Exposed missing buffer globals for compatibility

CHANGELOG.yaml

@@ -6,6 +6,7 @@ unreleased:
   fixed bugs:
     - GH-1036 Fixed `uncaughtException` event listener not being removed
     - GH-1034 Fixed an issue where sandbox crashes for large response body
+    - GH-1035 Added missing buffer APIs to expose a uniform interface across environments
   chores:
     - GH-1033 Update ci.yml to run coverage on latest node version
     - GH-1032 Add support for configuring module resolver based on environment

lib/vendor/buffer/buffer.js

@@ -1,9 +1,21 @@
+const NOT_IMPLEMENTED = function () {
+    throw new Error('Not implemented');
+};
+
 function getBufferModule (buffer) {
     return  {
         Buffer: buffer.Buffer,
         SlowBuffer: buffer.SlowBuffer,
         INSPECT_MAX_BYTES: buffer.INSPECT_MAX_BYTES,
-        kMaxLength: buffer.kMaxLength
+        kMaxLength: buffer.kMaxLength,
+        kStringMaxLength: buffer.kStringMaxLength,
+        constants: buffer.constants,
+        File: buffer.File,
+        Blob: buffer.Blob,
+        isAscii: NOT_IMPLEMENTED,
+        isUtf8: NOT_IMPLEMENTED,
+        resolveObjectURL: NOT_IMPLEMENTED,
+        transcode: NOT_IMPLEMENTED
     }
 }
 

lib/vendor/buffer/index.browser.js

@@ -2,7 +2,18 @@ const getBufferModule = require('./buffer');
 const SpecificBuffer = require('./specific-buffer');
 const buffer = require('buffer/');
 
+// Using 32-bit implementation value from Node
+// https://github.com/nodejs/node/blob/main/deps/v8/include/v8-primitive.h#L126
+const K_STRING_MAX_LENGTH = (1 << 28) - 16;
+
 module.exports = getBufferModule({
     ...buffer,
-    Buffer: SpecificBuffer(buffer.Buffer)
-})
+    Buffer: SpecificBuffer(buffer.Buffer),
+    kStringMaxLength: K_STRING_MAX_LENGTH,
+    constants: {
+        MAX_LENGTH: buffer.kMaxLength,
+        MAX_STRING_LENGTH: K_STRING_MAX_LENGTH
+    },
+    File: File,
+    Blob: Blob
+});

lib/vendor/buffer/specific-buffer.js

@@ -1,3 +1,7 @@
+const NOT_IMPLEMENTED = function () {
+    throw new Error('Not implemented');
+};
+
 function SpecificBuffer (_Buffer) {
     const Buffer = function () {
         if (typeof arguments[0] === 'number') {
@@ -51,6 +55,10 @@ function SpecificBuffer (_Buffer) {
         return _Buffer.byteLength(...arguments);
     };
 
+    Buffer.copyBytesFrom = NOT_IMPLEMENTED;
+
+    Buffer.of = NOT_IMPLEMENTED;
+
     return Buffer;
 }
 

test/unit/sandbox-libraries/buffer.test.js

@@ -243,8 +243,31 @@ describe('sandbox library - buffer', function () {
                 buffer = require('buffer');
 
             assert.strictEqual(typeof buffer.kMaxLength, 'number');
+            assert.strictEqual(typeof buffer.kStringMaxLength, 'number');
+            assert.strictEqual(typeof buffer.constants.MAX_LENGTH, 'number');
+            assert.strictEqual(typeof buffer.constants.MAX_STRING_LENGTH, 'number');
             assert.strictEqual(typeof buffer.INSPECT_MAX_BYTES, 'number');
 
         `, done);
     });
+
+    it('should expose File class', function (done) {
+        context.execute(`
+            const assert = require('assert'),
+                buffer = require('buffer');
+            const lastModified = Date.now();
+            const file = new buffer.File([], 'filename.txt', { type: 'text/plain', lastModified });
+            assert.strictEqual(file.name, 'filename.txt');
+            assert.strictEqual(file.lastModified, lastModified);
+        `, done);
+    });
+
+    it('should expose Blob class', function (done) {
+        context.execute(`
+            const assert = require('assert'),
+                buffer = require('buffer');
+            const blob = new buffer.Blob(['hello world'], { type: 'text/plain' });
+            assert.strictEqual(blob.size, 11);
+        `, done);
+    });
 });