Beaconcms backend hooks - how to create initial changeset on page load?

Questions / Help
1

I have an Elixir project with phoenix/ash/beacon cms.

This question is not related to ash per se.

I have 3 steps.

create changeset

on load/on mount

form = AshPhoenix.Form.for_create(MyEntity, :create)

on validate

form = AshPhoenix.Form.validate(form, params)

on save

AshPhoenix.Form.submit(form, params: params)

I think i got it working with event handlers for validate and save steps.

But I don’t understand how to create initial changeset on page load.

It seems reasonable (of course not for backend cms, but for light frontend facing interactions) to implement bossiness logic with ash that exposes all available actions and use them via beacon cms to make pretty forms.

1 Like
2

Hey Roberts,

There is currently no way to custiomize mount for a specific page, because navigation between beacon pages does not trigger a mount, it’s all done via patching in the same LiveView process.

However, you can customize mount for the entire Beacon site (similar to how Event Handlers work - you don’t define them for an individual page, but for the entire site). This is done by passing the :on_mount option to beacon_site/2, which works like the normal on_mount/1 that you would define for a live_session in Phoenix.Router.

Hope this helps!

PS. the #beacon-cms channel on Elixir Slack is quite active and many users are also incorporating Ash, so please check that out as well :slight_smile:

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3

Oh, now that I think about it, if all you’re doing is populating an assign, that could be a better fit for LiveData, which is scoped by path - still not per-page, but at least it’s not global (also changeable at runtime!).

To do this you would:

  • go to the “Live Data” section of the admin dashboard
  • click the button to create a new Live Data path
  • enter the path to your page(s) (can use globs e.g. /topics/:id/create)
  • define the assign with whatever name and code you want

Let me know what you end up going with!

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4

I added code in event handler:

{:noreply, assign(socket, form: AshPhoenix.Form.validate(socket.assigns.form, params))}

But on save it says:

nofile: cannot compile file (errors have been logged)

undefined variable "params"

Even tho on top there is: Variables available: params socket.

Am i missing something?

5

Ah, the expected variable is actually called event_params (instead of params). Sorry for the misleading text in BeaconLiveAdmin - I didn’t notice that before; we’ll have it fixed for the next release.

1 Like