feat: Add getFeatureFlagResult method to client (#103)

Author: dustinbyrne

lib/Client.php

@@ -254,13 +254,52 @@ public function getFeatureFlag(
         bool $onlyEvaluateLocally = false,
         bool $sendFeatureFlagEvents = true
     ): null | bool | string {
+        $result = $this->getFeatureFlagResult(
+            $key,
+            $distinctId,
+            $groups,
+            $personProperties,
+            $groupProperties,
+            $onlyEvaluateLocally,
+            $sendFeatureFlagEvents
+        );
+
+        return $result?->getValue();
+    }
+
+    /**
+     * Get the feature flag result including value and payload.
+     *
+     * This is the recommended method for getting feature flag data as it returns
+     * both the flag value and payload in a single call, while properly tracking analytics.
+     *
+     * @param string $key
+     * @param string $distinctId
+     * @param array $groups
+     * @param array $personProperties
+     * @param array $groupProperties
+     * @param bool $onlyEvaluateLocally
+     * @param bool $sendFeatureFlagEvents
+     * @return FeatureFlagResult|null
+     * @throws Exception
+     */
+    public function getFeatureFlagResult(
+        string $key,
+        string $distinctId,
+        array $groups = array(),
+        array $personProperties = array(),
+        array $groupProperties = array(),
+        bool $onlyEvaluateLocally = false,
+        bool $sendFeatureFlagEvents = true
+    ): ?FeatureFlagResult {
         [$personProperties, $groupProperties] = $this->addLocalPersonAndGroupProperties(
             $distinctId,
             $groups,
             $personProperties,
             $groupProperties
         );
         $result = null;
+        $payload = null;
         $featureFlagError = null;
 
         foreach ($this->featureFlags as $flag) {
@@ -309,6 +348,12 @@ public function getFeatureFlag(
                     $result = null;
                 }
 
+                // Extract payload from response
+                $rawPayload = $response['featureFlagPayloads'][$key] ?? null;
+                if ($rawPayload !== null) {
+                    $payload = json_decode($rawPayload, true);
+                }
+
                 if (!empty($errors)) {
                     $featureFlagError = implode(',', $errors);
                 }
@@ -371,13 +416,22 @@ public function getFeatureFlag(
             $this->distinctIdsFeatureFlagsReported->add($key, $distinctId);
         }
 
-        if (!is_null($result)) {
-            return $result;
+        if (is_null($result)) {
+            return null;
+        }
+
+        // Determine enabled and variant from result
+        if (is_bool($result)) {
+            return new FeatureFlagResult($key, $result, null, $payload);
+        } else {
+            return new FeatureFlagResult($key, true, $result, $payload);
         }
-        return null;
     }
 
     /**
+     * @deprecated Use `getFeatureFlagResult()` instead which properly tracks the feature flag call,
+     * and includes both the flag value and payload in a single method.
+     *
      * @param string $key
      * @param string $distinctId
      * @param array $groups
@@ -392,20 +446,17 @@ public function getFeatureFlagPayload(
         array $personProperties = array(),
         array $groupProperties = array(),
     ): mixed {
-        $results = $this->flags($distinctId, $groups, $personProperties, $groupProperties);
-
-        if (isset($results['featureFlags'][$key]) === false || $results['featureFlags'][$key] !== true) {
-            return null;
-        }
-
-        $payload = $results['featureFlagPayloads'][$key] ?? null;
-
-        if ($payload === null) {
-            return null;
-        }
+        $result = $this->getFeatureFlagResult(
+            $key,
+            $distinctId,
+            $groups,
+            $personProperties,
+            $groupProperties,
+            false,
+            false
+        );
 
-        # feature flag payloads are always JSON encoded strings.
-        return json_decode($payload, true);
+        return $result?->getPayload();
     }
 
     /**

lib/FeatureFlagResult.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace PostHog;
+
+/**
+ * Represents the result of a feature flag evaluation, including both the value and payload.
+ */
+class FeatureFlagResult
+{
+    private string $key;
+    private bool $enabled;
+    private ?string $variant;
+    private mixed $payload;
+
+    public function __construct(
+        string $key,
+        bool $enabled,
+        ?string $variant = null,
+        mixed $payload = null
+    ) {
+        $this->key = $key;
+        $this->enabled = $enabled;
+        $this->variant = $variant;
+        $this->payload = $payload;
+    }
+
+    /**
+     * Get the feature flag key.
+     */
+    public function getKey(): string
+    {
+        return $this->key;
+    }
+
+    /**
+     * Whether the flag is enabled.
+     */
+    public function isEnabled(): bool
+    {
+        return $this->enabled;
+    }
+
+    /**
+     * Get the variant value if this is a multivariate flag.
+     */
+    public function getVariant(): ?string
+    {
+        return $this->variant;
+    }
+
+    /**
+     * Get the decoded JSON payload associated with this flag.
+     */
+    public function getPayload(): mixed
+    {
+        return $this->payload;
+    }
+
+    /**
+     * Get the flag value in the same format as getFeatureFlag().
+     * Returns the variant if set, otherwise the enabled boolean.
+     * This matches the $feature_flag_response format.
+     */
+    public function getValue(): bool|string
+    {
+        if ($this->variant !== null) {
+            return $this->variant;
+        }
+        return $this->enabled;
+    }
+}

lib/PostHog.php

@@ -171,6 +171,46 @@ public static function getFeatureFlag(
     }
 
     /**
+     * Get the feature flag result including value and payload.
+     *
+     * This is the recommended method for getting feature flag data as it returns
+     * both the flag value and payload in a single call, while properly tracking analytics.
+     *
+     * @param string $key
+     * @param string $distinctId
+     * @param array $groups
+     * @param array $personProperties
+     * @param array $groupProperties
+     * @param bool $onlyEvaluateLocally
+     * @param bool $sendFeatureFlagEvents
+     * @return FeatureFlagResult|null
+     * @throws Exception
+     */
+    public static function getFeatureFlagResult(
+        string $key,
+        string $distinctId,
+        array $groups = array(),
+        array $personProperties = array(),
+        array $groupProperties = array(),
+        bool $onlyEvaluateLocally = false,
+        bool $sendFeatureFlagEvents = true
+    ): ?FeatureFlagResult {
+        self::checkClient();
+        return self::$client->getFeatureFlagResult(
+            $key,
+            $distinctId,
+            $groups,
+            $personProperties,
+            $groupProperties,
+            $onlyEvaluateLocally,
+            $sendFeatureFlagEvents
+        );
+    }
+
+    /**
+     * @deprecated Use getFeatureFlagResult() instead. This method does not send
+     * the $feature_flag_called event, leading to missing analytics.
+     *
      * @param string $key
      * @param string $distinctId
      * @param array $groups