更新

backend/app/service/DifyService.php

@@ -0,0 +1,406 @@
+<?php
+
+namespace app\service;
+
+use app\model\AiModel;
+use think\exception\HttpResponseException;
+
+/**
+ * Dify 应用 API 接入服务。
+ *
+ * Dify 使用的是自己的一套接口协议，跟 OpenAI 的 /chat/completions 完全不同：
+ * - 发送消息：POST {api_base_url}/chat-messages
+ * - 上传文件：POST {api_base_url}/files/upload
+ * - 会话上下文由 Dify 自己维护（通过 conversation_id 串联），不需要像 OpenAI 那样
+ *   每次把完整的历史消息数组传过去，只需要传当前这一句 query + 上一次返回的 conversation_id。
+ *
+ * 参考文档：https://docs.dify.ai/api-reference
+ */
+class DifyService
+{
+    public static function chat(AiModel $model, string $query, array $files, ?string $conversationId, string $userId): array
+    {
+        $url = rtrim($model->api_base_url, '/') . '/chat-messages';
+        $payload = self::buildPayload($query, $files, $conversationId, $userId, false);
+
+        $ch = curl_init($url);
+        curl_setopt_array($ch, [
+            CURLOPT_POST           => true,
+            CURLOPT_POSTFIELDS     => json_encode($payload),
+            CURLOPT_HTTPHEADER     => [
+                'Content-Type: application/json',
+                'Authorization: Bearer ' . $model->api_key,
+            ],
+            CURLOPT_RETURNTRANSFER => true,
+            CURLOPT_TIMEOUT        => 120,
+            CURLOPT_CONNECTTIMEOUT => 15,
+            CURLOPT_SSL_VERIFYPEER => false,
+        ]);
+
+        $response = curl_exec($ch);
+        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
+        $curlError = curl_error($ch);
+        curl_close($ch);
+
+        if ($response === false) {
+            throw new HttpResponseException(json([
+                'code'    => 1,
+                'message' => 'Dify 请求失败: ' . ($curlError ?: '网络错误'),
+                'data'    => null,
+            ], 502));
+        }
+
+        if ($httpCode !== 200) {
+            $detail = self::parseErrorBody($response) ?: ('HTTP ' . $httpCode);
+            throw new HttpResponseException(json([
+                'code'    => 1,
+                'message' => self::humanizeError('Dify 请求失败: ' . $detail . self::urlHint($httpCode)),
+                'data'    => null,
+            ], 502));
+        }
+
+        $data = json_decode($response, true);
+        if (!$data) {
+            throw new HttpResponseException(json([
+                'code'    => 1,
+                'message' => 'Dify 响应解析失败',
+                'data'    => null,
+            ], 502));
+        }
+
+        return [
+            'answer'          => $data['answer'] ?? '',
+            'conversation_id' => $data['conversation_id'] ?? null,
+            'tokens'          => $data['metadata']['usage']['total_tokens'] ?? 0,
+        ];
+    }
+
+    public static function streamChat(
+        AiModel $model,
+        string $query,
+        array $files,
+        ?string $conversationId,
+        string $userId,
+        callable $onChunk,
+        callable $onDone,
+        ?callable $onError = null
+    ): void {
+        $url = rtrim($model->api_base_url, '/') . '/chat-messages';
+        $payload = self::buildPayload($query, $files, $conversationId, $userId, true);
+
+        $errorBody = '';
+        $httpCode = 0;
+        $finalConversationId = $conversationId;
+        $finalTokens = 0;
+        $eventError = null;
+        $streamBuffer = '';
+
+        $ch = curl_init($url);
+        curl_setopt_array($ch, [
+            CURLOPT_POST           => true,
+            CURLOPT_POSTFIELDS     => json_encode($payload),
+            CURLOPT_HTTPHEADER     => [
+                'Content-Type: application/json',
+                'Authorization: Bearer ' . $model->api_key,
+            ],
+            CURLOPT_RETURNTRANSFER => false,
+            CURLOPT_HEADERFUNCTION => function ($ch, $header) use (&$httpCode) {
+                if (preg_match('/^HTTP\/\d+\.\d+\s+(\d+)/', $header, $m)) {
+                    $httpCode = (int) $m[1];
+                }
+                return strlen($header);
+            },
+            CURLOPT_WRITEFUNCTION => function ($ch, $data) use (
+                &$errorBody,
+                &$httpCode,
+                $onChunk,
+                &$finalConversationId,
+                &$finalTokens,
+                &$eventError,
+                &$streamBuffer
+            ) {
+                if ($httpCode >= 400) {
+                    $errorBody .= $data;
+                    return strlen($data);
+                }
+
+                // cURL may split one SSE data line across arbitrary network chunks.
+                $streamBuffer .= $data;
+                $lines = preg_split('/\r?\n/', $streamBuffer) ?: [];
+                $streamBuffer = (string) (array_pop($lines) ?? '');
+                foreach ($lines as $line) {
+                    $line = trim($line);
+                    if ($line === '' || !str_starts_with($line, 'data:')) {
+                        continue;
+                    }
+
+                    $json = json_decode(substr($line, 5), true);
+                    if (!$json) {
+                        continue;
+                    }
+
+                    $event = $json['event'] ?? '';
+
+                    if (!empty($json['conversation_id'])) {
+                        $finalConversationId = $json['conversation_id'];
+                    }
+
+                    if ($event === 'error') {
+                        $eventError = $json['message'] ?? 'Dify 返回错误';
+                        continue;
+                    }
+
+                    if (in_array($event, ['message', 'agent_message'], true)) {
+                        $delta = $json['answer'] ?? '';
+                        if ($delta !== '') {
+                            $onChunk($delta);
+                        }
+                    }
+
+                    if ($event === 'message_end') {
+                        $finalTokens = $json['metadata']['usage']['total_tokens'] ?? $finalTokens;
+                    }
+                }
+
+                return strlen($data);
+            },
+            CURLOPT_TIMEOUT        => 120,
+            CURLOPT_CONNECTTIMEOUT => 15,
+            CURLOPT_SSL_VERIFYPEER => false,
+        ]);
+
+        try {
+            $result = curl_exec($ch);
+
+            if ($result === false) {
+                $message = 'Dify 请求失败: ' . curl_error($ch);
+                $onError ? $onError($message) : null;
+                return;
+            }
+
+            if ($httpCode >= 400) {
+                $detail = self::parseErrorBody($errorBody) ?: ('HTTP ' . $httpCode);
+                $onError ? $onError(self::humanizeError('Dify 请求失败: ' . $detail . self::urlHint($httpCode))) : null;
+                return;
+            }
+
+            if ($eventError) {
+                $onError ? $onError(self::humanizeError('Dify 请求失败: ' . $eventError)) : null;
+                return;
+            }
+        } finally {
+            curl_close($ch);
+        }
+
+        $onDone($finalConversationId, $finalTokens);
+    }
+
+    /**
+     * 把本地已上传的文件转发上传到 Dify（Dify 需要自己的 upload_file_id 才能在
+     * chat-messages 里引用文件），失败时返回 null，调用方应做优雅降级处理。
+     */
+    public static function uploadFile(AiModel $model, string $path, string $mime, string $originalName, string $userId): ?string
+    {
+        [$fileId] = self::uploadFileWithDetail($model, $path, $mime, $originalName, $userId);
+        return $fileId;
+    }
+
+    /**
+     * 上传文件到 Dify，失败时返回 [null, errorMessage]
+     */
+    public static function uploadFileWithDetail(AiModel $model, string $path, string $mime, string $originalName, string $userId): array
+    {
+        if (!is_file($path)) {
+            return [null, '本地文件不存在'];
+        }
+
+        $url = rtrim($model->api_base_url, '/') . '/files/upload';
+        $safeName = self::safeUploadFilename($originalName, $path, $mime);
+
+        $ch = curl_init($url);
+        curl_setopt_array($ch, [
+            CURLOPT_POST           => true,
+            CURLOPT_POSTFIELDS     => [
+                'file' => curl_file_create($path, $mime, $safeName),
+                'user' => $userId,
+            ],
+            CURLOPT_HTTPHEADER     => [
+                'Authorization: Bearer ' . $model->api_key,
+            ],
+            CURLOPT_RETURNTRANSFER => true,
+            CURLOPT_TIMEOUT        => 60,
+            CURLOPT_CONNECTTIMEOUT => 15,
+            CURLOPT_SSL_VERIFYPEER => false,
+        ]);
+
+        $response = curl_exec($ch);
+        $httpCode = (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
+        $curlError = curl_error($ch);
+        curl_close($ch);
+
+        if ($response === false) {
+            return [null, '网络错误: ' . ($curlError ?: '无法连接 Dify')];
+        }
+
+        if ($httpCode !== 200 && $httpCode !== 201) {
+            $detail = self::parseErrorBody($response) ?: ('HTTP ' . $httpCode);
+            return [null, $detail];
+        }
+
+        $data = json_decode($response, true);
+        $fileId = $data['id'] ?? ($data['data']['id'] ?? null);
+
+        return $fileId ? [$fileId, null] : [null, 'Dify 未返回 file_id'];
+    }
+
+    private static function safeUploadFilename(string $originalName, string $path, string $mime): string
+    {
+        $ext = strtolower(pathinfo($originalName, PATHINFO_EXTENSION) ?: pathinfo($path, PATHINFO_EXTENSION));
+        if ($ext === '') {
+            $ext = match (true) {
+                str_starts_with($mime, 'image/png') => 'png',
+                str_starts_with($mime, 'image/gif') => 'gif',
+                str_starts_with($mime, 'image/webp') => 'webp',
+                default => 'jpg',
+            };
+        }
+
+        return 'upload_' . uniqid('', true) . '.' . $ext;
+    }
+
+    /**
+     * 测试 Dify 应用连接是否正常
+     */
+    public static function testConnection(array $config): array
+    {
+        $apiBaseUrl = rtrim($config['api_base_url'] ?? '', '/');
+        $apiKey = $config['api_key'] ?? '';
+
+        if (!$apiBaseUrl) {
+            throw new \InvalidArgumentException('请填写 API 地址（Dify 应用的 API Base URL，如 https://api.dify.ai/v1）');
+        }
+        if (!$apiKey) {
+            throw new \InvalidArgumentException('请填写 API Key（在 Dify 应用的"访问 API"页面获取）');
+        }
+
+        $url = $apiBaseUrl . '/chat-messages';
+        $payload = [
+            'inputs'          => new \stdClass(),
+            'query'           => '请只回复：测试成功',
+            'response_mode'   => 'blocking',
+            'conversation_id' => '',
+            'user'            => 'connection-test',
+        ];
+
+        $start = microtime(true);
+        $ch = curl_init($url);
+        curl_setopt_array($ch, [
+            CURLOPT_POST           => true,
+            CURLOPT_POSTFIELDS     => json_encode($payload),
+            CURLOPT_HTTPHEADER     => [
+                'Content-Type: application/json',
+                'Authorization: Bearer ' . $apiKey,
+            ],
+            CURLOPT_RETURNTRANSFER => true,
+            CURLOPT_TIMEOUT        => 30,
+            CURLOPT_CONNECTTIMEOUT => 10,
+            CURLOPT_SSL_VERIFYPEER => false,
+        ]);
+
+        $response = curl_exec($ch);
+        $httpCode = (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
+        $curlError = curl_error($ch);
+        curl_close($ch);
+
+        $latencyMs = (int) round((microtime(true) - $start) * 1000);
+
+        if ($response === false) {
+            throw new \RuntimeException('连接失败: ' . ($curlError ?: '网络不可达'));
+        }
+
+        if ($httpCode !== 200) {
+            $detail = self::parseErrorBody($response) ?: ('HTTP ' . $httpCode);
+            throw new \RuntimeException('API 返回错误: ' . $detail . self::urlHint($httpCode));
+        }
+
+        $data = json_decode($response, true);
+        if (!$data) {
+            throw new \RuntimeException('响应解析失败，请确认接口地址正确');
+        }
+
+        $reply = $data['answer'] ?? '';
+        if ($reply === '') {
+            throw new \RuntimeException('接口连接成功，但未返回有效内容');
+        }
+
+        return [
+            'success'    => true,
+            'latency_ms' => $latencyMs,
+            'reply'      => $reply,
+            'model'      => 'dify',
+            'tokens'     => $data['metadata']['usage']['total_tokens'] ?? null,
+        ];
+    }
+
+    private static function buildPayload(string $query, array $files, ?string $conversationId, string $userId, bool $streaming): array
+    {
+        $payload = [
+            // 注意：必须用 stdClass 而不是 []，PHP 的空数组 json_encode 后是 "[]"，
+            // 但 Dify（Pydantic）要求 inputs 必须是字典 "{}"，否则会报
+            // "Input should be a valid dictionary" 的校验错误
+            'inputs'          => new \stdClass(),
+            'query'           => $query,
+            'response_mode'   => $streaming ? 'streaming' : 'blocking',
+            'conversation_id' => $conversationId ?: '',
+            'user'            => $userId,
+        ];
+
+        if ($files) {
+            $payload['files'] = $files;
+        }
+
+        return $payload;
+    }
+
+    private static function urlHint(int $httpCode): string
+    {
+        if ($httpCode === 404) {
+            return '（请确认 API 地址填写的是 Dify 的 API 根路径，如 https://api.dify.ai/v1 或自部署的 http://your-host/v1，Dify 使用 /chat-messages 接口，不是 OpenAI 的 /chat/completions）';
+        }
+        if ($httpCode === 401) {
+            return '（请确认 API Key 是在 Dify 应用"访问 API"页面获取的密钥，而不是账号登录密码或 OpenAI Key）';
+        }
+        return '';
+    }
+
+    private static function parseErrorBody(?string $body): ?string
+    {
+        if (!$body) {
+            return null;
+        }
+        $json = json_decode($body, true);
+        if (json_last_error() === JSON_ERROR_NONE) {
+            return $json['message'] ?? null;
+        }
+        return trim($body) ?: null;
+    }
+
+    /**
+     * 将 Dify 插件/模型层的英文错误转为可操作的中文提示
+     */
+    public static function humanizeError(string $message): string
+    {
+        if (str_contains($message, "Unsupported chat content part type: 'file'")
+            || str_contains($message, 'Unsupported chat content part type')) {
+            return 'Dify 模型层仍不接受 file 类型。请确认 Dify 应用已开启文档上传，且 files.type 使用 document（不是 file）。'
+                . ' 原始错误：' . mb_substr($message, 0, 180);
+        }
+
+        if (str_contains($message, 'PluginInvokeError')) {
+            return 'Dify 插件调用失败，请检查 Dify 应用内模型供应商配置是否与图片输入兼容。'
+                . ' 详情：' . mb_substr($message, 0, 300);
+        }
+
+        return $message;
+    }
+}