[BUG] The Serve-Send-Event request cannot receive a close event.

[StringKe]

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
      Platform: darwin
      Arch: arm64
      Version: Darwin Kernel Version 22.5.0: Mon Apr 24 20:52:24 PDT 2023; root:xnu-8796.121.2~5/RELEASE_ARM64_T6000
    Binaries:
      Node: 18.16.0
      npm: 9.5.1
      Yarn: 1.22.19
      pnpm: 8.6.0
    Relevant packages:
      next: 13.4.4
      eslint-config-next: 13.4.4
      react: 18.2.0
      react-dom: 18.2.0
      typescript: 5.1.3

Which area(s) of Next.js are affected? (leave empty if unsure)

Middleware / Edge (API routes, runtime)

Link to the code that reproduces this issue or a replay of the bug

https://stackblitz.com/edit/stackblitz-starters-n5uvup?file=pages%2Findex.js

To Reproduce

1. open the recurrence connection (I did not find the page function of CodeSandbox, I used StackBlitz)
2. Open the browser console
3. Click the button and wait a while
4. Click the button again.

Describe the Bug

Create an SSE (Server-Sent-Event) request using an API Endpoint that does not receive a disconnect event properly when the client disconnects.

Expected Behavior

API Request is able to accept disconnected events, as the inability to accept events causes the timer to run forever and add a new one each time it runs.

Which browser are you using? (if relevant)

Microsoft Edge 113.0.1774.57

How are you deploying your application? (if relevant)

none

note 2023-6-6

I tried to write an api with the same functionality using express and I can receive the close event.

https://github.com/StringKe/node-sse-example

link1: #48682

[helmturner]

Is this expected behavior? It seems to be mentioned in the fastify docs https://www.fastify.io/docs/latest/Guides/Detecting-When-Clients-Abort/

[timcole]

Heyo, I tested this out and noticed two things.

1. I tried it locally and same issue, however if I downgrade next to v12.3.4 it works as expected, and 3 of the 4 on close events fire. The issue seems to be next v13 related.
2. Stackblitz's proxy seems to keep the connection alive so it never closes no matter which version I use.

[TCatshoek]

I also tested it locally, and it seems to work on next@13.0.6, but not on latest. It seems like any version higher than 13.2.4 causes issues (13.3.0 does not work properly)

[StringKe]

I tested the version and found that this issue first appeared in 13.2.5-canary.27.

13.2.5-canary.26 is work

I checked all commit records in 13.2.5-canary.26 through 13.2.5-canary.27, and this commit may be the cause.

fdacca8

https://github.com/vercel/next.js/commits/canary?before=819453e3a6cc4f35be4d988d4119579c8e46488e+35

[StringKe]

next@13.4.7 The presence of this problem remains.

v13.4.8-canary.5 The problem was not detected

[jridgewell]

Fixed by #51727