RailsCaddyDev

Automatically configures Caddy as a local reverse proxy for Rails development. When you start rails server, it registers routes via the Caddy admin API so that <project_name>.localhost proxies to your locally running Rails server with HTTPS.

Prerequisites

• Caddy installed and running locally
• Ruby >= 3.1

Installation

Add it to your application's Gemfile:

gem 'rails_caddy_dev', group: :development

Then run:

bundle install

Setup

In your application's bin/rails file, replace this:

require "rails/commands"

with this:

require "rails_caddy_dev/commands"

This will ensure your Caddy configuration is updated each time you start your Rails server in development.

Usage

Start your Rails server with the DEVCADDY and PROJECT_NAME environment variables:

DEVCADDY=1 PROJECT_NAME=myapp rails server

This will configure Caddy to proxy myapp.localhost to your Rails server, accessible over HTTPS.

Environment Variables

Variable	Description	Default
DEVCADDY	Enables Caddy configuration (must be set)	—
PROJECT_NAME	Used to derive the .localhost hostname (required)	—
PORT	Rails server port to proxy to	3000
CADDY_HOST	Caddy admin API host	localhost
CADDY_PORT	Caddy admin API port	2019

Dynamic Port Allocation

The gem also provides a CLI command to find an available TCP port, which can be useful if you want to run multiple Rails servers without port conflicts:

export PORT=$(bundle exec rails rails_caddy_dev:available_port)

RailsCaddyDev will then configure Caddy to proxy to the dynamically allocated port, and start your Rails server on that port.

Subdomains

Subdomains are also supported due to a wildcard Caddy route that will be configured. For example, if you set PROJECT_NAME=myapp, then api.myapp.localhost will also proxy to your Rails server.

Usage with Mise

If you're using Mise, you can integrate RailsCaddyDev by setting the PORT environment variable dynamically using the CLI command provided by RailsCaddyDev. Add this to your Mise config (eg. mise.toml):

[env]
PORT = { value = "${env.PORT:-{{exec(command='bundle exec rails rails_caddy_dev:available_port')}}}", tools = true }

Now the PORT environment variable will be set to an available port each time you start your Mise environment, allowing you to run multiple Rails servers without port conflicts.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run bundle exec rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/joelmoss/rails_caddy_dev.

License

The gem is available as open source under the terms of the MIT License.