无法运行localhost:3000 :呈现白色空页

Question

在过去的几天里，我使用的是Rails 4.2.6和Ruby2.3.0以及Puma 3.3.0，我运行了一些包更新，在rails对同一个URL本地主机的所有浏览器:3000都呈现相同的空白页面之后。这是一致的所有6-7应用程序，我正在玩。然而，当部署到Heroku时，所有人都在“生产”中工作。似乎只是与我的dev env有关的问题。

不知道怎么解决这个问题。任何帮助都将不胜感激。如果不能对我正在开发的代码运行单元测试，则无法继续开发。

然而，当我使用另一个端口时，所有操作都很好。例如，当使用rails的-p 3001或端口3002启动应用服务器时，使用:3001或localhost:3002在任何浏览器中运行应用程序都没有问题。

我的3000端口或美洲狮或两者都有什么问题？

Answer 1

这种情况可能发生在本地的dev中，而从未出现在"prod“中，即Heroku，因为在停止Puma时出现了bug。有些时候，由于以下原因，某些进程没有被终止：

levi-test-01 liviu-mac $ rails s
=> Booting Puma
=> Rails 4.2.6 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server
[4589] Puma starting in cluster mode...
[4589] * Version 3.3.0 (ruby 2.3.0-p0), codename: Jovial Platypus
[4589] * Min threads: 5, max threads: 5
[4589] * Environment: development
[4589] * Process workers: 2
[4589] * Preloading application
[4589] * Listening on tcp://localhost:3000
[4589] Use Ctrl-C to stop
[4589] - Worker 1 (pid: 4603) booted, phase: 0
[4589] - Worker 0 (pid: 4602) booted, phase: 0
^C[4589] - Gracefully shutting down workers...
/Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/server.rb:355:in `delete': No such file or directory @ unlink_internal - /Users/liviu-mac/ror/levi-test-01/tmp/pids/server.pid (Errno::ENOENT)
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/server.rb:355:in `block in write_pid'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/puma-3.3.0/lib/puma/cluster.rb:120:in `fork'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/puma-3.3.0/lib/puma/cluster.rb:120:in `block in spawn_workers'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/puma-3.3.0/lib/puma/cluster.rb:116:in `times'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/puma-3.3.0/lib/puma/cluster.rb:116:in `spawn_workers'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/puma-3.3.0/lib/puma/cluster.rb:418:in `run'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/puma-3.3.0/lib/puma/launcher.rb:172:in `run'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/puma-3.3.0/lib/rack/handler/puma.rb:51:in `run'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/server.rb:286:in `start'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/railties-4.2.6/lib/rails/commands/server.rb:80:in `start'
    from /Users/liviu-mac/.rbenv/versions/2.3.0/lib/ruby/gems/2.3.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:80:in `block in server'

运行这样的命令：

levi-test-01 liviu-mac $ lsof -i :3000

列出使用port 3000的所有剩余进程。

像这样的命令

levi-test-01 liviu-mac $ kill -9 PID

解决了问题。