feat: Only load bandits when new models are needed

src/Config/Configuration.php

@@ -4,15 +4,13 @@
 
 use Eppo\DTO\Bandit\Bandit;
 use Eppo\DTO\BanditParametersResponse;
-use Eppo\DTO\BanditReference;
 use Eppo\DTO\ConfigurationWire\ConfigResponse;
 use Eppo\DTO\ConfigurationWire\ConfigurationWire;
 use Eppo\DTO\Flag;
 use Eppo\DTO\FlagConfigResponse;
 
 class Configuration
 {
-    private array $parsedFlags = [];
     private readonly FlagConfigResponse $flags;
     private readonly BanditParametersResponse $bandits;
 
@@ -23,8 +21,8 @@ private function __construct(
     ) {
         $flagJson = json_decode($this->flagsConfig->response, true);
         $banditsJson = json_decode($this->banditsConfig?->response ?? "", true);
-        $this->flags = FlagConfigResponse::fromJson($flagJson ?? []);
-        $this->bandits = BanditParametersResponse::fromJson($banditsJson ?? []);
+        $this->flags = FlagConfigResponse::fromArray($flagJson ?? []);
+        $this->bandits = BanditParametersResponse::fromArray($banditsJson ?? []);
     }
 
     public static function fromUfcResponses(ConfigResponse $flagsConfig, ?ConfigResponse $banditsConfig): Configuration
@@ -39,10 +37,9 @@ public static function fromConfigurationWire(ConfigurationWire $configurationWir
 
     public static function fromFlags(array $flags, ?array $bandits = null)
     {
-        $fcr = FlagConfigResponse::fromJson(["flags" => $flags]);
-        $flagsConfig = new ConfigResponse(response: json_encode($fcr));
+        $flagsConfig = new ConfigResponse(response: json_encode(["flags" => $flags]));
         $banditsConfig = $bandits ? new ConfigResponse(
-            response: json_encode(BanditParametersResponse::fromJson(["bandits" => $bandits]))
+            response: json_encode(BanditParametersResponse::fromArray(["bandits" => $bandits]))
         ) : null;
         return new self($flagsConfig, $banditsConfig);
     }
@@ -54,27 +51,20 @@ public static function emptyConfig(): self
 
     public function getFlag(string $key): ?Flag
     {
-        if (!isset($this->parsedFlags[$key])) {
-            $flagObj = $this->flags->flags[$key] ?? null;
-            if ($flagObj !== null) {
-                $this->parsedFlags[$key] = Flag::fromJson($flagObj);
-            }
-        }
-        return $this->parsedFlags[$key] ?? null;
+        return $this->flags->flags[$key] ?? null;
     }
 
     public function getBandit(string $banditKey): ?Bandit
     {
         if (!isset($this->bandits->bandits[$banditKey])) {
             return null;
         }
-        return Bandit::fromJson($this->bandits?->bandits[$banditKey]) ?? null;
+        return Bandit::fromArray($this->bandits?->bandits[$banditKey]) ?? null;
     }
 
     public function getBanditByVariation(string $flagKey, string $variation): ?string
     {
-        foreach ($this->flags->banditReferences as $banditKey => $banditReferenceObj) {
-            $banditReference = BanditReference::fromJson($banditReferenceObj);
+        foreach ($this->flags->banditReferences as $banditKey => $banditReference) {
             foreach ($banditReference->flagVariations as $flagVariation) {
                 if ($flagVariation->flagKey === $flagKey && $flagVariation->variationKey === $variation) {
                     return $banditKey;
@@ -101,4 +91,14 @@ public function getFlagETag(): ?string
     {
         return $this->flagsConfig?->eTag ?? null;
     }
+
+    public function getBanditModels(): array
+    {
+        $models = [];
+        foreach ($this->bandits->bandits as $key => $banditArr) {
+            $bandit = Bandit::fromArray($banditArr);
+            $models[$key] = $bandit->modelVersion;
+        }
+        return $models;
+    }
 }

src/Config/ConfigurationLoader.php

@@ -35,6 +35,7 @@ public function reloadConfigurationIfExpired(): void
      */
     public function fetchAndStoreConfiguration(?string $flagETag): void
     {
+        $currentConfig = $this->configurationStore->getConfiguration();
         $response = $this->apiRequestWrapper->getUFC($flagETag);
         if ($response->isModified) {
             $configResponse = new ConfigResponse(
@@ -48,12 +49,34 @@ public function fetchAndStoreConfiguration(?string $flagETag): void
                 syslog(LOG_WARNING, "[Eppo SDK] Empty or invalid response from the configuration server.");
                 return;
             }
-            $fcr = FlagConfigResponse::fromJson($responseData);
+            $fcr = FlagConfigResponse::fromArray($responseData);
             $banditResponse = null;
-            // TODO: Also check current bandit models loaded for optimized bandit loading.
             if (count($fcr->banditReferences) > 0) {
-                $bandits = $this->apiRequestWrapper->getBandits();
-                $banditResponse = new ConfigResponse($bandits->body, date('c'), $bandits->eTag);
+                $canReuseBandits = true;
+                $currentBandits = $currentConfig->getBanditModels();
+
+                foreach ($fcr->banditReferences as $banditKey => $banditReference) {
+                    if (
+                        !array_key_exists(
+                            $banditKey,
+                            $currentBandits
+                        ) || $banditReference->modelVersion !== $currentBandits[$banditKey]
+                    ) {
+                        $canReuseBandits = false;
+                        break;
+                    }
+                }
+
+                if ($canReuseBandits) {
+                    $banditResponse = $currentConfig->toConfigurationWire()->bandits;
+                } else {
+                    $banditResource = $this->apiRequestWrapper->getBandits();
+                    if (!$banditResource?->body) {
+                        syslog(E_ERROR, "[Eppo SDK] Empty or invalid bandit response from the configuration server.");
+                    } else {
+                        $banditResponse = new ConfigResponse($banditResource->body, date('c'), $banditResource->eTag);
+                    }
+                }
             }
 
             $configuration = Configuration::fromUfcResponses($configResponse, $banditResponse);

src/DTO/Bandit/ActionCoefficients.php

@@ -47,29 +47,29 @@ public function __construct(
      * @return array
      * @throws InvalidArgumentException
      */
-    public static function arrayFromJson(array $coefficients): array
+    public static function parseArray(array $coefficients): array
     {
         $res = [];
         foreach ($coefficients as $key => $coefficient) {
-            $res[$key] = ActionCoefficients::fromJson($coefficient);
+            $res[$key] = ActionCoefficients::fromArray($coefficient);
         }
         return $res;
     }
 
     /**
-     * @param array $json
+     * @param array $arr
      * @return ActionCoefficients
      * @throws InvalidArgumentException
      */
-    public static function fromJson(array $json): ActionCoefficients
+    public static function fromArray(array $arr): ActionCoefficients
     {
         return new ActionCoefficients(
-            $json['actionKey'],
-            $json['intercept'],
-            NumericAttributeCoefficient::arrayFromJson($json['subjectNumericCoefficients']),
-            CategoricalAttributeCoefficient::arrayFromJson($json['subjectCategoricalCoefficients']),
-            NumericAttributeCoefficient::arrayFromJson($json['actionNumericCoefficients']),
-            CategoricalAttributeCoefficient::arrayFromJson($json['actionCategoricalCoefficients'])
+            $arr['actionKey'],
+            $arr['intercept'],
+            NumericAttributeCoefficient::parseArray($arr['subjectNumericCoefficients']),
+            CategoricalAttributeCoefficient::parseArray($arr['subjectCategoricalCoefficients']),
+            NumericAttributeCoefficient::parseArray($arr['actionNumericCoefficients']),
+            CategoricalAttributeCoefficient::parseArray($arr['actionCategoricalCoefficients'])
         );
     }
 }

src/DTO/Bandit/Bandit.php

@@ -16,32 +16,32 @@ public function __construct(
     }
 
     /**
-     * @param array $json
+     * @param array $arr
      * @return Bandit
      */
-    public static function fromJson(array $json): Bandit
+    public static function fromArray(array $arr): Bandit
     {
         try {
-            if (!isset($json['updatedAt'])) {
+            if (!isset($arr['updatedAt'])) {
                 $updatedAt = new DateTime();
-            } elseif (is_array($json['updatedAt'])) {// serialized datetime
-                $updatedAt = new DateTime($json['updatedAt']['date']);
+            } elseif (is_array($arr['updatedAt'])) {// serialized datetime
+                $updatedAt = new DateTime($arr['updatedAt']['date']);
             } else {
-                $updatedAt = new DateTime($json['updatedAt']);
+                $updatedAt = new DateTime($arr['updatedAt']);
             }
         } catch (\Exception $e) {
             syslog(
                 LOG_WARNING,
-                "[Eppo SDK] invalid timestamp for bandit model ${json['updatedAt']}: " . $e->getMessage()
+                "[Eppo SDK] invalid timestamp for bandit model ${arr['updatedAt']}: " . $e->getMessage()
             );
             $updatedAt = new DateTime();
         } finally {
             return new Bandit(
-                $json['banditKey'],
-                $json['modelName'],
+                $arr['banditKey'],
+                $arr['modelName'],
                 $updatedAt,
-                $json['modelVersion'],
-                BanditModelData::fromJson($json['modelData'])
+                $arr['modelVersion'],
+                BanditModelData::fromArray($arr['modelData'])
             );
         }
     }

src/DTO/Bandit/BanditModelData.php

@@ -18,13 +18,13 @@ public function __construct(
     ) {
     }
 
-    public static function fromJson($json): BanditModelData
+    public static function fromArray($arr): BanditModelData
     {
         return new BanditModelData(
-            $json['gamma'],
-            ActionCoefficients::arrayFromJson($json['coefficients']),
-            $json['defaultActionScore'],
-            $json['actionProbabilityFloor']
+            $arr['gamma'],
+            ActionCoefficients::parseArray($arr['coefficients']),
+            $arr['defaultActionScore'],
+            $arr['actionProbabilityFloor']
         );
     }
 }

src/DTO/Bandit/BanditResult.php

@@ -26,8 +26,8 @@ public function __toString(): string
         return $this->action ?? $this->variation;
     }
 
-    public static function fromJson($json): self
+    public static function fromArray($arr): self
     {
-        return new self($json['Variation'], $json['Action'] ?? null);
+        return new self($arr['Variation'], $arr['Action'] ?? null);
     }
 }

src/DTO/Bandit/CategoricalAttributeCoefficient.php

@@ -17,20 +17,20 @@ public function __construct(
     }
 
     /**
-     * @param array $json
+     * @param array $arr
      * @return CategoricalAttributeCoefficient
      */
-    public static function fromJson(array $json): CategoricalAttributeCoefficient
+    public static function fromArray(array $arr): CategoricalAttributeCoefficient
     {
-        return new self($json['attributeKey'], $json['missingValueCoefficient'], $json['valueCoefficients']);
+        return new self($arr['attributeKey'], $arr['missingValueCoefficient'], $arr['valueCoefficients']);
     }
 
     /**
      * @param array $categoricalCoefficients
      * @return CategoricalAttributeCoefficient[]
      */
-    public static function arrayFromJson(array $categoricalCoefficients): array
+    public static function parseArray(array $categoricalCoefficients): array
     {
-        return array_map(fn($item) => self::fromJson($item), $categoricalCoefficients);
+        return array_map(fn($item) => self::fromArray($item), $categoricalCoefficients);
     }
 }

src/DTO/Bandit/NumericAttributeCoefficient.php

@@ -12,20 +12,20 @@ public function __construct(
     }
 
     /**
-     * @param array $json
+     * @param array $arr
      * @return NumericAttributeCoefficient
      */
-    public static function fromJson(array $json): NumericAttributeCoefficient
+    public static function fromArray(array $arr): NumericAttributeCoefficient
     {
-        return new self($json['attributeKey'], $json['coefficient'], $json['missingValueCoefficient']);
+        return new self($arr['attributeKey'], $arr['coefficient'], $arr['missingValueCoefficient']);
     }
 
     /**
      * @param array $numericCoefficients
      * @return NumericAttributeCoefficient[]
      */
-    public static function arrayFromJson(array $numericCoefficients): array
+    public static function parseArray(array $numericCoefficients): array
     {
-        return array_map(fn($item) => self::fromJson($item), $numericCoefficients);
+        return array_map(fn($item) => self::fromArray($item), $numericCoefficients);
     }
 }

src/DTO/BanditFlagVariation.php

@@ -13,14 +13,14 @@ public function __construct(
     ) {
     }
 
-    public static function fromJson($json): BanditFlagVariation
+    public static function fromArray($arr): BanditFlagVariation
     {
         return new self(
-            $json['key'],
-            $json['flagKey'],
-            $json['allocationKey'],
-            $json['variationKey'],
-            $json['variationValue']
+            $arr['key'],
+            $arr['flagKey'],
+            $arr['allocationKey'],
+            $arr['variationKey'],
+            $arr['variationValue']
         );
     }
 

src/DTO/BanditParametersResponse.php

@@ -2,12 +2,12 @@
 
 namespace Eppo\DTO;
 
-use Eppo\Traits\StaticFromJson;
+use Eppo\Traits\StaticFromArray;
 use Eppo\Traits\ToArray;
 
 class BanditParametersResponse
 {
-    use StaticFromJson;
+    use StaticFromArray;
     use ToArray;
 
     public array $bandits;

src/DTO/BanditReference.php

@@ -14,17 +14,17 @@ public function __construct(
     ) {
     }
 
-    public static function fromJson(mixed $json): BanditReference
+    public static function fromArray(mixed $arr): BanditReference
     {
         $flagVariations = [];
-        if (isset($json['flagVariations']) && is_array($json['flagVariations'])) {
-            foreach ($json['flagVariations'] as $variation) {
-                $flagVariations[] = BanditFlagVariation::fromJson($variation);
+        if (isset($arr['flagVariations']) && is_array($arr['flagVariations'])) {
+            foreach ($arr['flagVariations'] as $variation) {
+                $flagVariations[] = BanditFlagVariation::fromArray($variation);
             }
         }
 
         return new BanditReference(
-            modelVersion: $json['modelVersion'],
+            modelVersion: $arr['modelVersion'],
             flagVariations: $flagVariations
         );
     }

src/DTO/ConfigurationWire/ConfigResponse.php

@@ -2,13 +2,13 @@
 
 namespace Eppo\DTO\ConfigurationWire;
 
-use Eppo\Traits\StaticFromJson;
+use Eppo\Traits\StaticFromArray;
 use Eppo\Traits\ToArray;
 
 class ConfigResponse
 {
     use ToArray;
-    use StaticFromJson;
+    use StaticFromArray;
 
     public function __construct(
         public string $response = "",

src/DTO/ConfigurationWire/ConfigurationWire.php

@@ -30,10 +30,10 @@ public static function fromArray(array $arr): self
         $dto = new self();
         $dto->version = $arr['version'] ?? 1;
         if (isset($arr['config'])) {
-            $dto->config = ConfigResponse::fromJson($arr['config']);
+            $dto->config = ConfigResponse::fromArray($arr['config']);
         }
         if (isset($arr['bandits'])) {
-            $dto->bandits = ConfigResponse::fromJson($arr['bandits']);
+            $dto->bandits = ConfigResponse::fromArray($arr['bandits']);
         }
         return $dto;
     }
@@ -46,9 +46,9 @@ public static function fromResponses(ConfigResponse $flags, ?ConfigResponse $ban
         return $dto;
     }
 
-    public static function fromJsonString(string $jsonEncodedString): self
+    public static function fromJson(string $jsonEncodedObject): self
     {
-        return ConfigurationWire::fromArray(json_decode($jsonEncodedString, associative: true));
+        return ConfigurationWire::fromArray(json_decode($jsonEncodedObject, associative: true));
     }
 
     public function toJsonString(): string