Add ActiveStorage::Blob#open

[David Robertson & George Claghorn]

4 files changed, 59 insertions, 7 deletions

diff --git a/activestorage/lib/active_storage/analyzer.rb b/activestorage/lib/active_storage/analyzer.rb
index 7c4168c1a0..87e9e42aa2 100644
--- a/activestorage/lib/active_storage/analyzer.rb
+++ b/activestorage/lib/active_storage/analyzer.rb
@@ -1,13 +1,9 @@
 # frozen_string_literal: true
 
-require "active_storage/downloading"
-
 module ActiveStorage
   # This is an abstract base class for analyzers, which extract metadata from blobs. See
   # ActiveStorage::Analyzer::ImageAnalyzer for an example of a concrete subclass.
   class Analyzer
-    include Downloading
-
     attr_reader :blob
 
     # Implement this method in a concrete subclass. Have it return true when given a blob from which
@@ -26,6 +22,11 @@ module ActiveStorage
     end
 
     private
+      # Downloads the blob to a tempfile on disk. Yields the tempfile.
+      def download_blob_to_tempfile #:doc:
+        blob.open(&block)
+      end
+
       def logger #:doc:
         ActiveStorage.logger
       end
diff --git a/activestorage/lib/active_storage/downloader.rb b/activestorage/lib/active_storage/downloader.rb
new file mode 100644
index 0000000000..7f5b4936a5
--- /dev/null
+++ b/activestorage/lib/active_storage/downloader.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module ActiveStorage
+  class Downloader
+    def initialize(blob)
+      @blob = blob
+    end
+
+    def download_blob_to_tempfile
+      open_tempfile do |file|
+        download_blob_to file
+        yield file
+      end
+    end
+
+    private
+      attr_reader :blob
+
+      def open_tempfile
+        file = Tempfile.open([ "ActiveStorage", tempfile_extension_with_delimiter ])
+
+        begin
+          yield file
+        ensure
+          file.close!
+        end
+      end
+
+      def download_blob_to(file)
+        file.binmode
+        blob.download { |chunk| file.write(chunk) }
+        file.flush
+        file.rewind
+      end
+
+      def tempfile_extension_with_delimiter
+        blob.filename.extension_with_delimiter
+      end
+  end
+end
diff --git a/activestorage/lib/active_storage/downloading.rb b/activestorage/lib/active_storage/downloading.rb
index 7c3d20ade0..df820bc088 100644
--- a/activestorage/lib/active_storage/downloading.rb
+++ b/activestorage/lib/active_storage/downloading.rb
@@ -1,9 +1,17 @@
 # frozen_string_literal: true
 
 require "tmpdir"
+require "active_support/core_ext/string/filters"
 
 module ActiveStorage
   module Downloading
+    def self.included(klass)
+      ActiveSupport::Deprecation.warn <<~MESSAGE.squish, caller_locations(2)
+        ActiveStorage::Downloading is deprecated and will be removed in Active Storage 6.1.
+        Use ActiveStorage::Blob#open instead.
+      MESSAGE
+    end
+
     private
       # Opens a new tempfile in #tempdir and copies blob data into it. Yields the tempfile.
       def download_blob_to_tempfile #:doc:
diff --git a/activestorage/lib/active_storage/previewer.rb b/activestorage/lib/active_storage/previewer.rb
index cf19987d72..2053ed4511 100644
--- a/activestorage/lib/active_storage/previewer.rb
+++ b/activestorage/lib/active_storage/previewer.rb
@@ -1,14 +1,12 @@
 # frozen_string_literal: true
 
-require "active_storage/downloading"
+require "active_support/core_ext/string/filters"
 
 module ActiveStorage
   # This is an abstract base class for previewers, which generate images from blobs. See
   # ActiveStorage::Previewer::PDFPreviewer and ActiveStorage::Previewer::VideoPreviewer for examples of
   # concrete subclasses.
   class Previewer
-    include Downloading
-
     attr_reader :blob
 
     # Implement this method in a concrete subclass. Have it return true when given a blob from which
@@ -28,6 +26,11 @@ module ActiveStorage
     end
 
     private
+      # Downloads the blob to a tempfile on disk. Yields the tempfile.
+      def download_blob_to_tempfile #:doc:
+        blob.open(&block)
+      end
+
       # Executes a system command, capturing its binary output in a tempfile. Yields the tempfile.
       #
       # Use this method to shell out to a system library (e.g. mupdf or ffmpeg) for preview image