NodeHoster

A .NET solution aimed to simplify and provide the possibility to use IIS capabilities while hosting NodeJS applications on Windows Server.

Originally created by Hallbergs and later modified by jesade-vbg to include AD group lookup and a user cache etc.

Why?

I wanted to provide a way to host a NodeJS application on Windows server, without the hassle of dealing with setting up PM2 as a service etc. I also wanted to use the provided Windows Authentication from IIS, and pass the logged on user to the NodeJS application.

.NET Version and Visual Studio

Supported by .Net 8.0 and Visual Studio 2022

Application structure

The application contains three parts:

• A reverse proxy (YARP)
• A middleware adding name of the authenticated user to a header key of choice
• The middleware can also lookup AD groups for the user and add them to a header key of choice
• A service running a NodeJS application as a separate process

When the application is deployed to IIS, it will make sure that a proper version of Node is installed on the server, it will then start the NodeJS application and proxy all requests there.

The application listens to changes to the .env file in the node_directory (the directory set in appSettings.json that should contain the NodeJs application), and will restart the NodeJS application on changes to that file.

Deploying the application

The solution is to be deployed to IIS on Windows server. Publish the solution, and review the settings in appSettings.json:

{
  "AllowedHosts": "*",
  "ReverseProxy": {
    "Routes": {
      "noderoute": {
        "ClusterId": "nodecluster",
        "Match": {
          "Path": "{**catch-all}"
        }
      }
    },
    "Clusters": {
      "nodecluster": {
        "Destinations": {
          "node": {
            "Address": "http://localhost:3002" <--- Adress of the NodeJS application
          }
        }
      }
    }
  },
  "Serilog": {
    "Using": [],
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft": "Warning",
        "Yarp": "Warning"
      }
    },
    "Enrich": [ "FromLogContext" ],
    "WriteTo": [
      {
        "Name": "File",
        "Args": {
          "path": "Logs\\log.txt"
        }
      }
    ]
  },
  "ActiveDirectory": {
    "IsActive": true,
    "TrustedUserHeader": "X-Control-Header", <--- Key in which logged on user is sent
    "OverrideUserWithValue": "", <--- Override value for logged on user
    "TrustedGroupHeader": "X-Control-Group-Header", <--- Key in which logged on users groups is sent
    "OverrideGroupsWithValue": "" <--- Override value for users groups, comma separated.
  },
  "UserCache": {
    "TimeOut":  7200 <--- Seconds. The timeout for cached users and groups. Timeout is per user. (7200s = 2 hours)
  },
  "NodeHost": {
    "Enabled": "true", <--- Should the application host the NodeJS-application?
    "MinimumVersion": "20", <--- Minimum Node version required
    "EntryPoint": "index.js", <--- Which script should be ran to start the app?
    "FolderName": "node_server", <--- Folder containing the NodeJs-application
    "InstallNodeModules":  "false" <--- Should the app try to install node_modules?
  }
}

When you've made sure to check all the settings, you'll have to set up a new site in IIS and enable Windows Authentication. If the site fails to start, make sure to have a look at the log-directory in the project root.

TODO

This solution was thrown together, and there are probably several bugs etc. One known bug is that the installation of node_modules will sometimes fail. This is probably due to insufficient folder permissions. My suggestion would be to install the node_modules manually before deploying the solution to IIS.

Potential additions:

• Instead of just listening for changes in .env, adding a setting for which file types should be monitored would be good.
• TLS Support (Currently using DirectorySearcher which probably not have support for it)