facebook
Bug: server actions cannot be cancelled or given abort signals
React version: 18.2.0
Steps To Reproduce
- As in #28510, create a server action that has some long-running delay, e.g.: to simulate a large language model call.
- There is no API on the client or server to trigger cancellation, or to detect or handle the client navigating away from the page.
Link to code example: https://codesandbox.io/p/devbox/next-14-0-3-forked-7q86s7?file=%2Fapp%2Factions.ts%3A4%2C18&workspaceId=958ee911-ec8f-4ca3-9ce1-668005ecaeb8
The current behavior
When a long-running request is fired, the server will complete it regardless of client behavior, e.g.: client hangup.
The expected behavior
An API for server actions to obtain a reference to an AbortController (or similar API) for the request, perhaps via async local context.
An API for clients to signal cancellation of a server action, perhaps via an additional return value on startTransition, perhaps as part of the transition APIs. If a transition is explicitly created, there should be a mechanism to cancel it.
hey, To achieve the expected behavior, you would need to implement a mechanism on the server-side to handle this. One common approach is to use a unique token for each request. The client sends this token with each request, and if the client disconnects, it sends a cancellation request with the same token. The server then checks for cancellation requests with the same token before and during the processing of the request.
I don't think that seems like a reasonable solution, as it relies upon:
- Follow-up requests being routed to the same server as the original request
- Infrastructure to store and poll/react to cancellation tokens globally, i.e.: redis.
Both of those seem pretty absurd, given that fetches can be aborted, the client can hang up the request. It should be possible to react to that.
