primo-serve/src/primo.js

A simple Proxy that serves your local development files.

/**
* @file Primo proxy
* @author Mehmet Celik <mehmet.celik at kuleuven.be>
*
* KULeuven/LIBIS
* Mehmet Celik (c) 2018-2020
*/

var url = require('url');
var browserSync = require('browser-sync');
var mime = require('mime-types');
var fs = require('fs');
var chalk = require('chalk');
var proxy = require('proxy-middleware');


/** Primo proxy class */
class Primo {
//export default class Primo {
	/**
	* Create a proxy
	* @param {String} vid - The ViewID that you wish to open
	* @param {String} baseUrl - Base URL to your Primo environment that needs proxing
	* @param {String} baseDir - The directory your data is stored in. The proxy will look in this directory for every path that starts with /primo-explore/custom/.
	*/
	constructor(vid, baseUrl, baseDir, isVE = false, port = 8003) {
		this.vid = vid;
		this.baseUrl = baseUrl;
		this.baseDir = baseDir;
		this.isVE  = isVE;
    	this.port = port
		this.URLPrefix = this.isVE ? "/discovery" : "/primo-explore";
	}

	/**
	* Start proxy and serve files from disk
	*/
	serve() {
		const parsedBaseUrl = url.parse(this.baseUrl);
		let bs = browserSync.create(parsedBaseUrl.hostname);
		let startPath = `${this.URLPrefix}/search?vid=${this.vid}`;

		bs.init({
			ui: false,
			files: [`${this.baseDir}/**/*`],
			port: this.port,
			startPath: startPath,
			proxy: {
				target: `http://${parsedBaseUrl.hostname}`,
				middleware: [(req, res, next) => { this._fileProxy(this.baseDir, req, res, next) },
				proxy(parsedBaseUrl)]
			}
		});
	}

	/**
	* Proxies files from your baseDir
	* @access private
	* @param baseDir - The directory your data is stored in. The proxy will look in this directory for every path that starts with /primo-explore/custom/.
	* @param req - The original http(s) request
	* @param res - The original http(s) response
	* @param next - Call next middleware
	*/
	_fileProxy(baseDir, req, res, next) {
		const parsedUrl = url.parse(req.url);
		console.log(req.url);

		try {
			const filePath = `${baseDir}${parsedUrl.pathname.replace(`${this.URLPrefix}/custom`, '')}`;
      		console.log(chalk.red(filePath));
			const contentType = mime.lookup(filePath);
			const data = fs.readFileSync(filePath);
			console.log(`${chalk.bold.yellow('hijacking')} ${chalk.underline(parsedUrl.pathname)} from ${chalk.underline(filePath)} size ${chalk.bold(data.length)}`);

			try {
				res.writeHead(200, { 'Content-Type': contentType });
			} catch (e) {
				console.log(e);
			}
			res.write(data);
			res.end();
		} catch (err) {
			next();
		}
	}
}

module.exports = Primo;