Some commands hang my Ruby web app

Question

I'm playing around with Rails & Sinatra, and I want to execute commands on the server. Those commands are entered from a form. The thing is, if I enter a command which expects input, my whole app hangs. Here's the code I'm using to execute them:

@threads << Thread.new do Thread.current["buffer"] = "" puts "starting #{params[:command]}" IO.popen(params[:command]) do |io| io.each_line {|l| Thread.current["buffer"] += l} end end

this works ok for simple commands like ls ... but for example if I enter pause which will expect the user to press a key to continue, everything hangs. How can I get around that?

EDIT: I just remembered I asked last year about Ruby thread behaviour here: Why is this running like it isn't threaded? . I tried running Sinatra using a 1.9.1 interpreter and it worked. Under 1.8.6 it doesn't however. A mod can close this question if he wants.

I think you meant "The thing is, if I enter a command which expects input..." didn't you? — John Topley
– John Topley, Commented Feb 27, 2010 at 10:04
Do you wait for threads to finish with join later on? This piece of code seems to be ok to me. — vava
– vava, Commented Feb 27, 2010 at 10:38

hurikhan77 · Accepted Answer · 2010-02-27 14:28:37Z

0

Try piping /dev/null into your child process:

IO.popen("#{params[:command]} </dev/null") do ...

answered Feb 27, 2010 at 14:28

hurikhan77

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Community · Accepted Answer · 2017-05-23 10:32:58Z

Solution: I just remembered I asked last year about Ruby thread behaviour here: Why is this running like it isn't threaded? . I tried running Sinatra using a 1.9.1 interpreter and it worked. Under 1.8.6 it doesn't however.

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