From 93ab6efe65bf64ccc6d939019618731c564c58a1 Mon Sep 17 00:00:00 2001
From: Misha Wolfson <misha@ginkgobioworks.com>
Date: Fri, 23 Dec 2016 00:18:44 -0600
Subject: [PATCH] Add ROOT_URL_PATH parsing

---
 lib/arguments.js |  4 ++++
 lib/spserver.js  | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/lib/arguments.js b/lib/arguments.js
index 95e9d52..685b625 100644
--- a/lib/arguments.js
+++ b/lib/arguments.js
@@ -41,4 +41,8 @@ module.exports = {
     alias: 'i',
     describe: 'IP server runs on [default: 0.0.0.0]'
   },
+  rooturlpath: {
+    alias: 'r',
+    describe: 'Root URL path server is deployed on; will be removed from URL when resolving to files [default: /]'
+  },
 };
diff --git a/lib/spserver.js b/lib/spserver.js
index fa3e440..f1537b7 100644
--- a/lib/spserver.js
+++ b/lib/spserver.js
@@ -3,6 +3,7 @@
 var fs = require('fs');
 var http = require('http');
 var path = require('path');
+var url = require('url');
 
 var _ = require('lodash');
 var nStatic = require('node-static');
@@ -32,6 +33,8 @@ function _resolveFinalSettings(settings) {
     finalSettings[field] = settings[field] || settings[env][field];
   });
 
+  finalSettings.rooturlpath = config.get('rooturlpath') || config.get('ROOT_URL_PATH') || '/';
+
   // For 'staticOptions', there are no command-line flags, so individual configuration options
   // override global defaults where set
   finalSettings.staticOptions = _.defaultsDeep(settings.staticOptions, settings[env].staticOptions);
@@ -66,6 +69,16 @@ function generateBase(file, finalSettings) {
   };
 }
 
+function _rerouteRootUrl(reqUrl, rootUrl) {
+  var parsedUrl = url.parse(reqUrl);
+
+  parsedUrl.pathname = path.normalize(
+    parsedUrl.pathname.replace(rootUrl, '/') || '/'
+  );
+
+  return url.format(parsedUrl);
+}
+
 var spserver = function (settings) {
   var finalSettings = _resolveFinalSettings(settings);
 
@@ -86,6 +99,8 @@ var spserver = function (settings) {
         '(' + res.statusCode + ')', 'took', requestTime, 'ms');
     };
 
+    req.url = _rerouteRootUrl(req.url, finalSettings.rooturlpath);
+
     res.addListener('finish', done);
     res.addListener('close', done);