koa-web-kit/routes/proxy.js

A modern, production-ready, and full-stack node web framework

/**
 * Request proxy for backend api
 */

const { PassThrough } = require('stream');
const Router = require('koa-router');

const { HttpClient } = require('../services/HttpClient');

exports.handleApiRequests = function(prefix, endPoint) {
  const routerPrefix = prefix.endsWith('/') ? prefix : `${prefix}/`;
  // TODO: a path rewrite?
  const router = new Router({ prefix: routerPrefix });
  const apiProxy = new HttpClient({ endPoint, prefix });
  router.all('*', async ctx => {
    const requestStream = apiProxy.proxyRequest(ctx);
    const pt = requestStream.pipe(PassThrough());
    try {
      await new Promise((resolve, reject) => {
        requestStream.on('response', response => {
          ctx.status = response.statusCode;
          ctx.set(response.headers);
          resolve();
        });
        requestStream.on('error', error => {
          reject(error);
        });
      });
    } catch (err) {
      ctx.status = 500;
      ctx.body = {
        code: err.code,
      };
      return;
    }
    ctx.body = pt;
  });
  return router.routes();
};