1 files changed, 124 insertions, 0 deletions
diff --git a/activestorage/lib/active_storage/service/disk_service.rb b/activestorage/lib/active_storage/service/disk_service.rb
new file mode 100644
index 0000000000..35b0909297
--- /dev/null
+++ b/activestorage/lib/active_storage/service/disk_service.rb
@@ -0,0 +1,124 @@
+require "fileutils"
+require "pathname"
+require "digest/md5"
+require "active_support/core_ext/numeric/bytes"
+
+# Wraps a local disk path as a Active Storage service. See `ActiveStorage::Service` for the generic API
+# documentation that applies to all services.
+class ActiveStorage::Service::DiskService < ActiveStorage::Service
+  attr_reader :root
+
+  def initialize(root:)
+    @root = root
+  end
+
+  def upload(key, io, checksum: nil)
+    instrument :upload, key, checksum: checksum do
+      IO.copy_stream(io, make_path_for(key))
+      ensure_integrity_of(key, checksum) if checksum
+    end
+  end
+
+  def download(key)
+    if block_given?
+      instrument :streaming_download, key do
+        File.open(path_for(key), "rb") do |file|
+          while data = file.read(64.kilobytes)
+            yield data
+          end
+        end
+      end
+    else
+      instrument :download, key do
+        File.binread path_for(key)
+      end
+    end
+  end
+
+  def delete(key)
+    instrument :delete, key do
+      begin
+        File.delete path_for(key)
+      rescue Errno::ENOENT
+        # Ignore files already deleted
+      end
+    end
+  end
+
+  def exist?(key)
+    instrument :exist, key do |payload|
+      answer = File.exist? path_for(key)
+      payload[:exist] = answer
+      answer
+    end
+  end
+
+  def url(key, expires_in:, disposition:, filename:, content_type:)
+    instrument :url, key do |payload|
+      verified_key_with_expiration = ActiveStorage.verifier.generate(key, expires_in: expires_in, purpose: :blob_key)
+
+      generated_url =
+        if defined?(Rails.application)
+          Rails.application.routes.url_helpers.rails_disk_service_path \
+            verified_key_with_expiration,
+            disposition: disposition, filename: filename, content_type: content_type
+        else
+          "/rails/active_storage/disk/#{verified_key_with_expiration}/#{filename}?disposition=#{disposition}&content_type=#{content_type}"
+        end
+
+      payload[:url] = generated_url
+
+      generated_url
+    end
+  end
+
+  def url_for_direct_upload(key, expires_in:, content_type:, content_length:, checksum:)
+    instrument :url, key do |payload|
+      verified_token_with_expiration = ActiveStorage.verifier.generate(
+        {
+          key: key,
+          content_type: content_type,
+          content_length: content_length,
+          checksum: checksum
+        },
+        expires_in: expires_in,
+        purpose: :blob_token
+      )
+
+      generated_url =
+        if defined?(Rails.application)
+          Rails.application.routes.url_helpers.update_rails_disk_service_path verified_token_with_expiration
+        else
+          "/rails/active_storage/disk/#{verified_token_with_expiration}"
+        end
+
+      payload[:url] = generated_url
+
+      generated_url
+    end
+  end
+
+  def headers_for_direct_upload(key, content_type:, **)
+    { "Content-Type" => content_type }
+  end
+
+  private
+    def path_for(key)
+      File.join root, folder_for(key), key
+    end
+
+    def folder_for(key)
+      [ key[0..1], key[2..3] ].join("/")
+    end
+
+    def make_path_for(key)
+      path_for(key).tap { |path| FileUtils.mkdir_p File.dirname(path) }
+    end
+
+    def ensure_integrity_of(key, checksum)
+      unless Digest::MD5.file(path_for(key)).base64digest == checksum
+        delete key
+        raise ActiveStorage::IntegrityError
+      end
+    end
+end