nallwhy
I expected that the existing stream to be replaced with new items when stream is assigned again, but it isn’t.
It crashes with ** (ArgumentError) existing hook :messages(stream name) already attached on :after_render.
@impl true
def update(assigns, socket) do
...
socket =
socket
|> assign(assigns)
|> assign_messages(new_channel_name)
{:ok, socket}
end
@impl true
def render(assigns) do
~H"""
<div>
<.h2># <%= @channel_name %></.h2>
<p>Your ID: <%= @session_id %></p>
<div id="messages" class="h-96 overflow-y-auto" phx-update="stream" phx-hook="ChatMessages">
<div :for={{message_id, message} <- @streams.messages} id={message_id} class="mt-4">
<p>User id: <%= message.user_id %></p>
<p><%= message.created_at %></p>
<p><%= message.body %></p>
</div>
</div>
...
</div>
"""
end
defp assign_messages(socket, channel_name) do
{:ok, messages} = Chat.list_messages(channel_name)
socket
|> stream(:messages, messages)
...
end
You can test it on the page below, by changing channel.
Is it possible to replace stream with new items? (re-assigning)
page: Chat in Elixir · Json Media
code: json_corp/apps/json_corp_web/lib/json_corp_web/live/playgrounds/chat_live/channel.ex at chat · nallwhy/json_corp · GitHub
Trending in Questions
I having some trouble figuring out if I have set myself too strict of standards for my production server. Currently I can handle 75% of r...
New
Hi everyone.
My team and I have been working on a fairly modest app based around video streaming and chat, but we’ve landed a customer t...
New
Hello,
I’m trying to build a basic Phoenix web-app, and I’d like to use Tailwind.
However, when I launch mix phx.server, I get an error...
New
I really like the adapter patterns that ecto, nebulex, waffle, etc. use and would love find something similar for a key management servic...
New
Hello folks!
So at work, we are seeing some situations where we have to define some “fixed” strings that are used across the codebase in...
New
I’m working on a small exercise involving update_in/3, and I came up with this solution:
data = %{
name: "Periodic Table",
category:...
New
How Can I Optimise Compile Time Dependencies
I have been building an elixir application for about 2 years now. Many modules and files ha...
New
Other Trending Topics
Edit: 2026 May 15 - This post is archived.
Mob is alive!!
Main docs: mob v0.7.11 — Documentation
A bit of explanation for the slightly c...
New
A little off-topic, but I feel like people here have a good head on their shoulders.
I used to be quite good at making software. Was luc...
New
Hey. Is there anyone here who creates agents in their apps? Not talking about using agents, but creating them. I’m finding it pretty diff...
New
I fully migrated to my own harness from Anthropic/Gemini and I think it’s time to share it. Welcome DSH, the DeepSeek Harness, fully writ...
New
Beam Bots (or just BB for short) is a framework for building fault-tolerant robotics applications in Elixir using familiar OTP patterns. ...
New
There has been a thread to discuss the Stack Overflow Developer Survey on this forum every year since 2018, so here’s yet another one for...
New
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #library
- #deployment
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #elixirconf
- #channels
- #exunit
- #discussion
- #code-sync
- #podcasts
- #javascript
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #ai
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #blog-post
- #elixirconf-us
- #elixir-ls
- #phoenix_html
- #iex
- #graphql
- #genstage
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #processes
- #elixirconf-eu
- #api
- #forms
- #security
- #metaprogramming










Showing Posts 1 to 4- Show Best Posts
- Show All (oldest first)
- Show All (newest first)
codeanpeace
At the moment, you can
stream_insertto update or add orstream_deleteto delete individual elements e.g.messagewithin@streams.messageswithin an existing stream. Emptying/clearing out an existing stream at the@streams.messageslevel isn’t currently supported, but it is on the roadmap.nallwhy
Thank you!
rio517
FYI, this is now implemented.
rio517
FYI, if you do replace a stream, note that the entire collection in the stream is sent down the wire. For many items, that can be quite large. I generated a new app with the default CRUD UI and generated liveview scafolding for posts with a title, ID. For 1000 items, the WebSocket frame had 1.3MB of data sent down the wire. Consider using infinite scrolling as discussed in the guide here: Bindings — Phoenix LiveView v1.2.5