feat: custom dispatcher for Presence handle_diff broadcast #6500
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
josevalim
reviewed
Oct 4, 2025
| use Phoenix.Presence, | ||
| otp_app: :my_app, | ||
| pubsub_server: MyApp.PubSub, | ||
| dispatcher: MyApp.CustomDispatcher |
There was a problem hiding this comment.
We need some documentation or links on what is the dispatch and how a custom implementation would look like. I don't know if we want to link to the endpoint, Elixir's Registry or what else, but we just need a bit more context here. :)
There was a problem hiding this comment.
Makes sense! I added a link to https://hexdocs.pm/phoenix_pubsub/2.1.3/Phoenix.PubSub.html#module-custom-dispatching
edgurgel
force-pushed
the
feat/presence-custom-dispatcher
branch
from
48b5f51 to
331fcac
Compare
josevalim
approved these changes
Oct 5, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Hi there!
I've started a discussion in the Elixir forum about this change but then I noticed that the change in the end was pretty straightforward so I decided to open a PR as well.
If someone is using a non-standard metadata when subscribing to the topic it’s not possible to specify a custom dispatcher module. It will always use the
Phoenix.Channel.Server.dispatch/3function.At Realtime we use a custom metadata but our custom dispatcher can't be used as
Phoenix.Presencealways usePhoenix.Channel.Serveras dispatcher. We considered having our ownPresencemodule but it felt heavy handed given that we only needed a custom dispatcher in the end.Can totally understand if we don't want to expose this as a function but I thought I would try anyway 😅