From 497653d92e0f085580c6b8727114745a1e88a072 Mon Sep 17 00:00:00 2001
From: Lloyd Brookes <lloyd.brookes@gmail.com>
Date: Tue, 31 May 2016 09:31:44 +0100
Subject: [PATCH] proxy connection errors no longer crash the server, fixes #37

---
 bin/cli.js                             |  6 ++++++
 example/rewrite/.local-web-server.json |  1 +
 example/rewrite/index.html             |  2 ++
 lib/middleware.js                      | 21 +++++++++++----------
 4 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/bin/cli.js b/bin/cli.js
index 8de7ca6..056796a 100755
--- a/bin/cli.js
+++ b/bin/cli.js
@@ -62,6 +62,12 @@ if (options.misc.help) {
     mocks: options.server.mocks
   })
 
+  app.on('error', err => {
+    if (options.server['log-format']) {
+      console.error(ansi.format(err.message, 'red'))
+    }
+  })
+
   if (options.server.https) {
     options.server.key = path.resolve(__dirname, '..', 'ssl', '127.0.0.1.key')
     options.server.cert = path.resolve(__dirname, '..', 'ssl', '127.0.0.1.crt')
diff --git a/example/rewrite/.local-web-server.json b/example/rewrite/.local-web-server.json
index ae46592..1eb9003 100644
--- a/example/rewrite/.local-web-server.json
+++ b/example/rewrite/.local-web-server.json
@@ -2,6 +2,7 @@
   "rewrite": [
     { "from": "/css/*", "to": "/build/styles/$1" },
     { "from": "/npm/*", "to": "http://registry.npmjs.org/$1" },
+    { "from": "/broken/*", "to": "http://localhost:9999" },
     { "from": "/:user/repos/:name", "to": "https://api.github.com/repos/:user/:name" }
   ]
 }
diff --git a/example/rewrite/index.html b/example/rewrite/index.html
index 2711101..02dcfd3 100644
--- a/example/rewrite/index.html
+++ b/example/rewrite/index.html
@@ -9,6 +9,7 @@
   "rewrite": [
     { "from": "/css/*", "to": "/build/styles/$1" },
     { "from": "/npm/*", "to": "http://registry.npmjs.org/$1" },
+    { "from": "/broken/*", "to": "http://localhost:9999" },
     { "from": "/:user/repos/:name", "to": "https://api.github.com/repos/:user/:name" }
   ]
 }
@@ -18,5 +19,6 @@
 <ul>
   <li><a href="/css/style.css">/css/style.css</li>
   <li><a href="/npm/local-web-server">/npm/local-web-server</a></li>
+  <li><a href="/broken/">/broken/</a></li>
   <li><a href="/75lb/repos/work">/75lb/repos/work</a></li>
 </ul>
diff --git a/lib/middleware.js b/lib/middleware.js
index 559adac..984b768 100644
--- a/lib/middleware.js
+++ b/lib/middleware.js
@@ -15,14 +15,13 @@ exports.blacklist = blacklist
 exports.mockResponses = mockResponses
 exports.mime = mime
 
-function proxyRequest (route, app) {
+function proxyRequest (route) {
   const httpProxy = require('http-proxy')
   const proxy = httpProxy.createProxyServer({
     changeOrigin: true
   })
 
   return function proxyMiddleware () {
-    const next = arguments[arguments.length - 1]
     const keys = []
     route.re = pathToRegexp(route.from, keys)
     route.new = this.url.replace(route.re, route.to)
@@ -33,17 +32,19 @@ function proxyRequest (route, app) {
         .replace(re, arguments[index + 1] || '')
     })
 
-    this.response = false
     debug('proxy request', `from: ${this.path}, to: ${url.parse(route.new).href}`)
 
-    proxy.once('error', err => {
-      this.throw(500, `[PROXY] ${err.message}: ${route.new}`)
-    })
-    proxy.once('proxyReq', function (proxyReq) {
-      proxyReq.path = url.parse(route.new).path
+    return new Promise((resolve, reject) => {
+      proxy.once('error', err => {
+        err.message = `[PROXY] Error: ${err.message} Target: ${route.new}`
+        reject(err)
+      })
+      proxy.once('proxyReq', function (proxyReq) {
+        proxyReq.path = url.parse(route.new).path
+      })
+      proxy.once('close', resolve)
+      proxy.web(this.req, this.res, { target: route.new })
     })
-
-    proxy.web(this.req, this.res, { target: route.new })
   }
 }