feat(cli): add stdin option

Author: ylemkimon

examples/cli/stdin/README.md

@@ -0,0 +1,16 @@
+# CLI: Stdin Option
+
+Specifying this option instructs the server to close when `stdin` ends.
+
+```console
+npm run webpack-dev-server -- --stdin
+```
+
+## What Should Happen
+
+1. The server should begin running.
+2. Press `CTL+D` on your keyboard.
+3. The server should close.
+
+_Note: the keyboard shortcut for terminating `stdin` can vary depending on the
+operating systems._

examples/cli/stdin/app.js

@@ -0,0 +1,6 @@
+'use strict';
+
+const target = document.querySelector('#target');
+
+target.innerHTML =
+  'Press <code>CTL+D</code> on your keyboard to close the server.';

examples/cli/stdin/webpack.config.js

@@ -0,0 +1,6 @@
+'use strict';
+
+module.exports = {
+  context: __dirname,
+  entry: './app.js',
+};

examples/util.js

@@ -6,7 +6,6 @@ const fs = require('fs');
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
 const marked = require('marked');
-const webpack = require('webpack');
 
 module.exports = {
   setup(config) {
@@ -65,7 +64,6 @@ module.exports = {
 
     marked(readme, { renderer });
 
-    result.plugins.push(new webpack.NamedModulesPlugin());
     result.plugins.push(
       new HtmlWebpackPlugin({
         filename: 'index.html',

lib/Server.js

@@ -72,9 +72,7 @@ class Server {
     routes(this);
     killable(this.listeningApp);
 
-    if (this.options.setupExitSignals) {
-      setupExitSignals(this);
-    }
+    setupExitSignals(this);
 
     // Proxy WebSocket without the initial http request
     // https://github.com/chimurai/http-proxy-middleware#external-websocket-upgrade

lib/options.json

@@ -352,6 +352,9 @@
         }
       ]
     },
+    "stdin": {
+      "type": "boolean"
+    },
     "transportMode": {
       "anyOf": [
         {
@@ -411,6 +414,7 @@
       "public": "should be {String} (https://webpack.js.org/configuration/dev-server/#devserverpublic)",
       "setupExitSignals": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserversetupexitsignals)",
       "static": "should be {Boolean|String|Object|Array} (https://webpack.js.org/configuration/dev-server/#devserverstatic)",
+      "stdin": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserverstdin)",
       "transportMode": "should be {String|Object} (https://webpack.js.org/configuration/dev-server/#devservertransportmode)",
       "useLocalIp": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserveruselocalip)"
     }

lib/utils/setupExitSignals.js

@@ -3,19 +3,28 @@
 const signals = ['SIGINT', 'SIGTERM'];
 
 function setupExitSignals(server) {
-  signals.forEach((signal) => {
-    process.on(signal, () => {
-      if (server) {
-        server.close(() => {
-          // eslint-disable-next-line no-process-exit
-          process.exit();
-        });
-      } else {
+  const closeAndExit = () => {
+    if (server) {
+      server.close(() => {
         // eslint-disable-next-line no-process-exit
         process.exit();
-      }
+      });
+    } else {
+      // eslint-disable-next-line no-process-exit
+      process.exit();
+    }
+  };
+
+  if (server.options.setupExitSignals) {
+    signals.forEach((signal) => {
+      process.on(signal, closeAndExit);
     });
-  });
+  }
+
+  if (server.options.stdin) {
+    process.stdin.on('end', closeAndExit);
+    process.stdin.resume();
+  }
 }
 
 module.exports = setupExitSignals;

test/__snapshots__/Validation.test.js.snap

@@ -39,5 +39,5 @@ exports[`Validation validation should fail validation for invalid \`static\` con
 exports[`Validation validation should fail validation for no additional properties 1`] = `
 "Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
  - configuration has an unknown property 'additional'. These properties are valid:
-   object { bonjour?, client?, compress?, dev?, firewall?, headers?, historyApiFallback?, host?, hot?, http2?, https?, injectClient?, injectHot?, liveReload?, onAfterSetupMiddleware?, onBeforeSetupMiddleware?, onListening?, open?, openPage?, overlay?, port?, profile?, progress?, proxy?, public?, setupExitSignals?, static?, transportMode?, useLocalIp? }"
+   object { bonjour?, client?, compress?, dev?, firewall?, headers?, historyApiFallback?, host?, hot?, http2?, https?, injectClient?, injectHot?, liveReload?, onAfterSetupMiddleware?, onBeforeSetupMiddleware?, onListening?, open?, openPage?, overlay?, port?, profile?, progress?, proxy?, public?, setupExitSignals?, static?, stdin?, transportMode?, useLocalIp? }"
 `;

test/cli/cli.test.js

@@ -210,6 +210,50 @@ runCLITest('CLI', () => {
     });
   });
 
+  it('should exit the process when stdin ends if --stdin', (done) => {
+    const cliPath = resolve(__dirname, '../../bin/webpack-dev-server.js');
+    const examplePath = resolve(__dirname, '../../examples/cli/public');
+    const cp = execa('node', [cliPath, '--stdin'], { cwd: examplePath });
+
+    cp.stderr.on('data', (data) => {
+      const bits = data.toString();
+
+      if (/Compiled successfully/.test(bits)) {
+        expect(cp.pid !== 0).toBe(true);
+
+        cp.stdin.write('hello');
+        cp.stdin.end('world');
+      }
+    });
+
+    cp.on('exit', () => {
+      done();
+    });
+  });
+
+  it('should exit the process when stdin ends if --stdin, even before the compilation is done', (done) => {
+    const cliPath = resolve(__dirname, '../../bin/webpack-dev-server.js');
+    const cwd = resolve(__dirname, '../fixtures/cli');
+    const cp = execa('node', [cliPath, '--stdin'], { cwd });
+
+    let killed = false;
+
+    cp.stderr.on('data', () => {
+      if (!killed) {
+        expect(cp.pid !== 0).toBe(true);
+
+        cp.stdin.write('hello');
+        cp.stdin.end('world');
+      }
+
+      killed = true;
+    });
+
+    cp.on('exit', () => {
+      done();
+    });
+  });
+
   // TODO: do not skip after @webpack-cli/serve passes null port by default
   // https://github.com/webpack/webpack-cli/pull/2126
   it.skip('should use different random port when multiple instances are started on different processes', (done) => {

test/server/setupExitSignals-option.test.js

@@ -8,26 +8,33 @@ describe('setupExitSignals option', () => {
   let server;
   let exitSpy;
   let killSpy;
+  let stdinResumeSpy;
   const signals = ['SIGINT', 'SIGTERM'];
 
   beforeEach((done) => {
     server = testServer.start(
       config,
       {
         setupExitSignals: true,
+        stdin: true,
         port,
       },
       done
     );
     exitSpy = jest.spyOn(process, 'exit').mockImplementation(() => {});
+    stdinResumeSpy = jest
+      .spyOn(process.stdin, 'resume')
+      .mockImplementation(() => {});
     killSpy = jest.spyOn(server.listeningApp, 'kill');
   });
 
   afterEach((done) => {
     exitSpy.mockReset();
+    stdinResumeSpy.mockReset();
     signals.forEach((signal) => {
       process.removeAllListeners(signal);
     });
+    process.stdin.removeAllListeners('end');
     testServer.close(done);
   });
 
@@ -40,4 +47,14 @@ describe('setupExitSignals option', () => {
       done();
     }, 1000);
   });
+
+  it('should close and exit on stdin end', (done) => {
+    process.stdin.emit('end');
+
+    setTimeout(() => {
+      expect(killSpy.mock.calls.length).toEqual(1);
+      expect(exitSpy.mock.calls.length).toEqual(1);
+      done();
+    }, 1000);
+  });
 });