Merge pull request #8 from alleyinteractive/feature/in-memory-cache

Cache items fetched during the request in memory

CHANGELOG.md

@@ -2,9 +2,15 @@
 
 This library adheres to [Semantic Versioning](https://semver.org/) and [Keep a CHANGELOG](https://keepachangelog.com/en/1.0.0/).
 
+## 0.4.0
+
+### Added
+
+- In-memory cache of items fetched during the request.
+
 ## 0.3.0
 
-## Changed
+### Changed
 
 - When storing items with the PSR-16 adapter, the group name is now automatically prefixed to avoid unintended data loss when flushing the cache.
 

src/class-big-pit.php

@@ -30,6 +30,15 @@ final class Big_Pit implements Feature {
 	 */
 	private bool $ready = false;
 
+	/**
+	 * Cached values.
+	 *
+	 * @phpstan-var array<string, array<string, mixed>>
+	 *
+	 * @var array[]
+	 */
+	private array $cache = [];
+
 	/**
 	 * Instance.
 	 *
@@ -79,6 +88,17 @@ public function get( string $key, string $group ): mixed {
 			return null;
 		}
 
+		if ( isset( $this->cache[ $group ] ) && array_key_exists( $key, $this->cache[ $group ] ) ) {
+			$value = $this->cache[ $group ][ $key ];
+
+			if ( is_object( $value ) ) {
+				// Don't reuse the same instance across multiple calls.
+				$value = clone $value;
+			}
+
+			return $value;
+		}
+
 		$value = $wpdb->get_var(
 			$wpdb->prepare(
 				"SELECT item_value FROM {$wpdb->big_pit} WHERE item_group = %s AND item_key = %s LIMIT 1",
@@ -91,6 +111,8 @@ public function get( string $key, string $group ): mixed {
 			$value = maybe_unserialize( $value );
 		}
 
+		$this->cache[ $group ][ $key ] = $value;
+
 		return $value;
 	}
 
@@ -141,6 +163,8 @@ public function set( string $key, mixed $value, string $group ): void {
 				[ '%s', '%s', '%s' ],
 			);
 		}
+
+		unset( $this->cache[ $group ][ $key ] );
 	}
 
 	/**
@@ -164,6 +188,8 @@ public function delete( string $key, string $group ): void {
 			],
 			[ '%s', '%s' ],
 		);
+
+		unset( $this->cache[ $group ][ $key ] );
 	}
 
 	/**
@@ -185,6 +211,8 @@ public function flush_group( string $group ): void {
 			],
 			[ '%s' ],
 		);
+
+		unset( $this->cache[ $group ] );
 	}
 
 	/**

tests/TestCase.php

@@ -7,11 +7,32 @@
 
 namespace Alley\WP\Big_Pit\Tests;
 
+use Alley\WP\Big_Pit;
 use Mantle\Testkit\Test_Case as TestkitTest_Case;
 
 /**
  * Big Pit Base Test Case
  */
 abstract class TestCase extends TestkitTest_Case {
+	/**
+	 * Create the database table.
+	 */
+	public static function setUpBeforeClass(): void {
+		parent::setUpBeforeClass();
 
+		Big_Pit::instance()->boot();
+	}
+
+	/**
+	 * Drop the database table.
+	 */
+	public static function tearDownAfterClass(): void {
+		global $wpdb;
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.DirectDatabaseQuery.SchemaChange
+		$wpdb->query( 'DROP TABLE ' . $wpdb->big_pit );
+		delete_option( 'wp_big_pit_database_version' );
+
+		parent::tearDownAfterClass();
+	}
 }

tests/Unit/CrudUnitTest.php

@@ -8,34 +8,12 @@
 namespace Alley\WP\Big_Pit\Tests\Unit;
 
 use Alley\WP\Big_Pit;
-use PHPUnit\Framework\TestCase;
+use Alley\WP\Big_Pit\Tests\TestCase;
 
 /**
  * CRUD tests.
  */
 class CrudUnitTest extends TestCase {
-	/**
-	 * Create the database table.
-	 */
-	public static function setUpBeforeClass(): void {
-		parent::setUpBeforeClass();
-
-		Big_Pit::instance()->boot();
-	}
-
-	/**
-	 * Drop the database table.
-	 */
-	public static function tearDownAfterClass(): void {
-		global $wpdb;
-
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.DirectDatabaseQuery.SchemaChange
-		$wpdb->query( 'DROP TABLE ' . $wpdb->big_pit );
-		delete_option( 'wp_big_pit_database_version' );
-
-		parent::tearDownAfterClass();
-	}
-
 	/**
 	 * Test CRUD operations.
 	 */

tests/Unit/InMemoryCacheTest.php

@@ -0,0 +1,70 @@
+<?php
+/**
+ * Big Pit Tests: InMemoryCacheTest class file
+ *
+ * @package wp-big-pit
+ */
+
+namespace Alley\WP\Big_Pit\Tests\Unit;
+
+use Alley\WP\Big_Pit;
+use Alley\WP\Big_Pit\Tests\TestCase;
+
+/**
+ * Test in-memory cache.
+ */
+class InMemoryCacheTest extends TestCase {
+	/**
+	 * Test for expected number of queries with the in-memory cache.
+	 */
+	public function test_in_memory_cache() {
+		global $wpdb;
+
+		$big_pit = Big_Pit::instance();
+
+		// Two fetches of the same key should only result in one query.
+		$num_queries_before = $wpdb->num_queries;
+		$big_pit->get( 'key1', 'group1' );
+		$big_pit->get( 'key1', 'group1' );
+		$this->assertSame( 1, $wpdb->num_queries - $num_queries_before );
+
+		$big_pit->set( 'key1', 'value1', 'group1' );
+
+		// Value has changed, so there should be another query.
+		$num_queries_before = $wpdb->num_queries;
+		$big_pit->get( 'key1', 'group1' );
+		$this->assertSame( 1, $wpdb->num_queries - $num_queries_before );
+
+		// Fetching it again should not result in another query.
+		$big_pit->get( 'key1', 'group1' );
+		$this->assertSame( 1, $wpdb->num_queries - $num_queries_before );
+
+		$big_pit->delete( 'key1', 'group1' );
+
+		// Value has changed, so there should be another query.
+		$num_queries_before = $wpdb->num_queries;
+		$big_pit->get( 'key1', 'group1' );
+		$this->assertSame( 1, $wpdb->num_queries - $num_queries_before );
+
+		$big_pit->set( 'key1', 'value1', 'group1' );
+		$big_pit->set( 'key2', 'value2', 'group1' );
+		$big_pit->get( 'key1', 'group1' );
+		$big_pit->get( 'key2', 'group1' );
+		$big_pit->flush_group( 'group1' );
+
+		// All values have changed, so there should be queries for each value in the group that was set.
+		$num_queries_before = $wpdb->num_queries;
+		$big_pit->get( 'key1', 'group1' );
+		$big_pit->get( 'key2', 'group1' );
+		$this->assertSame( 2, $wpdb->num_queries - $num_queries_before );
+	}
+
+	/**
+	 * Check for improper reuse of a cached object.
+	 */
+	public function test_cached_object_reference() {
+		$big_pit = Big_Pit::instance();
+		$big_pit->set( 'key1', (object) [ 'foo' => 'bar' ], 'group1' );
+		$this->assertNotSame( $big_pit->get( 'key1', 'group1' ), $big_pit->get( 'key1', 'group1' ) );
+	}
+}