我对Ruby完全陌生，所以我的问题可能有一个非常简单的答案。然而，我在stackoverflow上找不到答案。我有以下非常简单的Sinatra应用程序：
# myapp.rb
require 'rubygems'
require 'sinatra'
require 'json'
range=(199..2000).step(1)
set :port, 8888
get '/hostname' do
content_type :json
return range.next.to_json
end
Sinatra正在启动：
ruby testsinatra.rb
== Sinatra/1.0 has taken the stage on 8888 for development with backup from WEBrick
[2014-09-11 08:43:18] INFO WEBrick 1.3.1
[2014-09-11 08:43:18] INFO ruby 1.8.7 (2011-06-30) [x86_64-linux]
[2014-09-11 08:43:18] INFO WEBrick::HTTPServer#start: pid=8215 port=8888
以及服务第一个请求：
curl -ks http://localhost:8888/hostname
199
但在第二次请求时出现错误而失败：
RuntimeError-跨线程调用continuation：
/usr/lib/ruby/1.8/generator.rb:131:in `call'
/usr/lib/ruby/1.8/generator.rb:131:in `next'
/usr/lib/ruby/1.8/generator.rb:189:in `next'
testsinatra.rb:30:in `GET /hostname'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:863:in `call'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:863:in `route'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:521:in `instance_eval'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:521:in `route_eval'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:500:in `route!'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:497:in `catch'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:497:in `route!'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:476:in `each'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:476:in `route!'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:601:in `dispatch!'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:411:in `call!'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:566:in `instance_eval'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:566:in `invoke'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:566:in `catch'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:566:in `invoke'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:411:in `call!'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:399:in `call'
/usr/lib/ruby/gems/1.8/gems/rack-1.5.2/lib/rack/showexceptions.rb:24:in `call'
/usr/lib/ruby/gems/1.8/gems/rack-1.5.2/lib/rack/methodoverride.rb:21:in `call'
/usr/lib/ruby/gems/1.8/gems/rack-1.5.2/lib/rack/commonlogger.rb:33:in `call'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:979:in `call'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:1003:in `synchronize'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:1003:in `synchronize'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:979:in `call'
/usr/lib/ruby/gems/1.8/gems/rack-1.5.2/lib/rack/handler/webrick.rb:60:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
/usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:95:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `each'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:23:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:82:in `start'
/usr/lib/ruby/gems/1.8/gems/rack-1.5.2/lib/rack/handler/webrick.rb:14:in `run'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/base.rb:946:in `run!'
/usr/lib/ruby/gems/1.8/gems/sinatra-1.0/lib/sinatra/main.rb:25
testsinatra.rb:27
很明显，我错过了一些基本的东西。请提供建议。
测试代码给出：
FiberError at /hostname
fiber called across threads
您可以在这里找到一个相关的问题：跨线程共享枚举器。Fiber代码似乎存储了第一个访问对象的线程的ID，当另一个线程尝试访问时，它会立即失败。显然，你不能在线程之间共享枚举器，必须采用不同的方法。
还请注意，全局变量可能由不同的线程同时访问，您应该始终使用线程安全对象或显式锁定。