From 51861e98a8f87e0905e71bb101b506f9512a9d7f Mon Sep 17 00:00:00 2001
From: "Travis D. Warlick, Jr" <twarlick@maxmedia.com>
Date: Thu, 12 Aug 2021 12:37:22 -0400
Subject: [PATCH] Fix(premature close) Redirect failing when response is
 chunked but empty (#1222)

* Fix redirect failing when response is chunked but empty. #1220 #1064

* Handle chunked responses where the final chunk and EOM code are in separate packets and where there is an additional data chunk in the same packet before the final chunk and EOM code.
---
 src/index.js         | 51 ++++++++++++++++++++++++++++----------------
 test/main.js         | 30 ++++++++++++++++++++++++++
 test/utils/server.js | 26 ++++++++++++++++++++++
 3 files changed, 89 insertions(+), 18 deletions(-)

diff --git a/src/index.js b/src/index.js
index 2cad269f9..d906fffa8 100644
--- a/src/index.js
+++ b/src/index.js
@@ -287,29 +287,44 @@ export default async function fetch(url, options_) {
 }
 
 function fixResponseChunkedTransferBadEnding(request, errorCallback) {
-	const LAST_CHUNK = Buffer.from('0\r\n');
-	let socket;
+	const LAST_CHUNK = Buffer.from('0\r\n\r\n');
 
-	request.on('socket', s => {
-		socket = s;
-	});
+	let isChunkedTransfer = false;
+	let properLastChunkReceived = false;
+	let previousChunk;
 
 	request.on('response', response => {
 		const {headers} = response;
-		if (headers['transfer-encoding'] === 'chunked' && !headers['content-length']) {
-			let properLastChunkReceived = false;
+		isChunkedTransfer = headers['transfer-encoding'] === 'chunked' && !headers['content-length'];
+	});
 
-			socket.on('data', buf => {
-				properLastChunkReceived = Buffer.compare(buf.slice(-3), LAST_CHUNK) === 0;
-			});
+	request.on('socket', socket => {
+		const onSocketClose = () => {
+			if (isChunkedTransfer && !properLastChunkReceived) {
+				const error = new Error('Premature close');
+				error.code = 'ERR_STREAM_PREMATURE_CLOSE';
+				errorCallback(error);
+			}
+		};
 
-			socket.prependListener('close', () => {
-				if (!properLastChunkReceived) {
-					const error = new Error('Premature close');
-					error.code = 'ERR_STREAM_PREMATURE_CLOSE';
-					errorCallback(error);
-				}
-			});
-		}
+		socket.prependListener('close', onSocketClose);
+
+		request.on('abort', () => {
+			socket.removeListener('close', onSocketClose);
+		});
+
+		socket.on('data', buf => {
+			properLastChunkReceived = Buffer.compare(buf.slice(-5), LAST_CHUNK) === 0;
+
+			// Sometimes final 0-length chunk and end of message code are in separate packets
+			if (!properLastChunkReceived && previousChunk) {
+				properLastChunkReceived = (
+					Buffer.compare(previousChunk.slice(-3), LAST_CHUNK.slice(0, 3)) === 0 &&
+					Buffer.compare(buf.slice(-2), LAST_CHUNK.slice(3)) === 0
+				);
+			}
+
+			previousChunk = buf;
+		});
 	});
 }
diff --git a/test/main.js b/test/main.js
index c50860e2f..1e1f368c3 100644
--- a/test/main.js
+++ b/test/main.js
@@ -684,6 +684,36 @@ describe('node-fetch', () => {
 		});
 	});
 
+	it('should follow redirect after empty chunked transfer-encoding', () => {
+		const url = `${base}redirect/chunked`;
+		return fetch(url).then(res => {
+			expect(res.status).to.equal(200);
+			expect(res.ok).to.be.true;
+		});
+	});
+
+	it('should handle chunked response with more than 1 chunk in the final packet', () => {
+		const url = `${base}chunked/multiple-ending`;
+		return fetch(url).then(res => {
+			expect(res.ok).to.be.true;
+
+			return res.text().then(result => {
+				expect(result).to.equal('foobar');
+			});
+		});
+	});
+
+	it('should handle chunked response with final chunk and EOM in separate packets', () => {
+		const url = `${base}chunked/split-ending`;
+		return fetch(url).then(res => {
+			expect(res.ok).to.be.true;
+
+			return res.text().then(result => {
+				expect(result).to.equal('foobar');
+			});
+		});
+	});
+
 	it('should handle DNS-error response', () => {
 		const url = 'http://domain.invalid';
 		return expect(fetch(url)).to.eventually.be.rejected
diff --git a/test/utils/server.js b/test/utils/server.js
index b9ba35188..9bfe1c5af 100644
--- a/test/utils/server.js
+++ b/test/utils/server.js
@@ -297,6 +297,14 @@ export default class TestServer {
 			res.socket.end('\r\n');
 		}
 
+		if (p === '/redirect/chunked') {
+			res.writeHead(301, {
+				Location: '/inspect',
+				'Transfer-Encoding': 'chunked'
+			});
+			setTimeout(() => res.end(), 10);
+		}
+
 		if (p === '/error/400') {
 			res.statusCode = 400;
 			res.setHeader('Content-Type', 'text/plain');
@@ -344,6 +352,24 @@ export default class TestServer {
 			}, 400);
 		}
 
+		if (p === '/chunked/split-ending') {
+			res.socket.write('HTTP/1.1 200\r\nTransfer-Encoding: chunked\r\n\r\n');
+			res.socket.write('3\r\nfoo\r\n3\r\nbar\r\n');
+
+			setTimeout(() => {
+				res.socket.write('0\r\n');
+			}, 10);
+
+			setTimeout(() => {
+				res.socket.end('\r\n');
+			}, 20);
+		}
+
+		if (p === '/chunked/multiple-ending') {
+			res.socket.write('HTTP/1.1 200\r\nTransfer-Encoding: chunked\r\n\r\n');
+			res.socket.write('3\r\nfoo\r\n3\r\nbar\r\n0\r\n\r\n');
+		}
+
 		if (p === '/error/json') {
 			res.statusCode = 200;
 			res.setHeader('Content-Type', 'application/json');