feature #324 [Platform] Add stream for ElevenLabs TTS (Guikingone)

This PR was merged into the main branch.

Discussion
----------

[Platform] Add stream for ElevenLabs TTS

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Docs?         | yes
| Issues        | None
| License       | MIT

Hi 👋🏻

This PR aim to introduce the support for streaming TTS.

Commits
-------

16c492e feat(platform): ElevenLabs stream for TTS

Author: chr-hertel

examples/elevenlabs/text-to-speech-as-stream.php

@@ -0,0 +1,35 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Symfony\AI\Platform\Bridge\ElevenLabs\ElevenLabs;
+use Symfony\AI\Platform\Bridge\ElevenLabs\PlatformFactory;
+use Symfony\AI\Platform\Message\Content\Text;
+
+require_once dirname(__DIR__).'/bootstrap.php';
+
+$platform = PlatformFactory::create(
+    apiKey: env('ELEVEN_LABS_API_KEY'),
+    httpClient: http_client(),
+);
+$model = new ElevenLabs(options: [
+    'voice' => 'Dslrhjl3ZpzrctukrQSN', // Brad (https://elevenlabs.io/app/voice-library?voiceId=Dslrhjl3ZpzrctukrQSN)
+    'stream' => true,
+]);
+
+$result = $platform->invoke($model, new Text('The first move is what sets everything in motion.'));
+
+$content = '';
+
+foreach ($result->asStream() as $chunk) {
+    echo $chunk;
+}
+
+echo \PHP_EOL;

src/platform/src/Bridge/ElevenLabs/ElevenLabsClient.php

@@ -42,7 +42,7 @@ public function request(Model $model, array|string $payload, array $options = []
         }
 
         if (\in_array($model->getName(), [ElevenLabs::SCRIBE_V1, ElevenLabs::SCRIBE_V1_EXPERIMENTAL], true)) {
-            return $this->doSpeechToTextRequest($model, $payload, $options);
+            return $this->doSpeechToTextRequest($model, $payload);
         }
 
         $capabilities = $this->retrieveCapabilities($model);
@@ -56,9 +56,8 @@ public function request(Model $model, array|string $payload, array $options = []
 
     /**
      * @param array<string|int, mixed> $payload
-     * @param array<string, mixed>     $options
      */
-    private function doSpeechToTextRequest(Model $model, array|string $payload, array $options): RawHttpResult
+    private function doSpeechToTextRequest(Model $model, array|string $payload): RawHttpResult
     {
         return new RawHttpResult($this->httpClient->request('POST', \sprintf('%s/speech-to-text', $this->hostUrl), [
             'headers' => [
@@ -86,8 +85,13 @@ private function doTextToSpeechRequest(Model $model, array|string $payload, arra
         }
 
         $voice = $options['voice'] ??= $model->getOptions()['voice'];
+        $stream = $options['stream'] ??= $model->getOptions()['stream'] ?? false;
+
+        $url = $stream
+            ? \sprintf('%s/text-to-speech/%s/stream', $this->hostUrl, $voice)
+            : \sprintf('%s/text-to-speech/%s', $this->hostUrl, $voice);
 
-        return new RawHttpResult($this->httpClient->request('POST', \sprintf('%s/text-to-speech/%s', $this->hostUrl, $voice), [
+        return new RawHttpResult($this->httpClient->request('POST', $url, [
             'headers' => [
                 'xi-api-key' => $this->apiKey,
             ],

src/platform/src/Bridge/ElevenLabs/ElevenLabsResultConverter.php

@@ -16,15 +16,22 @@
 use Symfony\AI\Platform\Result\BinaryResult;
 use Symfony\AI\Platform\Result\RawResultInterface;
 use Symfony\AI\Platform\Result\ResultInterface;
+use Symfony\AI\Platform\Result\StreamResult;
 use Symfony\AI\Platform\Result\TextResult;
 use Symfony\AI\Platform\ResultConverterInterface;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
 use Symfony\Contracts\HttpClient\ResponseInterface;
 
 /**
  * @author Guillaume Loulier <[email protected]>
  */
 final readonly class ElevenLabsResultConverter implements ResultConverterInterface
 {
+    public function __construct(
+        private HttpClientInterface $httpClient,
+    ) {
+    }
+
     public function supports(Model $model): bool
     {
         return $model instanceof ElevenLabs;
@@ -36,9 +43,25 @@ public function convert(RawResultInterface $result, array $options = []): Result
         $response = $result->getObject();
 
         return match (true) {
+            \array_key_exists('stream', $options) && $options['stream'] => new StreamResult($this->convertToGenerator($response)),
             str_contains($response->getInfo('url'), 'speech-to-text') => new TextResult($result->getData()['text']),
             str_contains($response->getInfo('url'), 'text-to-speech') => new BinaryResult($result->getObject()->getContent(), 'audio/mpeg'),
             default => throw new RuntimeException('Unsupported ElevenLabs response.'),
         };
     }
+
+    private function convertToGenerator(ResponseInterface $response): \Generator
+    {
+        foreach ($this->httpClient->stream($response) as $chunk) {
+            if ($chunk->isFirst() || $chunk->isLast()) {
+                continue;
+            }
+
+            if ('' === $chunk->getContent()) {
+                continue;
+            }
+
+            yield $chunk->getContent();
+        }
+    }
 }

src/platform/src/Bridge/ElevenLabs/PlatformFactory.php

@@ -32,7 +32,7 @@ public static function create(
 
         return new Platform(
             [new ElevenLabsClient($httpClient, $apiKey, $hostUrl)],
-            [new ElevenLabsResultConverter()],
+            [new ElevenLabsResultConverter($httpClient)],
             $contract ?? ElevenLabsContract::create(),
         );
     }

src/platform/tests/Bridge/ElevenLabs/ElevenLabsClientTest.php

@@ -12,7 +12,6 @@
 namespace Symfony\AI\Platform\Tests\Bridge\ElevenLabs;
 
 use PHPUnit\Framework\Attributes\CoversClass;
-use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\Attributes\UsesClass;
 use PHPUnit\Framework\TestCase;
 use Symfony\AI\Platform\Bridge\ElevenLabs\Contract\AudioNormalizer;
@@ -21,6 +20,7 @@
 use Symfony\AI\Platform\Exception\InvalidArgumentException;
 use Symfony\AI\Platform\Message\Content\Audio;
 use Symfony\AI\Platform\Model;
+use Symfony\AI\Platform\Result\RawHttpResult;
 use Symfony\Component\HttpClient\MockHttpClient;
 use Symfony\Component\HttpClient\Response\JsonMockResponse;
 use Symfony\Component\HttpClient\Response\MockResponse;
@@ -30,6 +30,7 @@
 #[UsesClass(Model::class)]
 #[UsesClass(Audio::class)]
 #[UsesClass(AudioNormalizer::class)]
+#[UsesClass(RawHttpResult::class)]
 final class ElevenLabsClientTest extends TestCase
 {
     public function testSupportsModel()
@@ -133,7 +134,6 @@ public function testClientCannotPerformTextToSpeechRequestWithoutValidPayload()
         ]), []);
     }
 
-    #[Group('foo')]
     public function testClientCanPerformTextToSpeechRequest()
     {
         $payload = Audio::fromFile(\dirname(__DIR__, 5).'/fixtures/audio.mp3');
@@ -162,4 +162,35 @@ public function testClientCanPerformTextToSpeechRequest()
 
         $this->assertSame(2, $httpClient->getRequestsCount());
     }
+
+    public function testClientCanPerformTextToSpeechRequestAsStream()
+    {
+        $payload = Audio::fromFile(\dirname(__DIR__, 5).'/fixtures/audio.mp3');
+
+        $httpClient = new MockHttpClient([
+            new JsonMockResponse([
+                [
+                    'model_id' => ElevenLabs::ELEVEN_MULTILINGUAL_V2,
+                    'can_do_text_to_speech' => true,
+                ],
+            ]),
+            new MockResponse($payload->asBinary()),
+        ]);
+
+        $client = new ElevenLabsClient(
+            $httpClient,
+            'https://api.elevenlabs.io/v1',
+            'my-api-key',
+        );
+
+        $result = $client->request(new ElevenLabs(options: [
+            'voice' => 'Dslrhjl3ZpzrctukrQSN',
+            'stream' => true,
+        ]), [
+            'text' => 'foo',
+        ]);
+
+        $this->assertInstanceOf(RawHttpResult::class, $result);
+        $this->assertSame(2, $httpClient->getRequestsCount());
+    }
 }

src/platform/tests/Bridge/ElevenLabs/ElevenLabsConverterTest.php

@@ -20,6 +20,7 @@
 use Symfony\AI\Platform\Result\BinaryResult;
 use Symfony\AI\Platform\Result\InMemoryRawResult;
 use Symfony\AI\Platform\Result\TextResult;
+use Symfony\Component\HttpClient\MockHttpClient;
 
 #[CoversClass(ElevenLabsResultConverter::class)]
 #[UsesClass(ElevenLabs::class)]
@@ -31,15 +32,15 @@ final class ElevenLabsConverterTest extends TestCase
 {
     public function testSupportsModel()
     {
-        $converter = new ElevenLabsResultConverter();
+        $converter = new ElevenLabsResultConverter(new MockHttpClient());
 
         $this->assertTrue($converter->supports(new ElevenLabs()));
         $this->assertFalse($converter->supports(new Model('any-model')));
     }
 
     public function testConvertSpeechToTextResponse()
     {
-        $converter = new ElevenLabsResultConverter();
+        $converter = new ElevenLabsResultConverter(new MockHttpClient());
         $rawResult = new InMemoryRawResult([
             'text' => 'Hello there',
         ], new class {
@@ -57,7 +58,7 @@ public function getInfo(): string
 
     public function testConvertTextToSpeechResponse()
     {
-        $converter = new ElevenLabsResultConverter();
+        $converter = new ElevenLabsResultConverter(new MockHttpClient());
         $rawResult = new InMemoryRawResult([], new class {
             public function getInfo(): string
             {