From 883ba3ba0223e7743e5e27eae805788b5795c383 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Pankowski?= <lukpank@o2.pl>
Date: Sun, 9 Jun 2019 13:54:59 +0200
Subject: [PATCH] add `--proxy` flag for reverse proxy

---
 packages/sirv-cli/boot.js   | 14 +++++++++++-
 packages/sirv-cli/index.js  |  2 ++
 packages/sirv-cli/readme.md |  2 ++
 packages/sirv/index.js      | 44 +++++++++++++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/packages/sirv-cli/boot.js b/packages/sirv-cli/boot.js
index e128d86..e881457 100644
--- a/packages/sirv-cli/boot.js
+++ b/packages/sirv-cli/boot.js
@@ -29,6 +29,18 @@ module.exports = function (dir, opts) {
 	dir = resolve(dir || '.');
 	opts.maxAge = opts.m;
 
+	if (opts.proxy) {
+		let i = opts.proxy.indexOf(':');
+		if (i == - 1) throw new Error('missing ":" in proxy argument');
+		let url = new URL(opts.proxy.substring(i + 1));
+		opts.proxy = {
+			prefix: opts.proxy.substring(0, i),
+			hostname: url.hostname,
+			port: url.port,
+			path: url.pathname
+		};
+	}
+
 	if (opts.cors) {
 		opts.setHeaders = res => {
 			res.setHeader('Access-Control-Allow-Origin', '*');
@@ -48,7 +60,7 @@ module.exports = function (dir, opts) {
 		let uri, dur, start, dash=colors.gray(' ─ ');
 		server.on('request', (req, res) => {
 			start = hrtime();
-			req.once('end', _ => {
+			res.once('close', _ => {
 				dur = hrtime(start);
 				uri = req.originalUrl || req.url;
 				stdout.write(PAD + toTime() + toCode(res.statusCode) + dash + toMS(dur) + dash + uri + '\n');
diff --git a/packages/sirv-cli/index.js b/packages/sirv-cli/index.js
index 0e71c26..f08e776 100644
--- a/packages/sirv-cli/index.js
+++ b/packages/sirv-cli/index.js
@@ -11,6 +11,7 @@ sade('sirv')
 		.example('start public -qeim 31536000')
 		.example('--port 8080 --etag')
 		.example('my-app --dev')
+		.example('my-app --dev --proxy /api/:http://localhost:4000/')
 	.command('start [dir]', 'Start a static file server.', { default:true })
 		.option('-D, --dev', 'Enable "dev" mode')
 		.option('-e, --etag', 'Enable "Etag" header')
@@ -22,5 +23,6 @@ sade('sirv')
 		.option('-q, --quiet', 'Disable logging to terminal')
 		.option('-H, --host', 'Hostname to bind', 'localhost')
 		.option('-p, --port', 'Port to bind', 5000)
+		.option('-P, --proxy', 'Enable reverse proxy (path:url)')
 		.action(boot)
 	.parse(process.argv);
diff --git a/packages/sirv-cli/readme.md b/packages/sirv-cli/readme.md
index f56b4d7..79d3766 100644
--- a/packages/sirv-cli/readme.md
+++ b/packages/sirv-cli/readme.md
@@ -61,6 +61,7 @@ $ sirv --help
     $ sirv public --quiet --etag --maxage 31536000 --immutable
     $ sirv start public -qeim 31536000
     $ sirv --port 8080 --etag
+    $ sirv public --dev --proxy /api/:http://localhost:4000/
 ```
 
 ```
@@ -83,6 +84,7 @@ $ sirv start --help
     -q, --quiet        Disable logging to terminal
     -H, --host         Hostname to bind  (default localhost)
     -p, --port         Port to bind  (default 5000)
+    -P, --proxy        Enable reverse proxy (path:url)
     -h, --help         Displays this message
 ```
 
diff --git a/packages/sirv/index.js b/packages/sirv/index.js
index caa9be0..6354a00 100644
--- a/packages/sirv/index.js
+++ b/packages/sirv/index.js
@@ -2,6 +2,7 @@ const fs = require('fs');
 const { join, resolve } = require('path');
 const parser = require('@polka/url');
 const mime = require('mime/lite');
+const http = require('http');
 
 const FILES = {};
 const noop = () => {};
@@ -69,6 +70,43 @@ function send(req, res, file, stats, headers={}) {
 	fs.createReadStream(file, opts).pipe(res);
 }
 
+function proxyMatch(url, opts) {
+	if (! url.startsWith(opts.prefix)) {
+		return undefined;
+	}
+	if (opts.prefix.endsWith('/')) {
+		return join(opts.path, url.substring(opts.prefix.length));
+	}
+	if (url.length === opts.prefix.length || url.charAt(opts.prefix.length) === '?') {
+		return url;
+	}
+	return undefined;
+}
+
+function proxy(req, res, opts) {
+	let url = proxyMatch(req.url, opts);
+	if (url === undefined) {
+		return false;
+	}
+	let options = {
+		hostname: opts.hostname,
+		port: opts.port,
+		path: url,
+		method: req.method,
+		headers: req.headers
+	};
+	let proxyReq = http.request(options, proxyRes => {
+		res.writeHead(proxyRes.statusCode, proxyRes.headers);
+		proxyRes.pipe(res);
+	});
+	proxyReq.on('error', _ => {
+		res.statusCode = 500;
+		res.end();
+	});
+	req.pipe(proxyReq);
+	return true;
+}
+
 module.exports = function (dir, opts={}) {
 	dir = resolve(dir || '.');
 
@@ -78,6 +116,9 @@ module.exports = function (dir, opts={}) {
 
 	if (opts.dev) {
 		return function (req, res, next) {
+			if (opts.proxy !== undefined && proxy(req, res, opts.proxy)) {
+				return;
+			}
 			let stats, file, uri=decodeURIComponent(req.path || req.pathname || parser(req).pathname);
 			let arr = [uri].concat(toAssume(uri, extensions)).map(x => join(dir, x)).filter(fs.existsSync);
 			while (file = arr.shift()) {
@@ -115,6 +156,9 @@ module.exports = function (dir, opts={}) {
 	});
 
 	return function (req, res, next) {
+		if (opts.proxy !== undefined && proxy(req, res, opts.proxy)) {
+			return;
+		}
 		let pathname = decodeURIComponent(req.path || req.pathname || parser(req).pathname);
 		let data = FILES[pathname] || find(pathname, extensions);
 		if (!data) return next ? next() : isNotFound(req, res);