当目标脚本被另一个Ruby脚本生成时找不到Ruby gem

Question

I've a watir script that I want to fire off from a Rails app on demand. My controller action looks something like this:

def run_scrape
  pid = Process.spawn('C:\Ruby22-x64\bin\ruby.exe "C:\Users\Admin\Dropbox\dev\watir-scripts\ds-vin.rb" 3VWB07AJ')
  Process.detach(pid)
  true
end

The actual script starts with:

require 'watir-webdriver'
b = Watir::Browser.new :ie
# etc

Now, if I navigate to the folder and just run the script directly, everything works fine. Once it's triggered from Rails (which is at a different location; seems like that's messing it up) I'm greeted with the following error:

`require': cannot load such file -- watir-webdriver (LoadError)

Watir-webdriver is in my gem list. I'm also requiring a couple of .rb files in the same folder, which was a problem until I used require_relative . I'm missing something simple here, I think. How do I require_relative a global gem?

Answer 1

First solution is to run your scraper in the same process as Rails, but in a different thread:

require 'C:\Users\Admin\Dropbox\dev\watir-scripts\ds-vin.rb'
thr = Thread.new do 
    b = Watir::Browser.new :ie
    ...
end

Second is to fix your environment if you are going to use Process.spawn - assuming your gems are installed system-wide you can do something like

ENV['GEM_PATH'] = "c:/Ruby220/lib/ruby/gems/2.2.0"

at the top of your ds-vin.rb script. To find the exact gem path you should use, make sure you run gem which watir-webdriver and gem environment and copy from there.