Prevent infinite push loop between multiple directories

- Add auto increment id to sync-push-queue table to add new profile urls
at the end
- Use REPLACE instead of INSERT to prevent unique key errors

dfrndir.sql

@@ -190,8 +190,10 @@ CREATE TABLE IF NOT EXISTS `sync-pull-queue` (
 --
 
 CREATE TABLE IF NOT EXISTS `sync-push-queue` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
   `url` varchar(255) CHARACTER SET utf8 NOT NULL,
-  PRIMARY KEY (`url`)
+  PRIMARY KEY (`id`),
+  UNIQUE KEY `url` (`url`) USING BTREE
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
 -- --------------------------------------------------------

include/sync.php

@@ -13,7 +13,7 @@ function sync_pull($url)
 
 	//If we support it that is.
 	if ($a->config['syncing']['enable_pulling']) {
-		q("INSERT INTO `sync-pull-queue` (`url`) VALUES ('%s')", dbesc($url));
+		q("REPLACE INTO `sync-pull-queue` (`url`) VALUES ('%s')", dbesc($url));
 	}
 }
 
@@ -28,7 +28,7 @@ function sync_push($url)
 
 	//If we support it that is.
 	if ($a->config['syncing']['enable_pushing']) {
-		q("INSERT INTO `sync-push-queue` (`url`) VALUES ('%s')", dbesc($url));
+		q("REPLACE INTO `sync-push-queue` (`url`) VALUES ('%s')", dbesc($url));
 	}
 
 	sync_mark($url);
@@ -96,7 +96,7 @@ function get_push_targets()
  */
 function get_push_batch(App $a)
 {
-	return q("SELECT * FROM `sync-push-queue` LIMIT %u", intval($a->config['syncing']['max_push_items']));
+	return q("SELECT * FROM `sync-push-queue` ORDER BY `id` LIMIT %u", intval($a->config['syncing']['max_push_items']));
 }
 
 /**