mosh

#!/bin/bash


###############################################################
## Mosh 2: Alternative frontend for Mosh                     ##
##                                                           ##
## Developed by Varun Agrawal (Varun@VarunAgw.com)           ##
###############################################################


show_help() {
	echo -e "Alternative frontend for MOSH by Varun Agrawal (www.VarunAgw.com)"
	echo -e "Usage: $0 [user@]host [mosh-options] [ssh-options]"
	echo -e ""
	echo -e "[mosh-options]"
	echo -e "-pd\t--predict=adaptive      local echo for slower links [default]"
	echo -e "-pa\t--predict=always        use local echo even on fast links"
	echo -e "-pn\t--predict=never         never use local echo"
	echo -e "-pe\t--predict=experimental  aggressively echo even when incorrect"
	echo -e ""
	echo -e "\t--ip=xxx.xxx.xxx.xxx    tell server IP to MOSH if it fails to find it"
	echo -e "\t--get                   return session connection command instead of connecting"
	echo -e ""
	echo -e "Example: $0 ec2 -pe -v -p 2020"
}

if [ "--h" == "$*" ] || [ "--help" == "$*" ] || [ -z "$*" ] ; then
	show_help
	exit
fi

error() {
	echo -e "MOSH: $*" >&2
}

# Set default value of arguments
ARG_PREDICT="adaptive"
ARG_IP=""
ARG_SSH=""
ARG_SERVER=""
ARG_GET=false

for i in "$@"
do
	case $i in
		-pd|--predict=adaptive)
			ARG_PREDICT="adaptive"
		;;
		-pa|--predict=always)
			ARG_PREDICT="always"
		;;
		-pn|--predict=never)
			ARG_PREDICT="never"
		;;
		-pe|--predict=experimental)
			ARG_PREDICT="experimental"
		;;
		--ip=*)
			ARG_IP="${i#*=}"
		;;
		--get)
				ARG_GET=true
		;;
		*)
			ARG_SSH="$ARG_SSH ${i#*=}"
		;;
	esac
done


if [ -n "$ARG_SSH" ]; then
	ARG_SSH_ARRAY=($ARG_SSH)
	ARG_SERVER=${ARG_SSH_ARRAY[0]}
else
	error "User/Hostname is missing. Exiting!"
	exit 1
fi

if [ -n "$ARG_IP" ]; then
	IP="$ARG_IP"
else
	if [[ "$ARG_SERVER" =~ .+@(.+) ]]; then
		HOSTNAME="${BASH_REMATCH[1]}"
	else
		config=`cat ~/.ssh/config`
		# grep -Po don't support ^. Prepending new line for Host on first line
		HOSTNAME=`echo $'\n'"$config" | grep -Pizo "(?s)\n\s*Host.*?\s$ARG_SERVER(\s|\n).*?\n\s*HostName .*?\n"`
		HOSTNAME=`echo "$HOSTNAME" | tail -n 1`
		HOSTNAME=`echo "$HOSTNAME" | sed -r "s/.*HostName\s*//i" | sed -r "s/\s+//i"`
	fi

	if [ -z "$HOSTNAME" ]; then
		error "Cannot find hostname. Please run with --ip=xxx.xxx.xxx.xxx. Exiting!"
		exit 1
	fi

	if [[ $HOSTNAME =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
		IP="$HOSTNAME"
	else
		IP=`dig +short $HOSTNAME`
	fi

	if [ -z "$IP" ]; then
		error "Cannot find IP address of server. Please run with --ip=xxx.xxx.xxx.xxx. Exiting!"
		exit 1
	fi
fi


SSH_COMMAND="ssh -t $ARG_SSH mosh-server new"
SSH_OUTPUT=`$SSH_COMMAND`
SSH_OUTPUT=`echo $SSH_OUTPUT | sed -r "s/\r|\n|//g" | sed -r "s/(^ *)|( *$)//g"`

if ! [[ "$SSH_OUTPUT" == MOSH\ CONNECT\ * ]]; then
	error ""
	error "SSH Failed to server"

	if [ -n "$SSH_OUTPUT" ]; then
		error "$SSH_OUTPUT"
	fi
	exit 1
fi


MOSH_CONNECTION=($SSH_OUTPUT)
MOSH_PORT=${MOSH_CONNECTION[2]}
MOSH_KEY=${MOSH_CONNECTION[3]}

if [ true == $ARG_GET ]; then
	echo "MOSH_PREDICTION_DISPLAY=$ARG_PREDICT MOSH_KEY=$MOSH_KEY mosh-client $IP $MOSH_PORT"
else
	MOSH_PREDICTION_DISPLAY=$ARG_PREDICT MOSH_KEY=$MOSH_KEY mosh-client $IP $MOSH_PORT
fi