[ruby-on-rails] How to change Rails 3 server default port in develoment?

On my development machine, I use port 10524. So I start my server this way :

rails s -p 10524

Is there a way to change the default port to 10524 so I wouldn't have to append the port each time I start the server?

I like to append the following to config/boot.rb:

require 'rails/commands/server'

module Rails
  class Server
    alias :default_options_alias :default_options
    def default_options
      default_options_alias.merge!(:Port => 3333)
    end    
  end
end

We're using Puma as a web server, and dotenv to set environment variables in development. This means I can set an environment variable for PORT, and reference it in the Puma config.

# .env
PORT=10524


# config/puma.rb
port ENV['PORT']

However, you'll have to start your app with foreman start instead of rails s, otherwise the puma config doesn't get read properly.

I like this approach because the configuration works the same way in development and production, you just change the value of the port if necessary.

Inspired by Radek and Spencer... On Rails 4(.0.2 - Ruby 2.1.0 ), I was able to append this to config/boot.rb:

# config/boot.rb

# ...existing code

require 'rails/commands/server'

module Rails
  # Override default development
  # Server port
  class Server
    def default_options
      super.merge(Port: 3100)
    end
  end
end

All other configuration in default_options are still set, and command-line switches still override defaults.

Combining two previous answers, for Rails 4.0.4 (and up, presumably), this suffices at the end of config/boot.rb:

require 'rails/commands/server'

module Rails
  class Server
    def default_options
      super.merge({Port: 10524})
    end
  end
end

One more idea for you. Create a rake task that calls rails server with the -p.

task "start" => :environment do
  system 'rails server -p 3001'
end

then call rake start instead of rails server

If you're using puma (I'm using this on Rails 6+):

To change default port for all environments:

The "{3000}" part sets the default port if undefined in ENV.

~/config/puma.rb

change:
    port ENV.fetch('PORT') { 3000 }
for:
    port ENV.fetch('PORT') { 10524 }

To define it depending on the environment, using Figaro gem for credentials/environment variable:

~/application.yml
local_db_username: your_user_name
?local_db_password: your_password
PORT: 10524

You can adapt this to you own environment variable manager.

You could install $ gem install foreman, and use foreman to start your server as defined in your Procfile like:

web: bundle exec rails -p 10524

You can check foreman gem docs here: https://github.com/ddollar/foreman for more info

The benefit of this approach is not only can you set/change the port in the config easily and that it doesn't require much code to be added but also you can add different steps in the Procfile that foreman will run for you so you don't have to go though them each time you want to start you application something like:

bundle: bundle install
web: bundle exec rails -p 10524
...
...

Cheers

Solution for Rails 2.3 - script/server:

#!/usr/bin/env ruby
require 'rack/handler'
module Rack::Handler
  class << WEBrick
    alias_method :old_run, :run
  end

  class WEBrick
    def self.run(app, options={})
      options[:Port] = 3010 if options[:Port] == 3000
      old_run(app, options)
    end
  end
end

require File.dirname(__FILE__) + '/../config/boot'
require 'commands/server'

Create alias in your shell for command with a specified port.