Add tag timelines.

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -111,6 +111,12 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
   end
   defp restrict_since(query, _), do: query
 
+  defp restrict_tag(query, %{"tag" => tag}) do
+    from activity in query,
+      where: fragment("? <@ (? #> '{\"object\",\"tag\"}')", ^tag, activity.data)
+  end
+  defp restrict_tag(query, _), do: query
+
   defp restrict_recipients(query, recipients) do
     Enum.reduce(recipients, query, fn (recipient, q) ->
       map = %{ to: [recipient] }
@@ -148,6 +154,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
 
     base_query
     |> restrict_recipients(recipients)
+    |> restrict_tag(opts)
     |> restrict_since(opts)
     |> restrict_local(opts)
     |> restrict_max(opts)

lib/pleroma/web/mastodon_api/mastodon_api_controller.ex

@@ -230,6 +230,18 @@ defmodule Pleroma.Web.MastodonAPI.MastodonAPIController do
     end
   end
 
+  def hashtag_timeline(%{assigns: %{user: user}} = conn, params) do
+    params = params
+    |> Map.put("type", "Create")
+    |> Map.put("local_only", !!params["local"])
+
+    activities = ActivityPub.fetch_public_activities(params)
+    |> Enum.reverse
+
+    conn
+    |> render(StatusView, "index.json", %{activities: activities, for: user, as: :activity})
+  end
+
   def empty_array(conn, _) do
     Logger.debug("Unimplemented, returning an empty array")
     json(conn, [])

lib/pleroma/web/router.ex

@@ -65,6 +65,7 @@ defmodule Pleroma.Web.Router do
     post "/apps", MastodonAPIController, :create_app
 
     get "/timelines/public", MastodonAPIController, :public_timeline
+    get "/timelines/tag/:tag", MastodonAPIController, :hashtag_timeline
 
     get "/statuses/:id", MastodonAPIController, :get_status
     get "/statuses/:id/context", MastodonAPIController, :get_context