Pass changes into on_item_updated callback

[wasnotrice]

I want to track changes made to my LiveResource. I can implement the on_item_updated callback on my LiveResource, but that callback only gets the updated item. I don't have a way to know what changed. Would it be possible to pass the changeset.changes here as well?

Instead of the current signature:

@callback on_item_updated(socket :: Phoenix.LiveView.Socket.t(), item :: map()) :: Phoenix.LiveView.Socket.t()

we would have:

@callback on_item_updated(socket :: Phoenix.LiveView.Socket.t(), item :: map(), changes :: map()) :: Phoenix.LiveView.Socket.t()

I'd be happy to work up a PR for this if it makes sense. Thanks!

[Flo0807]

Hey,

you can retrieve the old item from the socket:

def on_item_updated(socket, item) do
  socket.assigns.item # old item
  item # updated item
end

Maybe this helps you already?

[wasnotrice]

Oh, I missed that, and I also see that the socket.assigns.changeset is still populated with changes. I thought the changeset had already been cleared.

Yes, that works, thanks!

[tommasop]

@Flo0807, @wasnotrice sorry if I hijack this thread but it seemed to me the best place to ask this question.
Is there a way to override flash messages in the on_item_updated call (or other hook calls)?
I tried with the standard version:

        socket
        |> clear_flash()
        |> put_flash(:info, backpex_message)
        |> ok()

but it is not working.

Also tried forcing an error on the changeset both as a :base error and as an existing field error but the default flash is always showing up.

Thanks a lot.

[Flo0807]

Hey @tommasop!

There is no way to do this in on_item_updated as Backpex always puts the flash after the function has been called, but we recently introduced a way of overwriting texts in Backpex.

In your LiveResouce, add the translate/1 callback and match on the text in the flash messaage:

@impl Backpex.LiveResource
def translate({"New %{resource} has been created successfully.", opts}) do
  "Your custom text"
end

def translate({"%{resource} has been edited successfully.", opts}) do
  "Your custom text"
end

This will change the text of the default flash messages.

⚠️ Note that you will need Backpex v0.12 to be able to use this new callback.

[tommasop]

Hi @Flo0807 thanks for your feedback!

Is there a way to change translation based on opts and to pass opts in the on_item_update to differentiate translation?

Otherwise is there a way to entirely substitute the standard form edit action?

By the way updating to 0.12.0 is giving me a strange behavior because the edit route now gives me a layout with save and cancel buttons but with a show form

[Flo0807]

It looks like something is wrong with your setup. Did you properly update your app to Tailwind CSS v4 and daisyUI v5?

See https://hexdocs.pm/backpex/v0-12.html#upgrade-to-tailwind-4-and-daisyui-5

[tommasop]

You are right, I forgot to update the UI part. For the `on_item_updated` maybe it is possible to remove the fixed `{:ok, item}` return and pop up changeset errors assigning them to the socket? Thanks again

…

On Wed, Apr 2, 2025, at 12:09, Florian Arens wrote: It looks like something is wrong with your setup. Did you properly update your app to Tailwind CSS v4 and daisyUI v5? See https://hexdocs.pm/backpex/v0-12.html#upgrade-to-tailwind-4-and-daisyui-5 — Reply to this email directly, view it on GitHub <#959 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAM6IZEXT75AFDPAX7V3BT2XOZM3AVCNFSM6AAAAABZGCJXVGVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTENRZHA4DCMQ>. You are receiving this because you were mentioned.Message ID: ***@***.***>

[Flo0807]

For the on_item_updated maybe it is possible to remove the fixed {:ok, item} return and pop up changeset errors assigning them to the socket?

Hey, this is not possible as on_item_updated is called after the item has already been updated. We plan to add some hooks that are called before an item has been updated / created. See #982

[tommasop]

Great thanks

…

On Fri, Aug 22, 2025, at 08:42, Florian Arens wrote: > For the `on_item_updated` maybe it is possible to remove the fixed `{:ok, item}` return and pop up changeset errors assigning them to the socket? > Hey, this is not possible as `on_item_updated` is called after the item has already been updated. We plan to add some hooks that are called before an item has been updated / created. See #982 <#982> — Reply to this email directly, view it on GitHub <#959 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAM6IZ7RI6ZPUPS7PCLE5T3O23VDAVCNFSM6AAAAABZGCJXVGVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTIMJYGYZDKMA>. You are receiving this because you were mentioned.Message ID: ***@***.***>