Add RAILS_DEVELOPMENT_HOSTS to allow adding authorized hosts for development

Co-authored-by: Josh Abernathy <joshaber@gmail.com>

Update railties/CHANGELOG.md

Co-authored-by: Gannon McGibbon <gannon@hey.com>

Update railties/lib/rails/application/configuration.rb

Co-authored-by: Gannon McGibbon <gannon@hey.com>

Use yield block to safely alter env variables

Remove trailing whitespace

Update railties/CHANGELOG.md wording

Co-authored-by: Marivaldo Cavalheiro <marivaldo@gmail.com>

Have comma separated list ignore spaces

Add missing comma

guides/source/configuring.md

@@ -237,9 +237,10 @@ Every Rails application comes with a standard set of middleware which it uses in
 
     ```ruby
     Rails.application.config.hosts = [
-      IPAddr.new("0.0.0.0/0"), # All IPv4 addresses.
-      IPAddr.new("::/0"),      # All IPv6 addresses.
-      "localhost"              # The localhost reserved domain.
+      IPAddr.new("0.0.0.0/0"),        # All IPv4 addresses.
+      IPAddr.new("::/0"),             # All IPv6 addresses.
+      "localhost",                    # The localhost reserved domain.
+      ENV["RAILS_DEVELOPMENT_HOSTS"]  # Additional comma-separated hosts for development.
     ]
     ```
 

railties/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Allow adding additional authorized hosts in development via `ENV['RAILS_DEVELOPMENT_HOSTS']`
+
+    *Josh Abernathy*, *Debbie Milburn*
+
 *   Stop generating a license for in-app plugins.
 
     *Gannon McGibbon*

railties/lib/rails/application/configuration.rb

@@ -34,6 +34,7 @@ module Rails
         @filter_redirect                         = []
         @helpers_paths                           = []
         @hosts                                   = Array(([".localhost", IPAddr.new("0.0.0.0/0"), IPAddr.new("::/0")] if Rails.env.development?))
+        @hosts.concat(ENV["RAILS_DEVELOPMENT_HOSTS"].to_s.split(",").map(&:strip)) if Rails.env.development?
         @host_authorization                      = {}
         @public_file_server                      = ActiveSupport::OrderedOptions.new
         @public_file_server.enabled              = true

railties/test/application/configuration_test.rb

@@ -49,6 +49,14 @@ module ApplicationTests
       end
     end
 
+    def switch_development_hosts_to(*hosts)
+      old_development_hosts = ENV["RAILS_DEVELOPMENT_HOSTS"]
+      ENV["RAILS_DEVELOPMENT_HOSTS"] = hosts.join(",")
+      yield
+    ensure
+      ENV["RAILS_DEVELOPMENT_HOSTS"] = old_development_hosts
+    end
+
     def setup
       build_app
       suppress_default_config
@@ -2933,6 +2941,44 @@ module ApplicationTests
       assert_includes Rails.application.config.hosts, ".localhost"
     end
 
+    test "hosts reads multiple values from RAILS_DEVELOPMENT_HOSTS" do
+      host = "agoodhost.com"
+      another_host = "bananapants.com"
+      switch_development_hosts_to(host, another_host) do
+        app "development"
+        assert_includes Rails.application.config.hosts, host
+        assert_includes Rails.application.config.hosts, another_host
+      end
+    end
+
+    test "hosts reads multiple values from RAILS_DEVELOPMENT_HOSTS and trims white space" do
+      host = "agoodhost.com"
+      host_with_white_space = "  #{host} "
+      another_host = "bananapants.com"
+      another_host_with_white_space = "     #{another_host}"
+      switch_development_hosts_to(host_with_white_space, another_host_with_white_space) do
+        app "development"
+        assert_includes Rails.application.config.hosts, host
+        assert_includes Rails.application.config.hosts, another_host
+      end
+    end
+
+    test "hosts reads from RAILS_DEVELOPMENT_HOSTS" do
+      host = "agoodhost.com"
+      switch_development_hosts_to(host) do
+        app "development"
+        assert_includes Rails.application.config.hosts, host
+      end
+    end
+
+    test "hosts does not read from RAILS_DEVELOPMENT_HOSTS in production" do
+      host = "agoodhost.com"
+      switch_development_hosts_to(host) do
+        app "production"
+        assert_not_includes Rails.application.config.hosts, host
+      end
+    end
+
     test "disable_sandbox is false by default" do
       app "development"