squash! Expose expires_at datetime in mastoAPI only for the activity actor

NOTE: rewrite the commit msg

docs/api/differences_in_mastoapi_responses.md

@@ -25,7 +25,7 @@ Has these additional fields under the `pleroma` object:
 - `in_reply_to_account_acct`: the `acct` property of User entity for replied user (if any)
 - `content`: a map consisting of alternate representations of the `content` property with the key being it's mimetype. Currently the only alternate representation supported is `text/plain`
 - `spoiler_text`: a map consisting of alternate representations of the `spoiler_text` property with the key being it's mimetype. Currently the only alternate representation supported is `text/plain`
-- `expires_on`: a datetime (iso8601) that states when the post will expire (be deleted automatically), or empty if the post won't expire
+- `expires_in`:  the number of minutes until a post will expire (be deleted automatically), or empty if the post won't expire
 
 ## Attachments
 

lib/pleroma/web/mastodon_api/views/status_view.ex

@@ -168,11 +168,15 @@ def render("status.json", %{activity: %{data: %{"object" => _object}} = activity
 
     client_posted_this_activity = opts[:for] && user.id == opts[:for].id
 
-    expires_at =
+    expires_in =
       with true <- client_posted_this_activity,
            expiration when not is_nil(expiration) <-
              ActivityExpiration.get_by_activity_id(activity.id) do
-        expiration.scheduled_at
+        expires_in_seconds =
+          expiration.scheduled_at
+          |> NaiveDateTime.diff(NaiveDateTime.utc_now(), :second)
+
+        round(expires_in_seconds / 60)
       end
 
     thread_muted? =
@@ -273,7 +277,7 @@ def render("status.json", %{activity: %{data: %{"object" => _object}} = activity
         in_reply_to_account_acct: reply_to_user && reply_to_user.nickname,
         content: %{"text/plain" => content_plaintext},
         spoiler_text: %{"text/plain" => summary_plaintext},
-        expires_at: expires_at
+        expires_in: expires_in
       }
     }
   end

test/web/mastodon_api/mastodon_api_controller_test.exs

@@ -170,7 +170,7 @@ test "posting a status", %{conn: conn} do
       assert activity = Activity.get_by_id(fourth_id)
       assert expiration = ActivityExpiration.get_by_activity_id(fourth_id)
       assert expiration.scheduled_at == expires_at
-      assert fourth_response["pleroma"]["expires_at"] == NaiveDateTime.to_iso8601(expires_at)
+      assert fourth_response["pleroma"]["expires_in"] > 0
     end
 
     test "replying to a status", %{conn: conn} do

test/web/mastodon_api/status_view_test.exs

@@ -134,7 +134,7 @@ test "a note activity" do
         in_reply_to_account_acct: nil,
         content: %{"text/plain" => HtmlSanitizeEx.strip_tags(object_data["content"])},
         spoiler_text: %{"text/plain" => HtmlSanitizeEx.strip_tags(object_data["summary"])},
-        expires_at: nil
+        expires_in: nil
       }
     }