Git pre-commit hook for Rails to highlight route changes

pre-commit

#!/bin/sh

if git rev-parse --verify HEAD >/dev/null 2>&1
then
	against=HEAD
else
	# Initial commit: diff against an empty tree object
	against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

# Allows us to read user input below, assigns stdin to keyboard
exec < /dev/tty

if [ "$skiprouteswarning" != "true" ] && test $(git diff --name-only HEAD | grep "config/routes" | wc -l) -gt 0
then
  # Cache the altered filenames
  ALTERED_ROUTES_FILES=`git diff --name-only HEAD | grep "config/routes"`

  # Display holding message
	cat <<EOF

######### APPLICATION ROUTES HAVE BEEN ALTERED #########
________________________________________________________

Review to ensure NO UNNEEDED ROUTES have been added.

Houl yer whisht. Analysing route changes for review ...


EOF

  # Build a temp working directory
  NEW_UUID=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)
  WORKING_DIR=/tmp/routes_${NEW_UUID}
  mkdir -p ${WORKING_DIR}/config/routes

  # Capture the new routes config
  bundle exec rake routes > ${WORKING_DIR}/new_routes.txt
  bundle exec rake traceroute | sed '/Unreachable action methods/,$d' > ${WORKING_DIR}/new_traceroute.txt

  # Capture the old routes config
  for file in $ALTERED_ROUTES_FILES
  do
    cp ${file} ${WORKING_DIR}/${file}
    git checkout $against -- ${file}
  done
  bundle exec rake routes > ${WORKING_DIR}/old_routes.txt
  bundle exec rake traceroute | sed '/Unreachable action methods/,$d' > ${WORKING_DIR}/old_traceroute.txt

  # Calculate the diff
  ROUTES=`diff ${WORKING_DIR}/new_routes.txt ${WORKING_DIR}/old_routes.txt`
  TRACEROUTE=`diff ${WORKING_DIR}/new_traceroute.txt ${WORKING_DIR}/old_traceroute.txt`

  # Reset files as nature intended
  for file in $ALTERED_ROUTES_FILES
  do
    cp ${WORKING_DIR}/${file} ${file}
    git add ${file}
  done

  # Delete working directory
  rm -rf ${WORKING_DIR}

  # Output findings
	cat <<EOF

### ROUTE CHANGES ###
_____________________

${ROUTES}

_____________________


### NEW UNUSED ROUTES ###
_________________________

${TRACEROUTE}
_________________________



Know what you are doing? Disable check using:
  > git config hooks.skiprouteswarning true


EOF

  # Check if user wants to proceed
  echo -n "Proceed with commit (Y) or cancel?\n"
  read YN
  case $YN in
    Y | y | Yes | YES | yes ) echo "OK, you are happy. Let's commit"; exit 0;;
    * ) echo "I'll take that as a no. Abandoning commit!"; exit 1;;
  esac
fi

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