[501] Repairs => Can't use proxy() twice in Express middleware stack.

Author: nik-blue-lava

app/steps/buildProxyReq.js

@@ -10,15 +10,21 @@ function buildProxyReq(Container) {
   var host = Container.proxy.host;
 
   var parseBody = (!options.parseReqBody) ? Promise.resolve(null) : requestOptions.bodyContent(req, res, options);
+
   var createReqOptions = requestOptions.create(req, res, options, host);
 
   return Promise
     .all([parseBody, createReqOptions])
     .then(function (responseArray) {
+      req.body = responseArray[0];
       Container.proxy.bodyContent = responseArray[0];
       Container.proxy.reqBuilder = responseArray[1];
       debug('proxy request options:', Container.proxy.reqBuilder);
       return Container;
+    })
+    .catch(function (err) {
+      debug('error occurred while building proxy request:', err);
+      return Promise.reject(err);
     });
 }
 

app/steps/maybeSkipToNextHandler.js

@@ -11,7 +11,6 @@ function maybeSkipToNextHandler(container) {
     .resolve(resolverFn(container.proxy.res))
     .then(function (shouldSkipToNext) {
       if (shouldSkipToNext) {
-        container.user.res.expressHttpProxy = container.proxy;
         return Promise.reject();
       } else {
         return Promise.resolve(container);

index.js

@@ -44,16 +44,17 @@ module.exports = function proxy(host, userOptions) {
       .then(decorateUserRes)
       .then(sendUserRes)
       .catch(function (err) {
-        // I sometimes reject without an error to shortcircuit the remaining
-        // steps and return control to the host application.
-
         if (err) {
           var resolver = (container.options.proxyErrorHandler) ?
             container.options.proxyErrorHandler :
             handleProxyErrors;
           resolver(err, res, next);
         } else {
-          next();
+          // I sometimes reject without an error to shortcircuit the remaining
+          // steps -- e.g. in maybeSkipToNextHandler -- and return control to
+          // the host application for continuing on without raising an error.
+
+          return next();
         }
       });
   };

lib/requestOptions.js

@@ -91,7 +91,7 @@ function bodyContent(req, res, options) {
     if (req.body) {
       return Promise.resolve(req.body);
     } else {
-      // Returns a promise if no callback specified and global Promise exists.
+      // Returns a promise
 
       return getRawBody(req, {
         length: req.headers['content-length'],

package.json

@@ -8,7 +8,7 @@
   "main": "index.js",
   "scripts": {
     "test": "npm -s run mocha && npm run -s lint",
-    "test:debug": "mocha debug -R spec test --recursive --exit",
+    "test:debug": "mocha inspect --debug-brk -R spec test --recursive --exit",
     "mocha": "mocha -R spec test --recursive --exit",
     "lint": "eslint index.js app/**/*js lib/*js"
   },

test/defineMultipleProxyHandlers.js

@@ -0,0 +1,88 @@
+'use strict';
+
+var assert = require('assert');
+var express = require('express');
+var http = require('http');
+var startProxyTarget = require('./support/proxyTarget');
+var proxy = require('../');
+
+function fakeProxyServer({path, port, response}) {
+  var proxyRouteFn = [{
+    method: 'get',
+    path: path,
+    fn: function (req, res) {
+      res.write(response);
+      res.end();
+    }
+  }];
+
+  return startProxyTarget(port, 1000, proxyRouteFn);
+}
+
+function simulateUserRequest() {
+  return new Promise(function (resolve, reject) {
+
+    var req = http.request({ hostname: 'localhost', port: 8308, path: '/' }, function (res) {
+      var chunks = [];
+      res.on('data', function (chunk) { chunks.push(chunk.toString()); });
+      res.on('end', function () { resolve(chunks); });
+    });
+
+    req.on('error', function (e) {
+      reject('problem with request:', e.message);
+    });
+
+    req.end();
+  })
+}
+
+describe('handle multiple proxies in the same runtime', function () {
+  this.timeout(3000);
+
+  var server;
+  var  targetServer, targetServer2;
+
+  beforeEach(function () {
+    targetServer = fakeProxyServer({path:'/', port: '8309', response: '8309_response'});
+    targetServer2 = fakeProxyServer({path: '/', port: '8310', response: '8310_response'});
+  });
+
+  afterEach(function () {
+    server.close();
+    targetServer.close();
+    targetServer2.close();
+  });
+
+
+  describe("When two distinct proxies are defined for the global route", () => {
+    afterEach(() => server.close())
+
+    it('the first proxy definition should be used if it succeeds', function (done) {
+      var app = express();
+      app.use(proxy('http://localhost:8309', {}));
+      app.use(proxy('http://localhost:8310', {}));
+      server = app.listen(8308)
+      simulateUserRequest()
+        .then(function (res) {
+          assert.equal(res[0], '8309_response');
+          done();
+        })
+        .catch(done);
+    });
+
+    it('the fall through definition should be used if the prior skipsToNext', function (done) {
+      var app = express();
+      app.use(proxy('http://localhost:8309', {
+        skipToNextHandlerFilter: () => { return true } // no matter what, reject this proxy request, and call next()
+      }));
+      app.use(proxy('http://localhost:8310'))
+      server = app.listen(8308)
+      simulateUserRequest()
+        .then(function (res) {
+          assert.equal(res[0], '8310_response');
+          done();
+        })
+        .catch(done);
+    });
+  })
+});

test/maybeSkipToNextHandler.js

@@ -17,7 +17,7 @@ describe('when skipToNextHandlerFilter is defined', function () {
   beforeEach(function () {
     app = express();
     slowTarget = express();
-    slowTarget.use(function (req, res) { res.sendStatus(404); });
+    slowTarget.use(function (req, res) { res.sendStatus(407); });
     serverReference = slowTarget.listen(12345);
   });
 
@@ -26,8 +26,8 @@ describe('when skipToNextHandlerFilter is defined', function () {
   });
 
   var OUTCOMES = [
-    { shouldSkip: true, expectedStatus: 200 },
-    { shouldSkip: false, expectedStatus: 404 }
+    { shouldSkip: false, expectedStatus: 407 },
+    { shouldSkip: true, expectedStatus: 203 },
   ];
 
   OUTCOMES.forEach(function (outcome) {
@@ -41,10 +41,7 @@ describe('when skipToNextHandlerFilter is defined', function () {
         }));
 
         app.use(function (req, res) {
-          assert(res.expressHttpProxy instanceof Object);
-          assert(res.expressHttpProxy.res instanceof http.IncomingMessage);
-          assert(res.expressHttpProxy.req instanceof Object);
-          res.sendStatus(200);
+          res.sendStatus(203);
         });
 
         request(app)