From eaef4a3f473f5976fff5edba470b59815b64cf12 Mon Sep 17 00:00:00 2001
From: David Evans <davidje13@users.noreply.github.com>
Date: Sun, 29 Apr 2018 11:40:43 +0100
Subject: [PATCH] Split server code into logical chunks

---
 bin/handlers/render.js             |  78 ++++++
 bin/server.js                      | 126 +++------
 bin/server/HttpError.js            |   8 +
 bin/server/RequestHandler.js       |  40 +++
 bin/server/Server.js               | 403 ++++-------------------------
 bin/server/StaticRequestHandler.js | 256 ++++++++++++++++++
 bin/server/encoding.js             |  77 ++++++
 7 files changed, 534 insertions(+), 454 deletions(-)
 create mode 100755 bin/handlers/render.js
 create mode 100755 bin/server/HttpError.js
 create mode 100755 bin/server/RequestHandler.js
 create mode 100755 bin/server/StaticRequestHandler.js
 create mode 100755 bin/server/encoding.js

diff --git a/bin/handlers/render.js b/bin/handlers/render.js
new file mode 100755
index 0000000..4407701
--- /dev/null
+++ b/bin/handlers/render.js
@@ -0,0 +1,78 @@
+const {HttpError} = require('../server/HttpError');
+const {RequestHandler} = require('../server/RequestHandler');
+const {VirtualSequenceDiagram} = require('../../lib/sequence-diagram');
+
+function beginTimer() {
+	return process.hrtime();
+}
+
+function endTimer(timer) {
+	const delay = process.hrtime(timer);
+	return delay[0] * 1e9 + delay[1];
+}
+
+const NUM_MATCH = '[0-9]+(?:\\.[0-9]+)?';
+const MATCH_RENDER = new RegExp(
+	'^/render/' +
+	`(?:(?:w(${NUM_MATCH}))?(?:h(${NUM_MATCH}))?/|z(${NUM_MATCH})/)?` +
+	'(?:(uri|b64)/)?' +
+	'(.*?)' +
+	'(?:\\.(svg))?$',
+	'i'
+);
+
+function getNumeric(v, name) {
+	if(!v) {
+		return null;
+	}
+	const n = Number.parseFloat(v);
+	if(Number.isNaN(n)) {
+		throw new HttpError(400, 'Invalid value for ' + name);
+	}
+	return n;
+}
+
+function readEncoded(str, encoding) {
+	switch(encoding) {
+	case 'b64':
+		return Buffer
+			.from(decodeURIComponent(str), 'base64')
+			.toString('utf8');
+	case 'uri':
+		return str.split('/').map((ln) => decodeURIComponent(ln)).join('\n');
+	default:
+		throw new HttpError(400, 'Unknown encoding');
+	}
+}
+
+function handleRender(req, res, {match, pickEncoding, log, writeEncoded}) {
+	res.setHeader('Access-Control-Allow-Origin', '*');
+
+	const encoding = pickEncoding();
+	const size = {
+		height: getNumeric(match[2], 'height'),
+		width: getNumeric(match[1], 'width'),
+		zoom: getNumeric(match[3], 'zoom'),
+	};
+	const code = readEncoded(match[5], (match[4] || 'uri').toLowerCase());
+	const format = (match[6] || 'svg').toLowerCase();
+
+	const timer = beginTimer();
+	const svg = VirtualSequenceDiagram.render(code, {size});
+	const delay = endTimer(timer);
+	log('RENDER (' + (delay / 1e6).toFixed(3) + 'ms)');
+
+	switch(format) {
+	case 'svg':
+		res.setHeader('Content-Type', 'image/svg+xml; charset=utf-8');
+		writeEncoded(encoding, svg);
+		break;
+	default:
+		throw new HttpError(400, 'Unsupported image format');
+	}
+}
+
+const render = new RequestHandler('GET', MATCH_RENDER, handleRender);
+render.info = 'Rendering sequence diagrams at /render/';
+
+module.exports = {render};
diff --git a/bin/server.js b/bin/server.js
index 55c1f81..c219908 100755
--- a/bin/server.js
+++ b/bin/server.js
@@ -1,93 +1,13 @@
 #!/usr/bin/env node
 
-const {VirtualSequenceDiagram} = require('../lib/sequence-diagram');
-const {HttpError, Server} = require('./server/Server');
+const {Server} = require('./server/Server');
+const {StaticRequestHandler} = require('./server/StaticRequestHandler');
+const {render} = require('./handlers/render');
 
 const DEV = process.argv.includes('dev');
 const HOSTNAME = '127.0.0.1';
 const PORT = 8080;
 
-function beginTimer() {
-	return process.hrtime();
-}
-
-function endTimer(timer) {
-	const delay = process.hrtime(timer);
-	return delay[0] * 1e9 + delay[1];
-}
-
-const NUM_MATCH = '[0-9]+(?:\\.[0-9]+)?';
-const MATCH_RENDER = new RegExp(
-	'^/render/' +
-	`(?:(?:w(${NUM_MATCH}))?(?:h(${NUM_MATCH}))?/|z(${NUM_MATCH})/)?` +
-	'(?:(uri|b64)/)?' +
-	'(.*?)' +
-	'(?:\\.(svg))?$',
-	'i'
-);
-
-function getNumeric(v, name) {
-	if(!v) {
-		return null;
-	}
-	const n = Number.parseFloat(v);
-	if(Number.isNaN(n)) {
-		throw new HttpError(400, 'Invalid value for ' + name);
-	}
-	return n;
-}
-
-function readEncoded(str, encoding) {
-	switch(encoding) {
-	case 'b64':
-		return Buffer
-			.from(decodeURIComponent(str), 'base64')
-			.toString('utf8');
-	case 'uri':
-		return str.split('/').map((ln) => decodeURIComponent(ln)).join('\n');
-	default:
-		throw new HttpError(400, 'Unknown encoding');
-	}
-}
-
-function handleRender(req, res, {match, pickEncoding, log, writeEncoded}) {
-	res.setHeader('Access-Control-Allow-Origin', '*');
-
-	const encoding = pickEncoding();
-	const size = {
-		height: getNumeric(match[2], 'height'),
-		width: getNumeric(match[1], 'width'),
-		zoom: getNumeric(match[3], 'zoom'),
-	};
-	const code = readEncoded(match[5], (match[4] || 'uri').toLowerCase());
-	const format = (match[6] || 'svg').toLowerCase();
-
-	const timer = beginTimer();
-	const svg = VirtualSequenceDiagram.render(code, {size});
-	const delay = endTimer(timer);
-	log('RENDER (' + (delay / 1e6).toFixed(3) + 'ms)');
-
-	switch(format) {
-	case 'svg':
-		res.setHeader('Content-Type', 'image/svg+xml; charset=utf-8');
-		writeEncoded(encoding, svg);
-		break;
-	default:
-		throw new HttpError(400, 'Unsupported image format');
-	}
-}
-
-const server = new Server()
-	.addMimeType('htm', 'text/html; charset=utf-8')
-	.addMimeType('html', 'text/html; charset=utf-8')
-	.addMimeType('js', 'application/javascript; charset=utf-8')
-	.addMimeType('mjs', 'application/javascript; charset=utf-8')
-	.addMimeType('css', 'text/css; charset=utf-8')
-	.addMimeType('png', 'image/png')
-	.addMimeType('svg', 'image/svg+xml; charset=utf-8')
-	.addHandler('GET', MATCH_RENDER, handleRender)
-	.addShutdownHook(() => process.stdout.write('\nShutdown.\n'));
-
 function devMapper(file, type, data) {
 	if(!type.includes('text/html')) {
 		return data;
@@ -105,25 +25,39 @@ function devMapper(file, type, data) {
 	}
 }
 
-server.addStaticResources('/', '', [
-	'index.html',
-	'library.htm',
-	'styles',
-	'lib',
-	'weblib',
-	'favicon.png',
-	'apple-touch-icon.png',
-], devMapper);
+const statics = new StaticRequestHandler('')
+	.addMimeType('txt', 'text/plain; charset=utf-8')
+	.addMimeType('htm', 'text/html; charset=utf-8')
+	.addMimeType('html', 'text/html; charset=utf-8')
+	.addMimeType('js', 'application/javascript; charset=utf-8')
+	.addMimeType('mjs', 'application/javascript; charset=utf-8')
+	.addMimeType('css', 'text/css; charset=utf-8')
+	.addMimeType('png', 'image/png')
+	.addMimeType('svg', 'image/svg+xml; charset=utf-8');
+
+statics
+	.add('/robots.txt', '')
+	.addResources('/', '', [
+		'index.html',
+		'library.htm',
+		'styles',
+		'lib',
+		'weblib',
+		'favicon.png',
+		'apple-touch-icon.png',
+	], devMapper);
 
 if(DEV) {
-	server.addStaticResources('/', '', [
+	statics.addResources('/', '', [
 		'node_modules/requirejs/require.js',
 		'scripts',
 		'web',
 	]);
-	server.setFileWatch(true);
+	statics.setFileWatch(true);
 }
 
-server
+new Server()
+	.addHandler(render)
+	.addHandler(statics)
 	.listen(PORT, HOSTNAME)
-	.then(() => server.printListeningInfo(process.stdout));
+	.then((server) => server.printListeningInfo(process.stdout));
diff --git a/bin/server/HttpError.js b/bin/server/HttpError.js
new file mode 100755
index 0000000..88f43b3
--- /dev/null
+++ b/bin/server/HttpError.js
@@ -0,0 +1,8 @@
+class HttpError extends Error {
+	constructor(status, message) {
+		super(message);
+		this.status = status;
+	}
+}
+
+module.exports = {HttpError};
diff --git a/bin/server/RequestHandler.js b/bin/server/RequestHandler.js
new file mode 100755
index 0000000..8548de6
--- /dev/null
+++ b/bin/server/RequestHandler.js
@@ -0,0 +1,40 @@
+class RequestHandler {
+	constructor(method, matcher, handleFn) {
+		this.method = method;
+		this.matcher = matcher;
+		this.handleFn = handleFn;
+		this.info = 'Custom handler at ' + this.method + ' ' + this.matcher;
+	}
+
+	apply(req, res, info) {
+		if(req.method !== this.method) {
+			return false;
+		}
+		const match = this.matcher.exec(req.url);
+		if(!match) {
+			return false;
+		}
+		if(this.handle(req, res, Object.assign({match}, info)) === false) {
+			return false;
+		}
+		return true;
+	}
+
+	handle(req, res, info) {
+		return this.handleFn(req, res, info);
+	}
+
+	printInfo(target) {
+		target.write(this.info + '\n');
+	}
+
+	begin() {
+		return true;
+	}
+
+	close() {
+		return true;
+	}
+}
+
+module.exports = {RequestHandler};
diff --git a/bin/server/Server.js b/bin/server/Server.js
index 28ef82a..7cc40ca 100755
--- a/bin/server/Server.js
+++ b/bin/server/Server.js
@@ -1,324 +1,38 @@
-const fs = require('fs');
+const {HttpError} = require('./HttpError');
 const http = require('http');
-const stream = require('stream');
-const util = require('util');
-const zlib = require('zlib');
+const {
+	parseAcceptEncoding,
+	pickAcceptEncoding,
+	writeEncoded,
+} = require('./encoding');
 
 const PREF_ENCODINGS = ['gzip', 'deflate', 'identity'];
 
-const PRE_COMPRESS_OPTS = {
-	level: 9,
-	memLevel: 8,
-	windowBits: 15,
-};
-
-const LIVE_COMPRESS_OPTS = {
-	level: 5,
-	memLevel: 9,
-	windowBits: 15,
-};
-
-const MATCH_ACCEPT = new RegExp('^ *([^;]+)(?:;q=([0-9]+(?:\\.[0-9]+)?))? *$');
-const MATCH_INDEX = new RegExp('^(.*/)index\\.[^./]+$', 'i');
-
-function passthroughMapper(file, type, data) {
-	return data;
-}
-
-class HttpError extends Error {
-	constructor(status, message) {
-		super(message);
-		this.status = status;
-	}
-}
-
-function parseAcceptEncoding(accept) {
-	// https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
-
-	const opts = (accept || 'identity;q=1, *;q=0.5').split(',');
-	const types = new Map();
-	opts.forEach((opt) => {
-		const match = MATCH_ACCEPT.exec(opt);
-		if(match) {
-			let q = Number.parseFloat(match[2] || '1');
-			if(q === 0) {
-				q = -1;
-			}
-			types.set(match[1], q);
-		}
-	});
-	if(!types.has('*')) {
-		if(!types.has('identity')) {
-			types.set('identity', -0.5);
-		}
-		types.set('*', -1);
-	}
-	return types;
-}
-
-function pickAcceptEncoding(types, preferred) {
-	let best = null;
-	let bestQ = -1;
-	const wildcard = types.get('*');
-
-	preferred.forEach((opt) => {
-		const q = types.get(opt) || wildcard;
-		if(q > bestQ) {
-			best = opt;
-			bestQ = q;
-		}
-	});
-	if(best === null) {
-		throw new HttpError(406, 'Not Acceptable');
-	}
-	return best;
-}
-
-class RequestHandler {
-	constructor(method, matcher, handler) {
-		this.method = method;
-		this.matcher = matcher;
-		this.handler = handler;
-	}
-
-	apply(req, res, info) {
-		if(req.method !== this.method) {
-			return false;
-		}
-		const match = this.matcher.exec(req.url);
-		if(!match) {
-			return false;
-		}
-		if(this.handler(req, res, Object.assign({match}, info)) === false) {
-			return false;
-		}
-		return true;
-	}
-}
-
-function bufferIfBetter(buffer, check) {
-	if(buffer.byteLength < check.byteLength) {
-		return buffer;
-	}
-	return null;
-}
-
-class StaticRequestHandler extends RequestHandler {
-	constructor(baseUrlPattern) {
-		super(
-			'GET',
-			new RegExp('^' + baseUrlPattern + '([^?]*)(\\?.*)?$'),
-			null
-		);
-		this.handler = this.handle.bind(this);
-		this.resources = new Map();
-	}
-
-	add(path, type, content) {
-		let data = content;
-		if(typeof content === 'string') {
-			data = Buffer.from(content, 'utf8');
-		}
-		const existing = this.resources.get(path);
-		if(existing && data.equals(existing.encodings.identity)) {
-			return Promise.resolve(false);
-		}
-		return Promise.all([
-			data,
-			util.promisify(zlib.deflate)(data, PRE_COMPRESS_OPTS),
-			util.promisify(zlib.gzip)(data, PRE_COMPRESS_OPTS),
-		])
-			.then(([identity, deflate, gzip]) => {
-				const resource = {
-					encodings: {
-						deflate: bufferIfBetter(deflate, identity),
-						gzip: bufferIfBetter(gzip, identity),
-						identity,
-					},
-					path,
-					type,
-				};
-
-				const match = MATCH_INDEX.exec(path);
-				if(match) {
-					this.resources.set(match[1], resource);
-				}
-				this.resources.set(path, resource);
-				return true;
-			});
-	}
-
-	handleResource(req, res, resource, {pickEncoding, log}) {
-		log('SERVE ' + resource.path);
-
-		const encoding = pickEncoding(
-			PREF_ENCODINGS.filter((enc) => (resource.encodings[enc] !== null))
-		);
-		if(encoding !== 'identity') {
-			res.setHeader('Content-Encoding', encoding);
-		}
-		res.setHeader('Content-Type', resource.type);
-		res.end(resource.encodings[encoding]);
-	}
-
-	handle(req, res, info) {
-		const resource = this.resources.get(info.match[1]);
-		if(!resource) {
-			return false;
-		}
-		return this.handleResource(req, res, resource, info);
-	}
-
-	write(target) {
-		let maxLen = 0;
-		for(const [path] of this.resources) {
-			maxLen = Math.max(maxLen, path.length);
-		}
-		let indent = '';
-		for(let i = 0; i < maxLen; ++ i) {
-			indent += ' ';
-		}
-		for(const [path, res] of this.resources) {
-			const {encodings} = res;
-			target.write(path + indent.substr(path.length));
-			target.write(' ' + encodings.identity.byteLength + 'b');
-			for(const enc of ['gzip', 'deflate']) {
-				const buf = encodings[enc];
-				if(buf !== null) {
-					target.write(', ' + enc + ': ' + buf.byteLength + 'b');
-				}
-			}
-			target.write('\n');
-		}
-	}
-}
-
-function writeEncoded(res, encoding, compressionOpts, data) {
-	if(encoding === 'identity') {
-		res.end(data);
-		return;
-	}
-
-	res.setHeader('Content-Encoding', encoding);
-
-	const raw = new stream.Readable();
-	raw.push(data, 'utf8');
-	raw.push(null);
-
-	switch(encoding) {
-	case 'gzip':
-		raw.pipe(zlib.createGzip(compressionOpts)).pipe(res);
-		break;
-	case 'deflate':
-		raw.pipe(zlib.createDeflate(compressionOpts)).pipe(res);
-		break;
-	default:
-		throw new HttpError(500, 'Failed to encode');
-	}
-}
-
 class Server {
 	constructor() {
-		this.awaiting = [];
-		this.mimes = new Map();
-		this.defaultMime = 'text/plain; charset=utf-8';
+		this.running = false;
 		this.handlers = [];
-		this.watchFiles = false;
-		this.watchers = [];
-		this.staticHandler = new StaticRequestHandler('');
 		this.urlMaxLength = 65536;
 		this.server = http.createServer(this._handleRequest.bind(this));
 		this.log = this.log.bind(this);
 		this.logTarget = process.stdout;
-		this.running = false;
-		this.registerShutdown = false;
 		this.shutdownCallbacks = [];
+		this.compressionOptions = {
+			level: 5,
+			memLevel: 9,
+			windowBits: 15,
+		};
 
 		this.close = this.close.bind(this);
 	}
 
-	setFileWatch(enabled) {
-		this.watchFiles = enabled;
-		return this;
-	}
-
-	addMimeType(extension, type) {
-		this.mimes.set(extension, type);
-		return this;
-	}
-
-	_addStaticFile(path, file, mapper) {
-		const ext = file.substr(file.lastIndexOf('.') + 1);
-		const type = this.mimes.get(ext) || this.defaultMime;
-		const map = mapper || passthroughMapper;
-		const fn = () => util.promisify(fs.readFile)(file)
-			.then((data) => map(file, type, data))
-			.then((data) => this.staticHandler.add(path, type, data));
-		this.watchers.push({file, fn, watcher: null});
-		return fn();
-	}
-
-	_addStaticDir(path, file, mapper) {
-		return util.promisify(fs.readdir)(file)
-			.then((subFiles) => this._addStaticResources(
-				path + '/',
-				file + '/',
-				subFiles.filter((sub) => !sub.startsWith('.')),
-				mapper
-			));
-	}
-
-	_addStaticResource(path, file, mapper) {
-		return util.promisify(fs.stat)(file)
-			.then((stats) => {
-				if(stats.isDirectory()) {
-					return this._addStaticDir(path, file, mapper);
-				} else {
-					return this._addStaticFile(path, file, mapper);
-				}
-			});
-	}
-
-	_addStaticResources(basePath, baseFs, files, mapper) {
-		return Promise.all(files.map((file) => this._addStaticResource(
-			basePath + file,
-			baseFs + file,
-			mapper
-		)));
-	}
-
-	addStaticFile(path, file, mapper = null) {
-		this.awaiting.push(this._addStaticFile(path, file, mapper));
-		return this;
-	}
-
-	addStaticDir(basePath, baseFile, mapper = null) {
-		this.awaiting.push(this._addStaticDir(basePath, baseFile, mapper));
-		return this;
-	}
-
-	addStaticResource(path, file, mapper = null) {
-		this.awaiting.push(this._addStaticResource(path, file, mapper));
-		return this;
-	}
-
-	addStaticResources(basePath, baseFs, files, mapper = null) {
-		this.awaiting.push(
-			this._addStaticResources(basePath, baseFs, files, mapper)
-		);
-		return this;
-	}
-
-	addHandler(method, matcher, handler) {
-		this.handlers.push(new RequestHandler(method, matcher, handler));
+	addHandler(handler) {
+		this.handlers.push(handler);
 		return this;
 	}
 
 	addShutdownHook(callback) {
-		if(callback) {
-			this.shutdownCallbacks.push(callback);
-		}
-		this.registerShutdown = true;
+		this.shutdownCallbacks.push(callback);
 		return this;
 	}
 
@@ -352,7 +66,7 @@ class Server {
 			writeEncoded: (encoding, data) => writeEncoded(
 				res,
 				encoding,
-				LIVE_COMPRESS_OPTS,
+				this.compressionOptions,
 				data
 			),
 		};
@@ -369,9 +83,7 @@ class Server {
 					return;
 				}
 			}
-			if(!this.staticHandler.apply(req, res, info)) {
-				throw new HttpError(404, 'Not Found');
-			}
+			throw new HttpError(404, 'Not Found');
 		} catch(e) {
 			this._handleError(req, res, e);
 		}
@@ -381,56 +93,25 @@ class Server {
 		return 'http://' + this.hostname + ':' + this.port + '/';
 	}
 
-	_addWatchers() {
-		if(this.watchFiles) {
-			this.watchers.forEach((entry) => {
-				if(entry.watcher) {
-					return;
-				}
-				const makeWatcher = () => fs.watch(entry.file, () => {
-					/*
-					 * If editor changed file by moving it, we are now
-					 * watching the wrong file, so re-create watcher:
-					 */
-					entry.watcher.close();
-					entry.watcher = makeWatcher();
-
-					entry.fn().then((changed) => {
-						if(changed) {
-							this.log('RELOADED ' + entry.file);
-						}
-					});
-				});
-				entry.watcher = makeWatcher();
-			});
-		}
-	}
-
-	_removeWatchers() {
-		this.watchers.forEach((entry) => {
-			if(entry.watcher) {
-				entry.watcher.close();
-				entry.watcher = null;
-			}
-		});
-	}
-
 	listen(port, hostname) {
 		if(this.running) {
 			throw new Error('Already listening');
 		}
-		this.port = port;
-		this.hostname = hostname;
-		return Promise.all(this.awaiting).then(() => new Promise((resolve) => {
-			this._addWatchers();
-			this.server.listen(port, hostname, () => {
-				this.running = true;
-				if(this.registerShutdown) {
+		const env = {
+			hostname,
+			log: this.log,
+			port,
+		};
+		return Promise.all(this.handlers.map((h) => h.begin(env)))
+			.then(() => new Promise((resolve) => {
+				this.server.listen(port, hostname, () => {
+					this.running = true;
+					this.port = port;
+					this.hostname = hostname;
 					process.on('SIGINT', this.close);
-				}
-				resolve(this);
-			});
-		}));
+					resolve(this);
+				});
+			}));
 	}
 
 	close() {
@@ -438,20 +119,26 @@ class Server {
 			return Promise.resolve(this);
 		}
 		this.running = false;
-		this._removeWatchers();
-		return new Promise((resolve) => {
-			this.server.close(() => {
+		const env = {
+			log: this.log,
+		};
+		this.logTarget.write('\n'); // Skip line containing Ctrl+C indicator
+		this.log('Shutting down...');
+		return new Promise((resolve) => this.server.close(() => resolve()))
+			.then(() => Promise.all(this.handlers.map((h) => h.close(env))))
+			.then(() => {
 				this.shutdownCallbacks.forEach((fn) => fn(this));
-				resolve(this);
 				process.removeListener('SIGINT', this.close);
+				this.log('Shutdown');
+				return this;
 			});
-		});
 	}
 
 	printListeningInfo(target) {
-		target.write('Serving static resources:\n');
-		this.staticHandler.write(target);
-		target.write('\n');
+		for(const handler of this.handlers) {
+			handler.printInfo(target);
+			target.write('\n');
+		}
 		target.write('Available at ' + this.baseurl() + '\n\n');
 	}
 }
diff --git a/bin/server/StaticRequestHandler.js b/bin/server/StaticRequestHandler.js
new file mode 100755
index 0000000..f2e1369
--- /dev/null
+++ b/bin/server/StaticRequestHandler.js
@@ -0,0 +1,256 @@
+const {RequestHandler} = require('./RequestHandler');
+const fs = require('fs');
+const util = require('util');
+const zlib = require('zlib');
+
+const MATCH_INDEX = new RegExp('^(.*/)index\\.[^./]+$', 'i');
+const PREF_ENCODINGS = ['gzip', 'deflate', 'identity'];
+
+function passthroughMapper(file, type, data) {
+	return data;
+}
+
+function bufferIfBetter(buffer, check) {
+	if(buffer.byteLength < check.byteLength) {
+		return buffer;
+	}
+	return null;
+}
+
+function getIndent(strings) {
+	let maxLen = 0;
+	for(const string of strings) {
+		maxLen = Math.max(maxLen, string.length);
+	}
+	let indent = '';
+	for(let i = 0; i < maxLen; ++ i) {
+		indent += ' ';
+	}
+	return indent;
+}
+
+class StaticRequestHandler extends RequestHandler {
+	constructor(baseUrlPattern) {
+		super('GET', new RegExp('^' + baseUrlPattern + '([^?]*)(\\?.*)?$'));
+
+		this.baseUrlPattern = baseUrlPattern;
+		this.mimes = new Map();
+		this.defaultMime = 'text/plain; charset=utf-8';
+		this.resources = new Map();
+		this.awaiting = [];
+		this.watchFiles = false;
+		this.watchers = [];
+
+		this.compressionOptions = {
+			level: 9,
+			memLevel: 8,
+			windowBits: 15,
+		};
+	}
+
+	_handleResource(req, res, resource, {pickEncoding, log}) {
+		log('SERVE ' + resource.path);
+
+		const encoding = pickEncoding(
+			PREF_ENCODINGS.filter((enc) => (resource.encodings[enc] !== null))
+		);
+		if(encoding !== 'identity') {
+			res.setHeader('Content-Encoding', encoding);
+		}
+		res.setHeader('Content-Type', resource.type);
+		res.end(resource.encodings[encoding]);
+	}
+
+	handle(req, res, info) {
+		const resource = this.resources.get(info.match[1]);
+		if(!resource) {
+			return false;
+		}
+		return this._handleResource(req, res, resource, info);
+	}
+
+	_addWatchers(log) {
+		this.watchers.forEach((entry) => {
+			if(entry.watcher) {
+				return;
+			}
+			const makeWatcher = () => fs.watch(entry.file, () => {
+				/*
+				 * If editor changed file by moving it, we are now
+				 * watching the wrong file, so re-create watcher:
+				 */
+				entry.watcher.close();
+				entry.watcher = makeWatcher();
+
+				entry.fn().then((changed) => {
+					if(changed) {
+						log('RELOADED ' + entry.file);
+					}
+				});
+			});
+			entry.watcher = makeWatcher();
+		});
+	}
+
+	_add(path, type, content) {
+		let data = content;
+		if(typeof content === 'string') {
+			data = Buffer.from(content, 'utf8');
+		}
+		const existing = this.resources.get(path);
+		if(existing && data.equals(existing.encodings.identity)) {
+			return Promise.resolve(false);
+		}
+		return Promise.all([
+			data,
+			util.promisify(zlib.deflate)(data, this.compressionOptions),
+			util.promisify(zlib.gzip)(data, this.compressionOptions),
+		])
+			.then(([identity, deflate, gzip]) => {
+				const resource = {
+					encodings: {
+						deflate: bufferIfBetter(deflate, identity),
+						gzip: bufferIfBetter(gzip, identity),
+						identity,
+					},
+					path,
+					type,
+				};
+
+				const match = MATCH_INDEX.exec(path);
+				if(match) {
+					this.resources.set(match[1], resource);
+				}
+				this.resources.set(path, resource);
+				return true;
+			});
+	}
+
+	_addFile(path, file, mapper) {
+		const type = this.mimeTypeFor(file);
+		const map = mapper || passthroughMapper;
+		const fn = () => util.promisify(fs.readFile)(file)
+			.then((data) => map(file, type, data))
+			.then((data) => this._add(path, type, data));
+		this.watchers.push({file, fn, watcher: null});
+		return fn();
+	}
+
+	_addDir(path, file, mapper) {
+		return util.promisify(fs.readdir)(file)
+			.then((subFiles) => this._addResources(
+				path + '/',
+				file + '/',
+				subFiles.filter((sub) => !sub.startsWith('.')),
+				mapper
+			));
+	}
+
+	_addResource(path, file, mapper) {
+		return util.promisify(fs.stat)(file)
+			.then((stats) => {
+				if(stats.isDirectory()) {
+					return this._addDir(path, file, mapper);
+				} else {
+					return this._addFile(path, file, mapper);
+				}
+			});
+	}
+
+	_addResources(basePath, baseFs, files, mapper) {
+		return Promise.all(files.map((file) => this._addResource(
+			basePath + file,
+			baseFs + file,
+			mapper
+		)));
+	}
+
+	addMimeType(extension, type) {
+		this.mimes.set(extension, type);
+		return this;
+	}
+
+	mimeTypeFor(file) {
+		const ext = file.substr(file.lastIndexOf('.') + 1);
+		return this.mimes.get(ext) || this.defaultMime;
+	}
+
+	add(path, type, content = null) {
+		let promise = null;
+		if(content === null) {
+			promise = this._add(path, this.mimeTypeFor(path), type);
+		} else {
+			promise = this._add(path, type, content);
+		}
+		this.awaiting.push(promise);
+		return this;
+	}
+
+	addFile(path, file, mapper = null) {
+		this.awaiting.push(this._addFile(path, file, mapper));
+		return this;
+	}
+
+	addDir(basePath, baseFile, mapper = null) {
+		this.awaiting.push(this._addDir(basePath, baseFile, mapper));
+		return this;
+	}
+
+	addResource(path, file, mapper = null) {
+		this.awaiting.push(this._addResource(path, file, mapper));
+		return this;
+	}
+
+	addResources(basePath, baseFs, files, mapper = null) {
+		this.awaiting.push(
+			this._addResources(basePath, baseFs, files, mapper)
+		);
+		return this;
+	}
+
+	setFileWatch(enabled) {
+		this.watchFiles = enabled;
+		return this;
+	}
+
+	printInfo(target) {
+		target.write(
+			'Serving static resources at ' +
+			(this.baseUrlPattern || '/') + ':\n'
+		);
+
+		const indent = getIndent(this.resources.keys());
+
+		for(const [path, res] of this.resources) {
+			const {encodings} = res;
+			target.write(path + indent.substr(path.length));
+			target.write(' ' + encodings.identity.byteLength + 'b');
+			for(const enc of ['gzip', 'deflate']) {
+				const buf = encodings[enc];
+				if(buf !== null) {
+					target.write(', ' + enc + ': ' + buf.byteLength + 'b');
+				}
+			}
+			target.write('\n');
+		}
+	}
+
+	begin({log}) {
+		return Promise.all(this.awaiting).then(() => {
+			if(this.watchFiles) {
+				this._addWatchers(log);
+			}
+		});
+	}
+
+	close() {
+		this.watchers.forEach((entry) => {
+			if(entry.watcher) {
+				entry.watcher.close();
+				entry.watcher = null;
+			}
+		});
+	}
+}
+
+module.exports = {StaticRequestHandler};
diff --git a/bin/server/encoding.js b/bin/server/encoding.js
new file mode 100755
index 0000000..e8dd68b
--- /dev/null
+++ b/bin/server/encoding.js
@@ -0,0 +1,77 @@
+const {HttpError} = require('./HttpError');
+const {Readable} = require('stream');
+const zlib = require('zlib');
+
+const MATCH_ACCEPT = new RegExp('^ *([^;]+)(?:;q=([0-9]+(?:\\.[0-9]+)?))? *$');
+
+function parseAcceptEncoding(accept) {
+	// https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
+
+	const opts = (accept || 'identity;q=1, *;q=0.5').split(',');
+	const types = new Map();
+	opts.forEach((opt) => {
+		const match = MATCH_ACCEPT.exec(opt);
+		if(match) {
+			let q = Number.parseFloat(match[2] || '1');
+			if(q === 0) {
+				q = -1;
+			}
+			types.set(match[1], q);
+		}
+	});
+	if(!types.has('*')) {
+		if(!types.has('identity')) {
+			types.set('identity', -0.5);
+		}
+		types.set('*', -1);
+	}
+	return types;
+}
+
+function pickAcceptEncoding(types, preferred) {
+	let best = null;
+	let bestQ = -1;
+	const wildcard = types.get('*');
+
+	preferred.forEach((opt) => {
+		const q = types.get(opt) || wildcard;
+		if(q > bestQ) {
+			best = opt;
+			bestQ = q;
+		}
+	});
+	if(best === null) {
+		throw new HttpError(406, 'Not Acceptable');
+	}
+	return best;
+}
+
+function writeEncoded(res, encoding, compressionOpts, data) {
+	if(encoding === 'identity') {
+		res.end(data);
+		return;
+	}
+
+	res.setHeader('Content-Encoding', encoding);
+
+	const raw = new Readable();
+	raw.push(data, 'utf8');
+	raw.push(null);
+
+	switch(encoding) {
+	case 'gzip':
+		raw.pipe(zlib.createGzip(compressionOpts)).pipe(res);
+		break;
+	case 'deflate':
+		raw.pipe(zlib.createDeflate(compressionOpts)).pipe(res);
+		break;
+	default:
+		throw new HttpError(500, 'Failed to encode');
+	}
+}
+
+module.exports = {
+	parseAcceptEncoding,
+	pickAcceptEncoding,
+	writeEncoded,
+};