fix: Remove content-encoding header from already decompressed responses

.changeset/dirty-moles-exercise.md

@@ -0,0 +1,5 @@
+---
+"@remix-run/web-fetch": patch
+---
+
+fix: Remove content-encoding header from already decompressed responses. This eases the use of fetch in senarios where you wish to use it as a sort of makeshift proxy.

packages/fetch/src/fetch.js

@@ -277,6 +277,7 @@ async function fetch(url, options_ = {}) {
 
  // For gzip
  if (codings === 'gzip' || codings === 'x-gzip') {
+ responseOptions.headers.delete("Content-Encoding");
  body = pump(body, zlib.createGunzip(zlibOptions), reject);
  response = new Response(fromAsyncIterable(body), responseOptions);
  resolve(response);
@@ -285,6 +286,7 @@ async function fetch(url, options_ = {}) {
 
  // For deflate
  if (codings === 'deflate' || codings === 'x-deflate') {
+ responseOptions.headers.delete("Content-Encoding");
  // Handle the infamous raw deflate response from old servers
  // a hack for old IIS and Apache servers
  const raw = pump(response_, new PassThrough(), reject);
@@ -304,6 +306,7 @@ async function fetch(url, options_ = {}) {
 
  // For br
  if (codings === 'br') {
+ responseOptions.headers.delete("Content-Encoding");
  body = pump(body, zlib.createBrotliDecompress(), reject);
  response = new Response(fromAsyncIterable(body), responseOptions);
  resolve(response);

packages/fetch/test/main.js

@@ -818,6 +818,7 @@ describe("node-fetch", () => {
  const url = `${base}gzip`;
  return fetch(url).then((res) => {
  expect(res.headers.get("content-type")).to.equal("text/plain");
+ expect(res.headers.get("content-encoding")).to.be.null;
  return res.text().then((result) => {
  expect(result).to.be.a("string");
  expect(result).to.equal("hello world");
@@ -836,10 +837,9 @@ describe("node-fetch", () => {
  });
  });
 
- it("should make capitalised Content-Encoding lowercase", () => {
+ it("should decompress capitalised Content-Encoding", () => {
  const url = `${base}gzip-capital`;
  return fetch(url).then((res) => {
- expect(res.headers.get("content-encoding")).to.equal("gzip");
  return res.text().then((result) => {
  expect(result).to.be.a("string");
  expect(result).to.equal("hello world");
@@ -851,6 +851,7 @@ describe("node-fetch", () => {
  const url = `${base}deflate`;
  return fetch(url).then((res) => {
  expect(res.headers.get("content-type")).to.equal("text/plain");
+ expect(res.headers.get("content-encoding")).to.be.null;
  return res.text().then((result) => {
  expect(result).to.be.a("string");
  expect(result).to.equal("hello world");
@@ -877,6 +878,7 @@ describe("node-fetch", () => {
  const url = `${base}brotli`;
  return fetch(url).then((res) => {
  expect(res.headers.get("content-type")).to.equal("text/plain");
+ expect(res.headers.get("content-encoding")).to.be.null;
  return res.text().then((result) => {
  expect(result).to.be.a("string");
  expect(result).to.equal("hello world");
@@ -906,6 +908,7 @@ describe("node-fetch", () => {
  const url = `${base}sdch`;
  return fetch(url).then((res) => {
  expect(res.headers.get("content-type")).to.equal("text/plain");
+ expect(res.headers.get("content-encoding")).to.equal("sdch");
  return res.text().then((result) => {
  expect(result).to.be.a("string");
  expect(result).to.equal("fake sdch string");
@@ -957,6 +960,7 @@ describe("node-fetch", () => {
  };
  return fetch(url, options).then((res) => {
  expect(res.headers.get("content-type")).to.equal("text/plain");
+ expect(res.headers.get("content-encoding")).to.equal("gzip");
  return res.text().then((result) => {
  expect(result).to.be.a("string");
  expect(result).to.not.equal("hello world");