main.rb

#!/usr/bin/ruby
['socket', 'cgi', 'json', 'cgi/util', 'shellwords', 'uri'].each(&method(:require))

port = ENV['PORT'] # lport
meths = ["html", "shell", "path"]

begin
server = TCPServer.new port
rescue => err
  abort err.to_s
end

#######################################################################################
def parseheader(head)
  req = head.split
  uri = URI(req[1])
  if uri.path != "/api"
    return 404
  end
  return CGI::parse(uri.query)
end

def sendreq(code, client, body)
  begin
    body = JSON.generate(body)
  rescue
    body = '{"ok": false, "message": "Internal Server Error"}'
  end
  head = "HTTP/1.1 #{code}\r\n"
  head += "Content-Length: #{body.size}\r\n"
  head += "Content-Type: application/json\r\n"
  head += "Access-Control-Allow-Origin: *\r\n"
  head += "\r\n"
  head += "#{body}\r\n"
  client.print(head)
end


#######################################################################################

while client = server.accept
  Thread.start do
    begin
      request = client.readpartial(3000)
      params = parseheader(request)
      if params == 404
        sendreq(404, client, {"ok": false, "message": "Not Found"})
      end

      func = params["method"][0]
      data = params["data"][0]

      if func == nil or data == nil or !meths.include?(func)
        sendreq(400, client, {"ok": false, "message": "Bad Request"})
      end

      if func == "html"
        dataencoded = CGI.escapeHTML(data)
        sendreq(200, client, {"ok": true, "data": dataencoded})
      elsif func == "path"
        dataencoded = data.gsub!(/\.+/, ".")
        sendreq(200, client, {"ok": true, "data": dataencoded})
      elsif func == "shell"
        dataencoded = data.shellescape
        sendreq(200, client, {"ok": true, "data": dataencoded})
      end

      rescue
      sendreq(500, client, {"ok":false, "message": "Internal Server Error"})
      ensure
      client.close
    end

  end

end