Provide a sensible default host

activestorage/lib/active_storage/service/disk_service.rb

@@ -11,7 +11,7 @@ module ActiveStorage
   class Service::DiskService < Service
     attr_reader :root, :host
 
-    def initialize(root:, host:)
+    def initialize(root:, host: "http://localhost:3000")
       @root, @host = root, host
     end
 

activestorage/test/dummy/config/storage.yml

@@ -1,4 +1,3 @@
 local:
   service: Disk
   root: <%= Rails.root.join("storage") %>
-  host: http://localhost:3000

activestorage/test/service/configurator_test.rb

@@ -4,7 +4,7 @@ require "service/shared_service_tests"
 
 class ActiveStorage::Service::ConfiguratorTest < ActiveSupport::TestCase
   test "builds correct service instance based on service name" do
-    service = ActiveStorage::Service::Configurator.build(:foo, foo: { service: "Disk", root: "path", host: "http://localhost:3000" })
+    service = ActiveStorage::Service::Configurator.build(:foo, foo: { service: "Disk", root: "path" })
 
     assert_instance_of ActiveStorage::Service::DiskService, service
     assert_equal "path", service.root

activestorage/test/service/disk_service_test.rb

@@ -3,7 +3,7 @@
 require "service/shared_service_tests"
 
 class ActiveStorage::Service::DiskServiceTest < ActiveSupport::TestCase
-  SERVICE = ActiveStorage::Service::DiskService.new(root: File.join(Dir.tmpdir, "active_storage"), host: "http://localhost:3000")
+  SERVICE = ActiveStorage::Service::DiskService.new(root: File.join(Dir.tmpdir, "active_storage"))
 
   include ActiveStorage::Service::SharedServiceTests
 

activestorage/test/service/mirror_service_test.rb

@@ -6,13 +6,12 @@ class ActiveStorage::Service::MirrorServiceTest < ActiveSupport::TestCase
   mirror_config = (1..3).map do |i|
     [ "mirror_#{i}",
       service: "Disk",
-      root: Dir.mktmpdir("active_storage_tests_mirror_#{i}"),
-      host: "http://localhost:3000" ]
+      root: Dir.mktmpdir("active_storage_tests_mirror_#{i}") ]
   end.to_h
 
   config = mirror_config.merge \
     mirror:  { service: "Mirror", primary: "primary", mirrors: mirror_config.keys },
-    primary: { service: "Disk", root: Dir.mktmpdir("active_storage_tests_primary"), host: "http://localhost:3000" }
+    primary: { service: "Disk", root: Dir.mktmpdir("active_storage_tests_primary") }
 
   SERVICE = ActiveStorage::Service.configure :mirror, config
 

activestorage/test/test_helper.rb

@@ -34,7 +34,7 @@ rescue Errno::ENOENT
 end
 
 require "tmpdir"
-ActiveStorage::Blob.service = ActiveStorage::Service::DiskService.new(root: Dir.mktmpdir("active_storage_tests"), host: "http://localhost:3000")
+ActiveStorage::Blob.service = ActiveStorage::Service::DiskService.new(root: Dir.mktmpdir("active_storage_tests"))
 
 ActiveStorage.logger = ActiveSupport::Logger.new(nil)
 ActiveStorage.verifier = ActiveSupport::MessageVerifier.new("Testing")

guides/source/active_storage_overview.md

@@ -49,12 +49,10 @@ below declares three services named `local`, `test`, and `amazon`:
 local:
   service: Disk
   root: <%= Rails.root.join("storage") %>
-  host: http://localhost:3000
 
 test:
   service: Disk
   root: <%= Rails.root.join("tmp/storage") %>
-  host: http://localhost:3000
 
 amazon:
   service: S3
@@ -93,7 +91,15 @@ Declare a Disk service in `config/storage.yml`:
 local:
   service: Disk
   root: <%= Rails.root.join("storage") %>
-  host: http://localhost:3000
+```
+
+Optionally specify a host for generating URLs (the default is `http://localhost:3000`):
+
+```yaml
+local:
+  service: Disk
+  root: <%= Rails.root.join("storage") %>
+  host: http://myapp.test
 ```
 
 ### Amazon S3 Service

railties/lib/rails/generators/rails/app/templates/config/storage.yml.tt

@@ -1,12 +1,10 @@
 test:
   service: Disk
   root: <%%= Rails.root.join("tmp/storage") %>
-  host: http://localhost:3000
 
 local:
   service: Disk
   root: <%%= Rails.root.join("storage") %>
-  host: http://localhost:3000
 
 # Use rails credentials:edit to set the AWS secrets (as aws:access_key_id|secret_access_key)
 # amazon: