4 files changed, 238 insertions, 0 deletions
diff --git a/lib/active_storage/service/disk_service.rb b/lib/active_storage/service/disk_service.rb
new file mode 100644
index 0000000000..6977b5b82e
--- /dev/null
+++ b/lib/active_storage/service/disk_service.rb
@@ -0,0 +1,71 @@
+require "fileutils"
+require "pathname"
+
+class ActiveStorage::Service::DiskService < ActiveStorage::Service
+  attr_reader :root
+
+  def initialize(root:)
+    @root = root
+  end
+
+  def upload(key, io)
+    File.open(make_path_for(key), "wb") do |file|
+      while chunk = io.read(65536)
+        file.write(chunk)
+      end
+    end
+  end
+
+  def download(key)
+    if block_given?
+      File.open(path_for(key)) do |file|
+        while data = file.read(65536)
+          yield data
+        end
+      end
+    else
+      File.open path_for(key), &:read
+    end
+  end
+
+  def delete(key)
+    File.delete path_for(key) rescue Errno::ENOENT # Ignore files already deleted
+  end
+
+  def exist?(key)
+    File.exist? path_for(key)
+  end
+
+
+  def url(key, expires_in:, disposition:, filename:)
+    verified_key_with_expiration = ActiveStorage::VerifiedKeyWithExpiration.encode(key, expires_in: expires_in)
+
+    if defined?(Rails) && defined?(Rails.application)
+      Rails.application.routes.url_helpers.rails_disk_blob_path(verified_key_with_expiration, disposition: disposition)
+    else
+      "/rails/blobs/#{verified_key_with_expiration}?disposition=#{disposition}"
+    end
+  end
+
+  def byte_size(key)
+    File.size path_for(key)
+  end
+
+  def checksum(key)
+    Digest::MD5.file(path_for(key)).hexdigest
+  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
+end
diff --git a/lib/active_storage/service/gcs_service.rb b/lib/active_storage/service/gcs_service.rb
new file mode 100644
index 0000000000..18ec1de133
--- /dev/null
+++ b/lib/active_storage/service/gcs_service.rb
@@ -0,0 +1,53 @@
+require "google/cloud/storage"
+require "active_support/core_ext/object/to_query"
+
+class ActiveStorage::Service::GCSService < ActiveStorage::Service
+  attr_reader :client, :bucket
+
+  def initialize(project:, keyfile:, bucket:)
+    @client = Google::Cloud::Storage.new(project: project, keyfile: keyfile)
+    @bucket = @client.bucket(bucket)
+  end
+
+  def upload(key, io)
+    bucket.create_file(io, key)
+  end
+
+  def download(key)
+    io = file_for(key).download
+    io.rewind
+    io.read
+  end
+
+  def delete(key)
+    file_for(key).try(:delete)
+  end
+
+  def exist?(key)
+    file_for(key).present?
+  end
+
+
+  def url(key, expires_in:, disposition:, filename:)
+    file_for(key).signed_url(expires: expires_in) + "&" +
+      { "response-content-disposition" => "#{disposition}; filename=\"#{filename}\"" }.to_query
+  end
+
+  def byte_size(key)
+    file_for(key).size
+  end
+
+  def checksum(key)
+    convert_to_hex base64: file_for(key).md5
+  end
+
+
+  private
+    def file_for(key)
+      bucket.file(key)
+    end
+
+    def convert_to_hex(base64:)
+      base64.unpack("m0").first.unpack("H*").first
+    end
+end
diff --git a/lib/active_storage/service/mirror_service.rb b/lib/active_storage/service/mirror_service.rb
new file mode 100644
index 0000000000..2a3518e59e
--- /dev/null
+++ b/lib/active_storage/service/mirror_service.rb
@@ -0,0 +1,51 @@
+class ActiveStorage::Service::MirrorService < ActiveStorage::Service
+  attr_reader :services
+
+  def initialize(services:)
+    @services = services
+  end
+
+  def upload(key, io)
+    services.collect do |service|
+      service.upload key, io
+      io.rewind
+    end
+  end
+
+  def download(key)
+    services.detect { |service| service.exist?(key) }.download(key)
+  end
+
+  def delete(key)
+    perform_across_services :delete, key
+  end
+
+  def exist?(key)
+    perform_across_services(:exist?, key).any?
+  end
+
+
+  def url(key, **options)
+    primary_service.url(key, **options)
+  end
+
+  def byte_size(key)
+    primary_service.byte_size(key)
+  end
+
+  def checksum(key)
+    primary_service.checksum(key)
+  end
+
+  private
+    def primary_service
+      services.first
+    end
+
+    def perform_across_services(method, *args)
+      # FIXME: Convert to be threaded
+      services.collect do |service|
+        service.public_send method, *args
+      end
+    end
+end
diff --git a/lib/active_storage/service/s3_service.rb b/lib/active_storage/service/s3_service.rb
new file mode 100644
index 0000000000..811321a172
--- /dev/null
+++ b/lib/active_storage/service/s3_service.rb
@@ -0,0 +1,63 @@
+require "aws-sdk"
+
+class ActiveStorage::Service::S3Service < ActiveStorage::Service
+  attr_reader :client, :bucket
+
+  def initialize(access_key_id:, secret_access_key:, region:, bucket:)
+    @client = Aws::S3::Resource.new(access_key_id: access_key_id, secret_access_key: secret_access_key, region: region)
+    @bucket = @client.bucket(bucket)
+  end
+
+  def upload(key, io)
+    object_for(key).put(body: io)
+  end
+
+  def download(key)
+    if block_given?
+      stream(key, &block)
+    else
+      object_for(key).get.body.read
+    end
+  end
+
+  def delete(key)
+    object_for(key).delete
+  end
+
+  def exist?(key)
+    object_for(key).exists?
+  end
+
+
+  def url(key, expires_in:, disposition:, filename:)
+    object_for(key).presigned_url :get, expires_in: expires_in,
+      response_content_disposition: "#{disposition}; filename=\"#{filename}\""
+  end
+
+  def byte_size(key)
+    object_for(key).size
+  end
+
+  def checksum(key)
+    object_for(key).etag.remove(/"/)
+  end
+
+
+  private
+    def object_for(key)
+      bucket.object(key)
+    end
+
+    # Reads the object for the given key in chunks, yielding each to the block.
+    def stream(key, options = {}, &block)
+      object = object_for(key)
+
+      chunk_size = 5242880 # 5 megabytes
+      offset = 0
+
+      while offset < object.content_length
+        yield object.read(options.merge(:range => "bytes=#{offset}-#{offset + chunk_size - 1}"))
+        offset += chunk_size
+      end
+    end
+end