Add endpoints for managing custom props in Sites API

extra/lib/plausible_web/controllers/api/external_sites_controller.ex

@@ -8,6 +8,7 @@ defmodule PlausibleWeb.Api.ExternalSitesController do
   alias Plausible.Sites
   alias Plausible.Goal
   alias Plausible.Goals
+  alias Plausible.Props
   alias Plausible.Teams
   alias PlausibleWeb.Api.Helpers, as: H
 
@@ -445,6 +446,86 @@ defmodule PlausibleWeb.Api.ExternalSitesController do
     end
   end
 
+  def custom_props_index(conn, params) do
+    user = conn.assigns.current_user
+    team = conn.assigns.current_team
+
+    with {:ok, site_id} <- expect_param_key(params, "site_id"),
+         {:ok, site} <- find_site(user, team, site_id, [:owner, :admin, :editor, :viewer]) do
+      properties =
+        (site.allowed_event_props || [])
+        |> Enum.sort()
+        |> Enum.map(fn prop -> %{property: prop} end)
+
+      json(conn, %{custom_properties: properties})
+    else
+      {:error, :site_not_found} ->
+        H.not_found(conn, "Site could not be found")
+
+      {:missing, "site_id"} ->
+        H.bad_request(conn, "Parameter `site_id` is required to list custom properties")
+    end
+  end
+
+  def add_custom_prop(conn, params) do
+    user = conn.assigns.current_user
+    team = conn.assigns.current_team
+
+    with {:ok, site_id} <- expect_param_key(params, "site_id"),
+         {:ok, property} <- expect_param_key(params, "property"),
+         {:ok, site} <- find_site(user, team, site_id, [:owner, :admin, :editor]),
+         {:ok, _} <- Props.allow(site, property) do
+      json(conn, %{"created" => true})
+    else
+      {:error, :site_not_found} ->
+        H.not_found(conn, "Site could not be found")
+
+      {:missing, param} ->
+        H.bad_request(conn, "Parameter `#{param}` is required to create a custom property")
+
+      {:error, changeset} ->
+        %{allowed_event_props: [error | _]} =
+          Ecto.Changeset.traverse_errors(changeset, fn {_msg, opts} ->
+            cond do
+              opts[:type] == :list and opts[:validation] == :length ->
+                "Can't add any more custom properties"
+
+              opts[:type] == :string and opts[:validation] == :length ->
+                "Parameter `property` is too long"
+
+              true ->
+                "Parameter `property` is invalid"
+            end
+          end)
+
+        H.bad_request(conn, error)
+    end
+  end
+
+  def delete_custom_prop(conn, params) do
+    user = conn.assigns.current_user
+    team = conn.assigns.current_team
+
+    with {:ok, site_id} <- expect_param_key(params, "site_id"),
+         {:ok, property} <- expect_param_key(params, "property"),
+         # Property name is extracted from route URL via wildcard,
+         # which returns a list.
+         property = Path.join(property),
+         {:ok, site} <- find_site(user, team, site_id, [:owner, :admin, :editor]),
+         {:ok, _} <- Props.disallow(site, property) do
+      json(conn, %{"deleted" => true})
+    else
+      {:error, :site_not_found} ->
+        H.not_found(conn, "Site could not be found")
+
+      {:missing, param} ->
+        H.bad_request(conn, "Parameter `#{param}` is required to delete a custom property")
+
+      e ->
+        H.bad_request(conn, "Something went wrong: #{inspect(e)}")
+    end
+  end
+
   defp pagination_meta(meta) do
     %{
       after: meta.after,

lib/plausible/props.ex

@@ -120,7 +120,11 @@ defmodule Plausible.Props do
     |> Ecto.Changeset.validate_change(:allowed_event_props, fn field, allowed_props ->
       if Enum.all?(allowed_props, &valid?/1),
         do: [],
-        else: [{field, "must be between 1 and #{@max_prop_key_length} characters"}]
+        else: [
+          {field,
+           {"must be between 1 and #{@max_prop_key_length} characters",
+            validation: :length, type: :string}}
+        ]
     end)
   end
 

lib/plausible_web/router.ex

@@ -337,6 +337,7 @@ defmodule PlausibleWeb.Router do
 
         scope assigns: %{api_context: :site} do
           get "/goals", ExternalSitesController, :goals_index
+          get "/custom-props", ExternalSitesController, :custom_props_index
           get "/guests", ExternalSitesController, :guests_index
           get "/:site_id", ExternalSitesController, :get_site
         end
@@ -353,6 +354,9 @@ defmodule PlausibleWeb.Router do
           put "/goals", ExternalSitesController, :find_or_create_goal
           delete "/goals/:goal_id", ExternalSitesController, :delete_goal
 
+          put "/custom-props", ExternalSitesController, :add_custom_prop
+          delete "/custom-props/*property", ExternalSitesController, :delete_custom_prop
+
           put "/guests", ExternalSitesController, :find_or_create_guest
           delete "/guests/:email", ExternalSitesController, :delete_guest
 

test/plausible/props_test.exs

@@ -54,17 +54,23 @@ defmodule Plausible.PropsTest do
 
     long_prop = String.duplicate("a", 301)
     assert {:error, changeset} = Plausible.Props.allow(site, long_prop)
-    assert {"must be between 1 and 300 characters", []} == changeset.errors[:allowed_event_props]
+
+    assert {"must be between 1 and 300 characters", [validation: :length, type: :string]} ==
+             changeset.errors[:allowed_event_props]
   end
 
   test "allow/2 fails when prop key is empty" do
     site = new_site()
 
     assert {:error, changeset} = Plausible.Props.allow(site, "")
-    assert {"must be between 1 and 300 characters", []} == changeset.errors[:allowed_event_props]
+
+    assert {"must be between 1 and 300 characters", [validation: :length, type: :string]} ==
+             changeset.errors[:allowed_event_props]
 
     assert {:error, changeset} = Plausible.Props.allow(site, " ")
-    assert {"must be between 1 and 300 characters", []} == changeset.errors[:allowed_event_props]
+
+    assert {"must be between 1 and 300 characters", [validation: :length, type: :string]} ==
+             changeset.errors[:allowed_event_props]
   end
 
   test "allow/2 does not fail when prop key is already in the list" do