✨ add events api

package.json

@@ -29,9 +29,11 @@
     "@types/cors": "^2.8.6",
     "@types/express": "^4.17.2",
     "@types/express-session": "^1.15.16",
+    "@types/ical": "^0.6.1",
     "@types/lodash": "^4.14.149",
     "@types/morgan": "^1.7.37",
     "@types/passport": "^1.0.2",
+    "@types/request-promise-native": "^1.0.17",
     "body-parser": "^1.19.0",
     "connect-redis": "^4.0.3",
     "convict": "^5.2.0",
@@ -42,11 +44,14 @@
     "express-async-handler": "^1.1.4",
     "express-session": "^1.17.0",
     "express-sms-auth": "^1.0.1",
+    "ical": "^0.6.0",
     "lodash": "^4.17.15",
     "morgan": "^1.9.1",
     "passport": "^0.4.1",
     "pg": "^7.17.1",
     "redis": "^2.8.0",
+    "request": "^2.88.0",
+    "request-promise-native": "^1.0.8",
     "ts-loader": "^6.2.1",
     "ts-node": "^8.6.1",
     "ts-node-dev": "^1.0.0-pre.44",

src/routes/publicApi.ts

@@ -1,9 +1,50 @@
 import { Router, Request, Response } from 'express'
 import expressAsyncHandler = require('express-async-handler');
 import Campus from 'src/models/Campus.model';
+import ical from "ical";
+import requestPromise = require('request-promise-native');
 
 const router = Router()
 
+async function getCalEvents(url: string) {
+    const ics = await requestPromise.get(url.replace('webcal://', 'http://'));
+    const events = ical.parseICS(ics);
+    return events;
+}
+
+const eventsCache = {
+    updatedAt: 0,
+    events: [] as any[],
+};
+
+const FIVE_MINUTES = 1000 * 60 * 5;
+async function getEvents(campuses: Campus[]) {
+    let allEvents;
+    if (eventsCache.updatedAt < (Date.now() - FIVE_MINUTES)) {
+        console.log(`Events cache invalidated, re-fetching`);
+        const calUrls = campuses.map(campus => campus.calendarUrl).filter(a => a);
+        const calendars = await Promise.all(
+            calUrls.map(getCalEvents)
+        );
+        allEvents = calendars
+            .flatMap(cal => Object.values(cal))
+            .sort((a, b) => a.start < b.start ? 1 : -1);
+    } else {
+        console.log(`Reading events from cache`);
+        allEvents = eventsCache.events;
+    }
+
+    const now = new Date();
+    const pastIndex = allEvents.findIndex(ev => ev.end < now);
+    const futureEvents = allEvents.slice(0, pastIndex);
+    const pastEvents = allEvents.slice(pastIndex);
+
+    return {
+        futureEvents,
+        pastEvents,
+    }
+}
+
 router.get(
     '/college.json',
     expressAsyncHandler(async (req: Request, res: Response) => {
@@ -13,8 +54,11 @@ router.get(
             Campus.find({ relations: ['dean'] })
         ]);
 
+        const events = await getEvents(campuses);
+
         res.send({
             campuses,
+            events,
         });
     })
 );

tsconfig.json

@@ -13,6 +13,7 @@
     "baseUrl": ".",
     "lib": [
       "es7",
+      "ESNext"
     ],
     "paths": {
       "src/*": [