how to access subdomains locally with Rails 5

subdomain-localhost-rails-5.md

Subdomaining Localhost with Rails 5

I've been following this blog post on how to set up an api-only Rails 5 application. One of the sections talks about creating a subdomain for your api

Rails.application.routes.draw do
  constraints subdomain: "api" do
    scope module: "api" do
      namespace :v1 do
        resources :users
      end
    end
  end
end

So that you can have namespacing and versioning like

http://api.my-website.com/v1/users

However, this seems to cause some issues locally. At first I just kept getting back a 404 error that the route I was searching for didn't exist despite it showing up correctly when I ran rake routes

  Prefix Verb   URI Pattern             Controller#Action
v1_users GET    /v1/users(.:format)     api/v1/users#index {:subdomain=>"api"}
         POST   /v1/users(.:format)     api/v1/users#create {:subdomain=>"api"}
 v1_user GET    /v1/users/:id(.:format) api/v1/users#show {:subdomain=>"api"}
         PATCH  /v1/users/:id(.:format) api/v1/users#update {:subdomain=>"api"}
         PUT    /v1/users/:id(.:format) api/v1/users#update {:subdomain=>"api"}
         DELETE /v1/users/:id(.:format) api/v1/users#destroy {:subdomain=>"api"}

Removing constraints subdomain: "api" gave back the correct response, allowing me to prove to myself that this was indeed the issue.

Attempted solutions

1. Editing /etc/hosts and adding in my subdomain to map to 127.0.0.1

As your machine gets started, it will need to know the mapping of some hostnames to IP addresses before DNS can be referenced. This mapping is kept in the /etc/hosts file. In the absence of a name server, any network program on your system consults this file to determine the IP address that corresponds to a host name.

I had seen a few forums that mentioned this as a solution, so I added this to /etc/hosts

127.0.0.1	api.dev.local

When I went to http://http://api.dev.local:3000/ all I got back from Chrome was

Trying this URL on Firefox and Safari resulted in the same thing (Safari never ended up actually giving that error, it just "loaded" the page indefinitely).

2. Using lvh.me and xip.io

I think this started with Tim Pope's invention of smackaho.st, which was simply a public domain pointed at 127.0.0.1 (localhost). lvh.me and xip.io are just spawns of that same idea since both are shorter and less offensive.

Unfortunately, lvh.me returns the same connection refused error as mentioned above and xip.io hangs indefinitely.

3. Changing proxy settings in Chrome to include localhost and lvh.me

Since I'm getting ERR_CONNECTION_REFUSED and not ERR_EMPTY_RESPONSE as would be expected if the domain wasn't working, I figured this was some sort of security check put in place by Chrome (and probably on Firefox and Safari too).

I tried ignoring the proxy settings for localhost, lvh.io, and xip.io as per this Stack Overflow answer. Nothing changed; I continued getting the same connection error.

Solution

config.action_dispatch.tld_length sets the TLD (top-level domain) length for the application. Defaults to 1.

Setting config.action_dispatch.tld_length = 0 in config/environments/development.rb. Simple as that. This works, although I am unsure of any unseen consequences with testing and cookies in, as is noted upon in the answer.

Resources:

• http://www.chrisaitchison.com/2013/03/17/testing-subdomains-in-rails/
• http://stackoverflow.com/questions/7227845/localhost-not-working-in-chrome-and-firefox
• http://railscasts.com/episodes/221-subdomains-in-rails-3
• http://stackoverflow.com/questions/20095318/rails-4-subdomain-routing

If there is something you notice I am doing wrong, something you would like to add, or some question you may have, please feel free to comment on this post :)