feat: handle proxy cookies, origin & body parsing (POST & PUT)

Author: ROUSSE Kevin

src/proxy.ts

@@ -1,12 +1,53 @@
 import express from 'express';
-import { createProxyServer } from 'http-proxy';
+import { ClientRequest } from 'http';
+import { createProxyServer, ProxyReqCallback, ProxyResCallback } from 'http-proxy';
+import * as querystring from 'querystring';
 
-const proxy = createProxyServer({ changeOrigin: true });
+import { ProxyParams } from './stubServer';
 
-// Exported for testing purposes only, see [Jest mock inner function](https://stackoverflow.com/q/51269431)
+// [Body Parsing with express](https://github.com/chimurai/http-proxy-middleware/issues/320)
+const handleBodyParsing: ProxyReqCallback = (proxyReq, req) => {
+  // @ts-ignore
+  const { body } = req;
 
-export const send = (
+  const contentType = proxyReq.getHeader('Content-Type');
+  const writeBody = (_body: string) => {
+    proxyReq.setHeader('Content-Length', Buffer.byteLength(_body));
+    proxyReq.write(_body);
+  };
+
+  if (
+    contentType === 'application/json' ||
+    (Array.isArray(contentType) && contentType.includes('application/json'))
+  ) {
+    writeBody(JSON.stringify(body));
+  }
+
+  if (
+    contentType === 'application/x-www-form-urlencoded' ||
+    (Array.isArray(contentType) && contentType.includes('application/x-www-form-urlencoded'))
+  ) {
+    writeBody(querystring.stringify(body));
+  }
+};
+
+const changeOrigin = (proxyReq: ClientRequest, origin: string | undefined) => {
+  if (origin) {
+    proxyReq.setHeader('Origin', origin);
+  }
+};
+
+const removeSecurityFromCookie: ProxyResCallback = proxyRes => {
+  /* eslint-disable no-param-reassign */
+  proxyRes.headers['set-cookie'] = proxyRes.headers['set-cookie']?.map((cookie: string) =>
+    cookie.replace('Path=/; Secure', 'Path=/')
+  );
+  /* eslint-enable no-param-reassign */
+};
+
+const send = (
   target: string,
+  params: ProxyParams,
   req: express.Request,
   res: express.Response,
   next: express.NextFunction
@@ -21,5 +62,20 @@ export const send = (
   //
   // [Proxy with express.js](https://stackoverflow.com/q/10435407)
 
+  const { host = false, origin } = params;
+
+  const proxy = createProxyServer({
+    target,
+    changeOrigin: true,
+    cookieDomainRewrite: host
+  });
+
+  proxy.on('proxyReq', (proxyReq, ...args) => {
+    changeOrigin(proxyReq, origin);
+    handleBodyParsing(proxyReq, ...args);
+  });
+  proxy.on('proxyRes', removeSecurityFromCookie);
   proxy.web(req, res, { target }, next);
 };
+
+export { send };

src/stubServer.test.ts

@@ -3,7 +3,7 @@ import path from 'path';
 import request from 'supertest';
 
 import * as proxy from './proxy';
-import { stubServer } from './stubServer';
+import { ProxyParams, stubServer } from './stubServer';
 
 const configPath = path.resolve(__dirname, 'config-test', 'config');
 
@@ -205,6 +205,7 @@ describe('proxy', () => {
         .mockImplementationOnce(
           (
             _target: string,
+            _params: ProxyParams,
             _req: express.Request,
             res: express.Response,
             _next: express.NextFunction
@@ -225,6 +226,7 @@ describe('proxy', () => {
         .mockImplementationOnce(
           (
             _target: string,
+            _params: ProxyParams,
             _req: express.Request,
             _res: express.Response,
             next: express.NextFunction
@@ -258,6 +260,7 @@ describe('proxy', () => {
         .mockImplementationOnce(
           (
             _target: string,
+            _params: ProxyParams,
             _req: express.Request,
             res: express.Response,
             _next: express.NextFunction

src/stubServer.ts

@@ -19,12 +19,17 @@ type Response = {
 
 type Route = { delay?: Delay } & { headers?: IncomingHttpHeaders } & Response;
 
+export interface ProxyParams {
+  host: string | undefined;
+  origin: string | undefined;
+}
 export interface StubServerConfig {
   delay?: Delay;
   headers?: IncomingHttpHeaders;
   routes: {
     [apiPath: string]: Route;
   };
+  proxyParams?: ProxyParams;
 }
 
 // Allows to modify the imported files without restarting the server
@@ -97,6 +102,7 @@ async function parseConfig(apiPath: string, req: express.Request) {
 
 async function processStubRequest(
   apiPath: string,
+  proxyParams: ProxyParams,
   req: express.Request,
   res: express.Response,
   next: express.NextFunction
@@ -105,7 +111,7 @@ async function processStubRequest(
 
   if (isUrl(stubName)) {
     const url = stubName;
-    send(url, req, res, next);
+    send(url, proxyParams, req, res, next);
   } else {
     const filename = stubName;
 
@@ -154,14 +160,16 @@ export function stubServer(configPath: string, app: express.Application) {
 
   _configPath = configPath;
 
-  const { routes } = getConfig();
+  const { routes, proxyParams } = getConfig();
+
+  const defaultProxyParams = { host: undefined, origin: undefined };
 
   Object.entries(routes).forEach(([apiPath, route]) => {
     Object.keys(route).forEach(httpVerb => {
       if (httpVerb !== 'delay' && httpVerb !== 'headers') {
         // If invalid HTTP verb, crash with "TypeError: app[httpVerb] is not a function"
         app[httpVerb.toLowerCase() as ExpressRoute](apiPath, (req, res, next) =>
-          processStubRequest(apiPath, req, res, next)
+          processStubRequest(apiPath, proxyParams || defaultProxyParams, req, res, next)
         );
       }
     });