How to iterate mongodb database in node.js to send to Algolia?

Question

In the documentation of Algolia, for the node.js part they specified to use MySQL for indexing but not MongoDB, I have another question regarding this issue but it is more a general question , check here

Some folks ask me to use mongo-connector but tried it and I got some unknown error, which got me to square one

My real question is, how do i iterate a list of collections in mongodb to algolia?

This is the Algolia's version of MySQL in Node.js

var _ = require('lodash');
var async = require('async');
var mysql = require('mysql');

var algoliasearch = require('algoliasearch');
var client = algoliasearch("RQGLD4LOQI", "••••••••••••••••••••••••••••••••");
var index = client.initIndex('YourIndexName');

var connection = mysql.createConnection({
  host: 'localhost',
  user: 'mysql_user',
  password: 'mysql_password',
  database: 'YourDatabaseName'
});

connection.query('SELECT * FROM TABLE_TO_IMPORT', function(err, results, fields) {
  if (err) {
    throw err;
  }

  // let's use table IDS as Algolia objectIDs
  results = results.map(function(result) {
    result.objectID = result.id;
    return result;
  });

  // split our results into chunks of 5,000 objects, to get a good indexing/insert performance
  var chunkedResults = _.chunk(results, 5000);

  // for each chunk of 5,000 objects, save to algolia, in parallel. Call end() when finished
  // or if any save produces an error
  // https://github.com/caolan/async#eacharr-iterator-callback
  async.each(chunkedResults, index.saveObjects.bind(index), end);
});

function end(err) {
  if (err) {
    throw err;
  }

  console.log('MySQL<>Algolia import done')
};

To be specific I'm using mongoose as my ORM, so I have no experience in other libraries. Please help me on this, so that I could some searching interface already :(.

Answer 1

You can use the following code to iterate over the whole MongoDB mydb.myCollection collection + create batches that will be sent to the Algolia index:

var Db = require('mongodb').Db,
    Server = require('mongodb').Server,
    algoliasearch = require('algoliasearch');

// init Algolia index
var client = algoliasearch("*********", "••••••••••••••••••••••••••••••••");
var index = client.initIndex('YourIndexName');

// init connection to MongoDB
var db = new Db('mydb', new Server('localhost', 27017));
db.open(function(err, db) {
  // get the collection
  db.collection('myCollection', function(err, collection) {
    // iterate over the whole collection using a cursor
    var batch = [];
    collection.find().forEach(function(doc) {
      batch.push(doc);
      if (batch.length > 10000) {
        // send documents by batch of 10000 to Algolia
        index.addObjects(batch);
        batch = [];
      }
    });
    // last batch
    if (batch.length > 0) {
      index.addObjects(batch);
    }
  });
});