Connect Reactivesearch to an external Elasticsearch cluster using proxy?

[mussa572]

I am trying to connect my reacetivesearch application to external elasticsearch provider( not AWS). They dont allow making changes to the elasticsearch cluster and also using nginx in front of the cluster .

As per the reacetivesearch documentation I have cloned the proxy code and only made changes to the target and the authentication setting(as per the code below ) .

https://github.com/appbaseio-apps/reactivesearch-proxy-server/blob/master/index.js

Proxy is successfully starting and able to connect the remote cluster . However when I connect reacetivesearch app through proxy I get the following error.

Access to XMLHttpRequest at 'http://localhost:7777/testing/_msearch?' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource

I repeated the same steps with my local elasticsearch cluster using the same proxy code and getting the same error .

Just was wondering do we need to make any extra changes to make sure the proxy sending the right request to the elasticsearch cluster ? I am using the below code for the proxy.

const express = require('express');
const proxy = require('http-proxy-middleware');
const btoa = require('btoa');
const app = express();
const bodyParser = require('body-parser')

/* This is where we specify options for the http-proxy-middleware
 * We set the target to appbase.io backend here. You can also
 * add your own backend url here */
const options = {
    target: 'http://my_elasticsearch_cluster_adddress:9200/',
    changeOrigin: true,
    onProxyReq: (proxyReq, req) => {
        proxyReq.setHeader(
            'Authorization',
            `Basic ${btoa('username:password')}`
        );
        /* transform the req body back from text */
        const { body } = req;
        if (body) {
            if (typeof body === 'object') {
                proxyReq.write(JSON.stringify(body));
            } else {
                proxyReq.write(body);
            }
        }
    }
}

/* Parse the ndjson as text */
app.use(bodyParser.text({ type: 'application/x-ndjson' }));

/* This is how we can extend this logic to do extra stuff before
 * sending requests to our backend for example doing verification
 * of access tokens or performing some other task */
app.use((req, res, next) => {
    const { body } = req;
    console.log('Verifying requests ✔', body);
    /* After this we call next to tell express to proceed
     * to the next middleware function which happens to be our
     * proxy middleware */
    next();
})

/* Here we proxy all the requests from reactivesearch to our backend */
app.use('*', proxy(options));

app.listen(7777, () => console.log('Server running at http://localhost:7777 🚀'));

[coolb0y]

I hope you have solved your issue but this might help someone to prevent the cors error you need to import cors module . Add lines below . You need to add one more line if you are facing 500 error of bad request in backend which probably you will . Change option to this code

const cors = require('cors')

const options = {
    target: 'http://my_elasticsearch_cluster_adddress:9200/',
    secure: 'false',
    changeOrigin: true,
    onProxyReq: (proxyReq, req) => {
        proxyReq.setHeader(
            'Authorization',
            `Basic ${btoa('username:password')}`
        );
        /* transform the req body back from text */
        const { body } = req;
        if (body) {
            if (typeof body === 'object') {
                proxyReq.write(JSON.stringify(body));
            } else {
                proxyReq.write(body);
            }
        }
    }
}
app.use(cors());