woocommerce/plugins/woocommerce-admin/includes/class-experimental-abtest.php

177 lines
4.9 KiB
PHP

<?php
/**
* NOTE: this is a temporary class and can be replaced by jetpack-abtest after
* https://github.com/Automattic/jetpack/issues/19596 has been fixed.
*
* A class that interacts with Explat A/B tests.
*
* This class is experimental. It is a fork of the jetpack-abtest package and
* updated for use with ExPlat. These changes are planned to be contributed
* back to the upstream Jetpack package. If accepted, this class should then
* be superseded by the Jetpack class using Composer.
*
* This class should not be used externally.
*
* @package WooCommerce\Admin
* @link https://packagist.org/packages/automattic/jetpack-abtest
*/
namespace WooCommerce\Admin;
/**
* This class provides an interface to the Explat A/B tests.
*
* @internal This class is experimental and should not be used externally due to planned breaking changes.
*/
final class Experimental_Abtest {
/**
* A variable to hold the tests we fetched, and their variations for the current user.
*
* @var array
*/
private $tests = array();
/**
* ExPlat Anonymous ID.
*
* @var string
*/
private $anon_id = null;
/**
* ExPlat Platform name.
*
* @var string
*/
private $platform = 'woocommerce';
/**
* Whether trcking consent is given.
*
* @var bool
*/
private $consent = false;
/**
* Constructor.
*
* @param string $anon_id ExPlat anonymous ID.
* @param string $platform ExPlat platform name.
* @param bool $consent Whether tracking consent is given.
*/
public function __construct( string $anon_id, string $platform, bool $consent ) {
$this->anon_id = $anon_id;
$this->platform = $platform;
$this->consent = $consent;
}
/**
* Retrieve the test variation for a provided A/B test.
*
* @param string $test_name Name of the A/B test.
* @return mixed|null A/B test variation, or null on failure.
*/
public function get_variation( $test_name ) {
// Default to the control variation when users haven't consented to tracking.
if ( ! $this->consent ) {
return 'control';
}
$variation = $this->fetch_variation( $test_name );
// If there was an error retrieving a variation, conceal the error for the consumer.
if ( is_wp_error( $variation ) ) {
return 'control';
}
return $variation;
}
/**
* Fetch and cache the test variation for a provided A/B test from WP.com.
*
* ExPlat returns a null value when the assigned variation is control or
* an assignment has not been set. In these instances, this method returns
* a value of "control".
*
* @param string $test_name Name of the A/B test.
* @return array|\WP_Error A/B test variation, or error on failure.
*/
protected function fetch_variation( $test_name ) {
// Make sure test name exists.
if ( ! $test_name ) {
return new \WP_Error( 'test_name_not_provided', 'A/B test name has not been provided.' );
}
// Make sure test name is a valid one.
if ( ! preg_match( '/^[A-Za-z0-9_]+$/', $test_name ) ) {
return new \WP_Error( 'invalid_test_name', 'Invalid A/B test name.' );
}
// Return internal-cached test variations.
if ( isset( $this->tests[ $test_name ] ) ) {
return $this->tests[ $test_name ];
}
// Return external-cached test variations.
if ( ! empty( get_transient( 'abtest_variation_' . $test_name ) ) ) {
return get_transient( 'abtest_variation_' . $test_name );
}
// Make the request to the WP.com API.
$response = $this->request_variation( $test_name );
// Bail if there was an error or malformed response.
if ( is_wp_error( $response ) || ! is_array( $response ) || ! isset( $response['body'] ) ) {
return new \WP_Error( 'failed_to_fetch_data', 'Unable to fetch the requested data.' );
}
// Decode the results.
$results = json_decode( $response['body'], true );
// Bail if there were no results or there is no test variation returned.
if ( ! is_array( $results ) || empty( $results['variations'] ) ) {
return new \WP_Error( 'unexpected_data_format', 'Data was not returned in the expected format.' );
}
// Store the variation in our internal cache.
$this->tests[ $test_name ] = $results['variations'][ $test_name ];
$variation = $results['variations'][ $test_name ] ?? 'control';
// Store the variation in our external cache.
if ( ! empty( $results['ttl'] ) ) {
set_transient( 'abtest_variation_' . $test_name, $variation, $results['ttl'] );
}
return $variation;
}
/**
* Perform the request for a variation of a provided A/B test from WP.com.
*
* @param string $test_name Name of the A/B test.
* @return array|\WP_Error A/B test variation error on failure.
*/
protected function request_variation( $test_name ) {
$args = array(
'experiment_name' => $test_name,
'anon_id' => $this->anon_id,
);
$url = add_query_arg(
$args,
sprintf(
'https://public-api.wordpress.com/wpcom/v2/experiments/0.1.0/assignments/%s',
$this->platform
)
);
$get = wp_remote_get( $url );
return $get;
}
}