From e696357c069b6b64ae6019ef28893d89d2c0989a Mon Sep 17 00:00:00 2001
From: Shish <shish@shishnet.org>
Date: Sat, 3 Oct 2020 12:50:37 +0000
Subject: [PATCH] database notification API

---
 core/database.php |  5 +++++
 core/dbengine.php | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/core/database.php b/core/database.php
index bd135c2d..ea3ac36f 100644
--- a/core/database.php
+++ b/core/database.php
@@ -169,6 +169,11 @@ class Database
         $this->engine->set_timeout($this->db, $time);
     }
 
+    public function notify(string $channel, ?string $data=null): void
+    {
+        $this->engine->notify($this->db, $channel, $data);
+    }
+
     public function execute(string $query, array $args = []): PDOStatement
     {
         try {
diff --git a/core/dbengine.php b/core/dbengine.php
index 66be9d2b..638da437 100644
--- a/core/dbengine.php
+++ b/core/dbengine.php
@@ -33,6 +33,8 @@ abstract class DBEngine
     abstract public function set_timeout(PDO $db, int $time);
 
     abstract public function get_version(PDO $db): string;
+
+    abstract public function notify(PDO $db, string $channel, ?string $data=null): void;
 }
 
 class MySQL extends DBEngine
@@ -71,6 +73,10 @@ class MySQL extends DBEngine
         // $db->exec("SET SESSION MAX_EXECUTION_TIME=".$time.";");
     }
 
+    public function notify(PDO $db, string $channel, ?string $data=null): void
+    {
+    }
+
     public function get_version(PDO $db): string
     {
         return $db->query('select version()')->fetch()[0];
@@ -118,6 +124,15 @@ class PostgreSQL extends DBEngine
         $db->exec("SET statement_timeout TO ".$time.";");
     }
 
+    public function notify(PDO $db, string $channel, ?string $data=null): void
+    {
+        if ($data) {
+            $db->exec("NOTIFY $channel, '$data';");
+        } else {
+            $db->exec("NOTIFY $channel;");
+        }
+    }
+
     public function get_version(PDO $db): string
     {
         return $db->query('select version()')->fetch()[0];
@@ -229,6 +244,10 @@ class SQLite extends DBEngine
         // There doesn't seem to be such a thing for SQLite, so it does nothing
     }
 
+    public function notify(PDO $db, string $channel, ?string $data=null): void
+    {
+    }
+
     public function get_version(PDO $db): string
     {
         return $db->query('select sqlite_version()')->fetch()[0];