a google classroom to discord webhook. WARNING: not the most efficient method (look: push notifs [can't afford that]). this takes (amount of classes * 2)+1 requests / run.

classroom-discord.gs

/**
 * @file Enhances student laziness by automatically posting classroom announcements and assignments through a Discord Webhook.
 * @author Nathan Adhitya <me@natha.my.id>
*/

/*
KNOWN THINGS THIS THING WON'T ACCOUNT FOR:
- Google servers cutting the amount of data returned is not accounted for.
- Updates to existing announcement/course works
- Support for class material?
*/

const scriptProperties = PropertiesService.getScriptProperties();

const hook = scriptProperties.getProperty("discordWebhook");

// Utility functions
function listAllCourses() {
  const response = Classroom.Courses.list();
  const courses = response.courses;
  return Array.prototype.filter.call(courses, (element) => element.courseState === "ACTIVE");
}

function getNewEntries(course) {
  const responseA = Classroom.Courses.Announcements.list(course.id);
  const responseB = Classroom.Courses.CourseWork.list(course.id);
  const announcements = responseA.announcements;
  const courseWorks = responseB.courseWork;
  const materials = course.
  
  // Now, let's get the newest ones.
  // TODO: Make this more efficient, just cut off the array since it is sorted descending.
  const lastUpdate = Number(scriptProperties.getProperty(`${course.id}_lastUpdate`));
  if (lastUpdate) {
    const filteredAnnouncements = !announcements ? null : announcements.filter((announcement) => new Date(announcement.creationTime).getTime() > lastUpdate);  
    const filteredCourseWorks = !courseWorks ? null : courseWorks.filter((announcement) => new Date(announcement.creationTime).getTime() > lastUpdate);
    // Update the last update data.
    scriptProperties.setProperty(`${course.id}_lastUpdate`, String(Date.now()));
    return {announcements: filteredAnnouncements, courseWorks: filteredCourseWorks}
  }
  
  // Update the last update data.
  scriptProperties.setProperty(`${course.id}_lastUpdate`, String(Date.now()));
  return {announcements, courseWorks};
}

function test(){
  const courses = listAllCourses();
  Array.prototype.forEach.call(courses, (entry) => {
    const entries = getNewEntries(entry);
    Logger.log(entries);
  });
}
 
/**
 * Here where you run the thing. yes. thing.
*/
function run(){
  // Piling up discord's webhook embeds to prevent rate limits.
  var embeds = [];
  const courses = listAllCourses();
  Array.prototype.forEach.call(courses, (entry) => {
    const {announcements, courseWorks} = getNewEntries(entry);
    if (announcements && announcements.length > 0) {
      announcements.forEach((announcement) => {
        embeds.push({
          title: `New Announcement`,
          url: announcement.alternateLink,
          description: announcement.text.length > 2000 ? announcement.text.substr(0, 2000) + "..." : announcement.text,
          color: 3066993,
          author: {
            name: entry.name,
            url: entry.alternateLink
          },
          timestamp: announcement.updateTime,
        });
      });
    }
    if (courseWorks && courseWorks.length > 0) {
      courseWorks.forEach((courseWork) => {
        embeds.push({
          title: `New Course Work: ${courseWork.title}`,
          url: courseWork.alternateLink,
          description: courseWork.description ? (courseWork.description.length > 2000 ? courseWork.description.substr(0, 2000) + "..." : courseWork.description) : "*No description specified.*",
          color: 15105570,
          author: {
            name: entry.name,
            url: entry.alternateLink
          },
          footer: {
            text: courseWork.dueTime ? `Due at [T]: ${courseWork.dueTime.hours}:${courseWork.dueTime.minutes} ${courseWork.dueDate ? `[D]: ${courseWork.dueDate.day}D ${courseWork.dueDate.month}M ${courseWork.dueDate.year}Y` : ""}` : "No due specified.",
          },
          timestamp: courseWork.updateTime,
        });
      });
    }
  });
  
  // stuff collected, let's shove em into discord's webhooks
  while (embeds.length > 0) {
    const data = embeds.slice(0,10);
    
    // Remove 10 elements from embeds
    embeds = embeds.splice(10);
    
    Logger.log(data);
    const options = {
      "method": "post",
      "contentType": "application/json",
      "payload": JSON.stringify({embeds: data}),
    };
    const resp = UrlFetchApp.fetch(hook, options);
  }
}