PHP调用DeepSeek API实现流式对话与记录保存指南

<?php

class DeepSeekChat {
    // 使用SiliconFlow兼容接口路径
    private $url = 'https://api.siliconflow.cn/v1/chat/completions';
    private $apiKey = 'YOUR_API_KEY';  // 替换为你的实际 Key
    private $logFile = 'conversation.txt';

    public function __construct() {
        // 初始化检查日志文件是否存在，若不存在则创建空文件
        if (!file_exists($this->logFile)) {
            touch($this->logFile);
        }
    }

    // 私有方法：负责格式化并追加写入文件
    private function saveToFile($content, $isQuestion = false) {
        $timestamp = date('Y-m-d H:i:s');
        if ($isQuestion) {
            // 用户提问格式
            $text = "\n[$timestamp] Question:\n$content\n\n[$timestamp] Answer:\n";
        } else {
            // AI回答直接追加
            $text = $content;
        }
        
        file_put_contents($this->logFile, $text, FILE_APPEND);
    }

    // 私有方法：解析流式响应数据块
    private function processStreamingResponse($handle) {
        $buffer = '';
        // 逐块读取直到数据结束
        while (!feof($handle)) {
            $chunk = fread($handle, 1024);
            $buffer .= $chunk;

            // 按行分割处理
            while (($pos = strpos($buffer, "\n")) !== false) {
                $line = substr($buffer, 0, $pos);
                $buffer = substr($buffer, $pos + 1);

                if (strlen(trim($line)) > 0) {
                    // SSE数据以data:开头
                    if (strpos($line, 'data: ') === 0) {
                        $data = substr($line, 6); // 去掉前缀
                        if ($data === '[DONE]') continue;

                        $json = json_decode($data, true);
                        // 提取delta content字段进行输出
                        if ($json && isset($json['choices'][0]['delta']['content'])) {
                            $content = $json['choices'][0]['delta']['content'];
                            echo $content;
                            flush(); // 强制刷新输出缓冲区
                            $this->saveToFile($content); // 实时保存片段
                        }
                    }
                }
            }
        }
    }

    public function chat() {
        while (true) {
            echo "\n请输入您的问题 (输入 q 退出): ";
            $question = trim(fgets(STDIN));

            if ($question === 'q') {
                echo "程序已退出\n";
                break;
            }

            // 保存用户问题
            $this->saveToFile($question, true);

            // 构建符合OpenAI标准的请求JSON
            $data = [
                'model' => 'deepseek-ai/DeepSeek-V3',
                'messages' => [
                    [
                        'role' => 'user',
                        'content' => $question
                    ]
                ],
                'stream' => true,
                'max_tokens' => 2048,
                'temperature' => 0.7,
                'top_p' => 0.7,
                'top_k' => 50,
                'frequency_penalty' => 0.5,
                'response_format' => [
                    'type' => 'text'
                ]
            ];

            // 初始化cURL会话
            $ch = curl_init($this->url);
            curl_setopt_array($ch, [
                CURLOPT_POST => true,
                CURLOPT_POSTFIELDS => json_encode($data),
                CURLOPT_RETURNTRANSFER => true, // 此处设为true配合手动处理回调
                CURLOPT_HTTPHEADER => [
                    'Content-Type: application/json',
                    'Authorization: Bearer ' . $this->apiKey
                ],
                // 注意：若要实时接收数据，CURLOPT_WRITEFUNCTION可能更灵活
                // 但上述processStreamingResponse依赖句柄，此处为了兼容性调整写法：
                // 在实际生产环境中，建议使用CURLOPT_WRITEFUNCTION直接回调，
                // 或者将下面改为CURLOPT_RETURNTRANSFER=false配合读取。
                // *修正*：为了匹配上方processStreamingResponse的逻辑，这里应关闭ReturnTransfer
            ]);
            // 修正点：开启返回原始数据流以便read
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);

            try {
                // 执行请求
                $handle = curl_exec($ch);
                
                if (curl_errno($ch)) {
                    throw new Exception(curl_error($ch));
                }

                echo "\n----------------------------------------\n";
                $this->saveToFile("\n----------------------------------------\n");

            } catch (Exception $e) {
                $error_msg = "请求发生错误: " . $e->getMessage() . "\n";
                echo $error_msg;
                $this->saveToFile($error_msg);
            } finally {
                curl_close($ch);
            }
        }
    }
}

// 实例化并启动
$chatbot = new DeepSeekChat();
$chatbot->chat();