get-file-checksum

#!/bin/bash

# This script has moved to https://github.com/sara-nl/GridScripts/blob/master/get-file-checksum.

# This script talks to a dCache webdav door to get the checksum(s) of a file.
#
# Changes:
# 2018-07-11 - Onno - Initial version

usage() {
  cat <<-EOF
	Lists checksum(s) for a file in a dCache storage system through WebDAV.
	Usage: $0 [options...]
	Options are:
	  --url <url>          - A webdav URL of a file in a dCache instance
	  --adler32            - List only the Adler32 checksum
	  --md5                - List only the MD5 checksum
	                         Default: list both Adler32 and MD5 if available
	  --proxy              - Authenticate with proxy specified in X509_USER_PROXY
	  --user <username>    - Authenticate with Username/password
	  --debug              - Show additional info for troubleshooting
	
	Examples:
	  $0 --url https://my-dcache-server.org/users/homer/disk-shared/ --user homer
	  $0 --url https://my-dcache-server.org:2882/users/homer/disk-shared/ --proxy --md5
	EOF
  exit 1
}

url=
adler32=false
md5=false
user=
proxy=false
recursive=false
debug=false

while [ $# -gt 0 ] ; do
  case "$1" in
    --url )
      url="$2"
      shift 2
      ;;
    --adler32 )
      adler32=true
      shift
      ;;
    --md5 )
      md5=true
      shift
      ;;
    --recursive )
      echo "Not implemented" ; exit 1
      recursive=true
      shift
      ;;
    --user )
      user=$2
      proxy=false
      shift 2
      ;;
    --proxy )
      proxy=true
      shift
      ;;
    --debug )
      debug=true
      shift 1
      ;;
    *)
      usage
      ;;
  esac
done

if [ -z "$url" ] ; then
  usage
fi

# If neither adler32 nor md5 is requested, show them both.
if ! $md5 && ! $adler32 ; then
  md5=true
  adler32=true
fi

if [ -n "$user" -a "$proxy" == "true" ] ; then
  echo "ERROR: you can't specify both --user and --proxy." 1>&2
  exit 1
fi

server=$(echo "$url" | egrep -o 'https://[^/]+/')
dir=$(echo "$url" | sed -e 's#https://[^/]\+##')
if [ -z "$dir" ] ; then
  dir=/
fi

if [ -z "$server" ] ; then
  echo "Please include the server in '--url'." 1>&2
  exit 1
fi

if $proxy ; then
  # Check if the proxy is still valid; if not, exit after the error message.
  if [ -x "$(command -v voms-proxy-info)" ]; then
    voms-proxy-info --exists 1>&2 || exit 1
  fi
  authn="--capath /etc/grid-security/certificates/ --cert $X509_USER_PROXY --cacert $X509_USER_PROXY"
else
  if [ -z "$user" ] ; then
    echo "Please specify --proxy, or specify a username with --user." 1>&2
    exit 1
  fi
  authn="-u $user"
fi

result=false

if $adler32 ; then
  if $debug ; then
    echo "Curl command:"
    echo "curl --head --header 'Want-Digest: ADLER32' --silent --fail " \
               "$authn " \
               "$url"
    echo
  fi
  result_adler32=$(curl --head --header 'Want-Digest: ADLER32' --silent --fail \
                        $authn \
                        $url \
                   | egrep -o 'adler32=[0-9a-f]+' )
  if [ -n "$result_adler32" ] ; then
    result=true
    echo "$result_adler32  $dir"
  fi
fi

if $md5 ; then
  if $debug ; then
    echo "Curl command:"
    echo "curl --head --header 'Want-Digest: MD5' --silent --fail " \
               "$authn " \
               "$url"
    echo
  fi
  result_md5=$(curl --head --header 'Want-Digest: MD5' --silent --fail \
                    $authn \
                    $url \
               | grep -o 'md5=.*' \
               | sed -e 's/md5=//' -e 's/[\r\n]*$//' \
               | base64 --decode \
               | xxd -p )
  if [ -n "$result_md5" ] ; then
    result=true
    echo "md5=$result_md5  $dir"
  fi
fi


# Still no result? Then show error.
if ! $result ; then
  echo "ERROR: no checksum found." 1>&2
  exit 1
fi