Zapier Node/JS step performing HTTP Digest Auth + Multipart/form-data example

zapier-http-digest-multipart-async-example.js

// Kudos for this repo: https://github.com/simme/node-http-digest-client
// Original `node-http-digest-client` license: Copyright (c) 2012, Simon Ljungberg <[email protected]>
// Adapted by @ddpelayo / github.com/davidpelayo / davidpelayo.com - to Modern Javascript
const HTTPDigest = function () {
  const crypto = require('crypto');
  let http = require('http');

  const HTTPDigest = function (username, password, https) {
    this.nc = 0;
    this.username = username;
    this.password = password;
    if (https === true) {
      http = require('https');
    }
  };

  HTTPDigest.prototype.request = function (options, callback) {
    const firstRequest = http.request({
      ...options,
      postData: undefined
    }, (firstRequestResponse) => this._handleResponse(options, firstRequestResponse, callback));

    for (let data of options.postData) {
      firstRequest.write(data);
    }

    return firstRequest.end();
  };

  HTTPDigest.prototype._handleResponse = function (options, res, callback) {
    const challenge = this._parseChallenge(res.headers['www-authenticate']);
    const ha1 = crypto.createHash('md5');
    ha1.update([this.username, challenge.realm, this.password].join(':'));
    const ha2 = crypto.createHash('md5');
    ha2.update([options.method, options.path].join(':'));

    // Generate cnonce
    let cnonce = false;
    let nc = false;
    if (typeof challenge.qop === 'string') {
      var cnonceHash = crypto.createHash('md5');
      cnonceHash.update(Math.random().toString(36));
      cnonce = cnonceHash.digest('hex').substr(0, 8);
      nc = this.updateNC();
    }

    // Generate response hash
    const response = crypto.createHash('md5');
    const responseParams = [
      ha1.digest('hex'),
      challenge.nonce
    ];

    if (cnonce) {
      responseParams.push(nc);
      responseParams.push(cnonce);
    }

    responseParams.push(challenge.qop);
    responseParams.push(ha2.digest('hex'));
    response.update(responseParams.join(':'));

    // Setup response parameters
    const authParams = {
      username: this.username,
      realm: challenge.realm,
      nonce: challenge.nonce,
      uri: options.path,
      qop: challenge.qop,
      response: response.digest('hex'),
      opaque: challenge.opaque
    };
    if (cnonce) {
      authParams.nc = nc;
      authParams.cnonce = cnonce;
    }

    const headers = options.headers || {};
    headers.Authorization = this._compileParams(authParams);
    options.headers = headers;

    const realmedRequest = http.request({
      ...options,
      postData: undefined
    }, callback);

    for (let data of options.postData) {
      realmedRequest.write(data);
    }

    realmedRequest.end();
  };

  HTTPDigest.prototype._parseChallenge = function (digest) {
    const prefix = "Digest ";
    const challenge = digest.substr(digest.indexOf(prefix) + prefix.length);
    const parts = challenge.split(',');
    const length = parts.length;
    const params = {};
    for (let i = 0; i < length; i++) {
      const part = parts[i].match(/^\s*?([a-zA-Z0-0]+)="(.*)"\s*?$/);
      if (part && part.length > 2) {
        params[part[1]] = part[2];
      }
    }

    return params;
  };

  HTTPDigest.prototype._compileParams = function (params) {
    const parts = [];
    for (let i in params) {
      parts.push(i + '="' + params[i] + '"');
    }
    return 'Digest ' + parts.join(',');
  };

  HTTPDigest.prototype.updateNC = function () {
    const max = 99999999;
    this.nc++;
    if (this.nc > max) {
      this.nc = 1;
    }
    const padding = new Array(8).join('0') + "";
    const nc = this.nc + "";
    return padding.substr(0, 8 - nc.length) + nc;
  };

  // Return response handler
  return HTTPDigest;
}();

// Look first how HTTP Digest Auth works: https://en.wikipedia.org/wiki/Digest_access_authentication
// Or Google, to know what the above `HTTPDigest` module is doing
// Read how the Zapier scripts work: https://zapier.com/help/create/code-webhooks/javascript-code-examples-in-zaps#step-1
const csvAttachmentData = `Some;csv;file`;
const boundary = '__X_PAW_BOUNDARY__';
const postData = [`--${boundary}`, `\r\nContent-Disposition: form-data; name=\"file\"; filename=\"file.csv\"\r\n`, `Content-Type: text/csv \r\n\r\n`, csvAttachmentData, `\r\n--${boundary}\r\n`];
const postDataLength = postData.reduce((acc, curr) => acc += Buffer.byteLength(curr), 0)
const digestClient = new HTTPDigest('user', 'password', true);
const digestRequestPayload = {
  host: 'httpbin.org',
  path: 'digest-auth/auth/user/pass',
  port: 443,
  method: 'POST',
  headers: {
    'Cache-Control': 'no-cache',
    'Content-Type': `multipart/form-data; charset=utf-8; boundary=${boundary}`,
    'Content-Length': postDataLength,
    'Accept': '*/*'
  },
  postData
};

const digestRequest = digestClient.request(digestRequestPayload, function (secondRequestResponse) {
  secondRequestResponse.on('data', (data) => {
    console.log('[Second request] data:', data.toString());
    callback(null, [{
      csv: csvAttachmentData
    }])
  });
  secondRequestResponse.on('error', () => {
    console.log('[Second request] Some error happened')
    callback(err.message, [])
  })
  secondRequestResponse.on('end', () => console.log('[Second request] connection ended'));
});

var output = [{
  id: digestRequest,
  hello: "world",
}];