From d12c9a8f581a22f2f9d04b73c85dce890fb037a1 Mon Sep 17 00:00:00 2001
From: Michael <heluecht@pirati.ca>
Date: Thu, 28 Jul 2022 19:05:04 +0000
Subject: [PATCH] Caching for fetched activities

---
 src/Protocol/ActivityPub/Processor.php | 47 ++++++++++++++++----------
 src/Protocol/ActivityPub/Receiver.php  |  8 ++---
 src/Util/HTTPSignature.php             |  2 +-
 3 files changed, 35 insertions(+), 22 deletions(-)

diff --git a/src/Protocol/ActivityPub/Processor.php b/src/Protocol/ActivityPub/Processor.php
index 421f2d4c0..bfff5f84b 100644
--- a/src/Protocol/ActivityPub/Processor.php
+++ b/src/Protocol/ActivityPub/Processor.php
@@ -1201,6 +1201,33 @@ class Processor
 		Logger::info('Fetched featured posts', ['new' => $new, 'old' => $old, 'contact' => $url]);
 	}
 
+	public static function fetchCachedActivity(string $url, int $uid): array
+	{
+		$cachekey = self::CACHEKEY_FETCH_ACTIVITY . $uid . ':' . $url;
+		$object = DI::cache()->get($cachekey);
+
+		if (!is_null($object)) {
+			Logger::debug('Fetch from cache', ['url' => $url, 'uid' => $uid]);
+			return $object;
+		}
+
+		$object = ActivityPub::fetchContent($url, $uid);
+		if (empty($object)) {
+			Logger::notice('Activity was not fetchable, aborting.', ['url' => $url, 'uid' => $uid]);
+			return [];
+		}
+
+		if (empty($object['id'])) {
+			Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
+			return [];
+		}
+		DI::cache()->set($cachekey, $object, Duration::FIVE_MINUTES);
+
+		Logger::debug('Activity was fetched successfully', ['url' => $url, 'uid' => $uid]);
+
+		return $object;
+	}
+
 	/**
 	 * Fetches missing posts
 	 *
@@ -1220,23 +1247,9 @@ class Processor
 			$uid = 0;
 		}
 
-		$cachekey = self::CACHEKEY_FETCH_ACTIVITY . $url;
-		$object = DI::cache()->get($cachekey);
-
-		if (is_null($object)) {
-			$object = ActivityPub::fetchContent($url, $uid);
-			if (empty($object)) {
-				Logger::notice('Activity was not fetchable, aborting.', ['url' => $url, 'uid' => $uid]);
-				return '';
-			}
-
-			if (empty($object['id'])) {
-				Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
-				return '';
-			}
-			DI::cache()->set($cachekey, $object, Duration::FIVE_MINUTES);
-		} else {
-			Logger::debug('Fetch from cache', ['url' => $url]);
+		$object = self::fetchCachedActivity($url, $uid);
+		if (empty($object)) {
+			return '';
 		}
 
 		$signer = [];
diff --git a/src/Protocol/ActivityPub/Receiver.php b/src/Protocol/ActivityPub/Receiver.php
index af6eca61e..f09541b13 100644
--- a/src/Protocol/ActivityPub/Receiver.php
+++ b/src/Protocol/ActivityPub/Receiver.php
@@ -241,7 +241,7 @@ class Receiver
 			return 'as:' . $profile['type'];
 		}
 
-		$data = ActivityPub::fetchContent($object_id, $uid);
+		$data = Processor::fetchCachedActivity($object_id, $uid);
 		if (!empty($data)) {
 			$object = JsonLD::compact($data);
 			$type = JsonLD::fetchElement($object, '@type');
@@ -284,7 +284,7 @@ class Receiver
 		if (!empty($id) && !$trust_source) {
 			$fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 
-			$fetched_activity = ActivityPub::fetchContent($fetch_id, $fetch_uid);
+			$fetched_activity = Processor::fetchCachedActivity($fetch_id, $fetch_uid);
 			if (!empty($fetched_activity)) {
 				$object = JsonLD::compact($fetched_activity);
 
@@ -358,7 +358,7 @@ class Receiver
 
 		// Fetch the activity on Lemmy "Announce" messages (announces of activities)
 		if (($type == 'as:Announce') && in_array($object_type, array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
-			$data = ActivityPub::fetchContent($object_id, $fetch_uid);
+			$data = Processor::fetchCachedActivity($object_id, $fetch_uid);
 			if (!empty($data)) {
 				$type = $object_type;
 				$activity = JsonLD::compact($data);
@@ -1273,7 +1273,7 @@ class Receiver
 		$type = JsonLD::fetchElement($object, '@type');
 
 		if (!$trust_source || empty($type)) {
-			$data = ActivityPub::fetchContent($object_id, $uid);
+			$data = Processor::fetchCachedActivity($object_id, $uid);
 			if (!empty($data)) {
 				$object = JsonLD::compact($data);
 				Logger::info('Fetched content for ' . $object_id);
diff --git a/src/Util/HTTPSignature.php b/src/Util/HTTPSignature.php
index 9f732acb6..f4f0a4e85 100644
--- a/src/Util/HTTPSignature.php
+++ b/src/Util/HTTPSignature.php
@@ -508,7 +508,7 @@ class HTTPSignature
 				return false;
 			}
 
-			$actor = JsonLD::fetchElement($object, 'actor', 'id');
+			$actor = JsonLD::fetchElement($object, 'actor', 'id') ?? '';
 		} else {
 			$actor = '';
 		}