Stats: Use option value instead of transient for cache buster

projects/packages/stats-admin/changelog/update-use-option-value-instead-of-transient

@@ -0,0 +1,4 @@
+Significance: patch
+Type: changed
+
+Odyssey Stats cache busting: use optioin instead of transient

projects/packages/stats-admin/src/class-odyssey-assets.php

@@ -75,36 +75,58 @@ public function load_admin_scripts( $asset_handle, $asset_name, $options = array
 	/**
 	 * Returns cache buster string for assets.
 	 * Development mode doesn't need this, as it's handled by `Assets` class.
+	 *
+	 * @return string
 	 */
 	protected function get_cdn_asset_cache_buster() {
+		$now_in_ms = floor( microtime( true ) * 1000 );
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
 		if ( isset( $_GET['force_refresh'] ) ) {
-			set_transient( self::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY, floor( microtime( true ) * 1000 ), 15 * MINUTE_IN_SECONDS );
+			update_option( self::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY, $this->get_cache_buster_option_value( $now_in_ms ), false );
 		}
 
 		// Use cached cache buster in production.
-		$remote_asset_version = get_transient( self::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY );
+		$remote_asset_version = get_option( self::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY );
 
 		if ( ! empty( $remote_asset_version ) ) {
-			return $remote_asset_version;
+			$remote_asset_version = json_decode( $remote_asset_version, true );
+			// If cache buster is cached and not expired (valid in 15 min), return it.
+			if ( ! empty( $remote_asset_version['cache_buster'] ) && $remote_asset_version['cached_at'] > $now_in_ms - MINUTE_IN_SECONDS * 1000 * 15 ) {
+				return $remote_asset_version['cache_buster'];
+			}
 		}
 
 		// If no cached cache buster, we fetch it from CDN and set to transient.
-		$response = wp_remote_get( sprintf( self::ODYSSEY_CDN_URL, self::ODYSSEY_STATS_VERSION, 'build_meta.json?t=' . time() ), array( 'timeout' => 5 ) );
+		$response = wp_remote_get( sprintf( self::ODYSSEY_CDN_URL, self::ODYSSEY_STATS_VERSION, 'build_meta.json?t=' . $now_in_ms ), array( 'timeout' => 5 ) );
 
 		if ( is_wp_error( $response ) ) {
-			// fallback to the package version.
-			return Main::VERSION;
+			// fallback to current timestamp.
+			return (string) $now_in_ms;
 		}
 
 		$build_meta = json_decode( wp_remote_retrieve_body( $response ), true );
 		if ( ! empty( $build_meta['cache_buster'] ) ) {
 			// Cache the cache buster for 15 mins.
-			set_transient( self::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY, $build_meta['cache_buster'], 15 * MINUTE_IN_SECONDS );
+			update_option( self::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY, $this->get_cache_buster_option_value( $build_meta['cache_buster'] ), false );
 			return $build_meta['cache_buster'];
 		}
 
-		// fallback to the package version.
-		return Main::VERSION;
+		// fallback to current timestamp.
+		return (string) $now_in_ms;
+	}
+
+	/**
+	 * Get the cache buster option value.
+	 *
+	 * @param string|int|float $cache_buster The cache buster.
+	 * @return string|false
+	 */
+	protected function get_cache_buster_option_value( $cache_buster ) {
+		return wp_json_encode(
+			array(
+				'cache_buster' => (string) $cache_buster,
+				'cached_at'    => floor( microtime( true ) * 1000 ), // milliseconds.
+			)
+		);
 	}
 }

projects/packages/stats-admin/tests/php/class-test-case.php

@@ -60,6 +60,7 @@ public function set_up() {
 
 		add_filter( 'jetpack_options', array( $this, 'mock_jetpack_site_connection_options' ), 10, 2 );
 		add_filter( 'pre_http_request', array( $this, 'plan_http_response_fixture' ), 10, 3 );
+		delete_option( Odyssey_Assets::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY );
 	}
 
 	/**
@@ -76,6 +77,7 @@ public function tear_down() {
 
 		remove_filter( 'pre_http_request', array( $this, 'plan_http_response_fixture' ) );
 		remove_filter( 'jetpack_options', array( $this, 'mock_jetpack_site_connection_options' ) );
+		delete_option( Odyssey_Assets::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY );
 	}
 
 	/**

projects/packages/stats-admin/tests/php/test-odyssey-assets.php

@@ -2,20 +2,114 @@
 namespace Automattic\Jetpack\Stats_Admin;
 
 use Automattic\Jetpack\Stats_Admin\Test_Case as Stats_Test_Case;
+use WP_Error;
 
 /**
  * Unit tests for the Odyssey_Assets class.
  *
  * @package automattic/jetpack-stats-admin
  */
 class Test_Odyssey_Assets extends Stats_Test_Case {
+
 	/**
 	 * Test remote cache buster.
 	 */
 	public function test_get_cdn_asset_cache_buster() {
+		$this->assertEquals( 'calypso-4917-8664-g72a154d63a', $this->get_cdn_asset_cache_buster_callable() );
+	}
+
+	/**
+	 * Test remote cache buster remote error.
+	 */
+	public function test_get_cdn_asset_cache_buster_remote_error() {
+		add_filter( 'pre_http_request', array( $this, 'break_cdn_cache_buster_request' ), 15, 3 );
+		$this->assertEquals( time(), floor( $this->get_cdn_asset_cache_buster_callable() / 1000 ) );
+		remove_filter( 'pre_http_request', array( $this, 'break_cdn_cache_buster_request' ), 15 );
+	}
+
+	/**
+	 * Test already cached cache buster.
+	 */
+	public function test_get_cdn_asset_cache_buster_already_cached() {
+		update_option(
+			Odyssey_Assets::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY,
+			wp_json_encode(
+				array(
+					'cache_buster' => 'calypso-4917-8664-123456',
+					'cached_at'    => floor( microtime( true ) * 1000 ), // milliseconds.
+				)
+			),
+			false
+		);
+		$this->assertEquals( 'calypso-4917-8664-123456', $this->get_cdn_asset_cache_buster_callable() );
+	}
+
+	/**
+	 * Test already cached cache buster expired.
+	 */
+	public function test_get_cdn_asset_cache_buster_already_cached_expired() {
+		update_option(
+			Odyssey_Assets::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY,
+			wp_json_encode(
+				array(
+					'cache_buster' => 'calypso-4917-8664-123456',
+					'cached_at'    => floor( microtime( true ) * 1000 - MINUTE_IN_SECONDS * 1000 * 20 ), // milliseconds.
+				)
+			),
+			false
+		);
+		$this->assertEquals( 'calypso-4917-8664-g72a154d63a', $this->get_cdn_asset_cache_buster_callable() );
+	}
+
+	/**
+	 * Test already cached cache buster expired and failed to fetch new one.
+	 */
+	public function test_get_cdn_asset_cache_buster_failed_to_fetch() {
+		add_filter( 'pre_http_request', array( $this, 'break_cdn_cache_buster_request' ), 15, 3 );
+		update_option(
+			Odyssey_Assets::ODYSSEY_STATS_CACHE_BUSTER_CACHE_KEY,
+			wp_json_encode(
+				array(
+					'cache_buster' => 'calypso-4917-8664-123456',
+					'cached_at'    => floor( microtime( true ) * 1000 - MINUTE_IN_SECONDS * 1000 * 20 ), // milliseconds.
+				)
+			),
+			false
+		);
+		$this->assertEquals( time(), floor( $this->get_cdn_asset_cache_buster_callable() / 1000 ) );
+		remove_filter( 'pre_http_request', array( $this, 'break_cdn_cache_buster_request' ), 15 );
+	}
+
+	/**
+	 * Test force refresh cache buster.
+	 */
+	public function test_get_cdn_asset_cache_buster_force_refresh_expired() {
+		$_GET['force_refresh'] = 1;
+		$this->assertEquals( time(), floor( $this->get_cdn_asset_cache_buster_callable() / 1000 ) );
+	}
+
+	/**
+	 * Test remote cache buster.
+	 *
+	 * @param mixed $response  The response array.
+	 * @param mixed $parsed_args  The parsed args.
+	 * @param mixed $url  The URL.
+	 * @return WP_Error | void
+	 */
+	public function break_cdn_cache_buster_request( $response, $parsed_args, $url ) {
+		if ( strpos( $url, '/build_meta.json' ) !== false ) {
+			return new WP_Error( 500, 'Internal Server Error' );
+		}
+	}
+
+	/**
+	 * Get CDN asset cache buster.
+	 */
+	protected function get_cdn_asset_cache_buster_callable() {
 		$odyssey_assets             = new Odyssey_Assets();
 		$get_cdn_asset_cache_buster = new \ReflectionMethod( $odyssey_assets, 'get_cdn_asset_cache_buster' );
 		$get_cdn_asset_cache_buster->setAccessible( true );
-		$this->assertEquals( 'calypso-4917-8664-g72a154d63a', $get_cdn_asset_cache_buster->invoke( $odyssey_assets ) );
+
+		return $get_cdn_asset_cache_buster->invoke( $odyssey_assets );
 	}
 }