index.js

const express = require('express');
const bodyParser = require('body-parser')
const path = require('path');
const elasticsearch = require('elasticsearch');

const client = new elasticsearch.Client({
    hosts: ['http://localhost:9200']
});

const app = express();


// ping the client to be sure Elasticsearch is up
client.ping({
    requestTimeout: 30000,
}, function(error) {
    if (error) {
        console.error('elasticsearch cluster is down!');
    } else {
        console.log('Everything is ok');
    }
});

app.use(bodyParser.json())

app.set('port', process.env.PORT || 3001);


app.use(express.static(path.join(__dirname, 'public')));


app.use(function(req, res, next) {
    res.header("Access-Control-Allow-Origin", "*");
    res.header('Access-Control-Allow-Methods', 'PUT, GET, POST, DELETE, OPTIONS');
    res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
    next();
});


app.get('/', function(req, res) {
    res.sendFile('template.html', {
        root: path.join(__dirname, '../views')
    });
})

app.get('/search', function(req, res) {

    let body = {
        size: 200,
        from: 0,
        query: {
            match: {
                name: req.query['q']
            }
        }
    }

    client.search({ index: 'scotch.io-tutorial', body: body, type: 'cities_list' })
        .then(results => {
            res.send(results.hits.hits);
        })
        .catch(err => {
            console.log(err)
            res.send([]);
        });

})

app.listen(app.get('port'), function() {
    console.log('Express server listening on port ' + app.get('port'));
});