1 files changed, 116 insertions, 0 deletions
diff --git a/activestorage/lib/active_storage/service/s3_service.rb b/activestorage/lib/active_storage/service/s3_service.rb
new file mode 100644
index 0000000000..382920ef61
--- /dev/null
+++ b/activestorage/lib/active_storage/service/s3_service.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+require "aws-sdk-s3"
+require "active_support/core_ext/numeric/bytes"
+
+module ActiveStorage
+  # Wraps the Amazon Simple Storage Service (S3) as an Active Storage service.
+  # See ActiveStorage::Service for the generic API documentation that applies to all services.
+  class Service::S3Service < Service
+    attr_reader :client, :bucket, :upload_options
+
+    def initialize(bucket:, upload: {}, **options)
+      @client = Aws::S3::Resource.new(**options)
+      @bucket = @client.bucket(bucket)
+
+      @upload_options = upload
+    end
+
+    def upload(key, io, checksum: nil, **)
+      instrument :upload, key: key, checksum: checksum do
+        object_for(key).put(upload_options.merge(body: io, content_md5: checksum))
+      rescue Aws::S3::Errors::BadDigest
+        raise ActiveStorage::IntegrityError
+      end
+    end
+
+    def download(key, &block)
+      if block_given?
+        instrument :streaming_download, key: key do
+          stream(key, &block)
+        end
+      else
+        instrument :download, key: key do
+          object_for(key).get.body.string.force_encoding(Encoding::BINARY)
+        rescue Aws::S3::Errors::NoSuchKey
+          raise ActiveStorage::FileNotFoundError
+        end
+      end
+    end
+
+    def download_chunk(key, range)
+      instrument :download_chunk, key: key, range: range do
+        object_for(key).get(range: "bytes=#{range.begin}-#{range.exclude_end? ? range.end - 1 : range.end}").body.read.force_encoding(Encoding::BINARY)
+      rescue Aws::S3::Errors::NoSuchKey
+        raise ActiveStorage::FileNotFoundError
+      end
+    end
+
+    def delete(key)
+      instrument :delete, key: key do
+        object_for(key).delete
+      end
+    end
+
+    def delete_prefixed(prefix)
+      instrument :delete_prefixed, prefix: prefix do
+        bucket.objects(prefix: prefix).batch_delete!
+      end
+    end
+
+    def exist?(key)
+      instrument :exist, key: key do |payload|
+        answer = object_for(key).exists?
+        payload[:exist] = answer
+        answer
+      end
+    end
+
+    def url(key, expires_in:, filename:, disposition:, content_type:)
+      instrument :url, key: key do |payload|
+        generated_url = object_for(key).presigned_url :get, expires_in: expires_in.to_i,
+          response_content_disposition: content_disposition_with(type: 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: key do |payload|
+        generated_url = object_for(key).presigned_url :put, expires_in: expires_in.to_i,
+          content_type: content_type, content_length: content_length, 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 object_for(key)
+        bucket.object(key)
+      end
+
+      # Reads the object for the given key in chunks, yielding each to the block.
+      def stream(key)
+        object = object_for(key)
+
+        chunk_size = 5.megabytes
+        offset = 0
+
+        raise ActiveStorage::FileNotFoundError unless object.exists?
+
+        while offset < object.content_length
+          yield object.get(range: "bytes=#{offset}-#{offset + chunk_size - 1}").body.read.force_encoding(Encoding::BINARY)
+          offset += chunk_size
+        end
+      end
+  end
+end