math_cms/app/Services/OCR/Drivers/BaiduOCRDriver.php

<?php

namespace App\Services\OCR\Drivers;

use App\Services\OCR\OCRInterface;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;

class BaiduOCRDriver implements OCRInterface
{
    protected $appId;
    protected $apiKey;
    protected $secretKey;
    protected $aesKey;

    public function __construct(array $config, $client = null)
    {
        if ($client) {
            // 使用模拟客户端（用于测试）
            $this->appId = $config['app_id'] ?? '';
            $this->apiKey = $config['api_key'] ?? '';
            $this->secretKey = $config['secret_key'] ?? '';
            $this->aesKey = $config['aes_key'] ?? '';
            return;
        }

        $this->appId = $config['app_id'] ?? '';
        $this->apiKey = $config['api_key'] ?? '';
        $this->secretKey = $config['secret_key'] ?? '';
        $this->aesKey = $config['aes_key'] ?? '';
    }

    public function recognize(string $imagePath, array $options = []): array
    {
        try {
            // Check if file exists
            if (!file_exists($imagePath)) {
                throw new \Exception("Image file not found: {$imagePath}");
            }

            // Get cutType from options
            $cutType = $options['cutType'] ?? 'question';
            $subject = $options['subject'] ?? 'Math';

            // Get access token
            $accessToken = $this->getAccessToken();

            // Read image file
            $imageData = base64_encode(file_get_contents($imagePath));

            // Call Baidu OCR API
            $response = Http::post("https://aip.baidubce.com/rest/2.0/ocr/v1/edu_paper?access_token={$accessToken}", [
                'image' => $imageData,
                'cut_type' => $cutType,
                'subject' => $subject,
            ]);

            if ($response->failed()) {
                throw new \Exception('Baidu OCR API failed: ' . $response->body());
            }

            $body = $response->json();

            // Log the response
            Log::info('Baidu OCR Full Response', [
                'cutType' => $cutType,
                'has_data' => isset($body['data']),
                'request_id' => $body['request_id'] ?? null,
                'error_code' => $body['error_code'] ?? null,
                'error_msg' => $body['error_msg'] ?? null,
                'body_keys' => array_keys($body ?? [])
            ]);

            // Log raw data if exists
            if (isset($body['data'])) {
                $dataPreview = is_string($body['data'])
                    ? substr($body['data'], 0, 500)
                    : json_encode($body['data']);
                Log::info('Baidu OCR Data Preview', ['data' => $dataPreview]);
            }

            // Parse Baidu OCR response
            $questions = [];

            if (isset($body['data'])) {
                $data = is_string($body['data']) ? json_decode($body['data'], true) : $body['data'];

                // Extract page_list -> subject_list OR answer_list
                if (isset($data['page_list']) && is_array($data['page_list'])) {
                    foreach ($data['page_list'] as $page) {
                        // Determine which list to use based on cutType
                        $itemList = null;
                        if ($cutType === 'answer' && isset($page['answer_list'])) {
                            $itemList = $page['answer_list'];
                        } elseif (isset($page['subject_list'])) {
                            $itemList = $page['subject_list'];
                        }

                        if ($itemList && is_array($itemList)) {
                            foreach ($itemList as $index => $item) {
                                // Extract question/answer data
                                $questionNumber = count($questions) + 1; // 默认使用索引

                                // 百度OCR的题号可能在不同的字段中
                                // 尝试从多个可能的字段获取题号
                                $idValue = null;
                                if (isset($item['question_id'])) {
                                    $idValue = $item['question_id'];
                                } elseif (isset($item['id'])) {
                                    $idValue = $item['id'];
                                } elseif (isset($item['index'])) {
                                    $idValue = $item['index'];
                                }

                                // 只有当 idValue 是数字时才使用它作为题号
                                if ($idValue !== null && is_numeric($idValue)) {
                                    $questionNumber = (int) $idValue;
                                }

                                // Get text
                                $text = $item['text'] ?? '';
                                if (empty($text) && isset($item['words'])) {
                                    // 百度OCR使用words字段
                                    if (is_array($item['words'])) {
                                        $words = array_column($item['words'], 'word');
                                        $text = implode('', $words);
                                    } else {
                                        $text = (string) $item['words'];
                                    }
                                }

                                // Calculate confidence
                                $confidence = 0.0;
                                if (isset($item['confidence'])) {
                                    $confidence = (float) $item['confidence'];
                                } elseif (isset($item['words']) && is_array($item['words'])) {
                                    // 计算words的平均置信度
                                    $totalProb = 0;
                                    $count = 0;
                                    foreach ($item['words'] as $word) {
                                        if (isset($word['confidence'])) {
                                            $totalProb += $word['confidence'];
                                            $count++;
                                        }
                                    }
                                    $confidence = $count > 0 ? ($totalProb / $count) / 100 : 0.0;
                                }

                                $questions[] = [
                                    'question_number' => $questionNumber,
                                    'content' => $text,
                                    'cut_type' => $cutType,
                                    'confidence' => $confidence,
                                    'raw_data' => $item
                                ];
                            }
                        }
                    }
                }
            }

            return [
                'raw' => $body,
                'questions' => $questions,
                'cut_type' => $cutType
            ];

        } catch (\Exception $e) {
            Log::error('Baidu OCR Error', [
                'message' => $e->getMessage(),
                'trace' => $e->getTraceAsString(),
            ]);
            throw $e;
        }
    }

    /**
     * 获取百度OCR的访问令牌
     */
    protected function getAccessToken(): string
    {
        // 缓存访问令牌以避免频繁请求
        $cacheKey = 'baidu_ocr_access_token';
        $cachedToken = cache($cacheKey);

        if ($cachedToken) {
            return $cachedToken;
        }

        // 获取新的访问令牌
        $response = Http::post('https://aip.baidubce.com/oauth/2.0/token', [
            'grant_type' => 'client_credentials',
            'client_id' => $this->apiKey,
            'client_secret' => $this->secretKey,
        ]);

        if ($response->failed()) {
            throw new \Exception('Failed to get Baidu OCR access token: ' . $response->body());
        }

        $data = $response->json();

        if (!isset($data['access_token'])) {
            throw new \Exception('Invalid response from Baidu OCR token API');
        }

        $accessToken = $data['access_token'];

        // 缓存访问令牌（默认25分钟过期，提前5分钟刷新）
        $expiresIn = $data['expires_in'] ?? 3600;
        cache([$cacheKey => $accessToken], now()->addMinutes($expiresIn / 60 - 5));

        return $accessToken;
    }
}