User friendly server errors and automatic port switching (#164)

* more userfriendly server errors and automatically asign free port if port is busy

* cleanup code a lil

* fix typo

* remove unused import

* minor improvements

* change double quotes into single quotes

* lil cleanup & restructuring

* bugfixes

Author: Jasper De Moor

bin/cli.js

@@ -81,7 +81,7 @@ if (!args[2] || !program.commands.some(c => c.name() === args[2])) {
 
 program.parse(args);
 
-function bundle(main, command) {
+async function bundle(main, command) {
   // Require bundler here so the help command is fast
   const Bundler = require('../');
 
@@ -94,7 +94,7 @@ function bundle(main, command) {
   const bundler = new Bundler(main, command);
 
   if (command.name() === 'serve') {
-    const server = bundler.serve(command.port || 1234);
+    const server = await bundler.serve(command.port || 1234);
     if (command.open) {
       require('opn')(`http://localhost:${server.address().port}`);
     }

package.json

@@ -18,6 +18,7 @@
     "chokidar": "^1.7.0",
     "commander": "^2.11.0",
     "cssnano": "^3.10.0",
+    "get-port": "^3.2.0",
     "glob": "^7.1.2",
     "htmlnano": "^0.1.6",
     "is-url": "^1.2.2",

src/Bundler.js

@@ -13,6 +13,7 @@ const {EventEmitter} = require('events');
 const Logger = require('./Logger');
 const PackagerRegistry = require('./packagers');
 const localRequire = require('./utils/localRequire');
+const customErrors = require('./utils/customErrors');
 
 /**
  * The Bundler is the main entry point. It resolves and loads assets,
@@ -452,12 +453,9 @@ class Bundler extends EventEmitter {
     return Server.middleware(this);
   }
 
-  serve(port = 1234) {
-    this.logger.persistent(
-      'Server running at ' + this.logger.chalk.cyan(`http://localhost:${port}`)
-    );
+  async serve(port = 1234) {
     this.bundle();
-    return Server.serve(this, port);
+    return await Server.serve(this, port);
   }
 }
 

src/Server.js

@@ -2,6 +2,8 @@ const http = require('http');
 const path = require('path');
 const url = require('url');
 const serveStatic = require('serve-static');
+const getPort = require('get-port');
+const serverErrors = require('./utils/customErrors').serverErrors;
 
 function middleware(bundler) {
   const serve = serveStatic(bundler.options.outDir, {index: false});
@@ -54,8 +56,29 @@ function middleware(bundler) {
   };
 }
 
-function serve(bundler, port) {
-  return http.createServer(middleware(bundler)).listen(port);
+async function serve(bundler, port) {
+  let freePort = await getPort({port});
+  let server = http.createServer(middleware(bundler)).listen(freePort);
+
+  server.on('error', err => {
+    bundler.logger.error(new Error(serverErrors(err, server.address().port)));
+  });
+
+  server.once('listening', connection => {
+    let addon =
+      server.address().port !== port
+        ? `- ${bundler.logger.chalk.red(
+            `configured port ${port} could not be used.`
+          )}`
+        : '';
+    bundler.logger.persistent(
+      `Server running at ${bundler.logger.chalk.cyan(
+        `http://localhost:${server.address().port}`
+      )} ${addon}\n`
+    );
+  });
+
+  return server;
 }
 
 exports.middleware = middleware;

src/utils/customErrors.js

@@ -0,0 +1,16 @@
+let serverErrorList = {
+  EACCES: "You don't have access to bind the server to port {port}.",
+  EADDRINUSE: 'There is already a process listening on port {port}.'
+};
+
+function serverErrors(err, port) {
+  let desc = serverErrorList[err.code].replace(/{port}/g, port);
+  if (!desc) {
+    desc = `Error: ${
+      err.code
+    } occurred while setting up server on port ${port}.`;
+  }
+  return desc;
+}
+
+module.exports.serverErrors = serverErrors;

test/server.js

@@ -31,15 +31,15 @@ describe('server', function() {
 
   it('should serve files', async function() {
     let b = bundler(__dirname + '/integration/commonjs/index.js');
-    server = b.serve(0);
+    server = await b.serve(0);
 
     let data = await get('/dist/index.js');
     assert.equal(data, fs.readFileSync(__dirname + '/dist/index.js', 'utf8'));
   });
 
   it('should serve a default page if the main bundle is an HTML asset', async function() {
     let b = bundler(__dirname + '/integration/html/index.html');
-    server = b.serve(0);
+    server = await b.serve(0);
 
     let data = await get('/');
     assert.equal(data, fs.readFileSync(__dirname + '/dist/index.html', 'utf8'));
@@ -50,7 +50,7 @@ describe('server', function() {
 
   it('should serve a 404 if the file does not exist', async function() {
     let b = bundler(__dirname + '/integration/commonjs/index.js');
-    server = b.serve(0);
+    server = await b.serve(0);
 
     let threw = false;
     try {
@@ -64,7 +64,7 @@ describe('server', function() {
 
   it('should serve a 500 if the bundler errored', async function() {
     let b = bundler(__dirname + '/integration/html/index.html');
-    server = b.serve(0);
+    server = await b.serve(0);
 
     b.errored = true;
 

yarn.lock

@@ -1900,6 +1900,10 @@ get-own-enumerable-property-symbols@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/get-own-enumerable-property-symbols/-/get-own-enumerable-property-symbols-2.0.1.tgz#5c4ad87f2834c4b9b4e84549dc1e0650fb38c24b"
 
+get-port@^3.2.0:
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/get-port/-/get-port-3.2.0.tgz#dd7ce7de187c06c8bf353796ac71e099f0980ebc"
+
 get-stdin@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/get-stdin/-/get-stdin-4.0.1.tgz#b968c6b0a04384324902e8bf1a5df32579a450fe"