API-32: Basic Endpoint for RaPla-Middleware, already able to remove blockers

app.ts

@@ -7,6 +7,7 @@ import {highlightMarkerRouter} from './src/models/twitch-highlight-marker/Highli
 import {dhbwServiceRouter} from './src/models/dhbw-service/DHBWService.router';
 import logger from './src/middleware/logger';
 import {dhbwRaPlaChangesRouter} from './src/models/dhbw-rapla-changes/DHBWRaPlaChanges.router';
+import {raPlaMiddlewareRouter} from './src/models/rapla-middleware/RaPlaMiddleware.router';
 
 let cors = require('cors');
 
@@ -33,6 +34,7 @@ app.use('/dhbw-service', dhbwServiceRouter);
 app.use('/twitch-highlight-marker', highlightMarkerRouter);
 app.use('/partyplaner', partyPlanerRouter);
 app.use('/raplachanges', dhbwRaPlaChangesRouter);
+app.use('/rapla-middleware', raPlaMiddlewareRouter);
 
 // this is a simple route to make sure everything is working properly
 app.get('/', (req: express.Request, res: express.Response) => {

src/models/rapla-middleware/RaPlaMiddleware.router.ts

@@ -0,0 +1,63 @@
+/**
+ * Required External Modules and Interfaces
+ */
+import express, {Request, Response} from 'express';
+import logger from '../../middleware/logger';
+import {Guid} from 'guid-typescript';
+import * as icalgenerator from './icalgenerator/icalgenerator.service';
+
+/**
+ * Router Definition
+ */
+export const raPlaMiddlewareRouter = express.Router();
+
+raPlaMiddlewareRouter.get('/', async (req: Request, res: Response) => {
+    try {
+        let user = (req.query.user ?? '').toString();
+        let file = (req.query.file ?? '').toString();
+        let blockers = (req.query.blockers ?? '').toString() === '1';
+        let wahl = (req.query.wahl ?? '').toString();
+        let pflicht = (req.query.pflicht ?? '').toString();
+
+        const allowedCharsRegex: RegExp = /^[a-zA-Z0-9]+$/;
+
+        if (user === '' || file === '') {
+            res.status(400).send('Please at least provide user and file for RaPla!');
+            return;
+        } else if (!allowedCharsRegex.test(user) || !allowedCharsRegex.test(file)) {
+            res.status(400).send('Please provide a valid user and file!');
+            return;
+        }
+
+        let resultingFile = await icalgenerator.getiCalFile(user, file, blockers, wahl, pflicht);
+
+        res.set({'Content-Disposition': 'attachment; filename=' + file + '.ics'});
+        res.status(200).send(resultingFile);
+    } catch (e) {
+        let errorGuid = Guid.create().toString();
+        logger.error('Error handling a request: ' + e.message, {reference: errorGuid});
+        res.status(500).send({
+            'status': 'PROCESSING_ERROR',
+            'message': 'Internal Server Error. Try again later.',
+            'reference': errorGuid
+        });
+    }
+});
+
+let electiveModules = {
+    1: {name: ''},
+    2: {name: ''},
+    3: {name: ''},
+    4: {name: ''},
+    5: {name: ''},
+    6: {name: ''},
+    7: {name: ''}
+};
+
+let profileModules = {
+    1: {name: ''},
+    2: {name: ''},
+    3: {name: ''},
+    4: {name: ''},
+    5: {name: ''}
+};

src/models/rapla-middleware/icalgenerator/icalgenerator.service.ts

@@ -0,0 +1,86 @@
+const fetch = require('node-fetch');
+
+export const getiCalFile = async (user: string, file: string, showBlockers: boolean, electiveModule: string, profileModule: string): Promise<string> => {
+    try {
+        let iCalFileContents = '';
+
+        let baseUrl = 'https://rapla.dhbw-karlsruhe.de/rapla?page=ical';
+        baseUrl += '&user=' + user;
+        baseUrl += '&file=' + file;
+
+        const response = await fetch(baseUrl);
+
+        let body = await response.text();
+
+        // Parse the ical file
+        let iCalFile = parseIcal(body);
+
+        // Now remove unwanted shit from the iCal file
+        if (!showBlockers) {
+            iCalFile = removeBlockers(iCalFile);
+        }
+
+        // Turn into one file again
+        let resultingFile = serializeIcal(iCalFile);
+
+        return resultingFile;
+    } catch (err) {
+        throw err;
+    }
+};
+
+export const parseIcal = function (icalContents: string): iCalFile {
+    const fileHeaderRegex: RegExp = /^BEGIN:VCALENDAR.*?BEGIN:VEVENT$/ms;
+    const eventRegex: RegExp = /^BEGIN:VEVENT.*?END:VEVENT$/msg;
+
+    let headerMatch = fileHeaderRegex.exec(icalContents);
+    let header = '';
+
+    if (headerMatch) {
+        header = headerMatch[0];
+    }
+
+    header = header.substr(0, header.lastIndexOf('\n'));
+
+    let events: string[] = [];
+    let match: any;
+    while (match = eventRegex.exec(icalContents)) {
+        if (match) {
+            events.push(match[0]);
+        }
+    }
+
+    return {
+        head: header,
+        body: events
+    };
+};
+
+export const serializeIcal = function (ical: iCalFile): string {
+    let resString = ical.head;
+    ical.body.forEach((event) => {
+        resString += event + '\n';
+    });
+    resString += 'END:VCALENDAR';
+
+    return resString;
+};
+
+export const removeBlockers = function (ical: iCalFile): iCalFile {
+    let remainingEvents: string[] = [];
+
+    ical.body.forEach((event) => {
+        if (!event.includes('CATEGORIES:Sonstiger Termin') && !event.includes('SUMMARY:Präsenz')) {
+            remainingEvents.push(event);
+        }
+    });
+
+    ical.body = remainingEvents;
+
+    return ical;
+};
+
+export interface iCalFile {
+    head: string;
+    body: string[];
+}