Automatically support different Express app deployment strategies such as FastCGI, Passenger, and node http.

Usage no npm install needed!

<script type="module">
  import expressHttpAutodetect from '';


This module is being renamed to express-autoserve.

Autodetect the server platform and delegate to an Express app.


const expressHttpAutodetect = require('express-http-autodetect');
const app = require('./app');




The node http module has no concept of baseUrl because it assumes it will get to open the TCP socket itself and just serve out pages at /. However, various deployment strategies supported by http-autodetect are commonly used to deploy applications at URIs other than /. Thus http-autodetect provides a getBaseUrl(req) function to discover the baseUrl for the current request (in FastCGI, the necessary information is not available until a request is received).

Express supports mounting applications at sub-paths. To enable mounted applications to generate absolute URIs to resources within the apps, it provide the req.baseUrl property. This enables the following to work sensibly:

const express = require('express');

const app = express();

const subApp = express();
subApp.get('/asdf', function (req, res) {
   // When mounted, will get /subApp/foo
  res.send(`Another resource on this app is ${req.baseUrl}/foo`);
subApp.get('/foo', function (req, res) {
  res.send(`You found me!`);

app.use('/subApp', subApp);

This module ensures that the passed app is treated like it is mounted in an express app at the baseUrl calculated by http-autodetect. This causes the baseUrl to be set properly for the passed app and ensures that routing is performed relative to the deployment baseUrl.