Handle empty API keys with no-op client

lib/Client.php

@@ -6,6 +6,7 @@
 use PostHog\Consumer\File;
 use PostHog\Consumer\ForkCurl;
 use PostHog\Consumer\LibCurl;
+use PostHog\Consumer\NoOp;
 use PostHog\Consumer\Socket;
 use Symfony\Component\Clock\Clock;
 
@@ -18,6 +19,7 @@ class Client
         "file" => File::class,
         "fork_curl" => ForkCurl::class,
         "lib_curl" => LibCurl::class,
+        "noop" => NoOp::class,
     ];
 
 
@@ -88,30 +90,37 @@ class Client
      */
     private $options;
 
+    /**
+     * @var bool
+     */
+    private $enabled;
+
     /**
      * Create a new posthog object with your app's API key
      * key
      *
-     * @param string $apiKey
+     * @param string|null $apiKey
      * @param array $options array of consumer options [optional]
      * @param HttpClient|null $httpClient
      */
     public function __construct(
-        string $apiKey,
+        ?string $apiKey = null,
         array $options = [],
         ?HttpClient $httpClient = null,
         ?string $personalAPIKey = null,
         bool $loadFeatureFlags = true,
     ) {
-        $this->apiKey = trim($apiKey);
+        $this->apiKey = trim($apiKey ?? '');
+        $this->enabled = $this->apiKey !== '';
         $this->personalAPIKey = StringNormalizer::normalizeOptional($personalAPIKey);
         $this->options = $options;
         $this->debug = $options["debug"] ?? false;
         $this->options['host'] = StringNormalizer::normalizeHost($options['host'] ?? null);
-        if ($this->apiKey === '') {
+        if (!$this->enabled) {
             error_log('[PostHog][Client] apiKey is empty after trimming whitespace; check your project API key');
+            $this->options['consumer'] = 'noop';
         }
-        $Consumer = self::CONSUMERS[$options["consumer"] ?? "lib_curl"];
+        $Consumer = self::CONSUMERS[$this->options["consumer"] ?? "lib_curl"];
         $this->consumer = new $Consumer($this->apiKey, $this->options, $httpClient);
         $this->httpClient = $httpClient !== null ? $httpClient : new HttpClient(
             $this->options['host'],
@@ -134,7 +143,8 @@ public function __construct(
 
         // Populate featureflags and grouptypemapping if possible
         if (
-            count($this->featureFlags) == 0
+            $this->enabled
+            && count($this->featureFlags) == 0
             && !is_null($this->personalAPIKey)
             && $loadFeatureFlags
         ) {
@@ -718,6 +728,17 @@ public function loadFlags()
 
     public function localFlags(): HttpResponse
     {
+        if (!$this->enabled) {
+            return new HttpResponse(
+                json_encode([
+                    'flags' => [],
+                    'group_type_mapping' => [],
+                    'cohorts' => [],
+                ]),
+                200
+            );
+        }
+
         $headers = [
             // Send user agent in the form of {library_name}/{library_version} as per RFC 7231.
             "User-Agent: posthog-php/" . PostHog::VERSION,
@@ -823,6 +844,14 @@ public function flags(
         array $personProperties = [],
         array $groupProperties = []
     ): array {
+        if (!$this->enabled) {
+            return [
+                'featureFlags' => [],
+                'featureFlagPayloads' => [],
+                'flags' => [],
+            ];
+        }
+
         $payload = array(
             'api_key' => $this->apiKey,
             'distinct_id' => $distinctId,

lib/Consumer/NoOp.php

@@ -0,0 +1,79 @@
+<?php
+
+namespace PostHog\Consumer;
+
+use PostHog\Consumer;
+
+class NoOp extends Consumer
+{
+    protected $type = "NoOp";
+
+    /**
+     * Define getter method for consumer type
+     *
+     * @return string
+     */
+    public function getConsumer()
+    {
+        return $this->type;
+    }
+
+    public function __destruct()
+    {
+        // No queued work to flush.
+    }
+
+    /**
+     * Captures a user action
+     *
+     * @param array $message
+     * @return boolean whether the capture call succeeded
+     */
+    public function capture(array $message)
+    {
+        return true;
+    }
+
+    /**
+     * Tags properties about the user.
+     *
+     * @param array $message
+     * @return boolean whether the identify call succeeded
+     */
+    public function identify(array $message)
+    {
+        return true;
+    }
+
+    /**
+     * Aliases from one user id to another
+     *
+     * @param array $message
+     * @return boolean whether the alias call succeeded
+     */
+    public function alias(array $message)
+    {
+        return true;
+    }
+
+    /**
+     * Queue a raw message.
+     *
+     * @param mixed $item
+     * @return boolean whether call has succeeded
+     */
+    public function enqueue($item)
+    {
+        return true;
+    }
+
+    /**
+     * Flush queued messages.
+     *
+     * @return boolean true if flushed successfully
+     */
+    public function flush()
+    {
+        return true;
+    }
+}

lib/PostHog.php

@@ -26,7 +26,11 @@ public static function init(
         ?string $personalAPIKey = null
     ): void {
         if (null === $client) {
-            $apiKey = $apiKey ?: getenv(self::ENV_API_KEY);
+            $options = $options ?? [];
+            if ($apiKey === null) {
+                $envApiKey = getenv(self::ENV_API_KEY);
+                $apiKey = $envApiKey === false ? null : $envApiKey;
+            }
 
             $rawHost = null;
             if (array_key_exists("host", $options)) {
@@ -50,7 +54,6 @@ public static function init(
                 }
             }
 
-            self::assert($apiKey, "PostHog::init() requires an apiKey");
             self::$client = new Client($apiKey, $options, null, $personalAPIKey);
         } else {
             self::$client = $client;

test/PostHogTest.php

@@ -8,6 +8,7 @@
 use Exception;
 use PHPUnit\Framework\TestCase;
 use PostHog\Client;
+use PostHog\Consumer\NoOp;
 use PostHog\PostHog;
 use PostHog\Test\Assets\MockedResponses;
 
@@ -46,6 +47,14 @@ public function checkEmptyErrorLogs(): void
         $this->assertEmpty($errorMessages);
     }
 
+    private function getConsumer(Client $client): object
+    {
+        $ref = new \ReflectionClass($client);
+        $consumerProp = $ref->getProperty('consumer');
+
+        return $consumerProp->getValue($client);
+    }
+
     public function testInitWithParamApiKey(): void
     {
         $this->expectNotToPerformAssertions();
@@ -204,11 +213,79 @@ public function testInitWithEnvHttpHostSetsSslFalse(): void
         putenv(PostHog::ENV_HOST);
     }
 
-    public function testInitThrowsExceptionWithNoApiKey(): void
+    public function testInitWithoutApiKeyConfiguresNoOpClient(): void
+    {
+        $previousApiKey = getenv(PostHog::ENV_API_KEY);
+        putenv(PostHog::ENV_API_KEY);
+
+        try {
+            PostHog::init();
+            $client = PostHog::getClient();
+
+            $this->assertInstanceOf(NoOp::class, $this->getConsumer($client));
+            $this->assertTrue(PostHog::capture([
+                "distinctId" => "john",
+                "event" => "Module PHP Event",
+            ]));
+        } finally {
+            if ($previousApiKey === false) {
+                putenv(PostHog::ENV_API_KEY);
+            } else {
+                putenv(PostHog::ENV_API_KEY . "=" . $previousApiKey);
+            }
+        }
+    }
+
+    public function testInitWithEmptyApiKeyConfiguresNoOpClient(): void
+    {
+        PostHog::init("", ["debug" => true]);
+        $client = PostHog::getClient();
+
+        $this->assertInstanceOf(NoOp::class, $this->getConsumer($client));
+        $this->assertTrue(PostHog::capture([
+            "distinctId" => "john",
+            "event" => "Module PHP Event",
+        ]));
+    }
+
+    public function testInitWithWhitespaceApiKeyConfiguresNoOpClient(): void
+    {
+        PostHog::init(" \n\t ", ["debug" => true]);
+        $client = PostHog::getClient();
+
+        $this->assertInstanceOf(NoOp::class, $this->getConsumer($client));
+        $this->assertTrue(PostHog::capture([
+            "distinctId" => "john",
+            "event" => "Module PHP Event",
+        ]));
+    }
+
+    public function testClientWithNullApiKeyDoesNotSendRequests(): void
     {
-        $this->expectException(Exception::class);
-        $this->expectExceptionMessage("PostHog::init() requires an apiKey");
-        PostHog::init(null);
+        $httpClient = new MockedHttpClient("app.posthog.com");
+        $client = new Client(null, ["debug" => true, "batch_size" => 1], $httpClient);
+
+        $this->assertInstanceOf(NoOp::class, $this->getConsumer($client));
+        $this->assertTrue($client->capture([
+            "distinctId" => "john",
+            "event" => "Module PHP Event",
+        ]));
+        $this->assertSame([], $client->getAllFlags("john"));
+        $this->assertSame([], $httpClient->calls ?? []);
+    }
+
+    public function testClientWithTrimEmptyApiKeyDoesNotSendRequests(): void
+    {
+        $httpClient = new MockedHttpClient("app.posthog.com");
+        $client = new Client(" \n\t ", ["debug" => true, "batch_size" => 1], $httpClient);
+
+        $this->assertInstanceOf(NoOp::class, $this->getConsumer($client));
+        $this->assertTrue($client->capture([
+            "distinctId" => "john",
+            "event" => "Module PHP Event",
+        ]));
+        $this->assertSame([], $client->fetchFeatureVariants("john"));
+        $this->assertSame([], $httpClient->calls ?? []);
     }
 
     public function testCapture(): void