Asymmetrik/mean2-starter

'use strict';

let path = require('path'),
    stream = require('stream'),
    q = require('q'),
    os = require('os'),

    deps = require(path.resolve('./src/server/dependencies.js')),
    dbs = deps.dbs,
    utilService = deps.utilService,
    logger = deps.logger,
    auditService = deps.auditService,
    csvStream = deps.csvStream,

    exportConfigService = require(path.resolve('./src/server/app/util/services/export-config.server.service.js')),
    User = dbs.admin.model('User'),
    ExportConfig = dbs.admin.model('ExportConfig');

/**
 * Request to generate an export configuration in preparation to serve a CSV download soon. The config document will
 * expire after a number of minutes (see export-config.server.service).
 */

exports.requestExport = function(req, res) {
    if (null != req.body.config.q) {
        // Stringify the query JSON because '$' is reserved in Mongo.
        req.body.config.q = JSON.stringify(req.body.config.q);
    }
    if (null == req.body.type) {
        return utilService.handleErrorResponse(res, { status: 400, type: 'missing export type', message: 'Missing export type.'});
    }

    exportConfigService.generateConfig(req)
        .then(
            (generatedConfig) => {
                return auditService.audit(`${req.body.type} config created`, 'export', 'create',
                    User.auditCopy(req.user, utilService.getHeaderField(req.headers, 'x-real-ip')),
                    ExportConfig.auditCopy(generatedConfig), req.headers)
                    .then(() => {
                        return q(generatedConfig);
                    });
            })
        .then(
            (result) => {
                res.status(200).json({ _id: result._id});
            },
            (err) => {
                utilService.handleErrorResponse(res, err);
            })
        .done();
};

exports.exportCSV = function(req, res, filename, columns, data) {

    if (null !== data) {
        // Set up streaming res
        res.set('Content-Type', 'text/csv;charset=utf-8');
        res.set('Content-Disposition', `attachment;filename="${filename}"`);
        res.set('Transfer-Encoding', 'chunked');

        // Put into stream the data object
        let s = new stream.Readable({objectMode:true});
        s._read = () => {
            data.forEach((row) => {
                s.push(row);
            });
            s.push(null);
        };

        let sc = s.pipe(csvStream(columns));

        // Pipe each row to the response
        sc.pipe(res);

        // If an error occurs, close the stream
        s.on('error', (err) => {
            logger.error(err, 'CSV export error occurred');

            // End the download
            res.end();
        });

        // If the client drops the connection, stop processing the stream
        req.on('close', () => {
            logger.info('CSV export aborted because client dropped the connection');
            if (s != null) {
                s.destroy();
            }
            // End the download.
            res.end();
        });
    }
};

exports.exportPlaintext = function(req, res, filename, text) {

    if (null !== text) {
        // Set up streaming res
        res.set('Content-Type', 'text/plain;charset=utf-8');
        res.set('Content-Disposition', `attachment;filename="${filename}"`);
        res.set('Transfer-Encoding', 'chunked');

        // Put into stream the data object
        let s = new stream.Readable({objectMode:true});
        s._read = () => {
            text.split(os.EOL).forEach((row) => {
                s.push(row);
            });
            s.push(null);
        };

        // Pipe each row to the response
        s.pipe(res);

        // If an error occurs, close the stream
        s.on('error', (err) => {
            logger.error(err, 'Plaintext export error occurred');

            // End the download
            res.end();
        });

        // If the client drops the connection, stop processing the stream
        req.on('close', () => {
            logger.info('Plaintext export aborted because client dropped the connection');
            if (s != null) {
                s.destroy();
            }
            // End the download.
            res.end();
        });
    }
};