frappe-mcp-server/src/errors.ts

Enhanced Model Context Protocol server for Frappe Framework with comprehensive API instructions and helper tools

import { AxiosError } from "axios";

/**
 * Error class for Frappe API errors
 */
export class FrappeApiError extends Error {
  statusCode?: number;
  endpoint?: string;
  details?: any;

  constructor(message: string, statusCode?: number, endpoint?: string, details?: any) {
    super(message);
    this.name = "FrappeApiError";
    this.statusCode = statusCode;
    this.endpoint = endpoint;
    this.details = details;
  }

  static fromAxiosError(error: AxiosError, operation: string): FrappeApiError {
    const statusCode = error.response?.status;
    const endpoint = error.config?.url || "unknown";
    let message = `Frappe API error during ${operation}: ${error.message}`;
    let details = null;

    // Check for connection errors first (no response)
    if (!error.response) {
      message = `Network error during ${operation}: ${error.message}`;
      details = { error: "Network error", code: error.code };
    }
    // Extract more detailed error information from Frappe's response
    else if (error.response) {
      const data = error.response.data as any;

      if (error.response.status === 401 || error.response.status === 403) {
        message = `Authentication failed during ${operation}. Check API key/secret.`;
        details = {
          error: "Authentication Error",
          status: error.response.status,
          statusText: error.response.statusText,
          responseData: data
        };
      } else if (data.exception) {
        message = `Frappe exception during ${operation}: ${data.exception}`;
        details = data;
      } else if (data._server_messages) {
        try {
          // Server messages are often JSON strings inside a string
          const serverMessages = JSON.parse(data._server_messages);
          const parsedMessages = Array.isArray(serverMessages)
            ? serverMessages.map((msg: string) => {
              try {
                return JSON.parse(msg);
              } catch {
                return msg;
              }
            })
            : [serverMessages];

          message = `Frappe server message during ${operation}: ${parsedMessages.map((m: any) => m.message || m).join("; ")}`;
          details = { serverMessages: parsedMessages };
        } catch (e) {
          message = `Frappe server message during ${operation}: ${data._server_messages}`;
          details = { serverMessages: data._server_messages };
        }
      } else if (data.message) {
        message = `Frappe API error during ${operation}: ${data.message}`;
        details = data;
      }
    }

    return new FrappeApiError(message, statusCode, endpoint, details);
  }
}

/**
 * Helper function to handle API errors
 */
export function handleApiError(error: any, operation: string): never {
  if (error.isAxiosError) {
    throw FrappeApiError.fromAxiosError(error, operation);
  } else {
    throw new FrappeApiError(
      `Error during ${operation}: ${(error as Error).message || 'Unknown error'}`,
      undefined, // statusCode
      undefined, // endpoint
      error // Pass original error as details
    );
  }
}