From 0696b20a049683e3a8e777dc30a496394f1eb32d Mon Sep 17 00:00:00 2001
From: Maciej Goszczycki <mgoszcz2@gmail.com>
Date: Sun, 26 Jul 2020 14:11:05 +0200
Subject: [PATCH] Handle zero-length OK deflate responses

---
 src/index.js   |  7 +++++++
 test/server.js |  7 +++++++
 test/test.js   | 11 +++++++++++
 3 files changed, 25 insertions(+)

diff --git a/src/index.js b/src/index.js
index 8bf9248fd..bde601a37 100644
--- a/src/index.js
+++ b/src/index.js
@@ -254,6 +254,13 @@ export default function fetch(url, opts) {
 					response = new Response(body, response_options);
 					resolve(response);
 				});
+				raw.on('end', () => {
+					// some old IIS servers return zero-length OK deflate responses, so 'data' is never emitted.
+					if (!response) {
+						response = new Response(body, response_options);
+						resolve(response);
+					}
+				})
 				return;
 			}
 
diff --git a/test/server.js b/test/server.js
index 06c715d65..a55814d7f 100644
--- a/test/server.js
+++ b/test/server.js
@@ -115,6 +115,13 @@ export default class TestServer {
 			});
 		}
 
+		if (p === '/empty/deflate') {
+			res.statusCode = 200;
+			res.setHeader('Content-Type', 'text/plain');
+			res.setHeader('Content-Encoding', 'deflate');
+			res.end();
+		}
+
 		if (p === '/sdch') {
 			res.statusCode = 200;
 			res.setHeader('Content-Type', 'text/plain');
diff --git a/test/test.js b/test/test.js
index c5d61c72a..e83e1555f 100644
--- a/test/test.js
+++ b/test/test.js
@@ -679,6 +679,17 @@ describe('node-fetch', () => {
 		});
 	});
 
+	it('should handle empty deflate response', function() {
+		const url = `${base}empty/deflate`;
+		return fetch(url).then(res => {
+			expect(res.headers.get('content-type')).to.equal('text/plain');
+			return res.text().then(result => {
+				expect(result).to.be.a('string');
+				expect(result).to.be.empty;
+			});
+		});
+	});
+
 	it('should decompress brotli response', function() {
 		if(typeof zlib.createBrotliDecompress !== 'function') this.skip();
 		const url = `${base}brotli`;