MCP to read XLSX table (by data/url)

intex.ts

import { WorkerEntrypoint } from 'cloudflare:workers'
import { ProxyToSelf } from 'workers-mcp'
import XLSX from 'xlsx'

export default class MCPTableReader extends WorkerEntrypoint<Env> {
  /**
   * Read an xlsx file from a url or binary data
   * @param source {string | ArrayBuffer | Uint8Array} the url or binary data to read
   * @param sheetName {string} the name of the sheet to read
   * @param startRow {number} the starting row to read
   * @param endRow {number} the ending row to read
   * @return {string} the contents as a string
   */
  async readXlsx(
    source: string | ArrayBuffer | Uint8Array,
    sheetName: string = 'Sheet1',
    startRow: number = 0,
    endRow: number = 100,
  ) {
    try {
      let data: Uint8Array;

      if (typeof source === 'string') {
        const response = await fetch(source, {
          headers: {
            'accept': '*/*',
            'accept-language': 'en-GB,en-US;q=0.9,en;q=0.8',
            'user-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36'
          }
        });

        if (!response.ok) {
          throw new Error(`Failed to download XLSX: ${response.status}`);
        }

        const arrayBuffer = await response.arrayBuffer();
        data = new Uint8Array(arrayBuffer);
      } else {
        data = source instanceof Uint8Array ? source : new Uint8Array(source);
      }

      const workbook = XLSX.read(data, { type: 'array' });
      
      const sheet = workbook.Sheets[sheetName];
      if (!sheet) {
        throw new Error(`Sheet "${sheetName}" not found`);
      }

      const rows = XLSX.utils.sheet_to_json(sheet, { header: 1, range: startRow });
      const selectedRows = rows.slice(0, endRow - startRow);

      return `XLSX data read successfully (rows ${startRow} - ${endRow}):\n ${JSON.stringify(selectedRows)}`;
    } catch (error) {
      console.error('Error reading XLSX:', error);
      throw error;
    }
  }
}