fix: send tracking events to /track with the JS/Go wire contract

lib/src/main/java/growthbook/sdk/java/evaluators/ExperimentEvaluator.java

@@ -439,7 +439,8 @@ private <ValueType> void dispatchExperimentViewed(
         }
         PluginRegistry pluginRegistry = context.getPluginRegistry();
         if (pluginRegistry != null) {
-            pluginRegistry.fireExperimentViewed(experiment, result);
+            pluginRegistry.fireExperimentViewed(experiment, result,
+                    context.getUser() != null ? context.getUser().getAttributes() : null);
         }
     }
 

lib/src/main/java/growthbook/sdk/java/evaluators/FeatureEvaluator.java

@@ -412,7 +412,8 @@ private <T> void dispatchFeatureUsage(EvaluationContext context, String key, Fea
         }
         PluginRegistry registry = context.getPluginRegistry();
         if (registry != null) {
-            registry.fireFeatureEvaluated(key, result);
+            registry.fireFeatureEvaluated(key, result,
+                    context.getUser() != null ? context.getUser().getAttributes() : null);
         }
     }
 

lib/src/main/java/growthbook/sdk/java/plugin/GrowthBookPlugin.java

@@ -1,9 +1,12 @@
 package growthbook.sdk.java.plugin;
 
+import com.google.gson.JsonObject;
 import growthbook.sdk.java.model.Experiment;
 import growthbook.sdk.java.model.ExperimentResult;
 import growthbook.sdk.java.model.FeatureResult;
 
+import javax.annotation.Nullable;
+
 /**
  * A plugin that can observe experiment and feature evaluations on a GrowthBook
  * instance. Mirrors the plugin contracts in the GrowthBook Python and Go SDKs.
@@ -31,12 +34,38 @@ default void init() {
     default <V> void onExperimentViewed(Experiment<V> experiment, ExperimentResult<V> result) {
     }
 
+    /**
+     * Invoked after a user is bucketed into an experiment, with the user's attributes at evaluation
+     * time. The default delegates to {@link #onExperimentViewed(Experiment, ExperimentResult)} so
+     * existing plugins keep working; override this overload to receive the attributes.
+     *
+     * @param userAttributes the evaluated user's attributes, or {@code null} when unavailable
+     */
+    default <V> void onExperimentViewed(Experiment<V> experiment,
+                                        ExperimentResult<V> result,
+                                        @Nullable JsonObject userAttributes) {
+        onExperimentViewed(experiment, result);
+    }
+
     /**
      * Invoked every time a feature is evaluated.
      */
     default <V> void onFeatureEvaluated(String featureKey, FeatureResult<V> result) {
     }
 
+    /**
+     * Invoked on every feature evaluation, with the user's attributes at evaluation time. The default
+     * delegates to {@link #onFeatureEvaluated(String, FeatureResult)} so existing plugins keep working;
+     * override this overload to receive the attributes.
+     *
+     * @param userAttributes the evaluated user's attributes, or {@code null} when unavailable
+     */
+    default <V> void onFeatureEvaluated(String featureKey,
+                                        FeatureResult<V> result,
+                                        @Nullable JsonObject userAttributes) {
+        onFeatureEvaluated(featureKey, result);
+    }
+
     /**
      * Invoked when the owning GrowthBook instance is closed. Implementations
      * should flush any buffered work synchronously. MUST be safe to call

lib/src/main/java/growthbook/sdk/java/plugin/PluginRegistry.java

@@ -1,5 +1,6 @@
 package growthbook.sdk.java.plugin;
 
+import com.google.gson.JsonObject;
 import growthbook.sdk.java.model.Experiment;
 import growthbook.sdk.java.model.ExperimentResult;
 import growthbook.sdk.java.model.FeatureResult;
@@ -60,12 +61,18 @@ public void initAll() {
     }
 
     public <V> void fireExperimentViewed(Experiment<V> experiment, ExperimentResult<V> result) {
+        fireExperimentViewed(experiment, result, null);
+    }
+
+    public <V> void fireExperimentViewed(Experiment<V> experiment,
+                                         ExperimentResult<V> result,
+                                         @Nullable JsonObject userAttributes) {
         if (plugins.isEmpty()) {
             return;
         }
         for (GrowthBookPlugin plugin : plugins) {
             try {
-                plugin.onExperimentViewed(experiment, result);
+                plugin.onExperimentViewed(experiment, result, userAttributes);
             } catch (Exception e) {
                 log.warn("Plugin {} onExperimentViewed failed",
                         plugin.getClass().getName(), e);
@@ -74,12 +81,18 @@ public <V> void fireExperimentViewed(Experiment<V> experiment, ExperimentResult<
     }
 
     public <V> void fireFeatureEvaluated(String featureKey, FeatureResult<V> result) {
+        fireFeatureEvaluated(featureKey, result, null);
+    }
+
+    public <V> void fireFeatureEvaluated(String featureKey,
+                                         FeatureResult<V> result,
+                                         @Nullable JsonObject userAttributes) {
         if (plugins.isEmpty()) {
             return;
         }
         for (GrowthBookPlugin plugin : plugins) {
             try {
-                plugin.onFeatureEvaluated(featureKey, result);
+                plugin.onFeatureEvaluated(featureKey, result, userAttributes);
             } catch (Exception e) {
                 log.warn("Plugin {} onFeatureEvaluated failed",
                         plugin.getClass().getName(), e);

lib/src/main/java/growthbook/sdk/java/plugin/tracking/GrowthBookTrackingPlugin.java

@@ -9,6 +9,7 @@
 import growthbook.sdk.java.util.GrowthBookJsonUtils;
 import growthbook.sdk.java.util.StringUtils;
 import lombok.extern.slf4j.Slf4j;
+import okhttp3.HttpUrl;
 import okhttp3.MediaType;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
@@ -36,9 +37,9 @@
 
 /**
  * Batches experiment/feature evaluation events and POSTs them to the
- * GrowthBook data-warehouse ingest endpoint. Wire contract mirrors the Go
- * SDK: {@code POST {ingestorHost}/events} with JSON body
- * {@code {"client_key": ..., "events": [...]}}.
+ * GrowthBook ingest endpoint. Wire contract mirrors the JS and Go SDKs:
+ * {@code POST {ingestorHost}/track?client_key={clientKey}} with a JSON array
+ * of events as the body.
  *
  * <p>Resources (HTTP client, scheduler, flush executor) are created in
  * {@link #init()}, not the constructor, so an unregistered plugin never leaks
@@ -149,18 +150,32 @@ public void init() {
 
     @Override
     public <V> void onExperimentViewed(Experiment<V> experiment, ExperimentResult<V> result) {
+        onExperimentViewed(experiment, result, null);
+    }
+
+    @Override
+    public <V> void onExperimentViewed(Experiment<V> experiment,
+                                       ExperimentResult<V> result,
+                                       @Nullable JsonObject userAttributes) {
         if (!isActive()) {
             return;
         }
-        enqueue(TrackingEvent.forExperiment(experiment, result));
+        enqueue(TrackingEvent.forExperiment(experiment, result, userAttributes));
     }
 
     @Override
     public <V> void onFeatureEvaluated(String featureKey, FeatureResult<V> result) {
+        onFeatureEvaluated(featureKey, result, null);
+    }
+
+    @Override
+    public <V> void onFeatureEvaluated(String featureKey,
+                                       FeatureResult<V> result,
+                                       @Nullable JsonObject userAttributes) {
         if (!isActive()) {
             return;
         }
-        enqueue(TrackingEvent.forFeature(featureKey, result));
+        enqueue(TrackingEvent.forFeature(featureKey, result, userAttributes));
     }
 
     @Override
@@ -320,20 +335,22 @@ private void flushBatch(List<TrackingEvent> batch, @Nullable OkHttpClient client
         if (batch.isEmpty() || client == null) {
             return;
         }
-        String url = config.resolvedIngestorHost() + "/events";
+        HttpUrl base = HttpUrl.parse(config.resolvedIngestorHost() + "/track");
+        if (base == null) {
+            log.warn("Tracking ingest host is not a valid URL: {}", config.resolvedIngestorHost());
+            return;
+        }
+        HttpUrl url = base.newBuilder().addQueryParameter("client_key", config.getClientKey()).build();
         try {
-            JsonObject body = new JsonObject();
-            body.addProperty("client_key", config.getClientKey());
             JsonArray events = new JsonArray();
             for (TrackingEvent event : batch) {
                 events.add(GrowthBookJsonUtils.getInstance().gson.toJsonTree(event));
             }
-            body.add("events", events);
 
             Request request = new Request.Builder()
                     .url(url)
                     .header("User-Agent", SdkMetadata.USER_AGENT)
-                    .post(RequestBody.create(body.toString(), JSON))
+                    .post(RequestBody.create(events.toString(), JSON))
                     .build();
 
             try (Response response = client.newCall(request).execute()) {