Bash script for fetching DHBW Dualis grades

dualis.sh

#!/bin/bash
# Dualis notification script by p-fruck <dev@p-fruck.de>
# License: Apache 2.0 (https://www.apache.org/licenses/LICENSE-2.0)
#
# This script is intended to be used within a cronjob and will use the
# notify-send command once it detects new grades. However you can simply
# modify the code and use e.g. email notification instead. Have fun.
username=user@dhbw.de
password=Password1!
baseurl="https://dualis.dhbw.de/scripts/mgrqispi.dll"

saves=$(dirname "$0")/.dualis.save

# This function is your entry-point to the code. It takes two parameters:
#  $1: The grade you've achieved
#  $2: The course you've achieved the grade in
# Now go ahead an decide what you do with the information,
#  or use notify-send like I do by default.
function grade_fetched() {
        info="$1 $2"
        touch "${saves}"
        isnew=$(grep "$info" "${saves}")
        # check if grade is new
        if [[ -z $isnew ]]; then
                echo "$info" >> "${saves}"
                notify-send "Neue Bewertung:" "$info"
        fi
}

## login to dualis
cookie=$(mktemp)
curl -X POST --cookie ${cookie} --cookie-jar ${cookie} -s \
        -F "usrname=${username}" \
        -F "pass=${password}" \
        -F 'APPNAME=CampusNet' \
        -F 'PRGNAME=LOGINCHECK' \
        -F 'ARGUMENTS=clino,usrname,pass,menuno,menu_type,browser,platform' \
        -F 'clino=000000000000001' \
        -F 'menuno=000324' \
        -F 'menu_type=classic' \
        -D 'header' \
        "${baseurl}" > /dev/null

# some authentication parameters needed for dualis
argVar=$(sed -n 's/.*ARGUMENTS=//p' header)
rm header

curl_cmd="curl -X GET --cookie ${cookie} --cookie-jar ${cookie} -s ${baseurl}?APPNAME=CampusNet&PRGNAME=COURSERESULTS&ARGUMENTS="

## fetch semesters
semester=`${curl_cmd}${argVar%,*} | sed -n '/<select id="semester"/,/<\/select>/p' | grep -oP '(?<=value=").*?(?=")'`
## fetch links to exams
links=""
for sem in ${semester}
do
        for link in `${curl_cmd}${argVar%,*},-N${sem} | grep -oP '(?<=href="/scripts/mgrqispi.dll).*RESULTDETAILS.*?(?=")'`
        do
                # add link to list if not already in there
                [[ "${links}" == *"${link}"* ]] || links+=" $link"
        done
done

# replace &-symbols in links
links=$(echo $links | sed 's/amp;//g')
## fetch exams and extract grades and course
for link in ${links}
do
        exam=$(curl --cookie ${cookie} --cookie-jar ${cookie} -s "${baseurl}${link}")
        grades=$(echo "$exam" | grep '^\s*[0-9]*,[0-9]')
        i=0
        for grade in $grades
        do
                ((i++))
                grade="${grade//[$'\t\r\n']}"
                course=$(echo "$exam" | grep '<td class="tbdata"' | tail -$((i*4-1)) | head -1 | grep -oP '(?<=">).*(?=<)')
                grade_fetched "$grade" "$course"
        done
done

rm $cookie