Add client for speculatively loading values based on URL

CHANGELOG.md

@@ -2,6 +2,24 @@
 
 This library adheres to [Semantic Versioning](https://semver.org/) and [Keep a CHANGELOG](https://keepachangelog.com/en/1.0.0/).
 
+## 0.5.0
+
+### Added
+
+- `Client` interface, extending `Alley\WP\Types\Feature`, for implementing a Big Pit client.
+- `Items` class for clients that want to keep their own in-memory cache of fetched items.
+- `Big_Speculative_Pit` client for preloading items used the last time a URL was requested.
+
+### Changed
+
+- `Big_Pit` is now in the `Alley\WP\Big_Pit` subnamespace, implements the `Client` interface, and must be instantiated with the `new` keyword.
+- The `boot()` method on clients must be called manually.
+- The `$wpdb->big_pit` property will be unset if the table is not available.
+
+### Removed
+
+- `Big_Pit::instance()` method.
+
 ## 0.4.0
 
 ### Added

README.md

@@ -10,13 +10,33 @@ You can install the package via Composer:
 composer require alleyinteractive/wp-big-pit
 ```
 
-## Usage
+## API
+
+The `Alley\WP\Big_Pit\Client` interface describes the create-read-update-delete operations that can be used with the Big Pit. You can type hint against this interface when using Big Pit as a dependency.
+
+```php
+namespace Alley\WP\Big_Pit;
+
+use Alley\WP\Types\Feature;
+
+interface Client extends Feature {
+	public function get( string $key, string $group ): mixed;
+
+	public function set( string $key, mixed $value, string $group ): void;
+
+	public function delete( string $key, string $group ): void;
+
+	public function flush_group( string $group ): void;
+}
+```
 
 Each item in the Big Pit has a key and a group, much like the WordPress object cache. Each key is unique within a group.
 
-### Direct Access
+`Client` extends the `Alley\WP\Types\Feature` interface from the [Type Extensions](https://github.com/alleyinteractive/wp-type-extensions) library, which includes a `boot()` method for performing side effects.
+
+You must call `boot()` before using the client. If you are compiling features using the `Features` instance from Type Extensions, you can include the Big Pit client, and it will be booted with the rest of your feature classes.
 
-You can perform CRUD operations directly on The Pit:
+## Usage
 
 ```php
 <?php
@@ -26,14 +46,32 @@ use Alley\WP\Big_Pit;
 $external_id  = 'abcdef12345';
 $api_response = '{"id":"abcdef12345","title":"The Best Movie Ever","rating":5}';
 
-$big_pit = Big_Pit::instance();
+$big_pit = new Big_Pit\Big_Pit();
+$big_pit->boot();
 
 $big_pit->set( $external_id, $api_response, 'movie_reviews' );
 $big_pit->get( $external_id, 'movie_reviews' ); // '{"id":"abcdef12345","title":"The Best Movie Ever","rating":5}'
 $big_pit->delete( $external_id, 'movie_reviews' );
 $big_pit->flush_group( 'movie_reviews' );
 ```
 
+### Speculative Client
+
+The `Big_Speculative_Pit` decorator class tracks the items that are fetched during a given request and preloads those items in a single query the next time the same page is requested.
+
+```php
+<?php
+
+use Alley\WP\Big_Pit;
+
+$request = \Symfony\Component\HttpFoundation\Request::createFromGlobals();
+
+$big_pit = new Big_Pit\Big_Speculative_Pit(
+  request: $request,
+  origin: new Big_Pit\Big_Pit(),
+);
+```
+
 ### PSR-16 Cache Adapter
 
 A PSR-16 adapter is available for caching data in The Pit:

composer.json

@@ -14,7 +14,8 @@
     "php": "^8.1",
     "alleyinteractive/composer-wordpress-autoloader": "^1.0",
     "alleyinteractive/wp-psr16": "^0.1.0",
-    "alleyinteractive/wp-type-extensions": "^2.1"
+    "alleyinteractive/wp-type-extensions": "^2.1",
+    "symfony/http-foundation": "^6.4"
   },
   "require-dev": {
     "alleyinteractive/alley-coding-standards": "^2.0",
@@ -68,4 +69,4 @@
     ],
     "tidy": "[ $COMPOSER_DEV_MODE -eq 0 ] || composer normalize"
   }
-}
+}

src/class-big-pit.php → src/big-pit/class-big-pit.php

@@ -8,49 +8,24 @@
 // phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery
 // phpcs:disable WordPress.DB.DirectDatabaseQuery.NoCaching
 
-namespace Alley\WP;
-
-use Alley\WP\Types\Feature;
+namespace Alley\WP\Big_Pit;
 
 /**
  * The Big Pit.
  */
-final class Big_Pit implements Feature {
+final class Big_Pit implements Client {
 	/**
-	 * Singleton.
+	 * Fetched items.
 	 *
-	 * @var self
+	 * @var Items
 	 */
-	private static ?self $instance = null;
+	private readonly Items $items;
 
 	/**
-	 * Whether the database is ready to accept queries.
-	 *
-	 * @var bool
-	 */
-	private bool $ready = false;
-
-	/**
-	 * Cached values.
-	 *
-	 * @phpstan-var array<string, array<string, mixed>>
-	 *
-	 * @var array[]
+	 * Constructor.
 	 */
-	private array $cache = [];
-
-	/**
-	 * Instance.
-	 *
-	 * @return self
-	 */
-	public static function instance(): self {
-		if ( null === self::$instance ) {
-			self::$instance = new self();
-			self::$instance->boot();
-		}
-
-		return self::$instance;
+	public function __construct() {
+		$this->items = new Items();
 	}
 
 	/**
@@ -67,10 +42,8 @@ public function boot(): void {
 
 		try {
 			$this->upsert();
-			$this->ready = true;
 		} catch ( \Exception $e ) {
-			// Do nothing.
-			unset( $e );
+			unset( $wpdb->big_pit );
 		}
 	}
 
@@ -84,24 +57,20 @@ public function boot(): void {
 	public function get( string $key, string $group ): mixed {
 		global $wpdb;
 
-		if ( ! $this->ready ) {
+		assert( $wpdb instanceof \wpdb );
+
+		if ( ! isset( $wpdb->big_pit ) ) {
 			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;
+		if ( $this->items->has( $key, $group ) ) {
+			return $this->items->get( $key, $group );
 		}
 
 		$value = $wpdb->get_var(
 			$wpdb->prepare(
-				"SELECT item_value FROM {$wpdb->big_pit} WHERE item_group = %s AND item_key = %s LIMIT 1",
+				'SELECT item_value FROM %i WHERE item_group = %s AND item_key = %s LIMIT 1',
+				$wpdb->big_pit,
 				$group,
 				$key
 			),
@@ -111,7 +80,7 @@ public function get( string $key, string $group ): mixed {
 			$value = maybe_unserialize( $value );
 		}
 
-		$this->cache[ $group ][ $key ] = $value;
+		$this->items->add( $key, $value, $group );
 
 		return $value;
 	}
@@ -126,15 +95,18 @@ public function get( string $key, string $group ): mixed {
 	public function set( string $key, mixed $value, string $group ): void {
 		global $wpdb;
 
-		if ( ! $this->ready ) {
+		assert( $wpdb instanceof \wpdb );
+
+		if ( ! isset( $wpdb->big_pit ) ) {
 			return;
 		}
 
 		$value = maybe_serialize( $value ); // @phpstan-ignore argument.type
 
 		$exists = $wpdb->get_var(
 			$wpdb->prepare(
-				"SELECT item_id FROM {$wpdb->big_pit} WHERE item_group = %s AND item_key = %s LIMIT 1",
+				'SELECT item_id FROM %i WHERE item_group = %s AND item_key = %s LIMIT 1',
+				$wpdb->big_pit,
 				$group,
 				$key
 			),
@@ -164,7 +136,7 @@ public function set( string $key, mixed $value, string $group ): void {
 			);
 		}
 
-		unset( $this->cache[ $group ][ $key ] );
+		$this->items->remove( $key, $group );
 	}
 
 	/**
@@ -176,7 +148,9 @@ public function set( string $key, mixed $value, string $group ): void {
 	public function delete( string $key, string $group ): void {
 		global $wpdb;
 
-		if ( ! $this->ready ) {
+		assert( $wpdb instanceof \wpdb );
+
+		if ( ! isset( $wpdb->big_pit ) ) {
 			return;
 		}
 
@@ -189,7 +163,7 @@ public function delete( string $key, string $group ): void {
 			[ '%s', '%s' ],
 		);
 
-		unset( $this->cache[ $group ][ $key ] );
+		$this->items->remove( $key, $group );
 	}
 
 	/**
@@ -200,7 +174,9 @@ public function delete( string $key, string $group ): void {
 	public function flush_group( string $group ): void {
 		global $wpdb;
 
-		if ( ! $this->ready ) {
+		assert( $wpdb instanceof \wpdb );
+
+		if ( ! isset( $wpdb->big_pit ) ) {
 			return;
 		}
 
@@ -212,7 +188,7 @@ public function flush_group( string $group ): void {
 			[ '%s' ],
 		);
 
-		unset( $this->cache[ $group ] );
+		$this->items->remove_group( $group );
 	}
 
 	/**
@@ -223,13 +199,19 @@ public function flush_group( string $group ): void {
 	private function upsert(): void {
 		global $wpdb;
 
+		assert( $wpdb instanceof \wpdb );
+
 		$available_version = '2';
 		$installed_version = get_option( 'wp_big_pit_database_version', '0' );
 
 		if ( $available_version === $installed_version ) {
 			return;
 		}
 
+		if ( ! isset( $wpdb->big_pit ) ) {
+			return;
+		}
+
 		if ( ! function_exists( 'dbDelta' ) ) {
 			require_once ABSPATH . '/wp-admin/includes/upgrade.php';
 		}