher>'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:30:in `instance_exec'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:30:in `run'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:55:in `block in run_initializers'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:54:in `each'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:54:in `run_initializers'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/application.rb:136:in `initialize!'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /home/anurag/rubyapp/config/environment.rb:5:in `<top (required)>'
from /home/anurag/rubyapp/config.ru:4:in `require'
from /home/anurag/rubyapp/config.ru:4:in `block in <main>'
from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval'
from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize'
from /home/anurag/rubyapp/config.ru:1:in `new'
from /home/anurag/rubyapp/config.ru:1:in `<main>'
from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:40:in `eval'
from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:40:in `parse_file'
from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:200:in `app'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands/server.rb:46:in `app'
from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:301:in `wrapped_app'
from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:252:in `start'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands/server.rb:70:in `start'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:55:in `block in <top (required)>'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:50:in `tap'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
I've tried to search about this error but did not find a working solution.
Apart from this I'd like to point me to some useful resource which explains best practices in Ruby on Rails.
-
I fixed the problem.
I went inside extracted source directory of Ruby then run these.
$cd /ext/openssl/
$ruby extconf.rb
$make
$make install
I hope other will get some help from this. :-)
Your ruby is not compiled with SSL support. Try using rvm:
https://rvm.io
https://rvm.io/packages/openssl/
I installed the Rails installer in my Win7 machine from http://railsinstaller.org/. I already had the Ruby 1.9.2-p290. After installing the ROR through the installer, I rain rails s to start the server and I get the following error. Could anybody help me understanding the reason of this error>?
C:\Sites\ridemo>rails s
=> Booting WEBrick
=> Rails 3.1.0.rc6 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/actionpack-3.1.0.rc6/lib/sp
rockets/railtie.rb:21:in `block (2 levels) in <class:Railtie>': undefined method
`static_root=' for #<Sprockets::Environment:0x361d178> (NoMethodError)
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/sprockets-2.0.
0/lib/sprockets/environment.rb:55:in `initialize'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/actionpack-3.1
.0.rc6/lib/sprockets/railtie.rb:20:in `new'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/actionpack-3.1
.0.rc6/lib/sprockets/railtie.rb:20:in `block in <class:Railtie>'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/initializable.rb:25:in `instance_exec'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/initializable.rb:25:in `run'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/initializable.rb:50:in `block in run_initializers'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/initializable.rb:49:in `each'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/initializable.rb:49:in `run_initializers'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/application.rb:92:in `initialize!'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/railtie/configurable.rb:30:in `method_missing'
from C:/Sites/ridemo/config/environment.rb:5:in `<top (required)>'
from C:/Sites/ridemo/config.ru:4:in `require'
from C:/Sites/ridemo/config.ru:4:in `block in <main>'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/rack-1.3.2/lib
/rack/builder.rb:51:in `instance_eval'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/rack-1.3.2/lib
/rack/builder.rb:51:in `initialize'
from C:/Sites/ridemo/config.ru:1:in `new'
from C:/Sites/ridemo/config.ru:1:in `<main>'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/rack-1.3.2/lib
/rack/builder.rb:40:in `eval'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/rack-1.3.2/lib
/rack/builder.rb:40:in `parse_file'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/rack-1.3.2/lib
/rack/server.rb:200:in `app'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/commands/server.rb:46:in `app'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/rack-1.3.2/lib
/rack/server.rb:301:in `wrapped_app'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/rack-1.3.2/lib
/rack/server.rb:252:in `start'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/commands/server.rb:70:in `start'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/commands.rb:54:in `block in <top (required)>'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/commands.rb:49:in `tap'
from C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/railties-3.1.0
.rc6/lib/rails/commands.rb:49:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
RailsInstaller now supports Rails 3.1, but promise nothing about previous RC versions. Like #Fabio said, try to update to the latest Rails version (change it in your Gemfile). Also, if you already had a ruby version installed, be sure you are using the RailsInstaller one by checking your system environment path variable. The one and only path to Ruby should be :
C:\RailsInstaller\Ruby1.9.2\bin;
needed to run the following and It resolved the problem:-
gem install rails -v=3.1.0.rc8
From (https://github.com/sstephenson/sprockets/issues/172)