Only handle subscription requests for now.

lib/pleroma/web/websub/websub.ex

@@ -52,7 +52,7 @@ def publish(topic, user, activity) do
     end)
   end
 
-  def incoming_subscription_request(user, params) do
+  def incoming_subscription_request(user, %{"hub.mode" => "subscribe"} = params) do
     with {:ok, topic} <- valid_topic(params, user),
          {:ok, lease_time} <- lease_time(params),
          secret <- params["hub.secret"],

test/web/websub/websub_controller_test.exs

@@ -9,7 +9,7 @@ test "websub subscription request", %{conn: conn} do
 
     data = %{
       "hub.callback": "http://example.org/sub",
-      "hub.mode": "subscription",
+      "hub.mode": "subscribe",
       "hub.topic": Pleroma.Web.OStatus.feed_path(user),
       "hub.secret": "a random secret",
       "hub.lease_seconds": "100"

test/web/websub/websub_test.exs

@@ -52,7 +52,7 @@ test "an incoming subscription request" do
 
     data = %{
       "hub.callback" => "http://example.org/sub",
-      "hub.mode" => "subscription",
+      "hub.mode" => "subscribe",
       "hub.topic" => Pleroma.Web.OStatus.feed_path(user),
       "hub.secret" => "a random secret",
       "hub.lease_seconds" => "100"
@@ -72,7 +72,7 @@ test "an incoming subscription request for an existing subscription" do
 
     data = %{
       "hub.callback" => sub.callback,
-      "hub.mode" => "subscription",
+      "hub.mode" => "subscribe",
       "hub.topic" => Pleroma.Web.OStatus.feed_path(user),
       "hub.secret" => "a random secret",
       "hub.lease_seconds" => "100"