Can emit in a room exclude particular socket id ? not sender.

[redchallengers]

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[darrachequesne]

Migrated from the Engine.IO repository.

No, it's not currently possible, but it shouldn't be that hard to implement. Could you please explain your use case?

EDIT: it's now available, see below

[darrachequesne]

This was implemented in 7de2e87 and included in socket.io@4.0.0.

Example:

io.except("room1").emit(/* ... */); // to all clients except the ones in "room1"
io.to("room2").except("room3").emit(/* ... */); // to all clients in "room2" except the ones in "room3"

socket.broadcast.except("room1").emit(/* ... */); // to all clients except the ones in "room1" and the sender
socket.except("room1").emit(/* ... */); // same as above
socket.to("room4").except("room5").emit(/* ... */); // to all clients in "room4" except the ones in "room5" and the sender

Documentation: https://socket.io/docs/v3/migrating-from-3-x-to-4-0/#Allow-excluding-specific-rooms-when-broadcasting

[plu-briteris-rl]

Migrated from the Engine.IO repository.

No, it's not currently possible, but it shouldn't be that hard to implement. Could you please explain your use case?

@darrachequesne

Hey, do you have any ideas on how to implement this? I have a use case for this, and would like to hear your thoughts.

[darrachequesne]

@pluiz-briteris this has been implemented in version 4.0.0, please see my answer above.

[plu-briteris-rl]

@pluiz-briteris this has been implemented in version 4.0.0, please see my answer above.

I may be mistaken, but isn't that for excluding a room? The original question says excluding a particular socket by id.

E.g. I use the underlying server to emit but exclude a given socket of a given room, by this socket id.

Or is this happening somehow in one of the examples you shared?

[darrachequesne]

Sorry, I wasn't clear enough! The socket id can be used as a room:

io.except(socketId).emit("some event");

Which is equivalent to:

socket.broadcast.emit("some event"); // if you have access to the socket object

Similarly, in a particular room:

io.to("some room").except(socketId).emit("some event");

[plu-briteris-rl]

Thank you for that! It probably cover my use case.

Do we have an example like this one in the docs? If not, it would be nice, happy to contribute if needed.

[darrachequesne]

@pluiz-briteris actually, we try to discourage users to use the socket ID in their application, since it's an ephemeral identifier which is lost upon reconnection. Instead you should rather use a session ID or a user ID for this use case.

[plu-briteris-rl]

@pluiz-briteris actually, we try to discourage users to use the socket ID in their application, since it's an ephemeral identifier which is lost upon reconnection. Instead you should rather use a session ID or a user ID for this use case.

In my use case specifically, this won't be an issue, due to that I think it's worth having this addressed in documentation/js docs (with the reconnection point), because other than this issue, I would have never figured out that this is possible and this helps me a lot with what I need to do...