向本地开发服务器发出请求时，jruby IO.popen读取将挂起 [英] jruby IO.popen read hangs in action when requests are made to the local dev server

问题描述

我只想将wkhtmltopdf的输出发送给用户.它不应该那么难.

I just want to send the output of wkhtmltopdf to the user. It shouldn't be so hard.

def it
    send_pdf "file.pdf"
end

def send_pdf(file)
  url= url_for(params) # Example: http://localhost:3000/report/it
  webkit= Rails.root.join('app', 'bin', 'wkhtmltopdf', 'current')
  cmd= "#{webkit} -q \"#{url_for(params)}\" -"

  data= IO.popen(cmd).read ############### HANGS HERE ###################

  send_data(data, type: "application/pdf", filename: file)
end

为什么挂起以及如何修复它?

Why does it hang and how to fix it?

推荐答案

我认为这里的线索可能是本地开发服务器-因此也许一次只能接受一个请求.

I think the clue here may be it's a local development server - so maybe it can only accept one request at a time.

要进行测试，请尝试从其他位置获取html:

To test, try getting the html from somewhere else:

def send_pdf(file)
  # [...]
  cmd= "#{webkit} -q http://brighterplanet.com -"
  # [...]
end

如果这行得通，那么您的问题的答案是开发服务器是单线程".

If that works, then the answer to your question is that the development server is "single-threaded".

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