Allow to change API version

Author: Erdem Köse

README.md

@@ -27,6 +27,7 @@ _This library is not developed or endorsed by Google._
   - [Tokens counting](#tokens-counting)
   - [Listing models](#listing-models)
   - [Advanced Usages](#advanced-usages)
+    - [Using Beta version](#using-beta-version)
     - [Safety Settings and Generation Configuration](#safety-settings-and-generation-configuration)
     - [Using your own HTTP client](#using-your-own-http-client)
     - [Using your own HTTP client for streaming responses](#using-your-own-http-client-for-streaming-responses)
@@ -329,6 +330,23 @@ print_r($response->models);
 
 ### Advanced Usages
 
+#### Using Beta version
+
+```php
+use GeminiAPI\Client;
+use GeminiAPI\Resources\ModelName;
+use GeminiAPI\Resources\Parts\TextPart;
+
+$client = (new Client('GEMINI_API_KEY'))
+    ->withV1BetaVersion();
+$response = $client->generativeModel(ModelName::GEMINI_PRO)->countTokens(
+    new TextPart('PHP in less than 100 chars'),
+);
+
+print $response->totalTokens;
+// 10
+```
+
 #### Safety Settings and Generation Configuration
 
 ```php

src/Client.php

@@ -40,6 +40,7 @@
 class Client implements GeminiClientInterface
 {
     private string $baseUrl = 'https://generativelanguage.googleapis.com';
+    private string $version = GeminiClientInterface::API_VERSION_V1;
 
     /**
      * @var array<string, string|string[]>
@@ -133,7 +134,7 @@ public function generateContentStream(
             }
         }
 
-        curl_setopt($ch, CURLOPT_URL, "{$this->baseUrl}/v1/{$request->getOperation()}");
+        curl_setopt($ch, CURLOPT_URL, $this->getRequestUrl($request));
         curl_setopt($ch, CURLOPT_POST, true);
         curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($request));
         curl_setopt($ch, CURLOPT_HTTPHEADER, $headerLines);
@@ -184,6 +185,19 @@ public function withBaseUrl(string $baseUrl): self
         return $clone;
     }
 
+    public function withV1BetaVersion(): self
+    {
+        return $this->withVersion(GeminiClientInterface::API_VERSION_V1_BETA);
+    }
+
+    public function withVersion(string $version): self
+    {
+        $clone = clone $this;
+        $clone->version = $version;
+
+        return $clone;
+    }
+
     /**
      * @param array<string, string|string[]> $headers
      * @return self
@@ -211,6 +225,16 @@ private function getRequestHeaders(): array
         ];
     }
 
+    private function getRequestUrl(RequestInterface $request): string
+    {
+        return sprintf(
+            '%s/%s/%s',
+            $this->baseUrl,
+            $this->version,
+            $request->getOperation(),
+        );
+    }
+
     /**
      * @throws ClientExceptionInterface
      */
@@ -220,9 +244,11 @@ private function doRequest(RequestInterface $request): string
             throw new RuntimeException('Missing client or factory for Gemini API operation');
         }
 
-        $uri = "{$this->baseUrl}/v1/{$request->getOperation()}";
         $httpRequest = $this->requestFactory
-            ->createRequest($request->getHttpMethod(), $uri);
+            ->createRequest(
+                $request->getHttpMethod(),
+                $this->getRequestUrl($request),
+            );
 
         foreach ($this->getRequestHeaders() as $name => $value) {
             $httpRequest = $httpRequest->withAddedHeader($name, $value);

src/ClientInterface.php

@@ -21,6 +21,8 @@
 interface ClientInterface
 {
     public const API_KEY_HEADER_NAME = 'x-goog-api-key';
+    public const API_VERSION_V1 = 'v1';
+    public const API_VERSION_V1_BETA = 'v1beta';
 
     public function countTokens(CountTokensRequest $request): CountTokensResponse;
     public function generateContent(GenerateContentRequest $request): GenerateContentResponse;