index.js

'use strict';

var async = require('async');
var crypto = require('crypto');
var Anyfetch = require('anyfetch');
var JSONc14n = require('./helpers/JSONc14n.js');

/**
 * HYDRATING FUNCTION
 *
 * @param {string} path Path of the specified file
 * @param {string} original document
 * @param {object} changes object provided by anyFetch's API. Update this object to send document's modification to anyFetch's API.
 * @param {function} cb Callback, first parameter is the error if any, then the processed data
 */
module.exports = function(path, document, changes, cb) {
  var anyfetch = new Anyfetch(document.access_token);
  anyfetch.setApiUrl(cb.apiUrl);

  var haveChanges = true;
  async.waterfall([
    function generateHash(cb) {
      var shasum = crypto.createHash('sha1');

      delete document.metadata.hash;

      shasum.update(JSONc14n.stringify(document.metadata));
      cb(null, shasum.digest('hex'));
    },
    function getDocumentsWithSameHash(hash, cb) {
      changes.metadata = {
        hash: hash
      };

      anyfetch.getDocuments({'@hash': hash, 'fields': 'data'}, cb);
    },
    function deleteOldDocuments(res, cb) {
      var documents = res.body.data;

      var containsDocument = documents.some(function(current) {
        return current.id === document.id;
      });

      if(!containsDocument) {
        documents.push(document);
      }

      var mostRecentDocument = documents.reduce(function(previousDoc, currentDoc) {
        if(new Date(previousDoc.modification_date) > new Date(currentDoc.modification_date)) {
          return previousDoc;
        }
        else {
          return currentDoc;
        }
      });

      haveChanges = (mostRecentDocument.id === document.id);

      async.each(documents, function(deletedDocument, cb) {
        if(deletedDocument.id !== mostRecentDocument.id) {
          console.log("DELETE", deletedDocument.identifier);
          anyfetch.deleteDocumentById(deletedDocument.id, function(err) {
            if(err && err.toString().match(/404/)) {
              err = null;
            }

            cb(err);
          });
        }
        else {
          cb(null);
        }
      }, cb);
    }
  ], function(err) {
    cb(err, haveChanges ? changes : null);
  });
};