New spdy option to enable/disable HTTP/2 with HTTPS

bin/options.js

@@ -87,6 +87,11 @@ const options = {
     group: SSL_GROUP,
     describe: 'HTTPS',
   },
+  http2: {
+    type: 'boolean',
+    group: SSL_GROUP,
+    describe: 'HTTP/2, must be used with HTTPS',
+  },
   key: {
     type: 'string',
     describe: 'Path to a SSL key.',

lib/Server.js

@@ -89,13 +89,19 @@ class Server {
     if (options.lazy && !options.filename) {
       throw new Error("'filename' option must be set in lazy mode.");
     }
-
+
+    // if the user enables http2, we can safely enable https
+    if (options.http2 && !options.https) {
+      options.https = true;
+    }
+
     updateCompiler(compiler, options);
 
     this.stats =
       options.stats && Object.keys(options.stats).length
         ? options.stats
         : Server.DEFAULT_STATS;
+
     this.hot = options.hot || options.hotOnly;
     this.headers = options.headers;
     this.progress = options.progress;
@@ -647,7 +653,21 @@ class Server {
       options.https.key = options.https.key || fakeCert;
       options.https.cert = options.https.cert || fakeCert;
 
-      if (!options.https.spdy) {
+      // Only prevent HTTP/2 if http2 is explicitly set to false
+      const isHttp2 = options.http2 !== false;
+
+      // note that options.spdy never existed. The user was able
+      // to set options.https.spdy before, though it was not in the
+      // docs. Keep options.https.spdy if the user sets it for
+      // backwards compatability, but log a deprecation warning.
+      if (options.https.spdy) {
+        // for backwards compatability: if options.https.spdy was passed in before,
+        // it was not altered in any way
+        this.log.warn(
+          'Providing custom spdy server options is deprecated and will be removed in the next major version.'
+        );
+      } else {
+        // if the normal https server gets this option, it will not affect it.
         options.https.spdy = {
           protocols: ['h2', 'http/1.1'],
         };
@@ -662,7 +682,14 @@ class Server {
       // - https://github.com/nodejs/node/issues/21665
       // - https://github.com/webpack/webpack-dev-server/issues/1449
       // - https://github.com/expressjs/express/issues/3388
-      if (semver.gte(process.version, '10.0.0')) {
+      if (semver.gte(process.version, '10.0.0') || !isHttp2) {
+        if (options.http2) {
+          // the user explicitly requested http2 but is not getting it because
+          // of the node version.
+          this.log.warn(
+            'HTTP/2 is currently unsupported for Node 10.0.0 and above, but will be supported once Express supports it'
+          );
+        }
         this.listeningApp = https.createServer(options.https, app);
       } else {
         /* eslint-disable global-require */

lib/options.json

@@ -162,6 +162,9 @@
         }
       ]
     },
+    "http2": {
+      "type": "boolean"
+    },
     "contentBase": {
       "anyOf": [
         {
@@ -321,6 +324,7 @@
       "disableHostCheck": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserver-disablehostcheck)",
       "public": "should be {String} (https://webpack.js.org/configuration/dev-server/#devserver-public)",
       "https": "should be {Object|Boolean} (https://webpack.js.org/configuration/dev-server/#devserver-https)",
+      "http2": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserver-http2)",
       "contentBase": "should be {Array} (https://webpack.js.org/configuration/dev-server/#devserver-contentbase)",
       "watchContentBase": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserver-watchcontentbase)",
       "open": "should be {String|Boolean} (https://webpack.js.org/configuration/dev-server/#devserver-open)",

lib/utils/createConfig.js

@@ -136,6 +136,10 @@ function createConfig(config, argv, { port }) {
     options.https = true;
   }
 
+  if (argv.http2) {
+    options.http2 = true;
+  }
+
   if (argv.key) {
     options.key = argv.key;
   }

test/CreateConfig.test.js

@@ -560,6 +560,28 @@ describe('createConfig', () => {
     expect(config).toMatchSnapshot();
   });
 
+  it('http2 option', () => {
+    const config = createConfig(
+      webpackConfig,
+      Object.assign({}, argv, { https: true, http2: true }),
+      { port: 8080 }
+    );
+
+    expect(config).toMatchSnapshot();
+  });
+
+  it('http2 option (in devServer config)', () => {
+    const config = createConfig(
+      Object.assign({}, webpackConfig, {
+        devServer: { https: true, http2: true },
+      }),
+      argv,
+      { port: 8080 }
+    );
+
+    expect(config).toMatchSnapshot();
+  });
+
   it('key option', () => {
     const config = createConfig(
       webpackConfig,