initial commit

includes/tracks/class-wc-tracks-client.php

@@ -0,0 +1,214 @@
+<?php
+/**
+ * Send Tracks events on behalf of a user.
+ *
+ * @package WooCommerce\Tracks
+ */
+
+use Automattic\Jetpack\Constants;
+use Automattic\WooCommerce\Utilities\NumberUtil;
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * WC_Tracks_Client class.
+ */
+class WC_Tracks_Client {
+
+	/**
+	 * Pixel URL.
+	 */
+	const PIXEL = 'https://pixel.wp.com/t.gif';
+
+	/**
+	 * Browser type.
+	 */
+	const BROWSER_TYPE = 'php-agent';
+
+	/**
+	 * User agent.
+	 */
+	const USER_AGENT_SLUG = 'tracks-client';
+
+	/**
+	 * Initialize tracks client class
+	 *
+	 * @return void
+	 */
+	public static function init() {
+		// Use wp hook for setting the identity cookie to avoid headers already sent warnings.
+		add_action( 'admin_init', array( __CLASS__, 'maybe_set_identity_cookie' ) );
+	}
+
+	/**
+	 * Check if identiy cookie is set, if not set it.
+	 *
+	 * @return void
+	 */
+	public static function maybe_set_identity_cookie() {
+		// Do not set on AJAX requests.
+		if ( Constants::is_true( 'DOING_AJAX' ) ) {
+			return;
+		}
+
+		// Bail if cookie already set.
+		if ( isset( $_COOKIE['tk_ai'] ) ) {
+			return;
+		}
+
+		$user = wp_get_current_user();
+
+		// We don't want to track user events during unit tests/CI runs.
+		if ( $user instanceof WP_User && 'wptests_capabilities' === $user->cap_key ) {
+			return false;
+		}
+		$user_id = $user->ID;
+		$anon_id = get_user_meta( $user_id, '_woocommerce_tracks_anon_id', true );
+
+		// If an id is still not found, create one and save it.
+		if ( ! $anon_id ) {
+			$anon_id = self::get_anon_id();
+			update_user_meta( $user_id, '_woocommerce_tracks_anon_id', $anon_id );
+		}
+
+		// Don't set cookie on API requests.
+		if ( ! Constants::is_true( 'REST_REQUEST' ) && ! Constants::is_true( 'XMLRPC_REQUEST' ) ) {
+			wc_setcookie( 'tk_ai', $anon_id );
+		}
+	}
+
+	/**
+	 * Record a Tracks event
+	 *
+	 * @param  array $event Array of event properties.
+	 * @return bool|WP_Error         True on success, WP_Error on failure.
+	 */
+	public static function record_event( $event ) {
+		if ( ! $event instanceof WC_Tracks_Event ) {
+			$event = new WC_Tracks_Event( $event );
+		}
+
+		if ( is_wp_error( $event ) ) {
+			return $event;
+		}
+
+		$pixel = $event->build_pixel_url( $event );
+
+		if ( ! $pixel ) {
+			return new WP_Error( 'invalid_pixel', 'cannot generate tracks pixel for given input', 400 );
+		}
+
+		return self::record_pixel( $pixel );
+	}
+
+	/**
+	 * Synchronously request the pixel.
+	 *
+	 * @param string $pixel pixel url and query string.
+	 * @return bool Always returns true.
+	 */
+	public static function record_pixel( $pixel ) {
+		// Add the Request Timestamp and URL terminator just before the HTTP request.
+		$pixel .= '&_rt=' . self::build_timestamp() . '&_=_';
+
+		wp_safe_remote_get(
+			$pixel,
+			array(
+				'blocking'    => false,
+				'redirection' => 2,
+				'httpversion' => '1.1',
+				'timeout'     => 1,
+			)
+		);
+
+		return true;
+	}
+
+	/**
+	 * Create a timestap representing milliseconds since 1970-01-01
+	 *
+	 * @return string A string representing a timestamp.
+	 */
+	public static function build_timestamp() {
+		$ts = NumberUtil::round( microtime( true ) * 1000 );
+
+		return number_format( $ts, 0, '', '' );
+	}
+
+	/**
+	 * Get a user's identity to send to Tracks. If Jetpack exists, default to its implementation.
+	 *
+	 * @param int $user_id User id.
+	 * @return array Identity properties.
+	 */
+	public static function get_identity( $user_id ) {
+		$jetpack_lib = '/tracks/client.php';
+
+		if ( class_exists( 'Jetpack' ) && Constants::is_defined( 'JETPACK__VERSION' ) ) {
+			if ( version_compare( Constants::get_constant( 'JETPACK__VERSION' ), '7.5', '<' ) ) {
+				if ( file_exists( jetpack_require_lib_dir() . $jetpack_lib ) ) {
+					include_once jetpack_require_lib_dir() . $jetpack_lib;
+					if ( function_exists( 'jetpack_tracks_get_identity' ) ) {
+						return jetpack_tracks_get_identity( $user_id );
+					}
+				}
+			} else {
+				$tracking = new Automattic\Jetpack\Tracking();
+				return $tracking->tracks_get_identity( $user_id );
+			}
+		}
+
+		// Start with a previously set cookie.
+		$anon_id = isset( $_COOKIE['tk_ai'] ) ? sanitize_text_field( wp_unslash( $_COOKIE['tk_ai'] ) ) : false;
+
+		// If there is no cookie, apply a saved id.
+		if ( ! $anon_id ) {
+			$anon_id = get_user_meta( $user_id, '_woocommerce_tracks_anon_id', true );
+		}
+
+		// If an id is still not found, create one and save it.
+		if ( ! $anon_id ) {
+			$anon_id = self::get_anon_id();
+
+			update_user_meta( $user_id, '_woocommerce_tracks_anon_id', $anon_id );
+		}
+
+		return array(
+			'_ut' => 'anon',
+			'_ui' => $anon_id,
+		);
+	}
+
+	/**
+	 * Grabs the user's anon id from cookies, or generates and sets a new one
+	 *
+	 * @return string An anon id for the user
+	 */
+	public static function get_anon_id() {
+		static $anon_id = null;
+
+		if ( ! isset( $anon_id ) ) {
+
+			// Did the browser send us a cookie?
+			if ( isset( $_COOKIE['tk_ai'] ) ) {
+				$anon_id = sanitize_text_field( wp_unslash( $_COOKIE['tk_ai'] ) );
+			} else {
+
+				$binary = '';
+
+				// Generate a new anonId and try to save it in the browser's cookies.
+				// Note that base64-encoding an 18 character string generates a 24-character anon id.
+				for ( $i = 0; $i < 18; ++$i ) {
+					$binary .= chr( wp_rand( 0, 255 ) );
+				}
+
+				// phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode
+				$anon_id = 'woo:' . base64_encode( $binary );
+			}
+		}
+
+		return $anon_id;
+	}
+}
+
+WC_Tracks_Client::init();