add url_slug column to pages table

Adds url_slug field for custom page URLs:
- Migration with unique partial index on non-null slugs
- Page schema with validation (format, uniqueness, reserved words)
- effective_url/1 helper to resolve custom or default slug
- Default page configs updated with url_slug field

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/berrypod/pages/defaults.ex

@@ -18,7 +18,8 @@ defmodule Berrypod.Pages.Defaults do
       meta_description: nil,
       show_in_nav: false,
       nav_label: nil,
-      nav_position: nil
+      nav_position: nil,
+      url_slug: nil
     }
   end
 

lib/berrypod/pages/page.ex

@@ -28,16 +28,36 @@ defmodule Berrypod.Pages.Page do
     field :show_in_nav, :boolean, default: false
     field :nav_label, :string
     field :nav_position, :integer
+    field :url_slug, :string
 
     timestamps(type: :utc_datetime)
   end
 
+  @doc """
+  Returns the effective URL path for this page.
+  Uses url_slug if set, otherwise falls back to slug.
+  Works with both Page structs and maps (from cache).
+  """
+  def effective_url(%__MODULE__{url_slug: url_slug, slug: slug}) do
+    url_slug || slug
+  end
+
+  def effective_url(%{url_slug: url_slug, slug: slug}) do
+    url_slug || slug
+  end
+
+  def effective_url(%{slug: slug}), do: slug
+
+  def effective_url(_), do: nil
+
   def system_changeset(page, attrs) do
     page
-    |> cast(attrs, [:slug, :title, :blocks])
+    |> cast(attrs, [:slug, :title, :blocks, :url_slug])
     |> validate_required([:slug, :title, :blocks])
     |> validate_inclusion(:slug, @system_slugs)
+    |> validate_url_slug()
     |> unique_constraint(:slug)
+    |> unique_constraint(:url_slug)
   end
 
   def custom_changeset(page, attrs) do
@@ -51,7 +71,8 @@ defmodule Berrypod.Pages.Page do
       :meta_description,
       :show_in_nav,
       :nav_label,
-      :nav_position
+      :nav_position,
+      :url_slug
     ])
     |> validate_required([:slug, :title])
     |> validate_format(:slug, ~r/^[a-z0-9]([a-z0-9-]*[a-z0-9])?$/,
@@ -61,8 +82,10 @@ defmodule Berrypod.Pages.Page do
     |> validate_length(:slug, max: 100)
     |> validate_length(:title, max: 200)
     |> validate_length(:meta_description, max: 300)
+    |> validate_url_slug()
     |> put_defaults()
     |> unique_constraint(:slug)
+    |> unique_constraint(:url_slug)
   end
 
   defp put_defaults(changeset) do
@@ -76,6 +99,36 @@ defmodule Berrypod.Pages.Page do
     if get_change(changeset, field), do: changeset, else: put_change(changeset, field, default)
   end
 
+  # Validates the url_slug format and ensures it doesn't conflict with reserved paths
+  defp validate_url_slug(changeset) do
+    case get_change(changeset, :url_slug) do
+      nil ->
+        changeset
+
+      "" ->
+        # Empty string means clear the custom URL
+        put_change(changeset, :url_slug, nil)
+
+      url_slug ->
+        changeset
+        |> validate_format(:url_slug, ~r/^[a-z0-9]([a-z0-9-]*[a-z0-9])?$/,
+          message: "must be lowercase letters, numbers, and hyphens only"
+        )
+        |> validate_exclusion(:url_slug, @reserved_paths, message: "is reserved")
+        |> validate_length(:url_slug, max: 100)
+        |> validate_url_slug_not_system_slug(url_slug)
+    end
+  end
+
+  # Ensure url_slug doesn't match another page's canonical slug
+  defp validate_url_slug_not_system_slug(changeset, url_slug) do
+    if url_slug in @system_slugs do
+      add_error(changeset, :url_slug, "cannot match a system page slug")
+    else
+      changeset
+    end
+  end
+
   def system_slugs, do: @system_slugs
   def reserved_paths, do: @reserved_paths
   def system_slug?(slug), do: slug in @system_slugs

priv/repo/migrations/20260329210409_add_url_slug_to_pages.exs

@@ -0,0 +1,12 @@
+defmodule Berrypod.Repo.Migrations.AddUrlSlugToPages do
+  use Ecto.Migration
+
+  def change do
+    alter table(:pages) do
+      add :url_slug, :string
+    end
+
+    # Unique index but only for non-null values
+    create unique_index(:pages, [:url_slug], where: "url_slug IS NOT NULL")
+  end
+end