From ec93f55eac62e54e5b416f52dd1dcf9d4b246af1 Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Thu, 30 Jan 2020 09:44:39 -0600
Subject: [PATCH 1/2] Update to not show API not ended warning when response is
 piped to

---
 packages/next/next-server/server/api-utils.ts      | 14 +++++++++++++-
 .../api-support/pages/api/test-res-pipe.js         | 10 ++++++++++
 test/integration/api-support/test/index.test.js    |  8 ++++++++
 3 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 test/integration/api-support/pages/api/test-res-pipe.js

diff --git a/packages/next/next-server/server/api-utils.ts b/packages/next/next-server/server/api-utils.ts
index 33c6d45f4ce73..5dccc334eda49 100644
--- a/packages/next/next-server/server/api-utils.ts
+++ b/packages/next/next-server/server/api-utils.ts
@@ -55,9 +55,21 @@ export async function apiResolver(
     apiRes.json = data => sendJson(apiRes, data)
 
     const resolver = interopDefault(resolverModule)
+    let wasPiped = false
+
+    if (process.env.NODE_ENV !== 'production') {
+      // listen for pipe event and don't show resolve warning
+      const handlePipe = () => {
+        wasPiped = true
+        res.removeListener('pipe', handlePipe)
+      }
+      res.addListener('pipe', handlePipe)
+    }
+
+    // Call API route method
     await resolver(req, res)
 
-    if (process.env.NODE_ENV !== 'production' && !isResSent(res)) {
+    if (process.env.NODE_ENV !== 'production' && !isResSent(res) && !wasPiped) {
       console.warn(
         `API resolved without sending a response for ${req.url}, this may result in stalled requests.`
       )
diff --git a/test/integration/api-support/pages/api/test-res-pipe.js b/test/integration/api-support/pages/api/test-res-pipe.js
new file mode 100644
index 0000000000000..c127f79c1fb9c
--- /dev/null
+++ b/test/integration/api-support/pages/api/test-res-pipe.js
@@ -0,0 +1,10 @@
+import fetch from 'node-fetch'
+
+export default async (req, res) => {
+  const dataRes = await fetch(
+    `http://localhost:${req.query.port}/api/query?hello=from-pipe`
+  )
+
+  res.status(dataRes.status)
+  dataRes.body.pipe(res)
+}
diff --git a/test/integration/api-support/test/index.test.js b/test/integration/api-support/test/index.test.js
index c66556733b2db..c4e5c7d389b37 100644
--- a/test/integration/api-support/test/index.test.js
+++ b/test/integration/api-support/test/index.test.js
@@ -363,6 +363,14 @@ function runTests(dev = false) {
         `API resolved without sending a response for /api/test-no-end, this may result in stalled requests.`
       )
     })
+
+    it('should not show warning when the API resolves and the response is piped', async () => {
+      const startIdx = stderr.length > 0 ? stderr.length - 1 : stderr.length
+      await fetchViaHTTP(appPort, `/api/test-res-pipe`, { port: appPort })
+      expect(stderr.substr(startIdx)).not.toContain(
+        `API resolved without sending a response for /api/test-res-pipe`
+      )
+    })
   } else {
     it('should build api routes', async () => {
       const pagesManifest = JSON.parse(

From 39e3074ef77fe72bc04735a14d97fcf271e6b6b8 Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Sun, 2 Feb 2020 21:27:18 -0600
Subject: [PATCH 2/2] Update to use res.once

---
 packages/next/next-server/server/api-utils.ts | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/packages/next/next-server/server/api-utils.ts b/packages/next/next-server/server/api-utils.ts
index 5dccc334eda49..85d0156b97007 100644
--- a/packages/next/next-server/server/api-utils.ts
+++ b/packages/next/next-server/server/api-utils.ts
@@ -59,11 +59,7 @@ export async function apiResolver(
 
     if (process.env.NODE_ENV !== 'production') {
       // listen for pipe event and don't show resolve warning
-      const handlePipe = () => {
-        wasPiped = true
-        res.removeListener('pipe', handlePipe)
-      }
-      res.addListener('pipe', handlePipe)
+      res.once('pipe', () => (wasPiped = true))
     }
 
     // Call API route method