1 files changed, 79 insertions, 0 deletions
diff --git a/activestorage/lib/active_storage/service/gcs_service.rb b/activestorage/lib/active_storage/service/gcs_service.rb
new file mode 100644
index 0000000000..73629f7486
--- /dev/null
+++ b/activestorage/lib/active_storage/service/gcs_service.rb
@@ -0,0 +1,79 @@
+require "google/cloud/storage"
+require "active_support/core_ext/object/to_query"
+
+# Wraps the Google Cloud Storage as a Active Storage service. See `ActiveStorage::Service` for the generic API
+# documentation that applies to all services.
+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, checksum: nil)
+    instrument :upload, key, checksum: checksum do
+      begin
+        bucket.create_file(io, key, md5: checksum)
+      rescue Google::Cloud::InvalidArgumentError
+        raise ActiveStorage::IntegrityError
+      end
+    end
+  end
+
+  # FIXME: Add streaming when given a block
+  def download(key)
+    instrument :download, key do
+      io = file_for(key).download
+      io.rewind
+      io.read
+    end
+  end
+
+  def delete(key)
+    instrument :delete, key do
+      file_for(key).try(:delete)
+    end
+  end
+
+  def exist?(key)
+    instrument :exist, key do |payload|
+      answer = file_for(key).present?
+      payload[:exist] = answer
+      answer
+    end
+  end
+
+  def url(key, expires_in:, disposition:, filename:, content_type:)
+    instrument :url, key do |payload|
+      generated_url = file_for(key).signed_url expires: expires_in, query: {
+        "response-content-disposition" => "#{disposition}; filename=\"#{filename}\"",
+        "response-content-type" => content_type
+      }
+
+      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|
+      generated_url = bucket.signed_url key, method: "PUT", expires: expires_in,
+        content_type: content_type, content_md5: checksum
+
+      payload[:url] = generated_url
+
+      generated_url
+    end
+  end
+
+  def headers_for_direct_upload(key, content_type:, checksum:, **)
+    { "Content-Type" => content_type, "Content-MD5" => checksum }
+  end
+
+  private
+    def file_for(key)
+      bucket.file(key)
+    end
+end