RPC support for SSE

[cybercoder-naj]

What is the feature you are proposing?

We require using EventSource to work with SSE routes, but can we have Hono's RPC to have this functionality as well?

const client = hc<typeof app>(`https://${BASE_URL}`)
client.sse.$get({
  onMessage(event) { /* do something with this */ },
  // other callbacks
}, {
  headers: {
    Authorization: 'Bearer booyah'
  }
})

[yusukebe]

This is super interesting.

@sor4chi @nakasyou @watany-dev @hagishi and others:

Any thoughts? Or can you work on it?

[nakasyou]

I think it is a good idea!

Also I thought, what do you think about typed JSON SSE? Now, SSE is used to stream LLM content. If we implement JSON SSE, development experience to create LLM app may get better.

[yusukebe]

JSON SSE

Great! As you mentioned, it is used in LLM apps often.