proxy-events.md

Proxy Events

Subscribe to http-proxy events: error, proxyReq, proxyReqWs, proxyRes, open, close, start, end, econnreset.

on.error

Subscribe to http-proxy's error event.

const { createProxyMiddleware } = require('http-proxy-middleware');

const onError = function (err, req, res) {
  console.log('Something went wrong.');
  console.log('And we are reporting a custom error message.');
};

const options = {
  target: 'http://localhost:3000',
  on: { 'error', onError }
};

const apiProxy = createProxyMiddleware(options);

on.proxyReq

Subscribe to http-proxy's proxyReq event.

const { createProxyMiddleware } = require('http-proxy-middleware');

const onProxyReq = function (proxyReq, req, res) {
  // add new header to request
  proxyReq.setHeader('x-added', 'foobar');
};

const options = {
  target: 'http://localhost:3000',
  on: { proxyReq: onProxyReq },
};

const apiProxy = createProxyMiddleware(options);

on.proxyReqWs

Subscribe to http-proxy's proxyReqWs event.

const { createProxyMiddleware } = require('http-proxy-middleware');

const onProxyReqWs = function (proxyReq, req, socket, options, head) {
  // add custom header
  proxyReq.setHeader('X-Special-Proxy-Header', 'foobar');
};

const options = {
  target: 'http://localhost:3000',
  on: { proxyReqWs: onProxyReqWs },
};

const apiProxy = createProxyMiddleware(options);

on.proxyRes

Subscribe to http-proxy's proxyRes event.

const { createProxyMiddleware } = require('http-proxy-middleware');

const onProxyRes = function (proxyRes, req, res) {
  // add new header to response
  proxyRes.headers['x-added'] = 'foobar';

  // remove header from response
  delete proxyRes.headers['x-removed'];
};

const options = {
  target: 'http://localhost:3000',
  on: { proxyRes: onProxyRes },
};

const apiProxy = createProxyMiddleware(options);