Rename to resolveUserIdUsing, extract getAnonymousId, pass driver to resolver

Author: jszobody

README.md

@@ -286,14 +286,18 @@ This is used by the PostHog driver as the `distinctId`, and is available to any
 
 ### Custom user ID resolver
 
-You can override the default resolution by providing your own closure:
+You can override the default resolution by providing your own closure. The driver instance is passed to your closure, so you can fall back to the built-in anonymous ID if needed:
 
 ```php
-Metrics::resolveUserIdWith(fn() => auth()->id());
+Metrics::resolveUserIdUsing(function($driver) {
+    return auth()->check()
+        ? 'custom-prefix:' . auth()->id()
+        : $driver->getAnonymousId();
+});
 ```
 
 This will apply to all drivers. You can also set it on a specific driver:
 
 ```php
-Metrics::driver('posthog')->resolveUserIdWith(fn() => $team->id);
+Metrics::driver('posthog')->resolveUserIdUsing(fn() => $team->id);
 ```

src/Drivers/AbstractDriver.php

@@ -66,7 +66,7 @@ public function setExtra(array|\Closure $extra): static
 
     protected ?\Closure $userIdResolver = null;
 
-    public function resolveUserIdWith(\Closure $resolver): static
+    public function resolveUserIdUsing(\Closure $resolver): static
     {
         $this->userIdResolver = $resolver;
 
@@ -76,18 +76,23 @@ public function resolveUserIdWith(\Closure $resolver): static
     public function getUserId(): mixed
     {
         if ($this->userIdResolver) {
-            return call_user_func($this->userIdResolver);
+            return call_user_func($this->userIdResolver, $this);
         }
 
-        static $anonymousId = null;
-
         return match(true) {
             auth()->check() => auth()->id(),
             session()->isStarted() => sha1(session()->getId()),
-            default => $anonymousId ??= Str::random()
+            default => $this->getAnonymousId()
         };
     }
 
+    public function getAnonymousId(): string
+    {
+        static $anonymousId = null;
+
+        return $anonymousId ??= Str::random();
+    }
+
     /**
      * Implement this, when the driver needs to expose metrics to be polled by a third party service such as prometheus
      */

src/Drivers/PostHog.php

@@ -53,7 +53,7 @@ public function format(Metric $metric): array
     public function getUserId(): mixed
     {
         if ($this->userIdResolver) {
-            return call_user_func($this->userIdResolver);
+            return call_user_func($this->userIdResolver, $this);
         }
 
         return $this->distinctPrefix . parent::getUserId();

src/MetricsManager.php

@@ -20,7 +20,7 @@ class MetricsManager extends Manager
 
     protected ?\Closure $userIdResolver = null;
 
-    public function resolveUserIdWith(\Closure $resolver): static
+    public function resolveUserIdUsing(\Closure $resolver): static
     {
         $this->userIdResolver = $resolver;
 
@@ -46,7 +46,7 @@ protected function createDriver($driver)
         $driver = parent::createDriver($driver);
 
         if($this->userIdResolver) {
-            $driver->resolveUserIdWith($this->userIdResolver);
+            $driver->resolveUserIdUsing($this->userIdResolver);
         }
 
         if($this->driverCreatedCallback) {

tests/PostHogDriverTest.php

@@ -53,7 +53,7 @@ public function testUserIdResolvedLazily()
 
         $callCount = 0;
         $driver = app(PostHog::class);
-        $driver->resolveUserIdWith(function () use (&$callCount) {
+        $driver->resolveUserIdUsing(function () use (&$callCount) {
             $callCount++;
             return 'user_' . $callCount;
         });
@@ -73,7 +73,7 @@ public function testCustomUserIdResolver()
         $this->setupPostHog();
 
         $driver = app(PostHog::class);
-        $driver->resolveUserIdWith(fn() => 'custom-user-42');
+        $driver->resolveUserIdUsing(fn() => 'custom-user-42');
 
         $metric = new \STS\Metrics\Metric("file_uploaded");
         $formatted = $driver->format($metric);
@@ -102,10 +102,23 @@ public function testDistinctPrefixAppliesWithDefaultResolver()
         $this->assertStringStartsWith('user:', $formatted['distinctId']);
     }
 
+    public function testCustomResolverReceivesDriverAndCanFallBack()
+    {
+        $driver = new PostHog();
+        $driver->resolveUserIdUsing(fn($driver) => $driver->getAnonymousId());
+
+        $metric = new \STS\Metrics\Metric("test");
+        $formatted1 = $driver->format($metric);
+        $formatted2 = $driver->format($metric);
+
+        $this->assertNotEmpty($formatted1['distinctId']);
+        $this->assertEquals($formatted1['distinctId'], $formatted2['distinctId']);
+    }
+
     public function testDistinctPrefixSkippedWithCustomResolver()
     {
         $driver = new PostHog('user:');
-        $driver->resolveUserIdWith(fn() => '42');
+        $driver->resolveUserIdUsing(fn() => '42');
 
         $metric = new \STS\Metrics\Metric("test");
         $formatted = $driver->format($metric);