modify-phoenix-code

name	modify-phoenix-code
description	Phoenix framework patterns for the CheddarFlow project. TRIGGER when: writing or modifying Phoenix controllers, LiveView modules, templates, routes, plugs, components, layouts, or any code in the cfx_web app that touches the web layer. Also trigger when working with core_components.ex, router.ex, or endpoint.ex. DO NOT TRIGGER when: working with non-web Elixir code that doesn't involve Phoenix.

Phoenix Code Guidelines

Phoenix v1.8 Patterns

• Always begin LiveView templates with <Layouts.app flash={@flash} ...> wrapping all inner content
• MyAppWeb.Layouts is aliased in the my_app_web.ex file — no need to alias again
• Errors about missing current_scope assign mean you failed to follow Authenticated Routes guidelines or didn't pass current_scope to <Layouts.app> — fix by moving routes to the proper live_session
• <.flash_group> belongs only in the layouts.ex module — never call it elsewhere
• Use the <.icon name="hero-x-mark" class="w-5 h-5"/> component for icons — never use Heroicons modules
• Use the imported <.input> component from core_components.ex for form inputs
• Overriding <.input class="..."> replaces all default classes — your custom classes must fully style the input
• Phoenix.View is not included — don't use it
• Phoenix hooks used in LiveView DOM elements need an id on the element

Router Patterns

• Router scope blocks include an optional alias prefixed for all routes within — be mindful to avoid duplicate module prefixes

• You never need to create your own alias for route definitions — the scope provides it:

  scope "/admin", AppWeb.Admin do
    pipe_through :browser
    live "/users", UserLive, :index
  end
  

  This points to AppWeb.Admin.UserLive

Project Router Structure

/api        — Absinthe.Plug (GraphQL endpoint, graphql pipeline with SessionContextPlug)
/api/graphiql — Absinthe.Plug.GraphiQL (playground, admin-only in dev/staging)

Router Pipelines

pipeline :auth_session do
  plug :fetch_session
  plug Auth0Session
end

pipeline :graphql do
  plug :accepts, ~w(json)
  plug SessionContextPlug
end

pipeline :admin do
  plug Auth0Session
  plug SessionContextPlug
  plug AdminRole
end