remon · June 20, 2019 11:50 · Jan 19, 2016
diff --git a/subdomain-localhost-rails-5.md b/subdomain-localhost-rails-5.md
@@ -0,0 +1,105 @@
+# Subdomaining Localhost with Rails 5
+
+I've been following [this](http://sourcey.com/building-the-prefect-rails-5-api-only-app/)
+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
+
+```rb
+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
+
+```sh
+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`
+
+```rb
+  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`
+
+```sh
+127.0.0.1	api.dev.local
+```
+
+When I went to `http://http://api.dev.local:3000/` all I got back from Chrome
+was
+
+![ERR_CONNECTION_REFUSED](http://i.imgur.com/clCNNvZ.jpg)
+
+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](http://tbaggery.com/2010/03/04/smack-a-ho-st.html).
+
+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](http://stackoverflow.com/questions/7227845/localhost-not-working-in-chrome-and-firefox)
+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](http://stackoverflow.com/questions/20095318/rails-4-subdomain-routing).
+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 :)