Dark Retriever

function getUrlFile(url)
  local status, mrHttpFile = pcall(http.get, url)
  if not status then
    print("\nFailed to get Program Versions file.")
    print("Error: ".. mrHttpFile)
    return exit
  end
  mrHttpFile = mrHttpFile.readAll()
  return mrHttpFile
end
function writeFile(filename, data)
  local file = fs.open(filename, "w")
  file.write(data)
  file.close()
end

if http then
  print("Grabbing retriever..")
  cat = getUrlFile("https://raw.github.com/darkrising/darkprograms/darkprograms/programVersions")
  if not cat then
    return exit
  end
  cat = textutils.unserialize(cat)
  currentRunning = shell.getRunningProgram()
  program = getUrlFile(cat["darkretriever"].GitURL)
  writeFile(currentRunning, program)

  shell.run(currentRunning)
else
  print("HTTP is not enabled.")
end