Dify Workflow MCP Tool Server

import fetch, { Response as FetchResponse } from "node-fetch"; import { DifyInfoResponse, DifyParametersResponse, DifyWorkflowResponse } from "../types.js"; import { Config } from "../config.js"; // APIリクエストに関するエラークラス export class ApiError extends Error { statusCode: number; statusText: string; endpoint: string; constructor(message: string, statusCode: number, statusText: string, endpoint: string) { super(message); this.name = "ApiError"; this.statusCode = statusCode; this.statusText = statusText; this.endpoint = endpoint; } } // HTTP通信インターフェース（テスト容易性のため抽象化） export interface HttpClient { request(url: string, options: RequestOptions): Promise<HttpResponse>; } export interface RequestOptions { method?: string; headers?: Record<string, string>; body?: string; } export interface HttpResponse { ok: boolean; status: number; statusText: string; text(): Promise<string>; } // Dify APIクライアントのインターフェース export interface DifyClient { fetchInfo(apiKey: string): Promise<DifyInfoResponse>; fetchParameters(apiKey: string): Promise<DifyParametersResponse>; runWorkflow(apiKey: string, params: Record<string, any>): Promise<DifyWorkflowResponse>; } // レスポンスパーサーインターフェース export interface ResponseParser { parse<T>(text: string): T; } // 標準のレスポンスパーサー実装 export class JsonResponseParser implements ResponseParser { parse<T>(text: string): T { return JSON.parse(text) as T; } } // 標準のHTTPクライアント実装 export class FetchHttpClient implements HttpClient { async request(url: string, options: RequestOptions): Promise<HttpResponse> { const response = await fetch(url, options as any); return { ok: response.ok, status: response.status, statusText: response.statusText, text: async () => response.text() }; } } // APIクライアントの実装 export class DifyApiClient implements DifyClient { private readonly config: Config; private readonly httpClient: HttpClient; private readonly responseParser: ResponseParser; constructor( config: Config, httpClient: HttpClient = new FetchHttpClient(), responseParser: ResponseParser = new JsonResponseParser() ) { this.config = config; this.httpClient = httpClient; this.responseParser = responseParser; } // APIキーをマスクする（ログ出力用） private maskApiKey(apiKey: string): string { if (apiKey.length <= 8) { return "********"; } return `${apiKey.substring(0, 4)}...${apiKey.substring(apiKey.length - 4)}`; } // レスポンスエラーを処理 private async handleApiResponseError(response: HttpResponse, endpoint: string, apiKey: string): Promise<never> { const errorText = await response.text().catch(() => "Could not retrieve response text"); console.error(`${endpoint} API error code: ${response.status}`); console.error(`${endpoint} API error message: ${response.statusText}`); console.error(`${endpoint} API error response: ${errorText}`); console.error(`API Key (masked): ${this.maskApiKey(apiKey)}`); throw new ApiError( `${endpoint} API error: ${response.status} ${response.statusText}`, response.status, response.statusText, endpoint ); } // JSONパースエラーを処理 private handleParseError(error: unknown, endpoint: string): never { console.error(`${endpoint} JSON parse error:`, error); if (error instanceof Error) { console.error(`Error stack: ${error.stack}`); } throw new Error(`Failed to parse ${endpoint} API response: ${error}`); } // 共通のリクエストヘッダーを生成 private createHeaders(apiKey: string): Record<string, string> { return { "Authorization": `Bearer ${apiKey}`, "Content-Type": "application/json" }; } // APIエンドポイントURLを生成 private getEndpointUrl(path: string): string { const baseUrl = this.config.getBaseUrl(); return `${baseUrl}${path}`; } // /info エンドポイントにリクエスト async fetchInfo(apiKey: string): Promise<DifyInfoResponse> { const url = this.getEndpointUrl("/info"); const headers = this.createHeaders(apiKey); const infoResponse = await this.httpClient.request(url, { headers }); if (!infoResponse.ok) { await this.handleApiResponseError(infoResponse, "/info", apiKey); } const infoDataText = await infoResponse.text(); try { return this.responseParser.parse<DifyInfoResponse>(infoDataText); } catch (parseError) { this.handleParseError(parseError, "/info"); } } // /parameters エンドポイントにリクエスト async fetchParameters(apiKey: string): Promise<DifyParametersResponse> { const url = this.getEndpointUrl("/parameters"); const headers = this.createHeaders(apiKey); const paramsResponse = await this.httpClient.request(url, { headers }); if (!paramsResponse.ok) { await this.handleApiResponseError(paramsResponse, "/parameters", apiKey); } const paramsDataText = await paramsResponse.text(); try { return this.responseParser.parse<DifyParametersResponse>(paramsDataText); } catch (parseError) { this.handleParseError(parseError, "/parameters"); } } // /workflows/run エンドポイントにリクエスト async runWorkflow(apiKey: string, params: Record<string, any>): Promise<DifyWorkflowResponse> { const url = this.getEndpointUrl("/workflows/run"); const headers = this.createHeaders(apiKey); const apiConfig = this.config.getApiRequestConfig(); const body = JSON.stringify({ inputs: params, response_mode: apiConfig.responseMode, user: apiConfig.userId }); const response = await this.httpClient.request(url, { method: "POST", headers, body }); if (!response.ok) { await this.handleApiResponseError(response, "/workflows/run", apiKey); } const resultText = await response.text(); try { return this.responseParser.parse<DifyWorkflowResponse>(resultText); } catch (parseError) { console.error("Failed to parse workflow execution response:", parseError); console.error("Response text:", resultText); this.handleParseError(parseError, "/workflows/run"); } } }