@fontoxml/fontoxml-development-tools/src/modules/editor/dev-cms/connectors-cms-standard/configureConnectorsCmsStandardProxyRouter.js

Development tools for Fonto.

import express from 'express';
import { createProxyMiddleware } from 'http-proxy-middleware';
import typeIs from 'type-is';

import configureBodyParserMiddleware from './configureBodyParserMiddleware.js';
import correlationIdRepository from './correlationIdRepository.js';

/** @typedef {import('../../src/getAppConfig.js').DevCmsConfig} DevCmsConfig */

function getEditSessionToken(req) {
	if (req.query && req.query.context) {
		if (req.query.context.editSessionToken) {
			return req.query.context.editSessionToken;
		}

		try {
			const context = JSON.parse(req.query.context);
			if (context && context.editSessionToken) {
				return context.editSessionToken;
			}
		} catch (_error) {
			// Could not parse context as JSON, so ignore.
		}
	}

	if (req.body && req.body.context && req.body.context.editSessionToken) {
		// Use the edit session token from the request body. This is not supported for multi-part requests.
		// TODO: Should we support this on multi-part requests?
		return req.body.context.editSessionToken;
	}

	return undefined;
}

function requestHasJsonBody(req) {
	return !!typeIs(req, ['application/json']);
}

/**
 * @param {DevCmsConfig} config
 */
function configureConnectorsCmsStandardProxyRouter(config) {
	// eslint-disable-next-line new-cap
	const connectorsCmsStandardProxyRouter = express.Router();

	const bodyParserMiddleware = configureBodyParserMiddleware(config);

	// Create the Proxy middleware.
	const proxyCurrentRequest = createProxyMiddleware({
		// Custom router function with the target object.
		router(req) {
			const proxyName = req.params.proxyName;
			return config.proxy[proxyName];
		},

		secure: false,
		changeOrigin: true,
		logger: {
			error: console.error.bind(console),
			warn: console.warn.bind(console),
			info: () => undefined,
		},

		on: {
			proxyReq: (proxyReq, req, _res) => {
				const editSessionToken = getEditSessionToken(req);
				const correlationId =
					correlationIdRepository.createNewWithAllRequestsAsValidValidator(
						editSessionToken,
					);
				proxyReq.setHeader('Fonto-Correlation-Id', correlationId);

				if (requestHasJsonBody(req) && req.body) {
					// Write the JSON body to the proxied request, update the content-length header
					// to account for any stringify/prettify differences, and remove the
					// content-encoding header if there is one as we are forwarding without encoding.
					const body = JSON.stringify(req.body);
					proxyReq.removeHeader('content-encoding');
					proxyReq.setHeader('content-length', Buffer.byteLength(body));
					proxyReq.write(body);
					proxyReq.end();
				}
			},

			proxyRes: (proxyRes, _req, _res) => {
				correlationIdRepository.delete(
					proxyRes.req.getHeader('Fonto-Correlation-Id'),
				);
			},
		},
	});

	connectorsCmsStandardProxyRouter.use(
		'/connectors/cms/standard/proxy/:proxyName/',
		(req, res, next) => {
			if (requestHasJsonBody(req)) {
				// Parse JSON body to try and get the editSessionToken.
				bodyParserMiddleware(req, res, () => {
					proxyCurrentRequest(req, res, next);
				});
			} else {
				proxyCurrentRequest(req, res, next);
			}
		},
	);

	return connectorsCmsStandardProxyRouter;
}

export default configureConnectorsCmsStandardProxyRouter;