From c8ad1542344f4f8ec1cb558af2f6957a0b8403bb Mon Sep 17 00:00:00 2001
From: Taku Amano <taku@taaas.jp>
Date: Mon, 19 Aug 2024 09:37:51 +0900
Subject: [PATCH] fix: return response from res.body if internal data is not
 ready to be returned directly (#188)

---
 src/listener.ts     | 29 +++++++++++++++++++----------
 test/server.test.ts | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/src/listener.ts b/src/listener.ts
index a9d46c2..9ea890f 100644
--- a/src/listener.ts
+++ b/src/listener.ts
@@ -92,18 +92,27 @@ const responseViaResponseObject = async (
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   const internalBody = getInternalBody(res as any)
   if (internalBody) {
-    if (internalBody.length) {
-      resHeaderRecord['content-length'] = internalBody.length
-    }
-    outgoing.writeHead(res.status, resHeaderRecord)
-    if (typeof internalBody.source === 'string' || internalBody.source instanceof Uint8Array) {
-      outgoing.end(internalBody.source)
-    } else if (internalBody.source instanceof Blob) {
-      outgoing.end(new Uint8Array(await internalBody.source.arrayBuffer()))
+    const { length, source, stream } = internalBody
+    if (source instanceof Uint8Array && source.byteLength !== length) {
+      // maybe `source` is detached, so we should send via res.body
     } else {
-      await writeFromReadableStream(internalBody.stream, outgoing)
+      // send via internal raw data
+      if (length) {
+        resHeaderRecord['content-length'] = length
+      }
+      outgoing.writeHead(res.status, resHeaderRecord)
+      if (typeof source === 'string' || source instanceof Uint8Array) {
+        outgoing.end(source)
+      } else if (source instanceof Blob) {
+        outgoing.end(new Uint8Array(await source.arrayBuffer()))
+      } else {
+        await writeFromReadableStream(stream, outgoing)
+      }
+      return
     }
-  } else if (res.body) {
+  }
+
+  if (res.body) {
     /**
      * If content-encoding is set, we assume that the response should be not decoded.
      * Else if transfer-encoding is set, we assume that the response should be streamed.
diff --git a/test/server.test.ts b/test/server.test.ts
index 5aa39c6..f7489fd 100644
--- a/test/server.test.ts
+++ b/test/server.test.ts
@@ -5,6 +5,7 @@ import { Response as PonyfillResponse } from '@whatwg-node/fetch'
 import { Hono } from 'hono'
 import { basicAuth } from 'hono/basic-auth'
 import { compress } from 'hono/compress'
+import { etag } from 'hono/etag'
 import { poweredBy } from 'hono/powered-by'
 import { stream } from 'hono/streaming'
 import request from 'supertest'
@@ -143,6 +144,20 @@ describe('via internal body', () => {
     })
     return new Response(stream)
   })
+  app.get('/buffer', () => {
+    const response = new Response(Buffer.from('Hello Hono!'), {
+      headers: { 'content-type': 'text/plain' },
+    })
+    return response
+  })
+
+  app.use('/etag/*', etag())
+  app.get('/etag/buffer', () => {
+    const response = new Response(Buffer.from('Hello Hono!'), {
+      headers: { 'content-type': 'text/plain' },
+    })
+    return response
+  })
 
   const server = createAdaptorServer(app)
 
@@ -186,6 +201,23 @@ describe('via internal body', () => {
     expect(res.headers['content-length']).toBeUndefined()
     expect(expectedChunks.length).toBe(0) // all chunks are received
   })
+
+  it('Should return 200 response - GET /buffer', async () => {
+    const res = await request(server).get('/buffer')
+    expect(res.status).toBe(200)
+    expect(res.headers['content-type']).toMatch('text/plain')
+    expect(res.headers['content-length']).toMatch('11')
+    expect(res.text).toBe('Hello Hono!')
+  })
+
+  it('Should return 200 response - GET /etag/buffer', async () => {
+    const res = await request(server).get('/etag/buffer')
+    expect(res.status).toBe(200)
+    expect(res.headers['content-type']).toMatch('text/plain')
+    expect(res.headers['etag']).toMatch('"7e03b9b8ed6156932691d111c81c34c3c02912f9"')
+    expect(res.headers['content-length']).toMatch('11')
+    expect(res.text).toBe('Hello Hono!')
+  })
 })
 
 describe('Routing', () => {