Travis Horn

Travis Horn

Reverse-Proxying Node.js Apps on Windows with IIS

Reverse-Proxying Node.js Apps on Windows with IIS

You can run Node.js apps on Windows with the added layer of a reverse-proxy with the built-in web service manager IIS. Together with a process manager like PM2, it’s a viable strategy to run apps for production.

Why use a reverse proxy?

Having a dedicated web server like IIS fielding your HTTP requests makes things more manageable and enables standard web server features like SSL termination, compression, and load balancing. For more information, I recommend Thomas Hunter II’s post “Why should I use a Reverse Proxy if Node.js is Production-Ready?

Another big benefit is being able to redirect traffic to appropriate web services by using URL rules. Let’s explore this last benefit further.

Run a Node.js web service

If you already have a running Node.js app that you want to use, you can skip this step. Otherwise, let’s create a really simple Node.js web server that will reply to HTTP requests.

  1. Create a new directory and initialize an npm project within it. Make sure the name of the directory makes sense in relation to the name of the app. In this case, we’re just making a simple test app.
mkdir testapp
cd testapp
npm init -y
  1. Install Fastify. It is a fast and low-overhead web framework for Node.js.
npm i fastify
  1. Create a file called server.js with the following contents.
const fastify = require("fastify")({ logger: true });

fastify.get("/", async () => {
  return { hello: "world" };
});

const start = async () => {
  try {
    await fastify.listen(process.env.PORT || 3000);
  } catch (err) {
    fastify.log.error(err);
    process.exit(1);
  }
};

start();
  1. Run the server and check if it responds correctly in your browser. By default, it will listen on port 3000.
node server

Manage your Node.js web services with PM2

Again, if you already have this part taken care of, you can skip this step. Otherwise, let’s manage our service(s) with PM2. PM2 is an advanced process manager for production Node.js applications.

  1. Make sure you kill any running Node.js processes, such as the one we started in the last section.

  2. Install PM2.

npm i -g pm2
  1. Create a PM2 configuration file called ecosystem.config.js somewhere appropriate. This might be in the root of your server or in your user directory. This file will contain configuration for all of your Node.js web apps.
module.exports = {
  apps: [
    {
      name: "Test App",
      script: "path/to/testapp/server.js",
      env: {
        PORT: 3000,
      },
    },
  ],
};

You can put as many apps in here as necessary. Make sure they all have different PORT values. I recommend naming each app something useful that matches the app’s directory name. This makes management easier.

  1. Run PM2 and start the apps by using the ecosystem configuration.
pm2 start ecosystem.config.js

With the app up and running, head back to your web browser and make sure everything is still working.

It’s worth noting that any time you make a change to ecosystem.config.js, such as when you create a new Node.js app and you add it to the list, you can reload the configuration.

pm2 reload ecosystem.config.js

Turn on Internet Information Services

Running the application like this works great, but you’d ideally want a dedicated web server like IIS fielding your HTTP requests for all of the reasons mentioned earlier in this post. Here, we’ll set up directing traffic to appropriate Node.js web services by using URL rules.

IIS is a web server product from Microsoft that you can turn on in Windows 10.

  1. Click the Start button or press the Windows key. Type “Turn Windows features on or off” and press Enter. The Windows Features window appears.

  1. Check the box for Internet Information Services. The box will be filled in with a square, indicating that some features within it are selected. The features that are selected by default are fine. So just click OK.

Make sure IIS is up and running by starting your web browser and navigating to http://localhost. If a site appears similar to the one below, you’re in business.

Install Application Request Routing and URL Rewrite

These two products from Microsoft are essential to using IIS as a reverse proxy.

  1. Click the Start button or press the Windows key. Type “Microsoft Web Platform Installer” and press Enter.

  2. If a User Account Control box appears, click Yes. The Web Platform Installer window appears.

  1. In the search box in the upper right corner, type “Application Request Routing” and press Enter.

  2. Click the Add button in the row labeled Application Request Routing 2.5 with KB2589179. If there’s a newer version, you could choose that one instead, but this is the one I’m familiar with.

  3. Back in the search box, type “URL Rewrite” and press Enter.

  4. Click the Add button in the row labeled URL Rewrite 2.1.

  5. Click the Install button.

Set up a URL Rewrite rule

  1. Open IIS Manager by clicking Start or pressing the Windows key, typing “Internet Information Services” and pressing Enter. The manager window appears.

  1. In the Connections pane, click the arrow next to your PC’s name, then the arrow next to Sites. Finally, click on Default Web Site to select it.

  1. Double-click URL Rewrite to open its features. There will probably be no rules in place by default.

  1. In the Actions pane on the right, click Add Rule(s)…

  1. Click to select Reverse Proxy and then click OK.

You may see a message about enabling Application Request Routing. Go ahead and accept it.

  1. Enter the server name or IP address where HTTP requests will be forwarded. This is where your Node.js server is listening. If you set up your environment according to this guide, this will be localhost:3000. You can leave the other options set to their default and click OK.

We’re almost done. With that rule saved, IIS will proxy any traffic heading towards localhost to localhost:3000. You can test that in your web browser.

Notice we didn’t have to specify the port this time.

This is great, except when you have multiple Node.js apps running and you want to direct users to the correct one based on the URL they are visiting. In our case, we want any user who visits http://localhost/testapp to see our Node.js test app.

  1. To make management easier, let’s give this rule a name. Click to select the newly created rule, then click Rename under Inbound Rules on the right.

Name it “Test App” or something else appropriate. I recommend naming it exactly the same as the name in your PM2 configuration.

  1. With the rule still selected, click Edit… under Inbound Rules on the right.

  1. In the Pattern box, type testapp/?(.*) and click Apply. You can replace testapp with whatever you like, but I recommend naming it similar to the Node.js app directory, the PM2 name, and the URL Rewrite rule.

Now any request to http://localhost/testapp any any URLs deeper in that path will be proxied to our Node.js app.

Load up the web browser one more time and check it out.

 
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