Add support for --preload-file in Node.js (#11785)

Author: sbc100

ChangeLog.md

@@ -20,6 +20,7 @@ See docs/process.md for more on how version tagging works.
 
 2.0.24
 ------
+- Support `--preload-file` in Node.js. (#11785)
 - CMake projects (those that either use emcmake or use Emscripten.cmake
   directly) are new configured to install (by default) directly into the
   emscripten sysroot.  This means that running `cmake --install` (or running the

tests/test_other.py

@@ -1399,7 +1399,12 @@ def test_export_from_archive(self):
     self.run_process([EMCC, 'main.c', '-L.', '-lexport', '-s', 'EXPORTED_FUNCTIONS=%s' % full_export_name])
     self.assertTrue(self.is_exported_in_wasm(export_name, 'a.out.wasm'))
 
-  def test_embed_file(self):
+  @parameterized({
+    'embed': (['--embed-file', 'somefile.txt'],),
+    'embed-twice': (['--embed-file', 'somefile.txt', '--embed-file', 'somefile.txt'],),
+    'preload': (['--preload-file', 'somefile.txt'],)
+  })
+  def test_include_file(self, args):
     create_file('somefile.txt', 'hello from a file with lots of data and stuff in it thank you very much')
     create_file('main.cpp', r'''
       #include <stdio.h>
@@ -1414,12 +1419,10 @@ def test_embed_file(self):
       }
     ''')
 
-    self.run_process([EMXX, 'main.cpp', '--embed-file', 'somefile.txt'])
-    self.assertContained('|hello from a file wi|', self.run_js('a.out.js'))
-
-    # preload twice, should not err
-    self.run_process([EMXX, 'main.cpp', '--embed-file', 'somefile.txt', '--embed-file', 'somefile.txt'])
-    self.assertContained('|hello from a file wi|', self.run_js('a.out.js'))
+    self.run_process([EMXX, 'main.cpp'] + args)
+    # run in node.js to ensure we verify that file preloading works there
+    result = self.run_js('a.out.js', engine=config.NODE_JS)
+    self.assertContained('|hello from a file wi|', result)
 
   def test_embed_file_dup(self):
     ensure_dir(self.in_dir('tst', 'test1'))

tools/file_packager.py

@@ -521,14 +521,12 @@ def was_seen(name):
     remote_package_size = os.path.getsize(package_name)
     remote_package_name = os.path.basename(package_name)
     ret += r'''
-      var PACKAGE_PATH;
+      var PACKAGE_PATH = '';
       if (typeof window === 'object') {
         PACKAGE_PATH = window['encodeURIComponent'](window.location.pathname.toString().substring(0, window.location.pathname.toString().lastIndexOf('/')) + '/');
       } else if (typeof location !== 'undefined') {
         // worker
         PACKAGE_PATH = encodeURIComponent(location.pathname.toString().substring(0, location.pathname.toString().lastIndexOf('/')) + '/');
-      } else {
-        throw 'using preloaded data can only be done on a web page or in a web worker';
       }
       var PACKAGE_NAME = '%s';
       var REMOTE_PACKAGE_BASE = '%s';
@@ -712,6 +710,17 @@ def was_seen(name):
 
     ret += r'''
       function fetchRemotePackage(packageName, packageSize, callback, errback) {
+        if (typeof process === 'object') {
+          fs = require('fs');
+          fs.readFile(packageName, function(err, contents) {
+            if (err) {
+              errback(err);
+            } else {
+              callback(contents.buffer);
+            }
+          });
+          return;
+        }
         var xhr = new XMLHttpRequest();
         xhr.open('GET', packageName, true);
         xhr.responseType = 'arraybuffer';