Introduce generic platform for openai embeddings- and completions-based platforms

Completions/ModelClient.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Generic\Completions;
+
+use Symfony\AI\Platform\Bridge\Generic\CompletionsModel;
+use Symfony\AI\Platform\Model;
+use Symfony\AI\Platform\ModelClientInterface;
+use Symfony\AI\Platform\Result\RawHttpResult;
+use Symfony\Component\HttpClient\EventSourceHttpClient;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * This default implementation is based on OpenAI's initial completion endpoint, that got later adopted by other
+ * providers as well. It can be used by any bridge or directly with the default PlatformFactory.
+ *
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+class ModelClient implements ModelClientInterface
+{
+    private readonly EventSourceHttpClient $httpClient;
+
+    public function __construct(
+        HttpClientInterface $httpClient,
+        private readonly string $baseUrl,
+        #[\SensitiveParameter] private readonly ?string $apiKey = null,
+        private readonly string $path = '/v1/chat/completions',
+    ) {
+        $this->httpClient = $httpClient instanceof EventSourceHttpClient ? $httpClient : new EventSourceHttpClient($httpClient);
+    }
+
+    public function supports(Model $model): bool
+    {
+        return $model instanceof CompletionsModel;
+    }
+
+    public function request(Model $model, array|string $payload, array $options = []): RawHttpResult
+    {
+        return new RawHttpResult($this->httpClient->request('POST', $this->baseUrl.$this->path, [
+            'auth_bearer' => $this->apiKey,
+            'headers' => ['Content-Type' => 'application/json'],
+            'json' => array_merge($options, $payload),
+        ]));
+    }
+}

Completions/ResultConverter.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Generic\Completions;
+
+use Symfony\AI\Platform\Bridge\Generic\CompletionsModel;
+use Symfony\AI\Platform\Exception\AuthenticationException;
+use Symfony\AI\Platform\Exception\BadRequestException;
+use Symfony\AI\Platform\Exception\ContentFilterException;
+use Symfony\AI\Platform\Exception\RateLimitExceededException;
+use Symfony\AI\Platform\Exception\RuntimeException;
+use Symfony\AI\Platform\Model;
+use Symfony\AI\Platform\Result\ChoiceResult;
+use Symfony\AI\Platform\Result\RawHttpResult;
+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\Result\ToolCall;
+use Symfony\AI\Platform\Result\ToolCallResult;
+use Symfony\AI\Platform\ResultConverterInterface;
+
+/**
+ * This default implementation is based on the OpenAI GPT completion API.
+ *
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ * @author Denis Zunke <denis.zunke@gmail.com>
+ */
+class ResultConverter implements ResultConverterInterface
+{
+    public function supports(Model $model): bool
+    {
+        return $model instanceof CompletionsModel;
+    }
+
+    public function convert(RawResultInterface|RawHttpResult $result, array $options = []): ResultInterface
+    {
+        $response = $result->getObject();
+
+        if (401 === $response->getStatusCode()) {
+            $errorMessage = json_decode($response->getContent(false), true)['error']['message'];
+            throw new AuthenticationException($errorMessage);
+        }
+
+        if (400 === $response->getStatusCode()) {
+            $errorMessage = json_decode($response->getContent(false), true)['error']['message'] ?? 'Bad Request';
+            throw new BadRequestException($errorMessage);
+        }
+
+        if (429 === $response->getStatusCode()) {
+            throw new RateLimitExceededException();
+        }
+
+        if ($options['stream'] ?? false) {
+            return new StreamResult($this->convertStream($result));
+        }
+
+        $data = $result->getData();
+
+        if (isset($data['error']['code']) && 'content_filter' === $data['error']['code']) {
+            throw new ContentFilterException($data['error']['message']);
+        }
+
+        if (isset($data['error'])) {
+            throw new RuntimeException(\sprintf('Error "%s"-%s (%s): "%s".', $data['error']['code'] ?? '-', $data['error']['type'] ?? '-', $data['error']['param'] ?? '-', $data['error']['message'] ?? '-'));
+        }
+
+        if (!isset($data['choices'])) {
+            throw new RuntimeException('Response does not contain choices.');
+        }
+
+        $choices = array_map($this->convertChoice(...), $data['choices']);
+
+        return 1 === \count($choices) ? $choices[0] : new ChoiceResult(...$choices);
+    }
+
+    private function convertStream(RawResultInterface|RawHttpResult $result): \Generator
+    {
+        $toolCalls = [];
+        foreach ($result->getDataStream() as $data) {
+            if ($this->streamIsToolCall($data)) {
+                $toolCalls = $this->convertStreamToToolCalls($toolCalls, $data);
+            }
+
+            if ([] !== $toolCalls && $this->isToolCallsStreamFinished($data)) {
+                yield new ToolCallResult(...array_map($this->convertToolCall(...), $toolCalls));
+            }
+
+            if (!isset($data['choices'][0]['delta']['content'])) {
+                continue;
+            }
+
+            yield $data['choices'][0]['delta']['content'];
+        }
+    }
+
+    /**
+     * @param array<string, mixed> $toolCalls
+     * @param array<string, mixed> $data
+     *
+     * @return array<string, mixed>
+     */
+    private function convertStreamToToolCalls(array $toolCalls, array $data): array
+    {
+        if (!isset($data['choices'][0]['delta']['tool_calls'])) {
+            return $toolCalls;
+        }
+
+        foreach ($data['choices'][0]['delta']['tool_calls'] as $i => $toolCall) {
+            if (isset($toolCall['id'])) {
+                // initialize tool call
+                $toolCalls[$i] = [
+                    'id' => $toolCall['id'],
+                    'function' => $toolCall['function'],
+                ];
+                continue;
+            }
+
+            // add arguments delta to tool call
+            $toolCalls[$i]['function']['arguments'] .= $toolCall['function']['arguments'];
+        }
+
+        return $toolCalls;
+    }
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    private function streamIsToolCall(array $data): bool
+    {
+        return isset($data['choices'][0]['delta']['tool_calls']);
+    }
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    private function isToolCallsStreamFinished(array $data): bool
+    {
+        return isset($data['choices'][0]['finish_reason']) && 'tool_calls' === $data['choices'][0]['finish_reason'];
+    }
+
+    /**
+     * @param array{
+     *     index: int,
+     *     message: array{
+     *         role: 'assistant',
+     *         content: ?string,
+     *         tool_calls: list<array{
+     *             id: string,
+     *             type: 'function',
+     *             function: array{
+     *                 name: string,
+     *                 arguments: string
+     *             },
+     *         }>,
+     *         refusal: ?mixed
+     *     },
+     *     logprobs: string,
+     *     finish_reason: 'stop'|'length'|'tool_calls'|'content_filter',
+     * } $choice
+     */
+    private function convertChoice(array $choice): ToolCallResult|TextResult
+    {
+        if ('tool_calls' === $choice['finish_reason']) {
+            return new ToolCallResult(...array_map([$this, 'convertToolCall'], $choice['message']['tool_calls']));
+        }
+
+        if (\in_array($choice['finish_reason'], ['stop', 'length'], true)) {
+            return new TextResult($choice['message']['content']);
+        }
+
+        throw new RuntimeException(\sprintf('Unsupported finish reason "%s".', $choice['finish_reason']));
+    }
+
+    /**
+     * @param array{
+     *     id: string,
+     *     type: 'function',
+     *     function: array{
+     *         name: string,
+     *         arguments: string
+     *     }
+     * } $toolCall
+     */
+    private function convertToolCall(array $toolCall): ToolCall
+    {
+        $arguments = json_decode($toolCall['function']['arguments'], true, flags: \JSON_THROW_ON_ERROR);
+
+        return new ToolCall($toolCall['id'], $toolCall['function']['name'], $arguments);
+    }
+}

CompletionsModel.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Generic;
+
+use Symfony\AI\Platform\Model;
+
+/**
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+class CompletionsModel extends Model
+{
+}

Embeddings/ModelClient.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Generic\Embeddings;
+
+use Symfony\AI\Platform\Bridge\Generic\EmbeddingsModel;
+use Symfony\AI\Platform\Model;
+use Symfony\AI\Platform\ModelClientInterface;
+use Symfony\AI\Platform\Result\RawHttpResult;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * This generic implementation is based on OpenAI's initial embeddings endpoint, that got later adopted by other
+ * providers as well. It can be used by any bridge or directly with the generic PlatformFactory.
+ *
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+class ModelClient implements ModelClientInterface
+{
+    public function __construct(
+        private readonly ?HttpClientInterface $httpClient,
+        private readonly string $baseUrl,
+        #[\SensitiveParameter] private readonly ?string $apiKey = null,
+        private readonly string $path = '/v1/embeddings',
+    ) {
+    }
+
+    public function supports(Model $model): bool
+    {
+        return $model instanceof EmbeddingsModel;
+    }
+
+    public function request(Model $model, array|string $payload, array $options = []): RawHttpResult
+    {
+        return new RawHttpResult($this->httpClient->request('POST', $this->baseUrl.$this->path, [
+            'auth_bearer' => $this->apiKey,
+            'headers' => ['Content-Type' => 'application/json'],
+            'json' => array_merge($options, [
+                'model' => $model->getName(),
+                'input' => $payload,
+            ]),
+        ]));
+    }
+}

Embeddings/ResultConverter.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Generic\Embeddings;
+
+use Symfony\AI\Platform\Bridge\Generic\EmbeddingsModel;
+use Symfony\AI\Platform\Exception\RuntimeException;
+use Symfony\AI\Platform\Model;
+use Symfony\AI\Platform\Result\RawResultInterface;
+use Symfony\AI\Platform\Result\VectorResult;
+use Symfony\AI\Platform\ResultConverterInterface;
+use Symfony\AI\Platform\Vector\Vector;
+
+/**
+ * This default result converter assumes the same response format as OpenAI's embeddings endpoint.
+ *
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+class ResultConverter implements ResultConverterInterface
+{
+    public function supports(Model $model): bool
+    {
+        return $model instanceof EmbeddingsModel;
+    }
+
+    public function convert(RawResultInterface $result, array $options = []): VectorResult
+    {
+        $data = $result->getData();
+
+        if (!isset($data['data'])) {
+            throw new RuntimeException('Response does not contain data.');
+        }
+
+        return new VectorResult(
+            ...array_map(
+                static fn (array $item): Vector => new Vector($item['embedding']),
+                $data['data']
+            ),
+        );
+    }
+}

EmbeddingsModel.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Generic;
+
+use Symfony\AI\Platform\Model;
+
+/**
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+class EmbeddingsModel extends Model
+{
+}

ModelCatalog.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Generic;
+
+use Symfony\AI\Platform\Capability;
+use Symfony\AI\Platform\ModelCatalog\AbstractModelCatalog;
+
+/**
+ * Models need to be registered explicitly here to be routed to the correct ModelClient and ResultConverter
+ * implementations.
+ *
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+final class ModelCatalog extends AbstractModelCatalog
+{
+    /**
+     * @param array<string, array{class: class-string, capabilities: list<Capability>}> $models
+     */
+    public function __construct(
+        protected array $models = [],
+    ) {
+    }
+}

PlatformFactory.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Generic;
+
+use Psr\EventDispatcher\EventDispatcherInterface;
+use Symfony\AI\Platform\Contract;
+use Symfony\AI\Platform\ModelCatalog\FallbackModelCatalog;
+use Symfony\AI\Platform\ModelCatalog\ModelCatalogInterface;
+use Symfony\AI\Platform\Platform;
+use Symfony\Component\HttpClient\EventSourceHttpClient;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * @author Christopher Hertel <mail@christopher-hertel.de>
+ */
+class PlatformFactory
+{
+    public static function create(
+        string $baseUrl,
+        ?string $apiKey = null,
+        ?HttpClientInterface $httpClient = null,
+        ModelCatalogInterface $modelCatalog = new FallbackModelCatalog(),
+        ?Contract $contract = null,
+        ?EventDispatcherInterface $eventDispatcher = null,
+        bool $supportsCompletions = true,
+        bool $supportsEmbeddings = true,
+        string $completionsPath = '/v1/chat/completions',
+        string $embeddingsPath = '/v1/embeddings',
+    ): Platform {
+        $httpClient = $httpClient instanceof EventSourceHttpClient ? $httpClient : new EventSourceHttpClient($httpClient);
+
+        $modelClients = [];
+        $resultConverters = [];
+        if ($supportsCompletions) {
+            $modelClients[] = new Completions\ModelClient($httpClient, $baseUrl, $apiKey, $completionsPath);
+            $resultConverters[] = new Completions\ResultConverter();
+        }
+        if ($supportsEmbeddings) {
+            $modelClients[] = new Embeddings\ModelClient($httpClient, $baseUrl, $apiKey, $embeddingsPath);
+            $resultConverters[] = new Embeddings\ResultConverter();
+        }
+
+        return new Platform($modelClients, $resultConverters, $modelCatalog, $contract, $eventDispatcher);
+    }
+}