virtual-host-proxy

A DNS and HTTP proxy to forward virtual hosts to ports on your local machine. (OS X only at the moment, PRs welcome.)

If you've developed any larger web applications, you're probably used to having half a dozen different services on different ports, so for example your main React application might be at http://localhost:8000/ and your API might be at http://localhost:3000. Once you start to add more services it starts to become harder to remember the ports, and then you'll have to trawl through configuration files to figure out what port you're aiming for.

Wouldn't it be nice if you could just have your application at e.g. http://app.localhost and your api at http://api.localhost and some bit of software would figure it all out for you?

You can already use dnsmasq to point domains to your local machine, but you would also have to install something like nginx to forward the HTTP requests to the correct service.

This utility, virtual-host-proxy, handles both parts for you from one set of simple configuration.

Setting up

You can install the utility globally:

npm install -g virtual-host-proxy

You can then run the init command to set up the resolver config:

virtual-host-proxy init

This basically sets up some config that tells OS X to forward all DNS requests for the TLD localhost (by default) to a local DNS server (which will be this utility if running).

If it doesn't have permission to do this, it will print the command you should run in order to set it up yourself.

You can then run the run command to start the server, or the start command to start it as a daemon:

virtual-host-proxy start

If you are running it inline, Ctrl+C will quit, while the stop command will stop the daemon.

You can also kill, restart or check the status of the daemon:

virtual-host-proxy kill
virtual-host-proxy restart
virtual-host-proxy status

If you want it to start automatically when you log in, you can use the autolaunch commands:

virtual-host-proxy autolaunch status
virtual-host-proxy autolaunch enable
virtual-host-proxy autolaunch disable

These check the autolaunch status, enable and disable it respectively.

Configuring virtual hosts

Each virtual host is represented by a file in the config directory (default ~/.virtual-host-proxy) with the file name being the full domain name represented (e.g. app.localhost). The file consists simply of the port number to forward to.

Note all subdomains of any domains you have defined will also map to the same service. The matching algorithm compares the incoming host name in an HTTP request with the defined virtual hosts and chooses the longest. Therefore, if you have two files, app.localhost with contents 8000 and secure.app.locahost with contents 8001, an HTTP request for secure.app.localhost will connect to 8001, and a request for other.app.localhost will connect to 8000.

You can either create these files manually, or use the add and remove commands:

virtual-host-proxy add app.localhost 8000
virtual-host-proxy remove app.localhost

Of course, the following code will do it too:

const { writeFileSync } = require('fs');
const { homedir } = require('os');
const { join } = require('path');
const hostname = 'app.localhost';
const port = '80';

writeFileSync(join(homedir, '.virtual-host-proxy', hostname), port);

Usage from virtual machines

The utility should be able to figure out if a DNS request is coming from a specific interface, such as a VM, and respond appropriately so that the VM connects to the correct IP address (i.e., it won't be 127.0.0.1 in the case of a VM).

OS X only for now

It shouldn't be too hard to adjust this for other platforms, I just haven't yet.