nestjs
`@nestjs/mercurius` graphql subscriptions not working on localhost
Is there an existing issue for this?
- [X] I have searched the existing issues
Current behavior
I recently experimented with migration from Apollo to Mercurius, and while I could get everything to work, I could not get graphql WebSocket subscriptions working at all.
The browser would instantly close all WebSocket connections to /graphql after they're open.
Here's a screenshot from Safari developer tools:
After 10 hours of painful troubleshooting, nothing made sense. It appeared that connecting via wscat from the terminal was working correctly, and I was able to send and receive messages. But the browser would not connect.
However, reverting to Apollo would get everything working again.
I then discovered https://github.com/fastify/fastify/issues/4053, where it is mentioned that the WebSocket listener either starts on ::1 or 127.0.0.1. wscat was using the one that was working, while the browser used the other one.
After changing the app.listen call to await app.listen(process.env.PORT || 1338, '127.0.0.1'); I was finally able to get the browser to connect properly.
I'm leaving this write-up here in case it helps someone. We probably need to come up with a better solution about this either in fastify or nest.
Minimum reproduction code
...
Steps to reproduce
No response
Expected behavior
Explicit IP should not be required.
Package version
not important
Graphql version
graphql:
apollo-server-express:
apollo-server-fastify:
NestJS version
No response
Node.js version
No response
In which operating systems have you tested?
- [ ] macOS
- [ ] Windows
- [ ] Linux
Other
This appears to be related to Fastify
