pushover

#! /bin/sh
#
# pushover - script to send notification to the  service PushOver
#
# https://pushover.net/
#
# Variables

Version="0.0.10"

USAGE="usage: `basename $0` [parameters] text"

ConfigFile="$HOME/.`basename $0`.conf"

# Defaults for additional parameters on priority 'emergency'
EmergencyRetry=60
EmergencyExpire=3600

# Functions
showUsage ()
{
cat <<EOUsageText
$USAGE

Use option -h for getting help.
EOUsageText
}

readConfig ()
{
#
# Read the config
#
# Check if config is readable (and existing)
if [ ! -r $1 ]; then
    echo "Error: The config file '$1'"
    echo "       does not exist or is not readable."
    exit 2
fi
# Check access rights
# Get access right in human readable form
#
# Linux and Mac OS/Darwin/BSD have not the same syntax for 'stat'
# Have to determine the OS flavour and use the matching syntax
if [ "$(uname | xargs printf "%s")" = "Linux" ]; then
    # We are on Linux
    ConfigFileMod=$(stat -c %A $1)
else
    # Not Linux. probably Mac OS/Darwin/BSD
    ConfigFileMod=$(stat -f %Sp $1)
fi

# Check if file writable for others
# Is mod g=w or o=w? -> error
if  [ "$(echo $ConfigFileMod | cut -c 6 | xargs printf "%s")" = "w" -o \
      "$(echo $ConfigFileMod | cut -c 9 | xargs printf "%s")" = "w" ]; then
    echo "Error: The config file '$1'"
    echo "       is writable by other users."
    echo "       The program was halted for security reasons."
    echo "       Check the file for malicious content and change the access rights:"
    echo "       chmod 600 $1"
    exit 3
fi
# Warn if file is readable for others
# Is mod g=r or o=r
if  [ "$(echo $ConfigFileMod | cut -c 5 | xargs printf "%s")" = "r" -o \
      "$(echo $ConfigFileMod | cut -c 8 | xargs printf "%s")" = "r" ]; then
    echo "Warning: The config file '$1'"
    echo "         is readable by other users."
    echo "         You should protect your API key."
    echo "         Change the access rights:"
    echo "         chmod 600 $1"
fi
# FixMe: Lazy and unsafe solution using sourcing
. $1
}

showHelp ()
{
cat <<EOHelpText
usage: `basename $0` [-t <title>] [-p <priority>] [-s <sound>] [-u <userid>]
                     <msg text>
       `basename $0` -h
       `basename $0` -v

Script for sending notification with Pushover (https://pushover.net)

Version $Version

-t  set title for the notification
-p  set priority for the notification
    Valid priorities are 'lowest', 'low', 'normal', 'high', and 'emergency'.
-s  set sound for the notification
    Valid sounds are  'pushover' , 'bike', 'bugle', 'cashregister',
    'classical', 'cosmic', 'falling', 'gamelan', 'incoming', 'intermission',
    'magic', 'mechanical', 'pianobar', 'siren', 'spacealarm', 'tugboat',
    'alien', 'climb', 'persistent', 'echo', 'updown', and 'none'.
-u  set key of the user or group which will receive the notification.
-h  print this text and exit
-v  print version and exit

If the message text is "-" (a single hyphen) the text will be read
from stdin.

EOHelpText
}

urlencode () {
#
# This implematation of urlencoding is taken from
# https://stackoverflow.com/a/3077738/747635
#
 [ $# -lt 1 ] &&  { return; }

 encodedurl="$*";

# make sure hexdump exists, if not, just return
 [ ! -x "/usr/bin/hexdump" ] && { return; }

echo $(echo $encodedurl | hexdump -v -e '1/1 "%02x\t"' -e '1/1 "%_c\n"' |
    LANG=C awk '
        $1 == "20"                    { printf("%s",   "%20"); next } # space    -> %20 # changed from original
        $1 ~  /0[adAD]$/              { printf("%s",   "%0A"); next } # newlines -> %0A # changed from original
        $2 ~  /^[a-zA-Z0-9.*()\/-]$/  { printf("%s",   $2);  next }   # pass through what we can
                                   { printf("%%%s", $1)        }   # take hex value of everything else
   ')
}

##########
#
# Cause 'urlencode' return no value, if 'hexdump' is not available
# here is a check for 'hexdump':
if  [ ! -x "/usr/bin/hexdump" ]; then
    echo "Error:  The tool 'hexdump' is not available."
    exit 1
fi

# EndFunctions

# Parse command line options.
while getopts hvt:u:p:s: OPT; do
    case "$OPT" in
        h)
            showHelp
            exit 0
            ;;
        v)
            echo "`basename $0` version $Version"
            exit 0
            ;;
        t)
            # Store MSGTitle from arguments
            ArgMSGTitle=$OPTARG
            ;;
        u)
            # Store UserKey from arguments
            ArgUserKey=$OPTARG
            ;;
        p)
            PrioOption=$OPTARG
            case "$PrioOption" in           #FixMe Move case to function ParsePriority
                lowest|stealth|-2)
                    MSGPriority="-2"
                    ;;
                low|silent|-1)
                    MSGPriority="-1"
                    ;;
                normal|0)
                    MSGPriority="0"
                    ;;
                high|1|+1)
                    MSGPriority="1"
                    ;;
                emergency|2|+2)
                    MSGPriority="2"
                    ;;
                *)
                    # invalid priority -> error
                    echo "Error: Invalid value \"$PrioOption\" for priority."   #FixMe Jump to help
                    exit 10
                    ;;
            esac
            ;;
        s)
            MSGSound=$OPTARG
            case "$MSGSound" in
                pushover|bike|bugle|cashregister|classical|cosmic|falling)
                    # Value o.k., perhaps my programming skills not...
                    ;;
                gamelan|incoming|intermission|magic|mechanical|pianobar)
                    # Value also .o.k. ...
                    ;;
                siren|spacealarm|tugboat|alien|climb|persistent|echo|updown|none)
                    # Value also o.k. ...
                    ;;
                *)
                    # invalid sound defined -> error
                    echo "Error: Invalid value \"$MSGSound\" for sound."
                    exit 10
                    ;;
            esac
            ;;
        \?)
            # getopts issues an error message
            showUsage >&2
            exit 10
            ;;
    esac
done

# Remove the options we parsed above.
shift `expr $OPTIND - 1`

# We need at least one non-option argument.
# If not then there is no message text
if [ $# -eq 0 ]; then
    showUsage >&2
    exit 11
fi

# The additional arguments ($*) are the message text or "-" for reading stdin
# id not "-" use the input
if [ "$*" !=  "-" ]; then
    MSG=$(urlencode $*)
else
    # else read stdin
    while read LINE; do
        MSG=$MSG+$(urlencode ${LINE})
    done
fi

#
# Read the config
#
readConfig $ConfigFile


# Overwriting setting from configfile with settings from arguments
# Only use ArgMSGTitle if it's not empty
if [ ! -z "$ArgMSGTitle"  ]; then
    MSGTitle=$ArgMSGTitle
fi
# Only use ArgUserKey if it's not empty
if [ ! -z "$ArgUserKey"  ]; then
    UserKey=$ArgUserKey
fi

# Check if all nessary values are set.
# (Values set within the script do not have to be checked.)
#
# Check APIKey
if [ -z "$APIKey"  ]; then
    echo "Error: API-Key is not provided."
    exit 4
fi

# Check User/Group-ID
if [ -z "$UserKey"  ]; then
    echo "Error: User/Group-ID is not provided."
    exit 4
fi


# Genrating string with command-sequence
CurlCall="curl -s   -d token=$APIKey&user=$UserKey&message="$MSG""

# Here some more option, when set (e.g. title, priority)
# embeded in conditional-constructs
#
# Is title set, add  -t
if [ ! -z "$MSGTitle"  ]; then
    CurlCall="$CurlCall&title=$(urlencode $MSGTitle)"
fi

# Is priority set
case $MSGPriority in
    -2|-1|1)
        CurlCall="$CurlCall&priority=$MSGPriority"
        ;;
    2)
        CurlCall="$CurlCall&priority=$MSGPriority&retry=$EmergencyRetry&expire=$EmergencyExpire"
        ;;
esac

# Is sound set
if [ ! -z "$MSGSound"  ]; then
        CurlCall="$CurlCall&sound=$MSGSound"
fi

# Add API-endpoint to the paraneter
CurlCall="$CurlCall https://api.pushover.net/1/messages.json"

# Call Pushover.net
PushoverResponse=$($CurlCall)
CurlReturnCode=$?

# Checking, if an error accured
#
# Phase 1: curl coneecting Pushover
#
# curl has thrown an error (exit code !=0 )
# codes: https://ec.haxx.se/usingcurl-returns.html
#
if [ !  $CurlReturnCode = "0"  ]; then
    echo "Error while connecting to Pushover.net (curl exit code $CurlReturnCode)."
    exit 20
fi

# Phase 2: Examine resppnse from Pushover.net
#
# If the first attribute is 'status', then call was successful
#
# Exception:
# If the priority is 'emergency' and the the call is successful,
# then the first attribute is 'receipt'
# We can use this information to get the  parameter for a call back function
#
# Parse the response
#
# cut the response at the first end second quotation mark to get th first
First=$(echo $PushoverResponse | cut -d'"' -f2)
case $First in
    status)
        # Success
        ;;
    receipt)
        # Also success, cause a receipt is only sended for an successful call
        # Parse and store the receipt ID for later use
        PushoverReceiptID=$(echo $PushoverResponse | cut -d'"' -f4)
        ;;
    *)
        # Everything else is an error (or I don't know it now...)
        # Error message is surounded by '[...]'
        # (if there is no error message, complete response will be echoed.)
        PushoverError=$(echo $PushoverResponse | cut -d[ -f2 | cut -d] -f1)
        echo "Error Message from Pushover.net: $PushoverError"
        exit 21
        ;;
esac