Tag Archives: computercraft

Controlling a computercraft turtle remotely

By | |

Screen Shot 2015-10-18 at 7.16.59 PM
Screen Shot 2015-10-18 at 7.17.30 PM

  1. Install Redis: https://www.digitalocean.com/community/tutorials/how-to-install-and-use-redis
  2. Install Webdis
  3. Start a minecraft server with computercraft. You will need to have the http API enabled, which is the default.
  4. Put down a turtle I recommend a turtle with a crafting square and a pickaxe. I also recommend giving it a label. If you’re not trying the turtle replication challenge, either disable fuel or get a fair bit of starting fuel. Write down the computer’s id.
  5. Put down a chunk loader, if you’re in a modpack that has them, or DON’T log out. Computers and turtles can’t operate unless the chunks are loaded. If you’re putting down a chunkloader, I surrounded them with bedrock for foolproofing.

  6. Open the turtle and download the following script, changing “redis.example.com” to your own redis instance: pastebin get 8FjggG9w startup
    After you have the script saved as ‘startup’, run it or reboot the computer, and it should start listening for instructions.

    redis = "http://redis.example.com" 
queue = "sshbot" .. os.getComputerID()
return_queue = queue .. "_return"
print("Remote webdis queues on icyego: " .. queue .. " and " .. return_queue)
print("Receiving remote commands.")

function exec(str)
  print("Running: " .. str)
  f = fs.open("tmp", "w")
  f.write(str)
  f.close()
  p = loadfile("tmp")
 status, err = pcall(function () p = loadfile("tmp"); return p() end)
  if status then
    status, ret = pcall(function() return textutils.serialize(err) end)
    if status then
      result = ret
    else
      result = ""
    end
  else
    result = "Error: " .. err
  end
  print(result)
  return result
end

print("Now receiving remote commands.")
while true do
  handle = http.get(redis .. "/BRPOP/" .. queue .. "/5.txt")
  if (handle and handle.getResponseCode() == 200) then 
    str = handle.readAll()
    handle.close()
    str = string.sub(str, string.len(queue) + 1)
    result = exec(str)
    if string.find(result, "Error: ") then
      result2 = exec("return " .. str)
      if string.find(result2, "Error: ") then a=0 else result=result2 end
    end
    http.post(redis, "LPUSH/" .. return_queue .. "/" .. result)
  end
end

  7. On your local machine, save the following, again replacing “redis.example.com”:

    #!/bin/bash
function send() {
  curl -s -X POST -d "LPUSH/sshbot${1}/${2}" "http://redis.example.com" >/dev/null

}

function get() {
  curl -s -X GET "http://redis.example.com/BRPOP/sshbot${1}_return/20.json" | jq .BRPOP[1]
}

if [ $# -ne 1 ]; then
  echo "Usage: rlwrap ./sshbot <COMPUTER_ID>"
  exit 1
fi
ID=$1

while read LINE; do
  send ${ID} "$LINE"
  get ${ID}
done

  8. Run: rlwrap ./sshbot , where is the turtle’s ID. You should be able to send commands to the computer now.

Tagged , ,