nest-digest-auth/src/index.ts

Digest Authentication wrapper using Axios, compatible with NestJS

import axios, { AxiosRequestHeaders, Method } from 'axios';
import * as crypto from 'crypto';

export class DigestAuthService {
  private md5(data: string): string {
    return crypto.createHash('md5').update(data).digest('hex');
  }

  private parseAuthHeader(authHeader: string): Record<string, string> {
    const authParams: Record<string, string> = {};
    const regex = /(\w+)=["]?([^",]+)["]?/g;
    let match: RegExpExecArray | null;

    while ((match = regex.exec(authHeader)) !== null) {
      authParams[match[1]] = match[2];
    }

    return authParams;
  }

  async digestRequest(
    options: {
      method: Method;
      url: string;
      headers?: AxiosRequestHeaders;
    },
    data: any,
    user: string,
    pass: string,
  ): Promise<any> {
    try {
      const initialRes = await axios({
        method: options.method,
        url: options.url,
        headers: options.headers || {},
        validateStatus: () => true,
      });

      if (
        initialRes.status !== 401 ||
        !initialRes.headers['www-authenticate']
      ) {
        throw new Error(
          `Expected 401 Unauthorized, got ${initialRes.status}`,
        );
      }

      const authDetails = this.parseAuthHeader(
        initialRes.headers['www-authenticate'],
      );

      const realm = authDetails.realm;
      const nonce = authDetails.nonce;
      const qop = authDetails.qop || 'auth';
      const cnonce = this.md5(Date.now().toString());
      const nc = '00000001';
      const method = options.method.toUpperCase();
      const urlObj = new URL(options.url);
      const path = urlObj.pathname + urlObj.search;

      const ha1 = this.md5(`${user}:${realm}:${pass}`);
      const ha2 = this.md5(`${method}:${path}`);
      const response = this.md5(
        `${ha1}:${nonce}:${nc}:${cnonce}:${qop}:${ha2}`,
      );

      const authHeader = `Digest username="${user}", realm="${realm}", nonce="${nonce}", uri="${path}", algorithm=MD5, response="${response}", qop=${qop}, nc=${nc}, cnonce="${cnonce}"`;

      const finalRes = await axios({
        method,
        url: options.url,
        headers: {
          ...(options.headers || {}),
          Authorization: authHeader,
          'Content-Type': 'application/json',
        },
        data,
      });

      return finalRes.data;
    } catch (error: any) {
      throw new Error(error?.message || 'Digest request failed');
    }
  }
}