workers: add support for data: URLs

PR-URL: #34584
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Bradley Farias <bradley.meck@gmail.com>
Reviewed-By: Jan Krems <jan.krems@gmail.com>

doc/api/worker_threads.md

@@ -621,6 +621,10 @@ if (isMainThread) {
 <!-- YAML
 added: v10.5.0
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/34584
+    description: The `filename` parameter can be a WHATWG `URL` object using
+                 `data:` protocol.
   - version: REPLACEME
     pr-url: https://github.com/nodejs/node/pull/34394
     description: The `trackUnmanagedFds` option was set to `true` by default.
@@ -654,7 +658,9 @@ changes:
 * `filename` {string|URL} The path to the Worker’s main script or module. Must
   be either an absolute path or a relative path (i.e. relative to the
   current working directory) starting with `./` or `../`, or a WHATWG `URL`
-  object using `file:` protocol.
+  object using `file:` or `data:` protocol.
+  When using a [`data:` URL][], the data is interpreted based on MIME type using
+  the [ECMAScript module loader][].
   If `options.eval` is `true`, this is a string containing JavaScript code
   rather than a path.
 * `options` {Object}
@@ -902,6 +908,7 @@ active handle in the event system. If the worker is already `unref()`ed calling
 [`AsyncResource`]: async_hooks.html#async_hooks_class_asyncresource
 [`Buffer`]: buffer.html
 [`Buffer.allocUnsafe()`]: buffer.html#buffer_static_method_buffer_allocunsafe_size
+[ECMAScript module loader]: esm.html#esm_data_imports
 [`ERR_MISSING_MESSAGE_PORT_IN_TRANSFER_LIST`]: errors.html#errors_err_missing_message_port_in_transfer_list
 [`ERR_WORKER_NOT_RUNNING`]: errors.html#ERR_WORKER_NOT_RUNNING
 [`EventEmitter`]: events.html
@@ -953,3 +960,4 @@ active handle in the event system. If the worker is already `unref()`ed calling
 [child processes]: child_process.html
 [contextified]: vm.html#vm_what_does_it_mean_to_contextify_an_object
 [v8.serdes]: v8.html#v8_serialization_api
+[`data:` URL]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs

lib/internal/errors.js

@@ -1470,6 +1470,9 @@ E('ERR_WORKER_PATH', (filename) =>
   (filename.startsWith('file://') ?
     ' Wrap file:// URLs with `new URL`.' : ''
   ) +
+  (filename.startsWith('data:text/javascript') ?
+    ' Wrap data: URLs with `new URL`.' : ''
+  ) +
   ` Received "${filename}"`,
   TypeError);
 E('ERR_WORKER_UNSERIALIZABLE_ERROR',

lib/internal/main/worker_thread.js

@@ -149,7 +149,7 @@ port.on('message', (message) => {
     debug(`[${threadId}] starts worker script ${filename} ` +
           `(eval = ${eval}) at cwd = ${process.cwd()}`);
     port.postMessage({ type: UP_AND_RUNNING });
-    if (doEval) {
+    if (doEval === 'classic') {
       const { evalScript } = require('internal/process/execution');
       const name = '[worker eval]';
       // This is necessary for CJS module compilation.
@@ -161,6 +161,11 @@ port.on('message', (message) => {
       });
       process.argv.splice(1, 0, name);
       evalScript(name, filename);
+    } else if (doEval === 'module') {
+      const { evalModule } = require('internal/process/execution');
+      evalModule(filename).catch((e) => {
+        workerOnGlobalUncaughtException(e, true);
+      });
     } else {
       // script filename
       // runMain here might be monkey-patched by users in --require.

lib/internal/process/execution.js

@@ -45,7 +45,7 @@ function evalModule(source, print) {
   const { log } = require('internal/console/global');
   const { loadESM } = require('internal/process/esm_loader');
   const { handleMainPromise } = require('internal/modules/run_main');
-  handleMainPromise(loadESM(async (loader) => {
+  return handleMainPromise(loadESM(async (loader) => {
     const { result } = await loader.eval(source);
     if (print) {
       log(result);

lib/internal/worker.js

@@ -4,6 +4,7 @@
 
 const {
   ArrayIsArray,
+  JSONStringify,
   MathMax,
   ObjectCreate,
   ObjectEntries,
@@ -100,7 +101,7 @@ class Worker extends EventEmitter {
       argv = options.argv.map(String);
     }
 
-    let url;
+    let url, doEval;
     if (options.eval) {
       if (typeof filename !== 'string') {
         throw new ERR_INVALID_ARG_VALUE(
@@ -110,7 +111,13 @@ class Worker extends EventEmitter {
         );
       }
       url = null;
+      doEval = 'classic';
+    } else if (isURLInstance(filename) && filename.protocol === 'data:') {
+      url = null;
+      doEval = 'module';
+      filename = `import ${JSONStringify(`${filename}`)}`;
     } else {
+      doEval = false;
       if (isURLInstance(filename)) {
         url = filename;
         filename = fileURLToPath(filename);
@@ -201,7 +208,7 @@ class Worker extends EventEmitter {
       argv,
       type: messageTypes.LOAD_SCRIPT,
       filename,
-      doEval: !!options.eval,
+      doEval,
       cwdCounter: cwdCounter || workerIo.sharedCwdCounter,
       workerData: options.workerData,
       publicPort: port2,

test/parallel/test-worker-data-url.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const common = require('../common');
+const { Worker } = require('worker_threads');
+const assert = require('assert');
+
+new Worker(new URL('data:text/javascript,'))
+  .on('error', common.mustNotCall(() => {}));
+new Worker(new URL('data:text/javascript,export{}'))
+  .on('error', common.mustNotCall(() => {}));
+
+new Worker(new URL('data:text/plain,'))
+  .on('error', common.mustCall(() => {}));
+new Worker(new URL('data:text/javascript,module.exports={}'))
+  .on('error', common.mustCall(() => {}));
+
+new Worker(new URL('data:text/javascript,await Promise.resolve()'))
+  .on('error', common.mustNotCall(() => {}));
+new Worker(new URL('data:text/javascript,await Promise.reject()'))
+  .on('error', common.mustCall(() => {}));
+new Worker(new URL('data:text/javascript,await new Promise(()=>{})'))
+  .on(
+    'exit',
+    common.mustCall((exitCode) => { assert.strictEqual(exitCode, 13); })
+  );

test/parallel/test-worker-unsupported-path.js

@@ -33,6 +33,10 @@ const { Worker } = require('worker_threads');
     () => { new Worker('file:///file_url'); },
     /Wrap file:\/\/ URLs with `new URL`/
   );
+  assert.throws(
+    () => { new Worker('data:text/javascript,'); },
+    /Wrap data: URLs with `new URL`/
+  );
   assert.throws(
     () => { new Worker('relative_no_dot'); },
     // eslint-disable-next-line node-core/no-unescaped-regexp-dot
@@ -47,6 +51,4 @@ const { Worker } = require('worker_threads');
   };
   assert.throws(() => { new Worker(new URL('https://www.url.com')); },
                 expectedErr);
-  assert.throws(() => { new Worker(new URL('data:application/javascript,')); },
-                expectedErr);
 }