UMN Schedule to Google Calendar

Updated Fall 2020

Now supports recurring events!

This script ports the class schedule from MyU to your google calendar. To use:

1. Go to MyU (myu.umn.edu) and click the Academics tab. Make sure the "My Classes" tab is selected and use the arrows navigate to the first week of classes.
2. Right click anywhere on the page and click "Inspect". On Firefox it's called "Inspect Element" and on Safari you can follow these instructions.
3. Scroll to the Console tab on the window that pops up. Copy and paste the following code directly into the console and press enter. Note: Never paste random code from the internet into your console! Make sure you trust me before continuing. A malicious attacker in my place could, for example, install malware, un-enroll you from all of your classes and pay your tuition.

   // to run: go to myU and to the schedule page, then inspect element and paste this in the console
   
   const ICS_HEADER = `BEGIN:VCALENDAR
   PRODID:Calendar
   VERSION:2.0
   BEGIN:VTIMEZONE
   TZID:America/Chicago
   X-LIC-LOCATION:America/Chicago
   BEGIN:DAYLIGHT
   TZOFFSETFROM:-0600
   TZOFFSETTO:-0500
   TZNAME:CDT
   DTSTART:19700308T020000
   RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
   END:DAYLIGHT
   BEGIN:STANDARD
   TZOFFSETFROM:-0500
   TZOFFSETTO:-0600
   TZNAME:CST
   DTSTART:19701101T020000
   RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
   END:STANDARD
   END:VTIMEZONE`;
   
   const ICS_FOOTER = '\nEND:VCALENDAR';
   
   let idCount = 0;
   function getICSEntry(name, type, place, startDateStr, endDateStr, rrule){
       let result = '\nBEGIN:VEVENT';
       result += '\n' + (idCount++) + '@default';
       result += '\nDESCRIPTION:' + type;
       result += rrule ? '\n' + rrule : '';
       const now = new Date();
       let hours = now.getHours();
       if(hours < 10){ hours = '0' + hours; }
       let minutes = now.getMinutes();
       if(minutes < 10){ minutes = '0' + minutes; }
       let timeStr = hours + '' + minutes;
       result += '\nDTSTAMP;TZID=America/Chicago:' + getICSDateString(now.getFullYear(), now.getMonth() + 1, now.getDate(), timeStr);
       result += '\nDTSTART;TZID=America/Chicago:' + startDateStr;
       result += '\nDTEND;TZID=America/Chicago:' + endDateStr;
       result += '\nLOCATION:' + place;
       result += '\nSUMMARY;LANGUAGE=en-us:' + name;
       result += '\nTRANSP:TRANSPARENT';
       result += '\nEND:VEVENT';
       return result;
   }
   
   function getWeekDateString(){
       let nextWeekButton = document.querySelector('[title=\'Next Week\']');
       let dateH = nextWeekButton.parentElement.children[1];
       let fullString = dateH.innerText;
       return fullString.match(/\d\d\/\d\d\/\d\d\d\d/g)[0];
   }
   
   function getICSDateString(year, month, day, timeStr){
       let monthStr = month + '';
       while(monthStr.length < 2){ monthStr = '0' + monthStr; }
       let dayStr = day + '';
       while(dayStr.length < 2){ dayStr = '0' + dayStr; }
       return year + '' + monthStr + dayStr + 'T' + timeStr + '00';
   }
   
   let days = ['Monday','Tuesday','Wednesday','Thursday','Friday'];
   
   function getClassDataForWeek(){
       let weekData = {};
       for(let d of days){
           weekData[d] = [];
       }
       for(let day of days){
           let dayGroup = document.querySelector('[data-day=\''+day+'\']');
           if(!dayGroup){
               return weekData;
           }
           // each class is an  element
           let classElements = [];
           for(let el of dayGroup.childNodes){
               if(el.nodeName === 'A'){
                   classElements.push(el);
               }
           }
   
           for(let c of classElements){
               let name = c.children[0].innerText;
               let details = c.children[1].innerText;
               let [type, time, place] = details.split('\n');
               weekData[day].push({name:name,time:time,place:place,type:type});
           }
       }
       return weekData;
   }
   
   function isWeekEmpty(data){
       for(let key in data){
           if(data[key].length > 0){
               return false;
           }
       }
       return true;
   }
   
   function nextWeek(){
       let nextWeekButton = document.querySelector('[title=\'Next Week\']');
       nextWeekButton.click();
   }
   
   Date.prototype.addDays = function(days) {
       var date = new Date(this.valueOf());
       date.setDate(date.getDate() + days);
       return date;
   }
   
   function mod(n, m) {
       return ((n % m) + m) % m;
   }
   
   function toMilitary(hour, isAM){
       if(isAM){
           if(hour === 12){
               return 0;
           }
           return hour;
       }
       if(hour === 12){
           return 12;
       }
       return hour + 12;
   }
   
   
   let weeks = [];
   let weeksEmpty = 0;
   
   function proceed(){
       let weekData = getClassDataForWeek();
       if(weeksEmpty <= 1){
           if(isWeekEmpty(weekData)){
               weeksEmpty++;
               weeks.push({isEmpty: true});
           }else{
               weeksEmpty = 0;
               weeks.push({isEmpty: false, weekDate:getWeekDateString(), data:weekData});
           }
           nextWeek();
           // wait until it finishes loading
           setTimeout(proceed, 3000);
       }else{
           let dayDateConversion = {'Monday':0,'Tuesday':1,'Wednesday':2,'Thursday':3,'Friday':4};
           for(let week of weeks){
               if(week.isEmpty){
                   continue;
               }
               // map days to dates
               let weekDate = new Date(week.weekDate);
               for(let d of days){
                   let classes = week.data[d];
                   for(let c of classes){
                       // english/US date format (locale)
                       let classDate = weekDate.addDays(dayDateConversion[d]);
                       let year = classDate.getFullYear();
                       let month = classDate.getMonth() + 1;
                       let day = classDate.getDate();
                       let classTime = c.time;
                       // isolate start/end time. myU uses the hh:mm - hh:mm AM/PM format
                       let lastIsAM = !!classTime.match(/AM/g);
                       let [startTime, endTime] = classTime.match(/\d{1,2}:\d{1,2}/g);
                       let [startTimeHour, endTimeHour] = [startTime.split(':')[0], endTime.split(':')[0]].map(x=>parseInt(x));
                       
                       // we want to know if the first hour occurs in the AM or the PM.
                       // we make the assumption that no class lasts more than 12 hours (apparently the folks
                       // who made myU thought so too), so we take the option (am vs pm) in which the class length is less
                       let militaryAMOption = toMilitary(startTimeHour, true);
                       let militaryPMOption = toMilitary(startTimeHour, false);
                       let militaryEnd = toMilitary(endTimeHour, lastIsAM);
   
                       let firstIsAM;
                       if(mod(militaryEnd - militaryAMOption, 24) < mod(militaryEnd - militaryPMOption, 24)){
                           firstIsAM = true;
                       } else {
                           firstIsAM = false;
                       }
   
                       c.year = year;
                       c.month = month;
                       c.day = day;
                       const toTimeString = (timeStr, isAM) => {
                           let [hr, minute] = timeStr.split(':');
                           let militaryHr = toMilitary(parseInt(hr), isAM) + '';
                           while(militaryHr.length < 2){ militaryHr = '0' + militaryHr; }
                           while(minute.length < 2){ minute = '0' + minute; }
                           return militaryHr + minute;
                       };
                       c.startTime = toTimeString(startTime, firstIsAM);
                       c.endTime = toTimeString(endTime, lastIsAM);
                       // flag so we don't process this event twice
                       c.used = false;
                   }
               }
           }
   
           // returns null if doesn't exist
           function getClassOnDay(weekIndex, dayIndex, originalClass){
               if(weeks[weekIndex].isEmpty){
                   return null;
               }
               for(let c of weeks[weekIndex].data[days[dayIndex]]){
                   if(c.name === originalClass.name && 
                       c.time === originalClass.time &&
                       c.place === originalClass.place &&
                       c.type === originalClass.type){
                       return c;
                   }
               }
               return null;
           }
   
           // our ical object
           let calendar = ICS_HEADER;
   
           for(let weekIndex = 0; weekIndex < weeks.length; weekIndex++){
               if(weeks[weekIndex].isEmpty){
                   continue;
               }
               for(let dayIndex = 0; dayIndex < 5; dayIndex++){
                   let classes = weeks[weekIndex].data[days[dayIndex]];
                   for(let c of classes){
                       if(c.used){
                           // already covered this single class instance in a recurring event
                           continue;
                       }
                       c.used = true;
                       // otherwise search for event to go in a recurring event along with this one
                       // first check the next days in this week 
                       let classDays = [dayIndex];
                       for(let i = dayIndex + 1; i < dayIndex + 5; i++){
                           let w = i >= 5 ? weekIndex + 1 : weekIndex;
                           let c2 = getClassOnDay(w, i % 5, c);
                           if(c2 != null){
                               classDays.push(i % 5);
                               c2.used = true;
                           }
                       }
                       let numEvents = classDays.length;
   
                       // now continue to following weeks until we find some day in classDays where this not a matching event
                       let classDaysIndex = 0;
                       let workingWeekIndex = weekIndex + 1;
                       while(true){
                           const day = classDays[classDaysIndex];
                           let c2 = getClassOnDay(workingWeekIndex, classDays[classDaysIndex], c);
                           if(c2 != null){
                               if(!c2.used){
                                   numEvents++;
                               }
                               c2.used = true;
                           }else {
                               break;
                           }
                           classDaysIndex = (classDaysIndex + 1) % classDays.length;
                           if(classDays[classDaysIndex] <= day){
                               workingWeekIndex++;
                           }
                       }
   
                       // now add a single event if we only found a single event, otherwise a recurring event 
                       let rrule = null;
                       if(numEvents > 1){
                           rrule = 'RRULE:FREQ=WEEKLY;COUNT=' + numEvents + ';BYDAY=' + classDays.map(x => ['MO', 'TU', 'WE', 'TH', 'FR'][x]).join(',');
                       }
                       
                       console.log(c);
                       calendar += getICSEntry(c.name, c.type, c.place, getICSDateString(c.year, c.month, c.day, c.startTime), getICSDateString(c.year, c.month, c.day, c.endTime), rrule);
                   }
               }
           }
   
           calendar += ICS_FOOTER;
           
           // download file
           download('umn_calendar_to_google.ics', calendar);
       }
   }
   
   // see https://stackoverflow.com/questions/3665115/how-to-create-a-file-in-memory-for-user-to-download-but-not-through-server
   function download(filename, text) {
       var element = document.createElement('a');
       element.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(text));
       element.setAttribute('download', filename);
       
       element.style.display = 'none';
       document.body.appendChild(element);
       
       element.click();
       
       document.body.removeChild(element);
   }
   
   proceed();
                   

4. Wait patiently while the program scrolls through all the weeks. If you are really impatient you can change the line setTimeout(proceed, 3000); to setTimeout(proceed, 1000); or even setTimeout(proceed, 500); if you have really fast internet and are feeling lucky. After it finishes it should download a ics file called umn_calendar_to_google.ics.
5. Follow step 2 from Import Events to Google Calendar.

Didn't work for you? Shoot me an email at koval048@umn.edu and I'll give it a look.

Excel Formula Tool

Harry's Tool

Typing long expressions into Google sheets or MS excel can be a challenge. A friend thought a tool that used an math expression editor to generate an excel-style formula would be helpful. I already had a half-way expression parser sitting around from Koval's 3D Grapher, so I repurposed it here. A few notes

• Be sure to separate adjacent variables with "*". I.e. write "a*b*c" (\(a\cdot b\cdot c\)) instead of "abc" (\(abc\)).
• Both Google Sheets and MS Excel have very strange behavior when evaluating exponents prefixed with a negative sign. Turns out that -x^n = (-x)^n in excel language. Instead write -1*x^n.