fix(ext/node): accept base64url encoding on StringDecoder

ext/node/lib.rs

@@ -619,7 +619,7 @@ deno_core::extension!(deno_node,
     "internal/http2/util.ts",
     "internal/idna.ts",
     "internal/net.ts",
-    "internal/normalize_encoding.mjs",
+    "internal/normalize_encoding.ts",
     "internal/options.ts",
     "internal/primordials.mjs",
     "internal/process/per_thread.mjs",

ext/node/polyfills/_utils.ts

@@ -5,7 +5,6 @@ const {
   Error,
   PromisePrototypeThen,
   ArrayPrototypePop,
-  StringPrototypeToLowerCase,
   NumberIsInteger,
   ObjectGetOwnPropertyNames,
   ReflectGetOwnPropertyDescriptor,
@@ -29,6 +28,7 @@ export type TextEncodings =
   | "ucs2"
   | "ucs-2"
   | "base64"
+  | "base64url"
   | "latin1"
   | "hex";
 
@@ -94,78 +94,6 @@ export function spliceOne(list: string[], index: number) {
   ArrayPrototypePop(list);
 }
 
-// Taken from: https://github.com/nodejs/node/blob/ba684805b6c0eded76e5cd89ee00328ac7a59365/lib/internal/util.js#L125
-// Return undefined if there is no match.
-// Move the "slow cases" to a separate function to make sure this function gets
-// inlined properly. That prioritizes the common case.
-export function normalizeEncoding(
-  enc: string | null,
-): TextEncodings | undefined {
-  if (enc == null || enc === "utf8" || enc === "utf-8") return "utf8";
-  return slowCases(enc);
-}
-
-// https://github.com/nodejs/node/blob/ba684805b6c0eded76e5cd89ee00328ac7a59365/lib/internal/util.js#L130
-function slowCases(enc: string): TextEncodings | undefined {
-  switch (enc.length) {
-    case 4:
-      if (enc === "UTF8") return "utf8";
-      if (enc === "ucs2" || enc === "UCS2") return "utf16le";
-      enc = StringPrototypeToLowerCase(enc);
-      if (enc === "utf8") return "utf8";
-      if (enc === "ucs2") return "utf16le";
-      break;
-    case 3:
-      if (
-        enc === "hex" || enc === "HEX" ||
-        StringPrototypeToLowerCase(enc) === "hex"
-      ) {
-        return "hex";
-      }
-      break;
-    case 5:
-      if (enc === "ascii") return "ascii";
-      if (enc === "ucs-2") return "utf16le";
-      if (enc === "UTF-8") return "utf8";
-      if (enc === "ASCII") return "ascii";
-      if (enc === "UCS-2") return "utf16le";
-      enc = StringPrototypeToLowerCase(enc);
-      if (enc === "utf-8") return "utf8";
-      if (enc === "ascii") return "ascii";
-      if (enc === "ucs-2") return "utf16le";
-      break;
-    case 6:
-      if (enc === "base64") return "base64";
-      if (enc === "latin1" || enc === "binary") return "latin1";
-      if (enc === "BASE64") return "base64";
-      if (enc === "LATIN1" || enc === "BINARY") return "latin1";
-      enc = StringPrototypeToLowerCase(enc);
-      if (enc === "base64") return "base64";
-      if (enc === "latin1" || enc === "binary") return "latin1";
-      break;
-    case 7:
-      if (
-        enc === "utf16le" ||
-        enc === "UTF16LE" ||
-        StringPrototypeToLowerCase(enc) === "utf16le"
-      ) {
-        return "utf16le";
-      }
-      break;
-    case 8:
-      if (
-        enc === "utf-16le" ||
-        enc === "UTF-16LE" ||
-        StringPrototypeToLowerCase(enc) === "utf-16le"
-      ) {
-        return "utf16le";
-      }
-      break;
-    default:
-      if (enc === "") return "utf8";
-  }
-}
-
 export function validateIntegerRange(
   value: number,
   name: string,

ext/node/polyfills/crypto.ts

@@ -164,9 +164,7 @@ import type {
   TransformOptions,
   WritableOptions,
 } from "ext:deno_node/_stream.d.ts";
-import {
-  normalizeEncoding,
-} from "ext:deno_node/internal/normalize_encoding.mjs";
+import { normalizeEncoding } from "ext:deno_node/internal/util.mjs";
 import { isArrayBufferView } from "ext:deno_node/internal/util/types.ts";
 import { validateString } from "ext:deno_node/internal/validators.mjs";
 import { crypto as webcrypto } from "ext:deno_crypto/00_crypto.js";

ext/node/polyfills/internal/normalize_encoding.mjs → ext/node/polyfills/internal/normalize_encoding.ts

@@ -2,13 +2,17 @@
 
 import { primordials } from "ext:core/mod.js";
 const { StringPrototypeToLowerCase } = primordials;
+import type { TextEncodings } from "ext:deno_node/_utils.ts";
 
-export function normalizeEncoding(enc) {
+// https://github.com/nodejs/node/blob/a73b575304722a3682fbec3a5fb13b39c5791342/lib/internal/util.js#L252
+export function normalizeEncoding(
+  enc: string | null,
+): TextEncodings | undefined {
   if (enc == null || enc === "utf8" || enc === "utf-8") return "utf8";
   return slowCases(enc);
 }
 
-export function slowCases(enc) {
+function slowCases(enc: string): TextEncodings | undefined {
   switch (enc.length) {
     case 4:
       if (enc === "UTF8") return "utf8";

ext/node/polyfills/internal/util.mjs

@@ -1,11 +1,8 @@
 // Copyright 2018-2025 the Deno authors. MIT license.
 
 import { validateFunction } from "ext:deno_node/internal/validators.mjs";
-import {
-  normalizeEncoding,
-  slowCases,
-} from "ext:deno_node/internal/normalize_encoding.mjs";
-export { normalizeEncoding, slowCases };
+import { normalizeEncoding } from "ext:deno_node/internal/normalize_encoding.ts";
+export { normalizeEncoding };
 import {
   ObjectCreate,
   StringPrototypeToUpperCase,
@@ -186,5 +183,4 @@ export default {
   normalizeEncoding,
   once,
   promisify,
-  slowCases,
 };

ext/node/polyfills/internal/validators.mjs

@@ -23,7 +23,7 @@ const {
 import { codes } from "ext:deno_node/internal/error_codes.ts";
 import { hideStackFrames } from "ext:deno_node/internal/hide_stack_frames.ts";
 import { isArrayBufferView } from "ext:deno_node/internal/util/types.ts";
-import { normalizeEncoding } from "ext:deno_node/internal/normalize_encoding.mjs";
+import { normalizeEncoding } from "ext:deno_node/internal/util.mjs";
 
 /**
  * @param {number} value

ext/node/polyfills/string_decoder.ts

@@ -24,7 +24,7 @@
 // (https://github.com/nodejs/node/blob/ba06c5c509956dc413f91b755c1c93798bb700d4/src/string_decoder.cc)
 
 import { Buffer, constants } from "node:buffer";
-import { normalizeEncoding as castEncoding } from "ext:deno_node/_utils.ts";
+import { normalizeEncoding as castEncoding } from "ext:deno_node/internal/util.mjs";
 import {
   ERR_INVALID_ARG_TYPE,
   ERR_INVALID_THIS,
@@ -132,7 +132,8 @@ function decode(this: StringDecoder, buf: Buffer) {
   let rest = "";
 
   if (
-    enc === Encoding.Utf8 || enc === Encoding.Utf16 || enc === Encoding.Base64
+    enc === Encoding.Utf8 || enc === Encoding.Utf16 ||
+    enc === Encoding.Base64 || enc === Encoding.Base64Url
   ) {
     // check if we need to finish an incomplete char from the last chunk
     // written. If we do, we copy the bytes into our `lastChar` buffer
@@ -242,7 +243,7 @@ function decode(this: StringDecoder, buf: Buffer) {
           this[kBufferedBytes] = 2;
           this[kMissingBytes] = 2;
         }
-      } else if (enc === Encoding.Base64) {
+      } else if (enc === Encoding.Base64 || enc === Encoding.Base64Url) {
         this[kBufferedBytes] = (buf.length - bufIdx) % 3;
         if (this[kBufferedBytes] > 0) {
           this[kMissingBytes] = 3 - this[kBufferedBytes];
@@ -302,6 +303,7 @@ function flush(this: StringDecoder) {
 enum Encoding {
   Utf8,
   Base64,
+  Base64Url,
   Utf16,
   Ascii,
   Latin1,
@@ -345,7 +347,11 @@ export function StringDecoder(this: Partial<StringDecoder>, encoding?: string) {
       break;
     case "base64":
       enc = Encoding.Base64;
-      bufLen = 3;
+      bufLen = 4;
+      break;
+    case "base64url":
+      enc = Encoding.Base64Url;
+      bufLen = 4;
       break;
     case "utf16le":
       enc = Encoding.Utf16;

tests/node_compat/config.toml

@@ -1120,6 +1120,8 @@
 "parallel/test-stream3-pause-then-read.js" = {}
 "parallel/test-stream3-pipeline-async-iterator.js" = {}
 "parallel/test-streams-highwatermark.js" = {}
+"parallel/test-string-decoder-end.js" = {}
+"parallel/test-string-decoder-fuzz.js" = {}
 "parallel/test-string-decoder.js" = { flaky = true }
 "parallel/test-sys.js" = {}
 "parallel/test-timers-api-refs.js" = {}

tests/unit_node/string_decoder_test.ts

@@ -73,6 +73,41 @@ Deno.test({
   },
 });
 
+Deno.test({
+  name: "String decoder is encoding base64url correctly",
+  fn() {
+    let decoder;
+
+    decoder = new StringDecoder("base64url");
+    assertEquals(decoder.write(Buffer.from("E1", "hex")), "");
+    assertEquals(decoder.end(), "4Q");
+
+    decoder = new StringDecoder("base64url");
+    assertEquals(decoder.write(Buffer.from("E18B", "hex")), "");
+    assertEquals(decoder.end(), "4Ys");
+
+    decoder = new StringDecoder("base64url");
+    assertEquals(decoder.write(Buffer.from("\ufffd")), "77-9");
+    assertEquals(decoder.end(), "");
+
+    decoder = new StringDecoder("base64url");
+    assertEquals(
+      decoder.write(Buffer.from("\ufffd\ufffd\ufffd")),
+      "77-977-977-9",
+    );
+    assertEquals(decoder.end(), "");
+
+    decoder = new StringDecoder("base64url");
+    assertEquals(decoder.write(Buffer.from("EFBFBDE2", "hex")), "77-9");
+    assertEquals(decoder.end(), "4g");
+
+    decoder = new StringDecoder("base64url");
+    assertEquals(decoder.write(Buffer.from("F1", "hex")), "");
+    assertEquals(decoder.write(Buffer.from("41F2", "hex")), "8UHy");
+    assertEquals(decoder.end(), "");
+  },
+});
+
 Deno.test({
   name: "String decoder is encoding hex correctly",
   fn() {

tools/core_import_map.json

@@ -144,7 +144,7 @@
     "ext:deno_node/internal/http.ts": "../ext/node/polyfills/internal/http.ts",
     "ext:deno_node/internal/http2/util.ts": "../ext/node/polyfills/internal/http2/util.ts",
     "ext:deno_node/internal/net.ts": "../ext/node/polyfills/internal/net.ts",
-    "ext:deno_node/internal/normalize_encoding.mjs": "../ext/node/polyfills/internal/normalize_encoding.mjs",
+    "ext:deno_node/internal/normalize_encoding.ts": "../ext/node/polyfills/internal/normalize_encoding.ts",
     "ext:deno_node/internal/options.ts": "../ext/node/polyfills/internal/options.ts",
     "ext:deno_node/internal/primordials.mjs": "../ext/node/polyfills/internal/primordials.mjs",
     "ext:deno_node/internal/process/per_thread.mjs": "../ext/node/polyfills/internal/process/per_thread.mjs",