Flexso LMS FTP

Fetching and caching LMS CSV data from FTP server

Setup

Example from the Extension factory - Training Dashboard

• connector : Is needed because we need to read out a destination to get the FTP credentials to put it into the connectionConfig.

import { DefaultFTPFormatConfig, FTPAdapter, FTPConnectionConfig, DBConfig, DBEntityConfig } from "flexso-lms-ftp";
import { readDestination } from 'sap-cf-destconn';

export class FTPConnector {

    private static instance?: FTPConnector;
    private adapter: FTPAdapter;

    constructor(adapter: FTPAdapter) {
        this.adapter = adapter;

        if (!FTPConnector.instance) {
            FTPConnector.instance = this;
        }

        FTPConnector.instance.adapter = adapter;
        return FTPConnector.instance;
    }

    // gets records from in mem db if present otherwise fetch data from remote source
    public async getRecords(path: string, tenant: string, collectionName: string): Promise<any> {
        return this.adapter.getDataFromFile(tenant, collectionName, path);
    }

    // gets records from in mem db if present otherwise fetch data from remote source with dbEntityConfig
    public async getRecordsWithDBEntityConfig(tenant: string, dbEntityConfig: DBEntityConfig): Promise<any> {
        return this.getRecords(dbEntityConfig.path, tenant, dbEntityConfig.entityName)
    }

    public async loadRecords(tenant: string) {
        this.adapter.loadDataForTenant(tenant);
    }

    static async build(tenantName: string, ftpDest: string, dbConfig: DBConfig) {
        let destinationConfig = await readDestination(ftpDest, undefined, tenantName);
        let _o: any = destinationConfig.destinationConfiguration;
        let connectionConfig = new FTPConnectionConfig(
            _o.URL.replace(/(^\w+:|^)\/\//, ''),
            _o.port,
            _o.User,
            _o.Password
        )
        let adapter = new FTPAdapter(tenantName, connectionConfig, new DefaultFTPFormatConfig(), dbConfig);
        
        return new FTPConnector(adapter);
    }

}

• Middleware init: We initiate everything here.

export default async function SFMiddleware(req: express.Request, _res: express.Response, next: express.NextFunction) {
    try {
        let oRequestConfig = getRequestConfig(req);
        let tenantName = oRequestConfig.subscribedDomain || '';
        let sfsfRequests = new SFSFRequests(oRequestConfig);

        // --------------NEW FPT LOGIC--------------------------------
        // TODO: get lifetime for each entity from config
        // without dir path, files can have a different location
        let lifeTime = Constants.DEFAULT_ENTITY_LIFETIME;
        let entities = {
            ITEMS: new DBEntityConfig("items", lifeTime, await getItemsPath(tenantName)),
            CLASSES: new DBEntityConfig("classes", lifeTime, await getClassRequestPath(tenantName)),
            SEGMENTS: new DBEntityConfig("segments", lifeTime, await getSegmentRequestPath(tenantName)),
            ENROLLMENTS: new DBEntityConfig("enrollments", lifeTime, await getEnrollmentRequestPath(tenantName)),
            CLASSREQUESTS: new DBEntityConfig("classRequests", lifeTime, await getItemRequestPath(tenantName))
        };
        Constants.ENTITIES = entities;
        let dbConfig = new DBConfigWithoutDirPath(tenantName, Object.values(entities));
        // with dir path, files have a shared parent folder and can't have a diff location
        // entityConfig is generated with the dir content to build collections and config.json in folder for stating lifetime (TODO)
        /*
            let dirPath = await getFTPDirectoryPath();
            let dbConfig = new DBConfigWithDirPath(tenantName, dirPath, lifeTime); 
        */ 
        let ftpConnector = await FTPConnector.build(tenantName, DESTINATIONS.FTP, dbConfig );
       // await ftpConnector.loadRecords(tenantName);
        let ftpRequests = new FTPRequests(oRequestConfig, ftpConnector);


        //--------------END FTP LOGIC--------------------------------
        let currentUser = await sfsfRequests.readCurrentUser(req.user?.id || "", req.headers['accept-language']);
        req.sfsfRequests = sfsfRequests;
        req.ftpRequests = ftpRequests;
        req.currentUser = currentUser;
        req.tenantName = tenantName;
        next();
    } catch (err) {
        next(err);
    }

}

• insert Middleware The middleware needs to be inserted before your custom routes in Express.

const app = express();
const port = process.env.PORT || 3002; // default port to listen

// add authentication to all requests
app.use(btppassport.initialize());
app.use(btppassport.authenticate("JWT", { session: false }));

// add logging and set the minimum logging level (off, error, warn, info, verbose, debug, silly)
log.setLoggingLevel("info");
// Set custom sink for debugging
if (process.env.debug_session) {
  log.setSinkFunction((level: string, output: any) => {
    let message = JSON.parse(output);
    if (message.request) {
      console.log(message.method + " " + message.request);
    } else if (message.msg) {
      console.log(message.msg);
    } else {
      console.log(message);
    }
  });
}
app.use(log.logNetwork);// Bind to express app

// ---------------- INSERT MIDDLEWARE FUNC-----------------
app.use(SFMiddleware);
//---------------------------------------------------------

// routers
app.use("/authentication", authenticationRouter);
app.use("/config", configRouter);
app.use("/sfsf", SFSFRouter);
app.use("/ftp", FTPRouter);
app.use("/i18n", translationRouter);

// if no routes are matched, or there is an error -> show the error!
app.use(handleErrors);

// start the Express server
app.listen(port, () => {
  log.info("Server is listening on port %d", port);
});