[WIP] Handle byte range requests for local files (#2816)

Handle byte range requests for local files

.rubocop_fixme.yml

@@ -6,6 +6,7 @@ Metrics/ClassLength:
   Exclude:
     - 'app/controllers/hyrax/dashboard/collections_controller.rb'
     - 'app/controllers/hyrax/admin/admin_sets_controller.rb'
+    - 'app/controllers/hyrax/downloads_controller.rb'
     - 'app/controllers/hyrax/file_sets_controller.rb'
     - 'app/forms/hyrax/forms/permission_template_form.rb'
     - 'app/presenters/hyrax/work_show_presenter.rb'

app/controllers/concerns/hyrax/local_file_downloads_controller_behavior.rb

@@ -0,0 +1,86 @@
+module Hyrax
+  module LocalFileDownloadsControllerBehavior
+    protected
+
+      # Handle the HTTP show request
+      def send_local_content
+        response.headers['Accept-Ranges'] = 'bytes'
+        if request.head?
+          local_content_head
+        elsif request.headers['Range']
+          send_range_for_local_file
+        else
+          send_local_file_contents
+        end
+      end
+
+      # render an HTTP Range response
+      def send_range_for_local_file
+        _, range = request.headers['Range'].split('bytes=')
+        from, to = range.split('-').map(&:to_i)
+        to = local_file_size - 1 unless to
+        length = to - from + 1
+        response.headers['Content-Range'] = "bytes #{from}-#{to}/#{local_file_size}"
+        response.headers['Content-Length'] = length.to_s
+        self.status = 206
+        prepare_local_file_headers
+        # For derivatives stored on the local file system
+        send_data IO.binread(file, length, from), local_derivative_download_options.merge(status: status)
+      end
+
+      def send_local_file_contents
+        self.status = 200
+        prepare_local_file_headers
+        # For derivatives stored on the local file system
+        send_file file, local_derivative_download_options
+      end
+
+      def local_file_size
+        File.size(file)
+      end
+
+      def local_file_mime_type
+        mime_type_for(file)
+      end
+
+      # @return [String] the filename
+      def local_file_name
+        params[:filename] || File.basename(file) || (asset.respond_to?(:label) && asset.label)
+      end
+
+      def local_file_last_modified
+        File.mtime(file) if file.is_a? String
+      end
+
+      # Override
+      # render an HTTP HEAD response
+      def local_content_head
+        response.headers['Content-Length'] = local_file_size.to_s
+        head :ok, content_type: local_file_mime_type
+      end
+
+      # Override
+      def prepare_local_file_headers
+        send_file_headers! local_content_options
+        response.headers['Content-Type'] = local_file_mime_type
+        response.headers['Content-Length'] ||= local_file_size.to_s
+        # Prevent Rack::ETag from calculating a digest over body
+        response.headers['Last-Modified'] = local_file_last_modified.utc.strftime("%a, %d %b %Y %T GMT")
+        self.content_type = local_file_mime_type
+      end
+
+    private
+
+      # Override the Hydra::Controller::DownloadBehavior#content_options so that
+      # we have an attachement rather than 'inline'
+      def local_content_options
+        { type: local_file_mime_type, filename: local_file_name, disposition: 'attachment' }
+      end
+
+      # Override this method if you want to change the options sent when downloading
+      # a derivative file
+      def local_derivative_download_options
+        { type: local_file_mime_type, filename: local_file_name, disposition: 'inline' }
+      end
+  end
+end

app/controllers/hyrax/downloads_controller.rb

@@ -1,6 +1,7 @@
 module Hyrax
   class DownloadsController < ApplicationController
     include Hydra::Controller::DownloadBehavior
+    include Hyrax::LocalFileDownloadsControllerBehavior
 
     def self.default_content_path
       :original_file
@@ -15,9 +16,7 @@ def show
         super
       when String
         # For derivatives stored on the local file system
-        response.headers['Accept-Ranges'] = 'bytes'
-        response.headers['Content-Length'] = File.size(file).to_s
-        send_file file, derivative_download_options
+        send_local_content
       else
         raise ActiveFedora::ObjectNotFoundError
       end
@@ -55,7 +54,7 @@ def default_image
       # Loads the file specified by the HTTP parameter `:file`.
       # If this object does not have a file by that name, return the default file
       # as returned by {#default_file}
-      # @return [ActiveFedora::File, String, NilClass] Returns the file from the repository or a path to a file on the local file system, if it exists.
+      # @return [ActiveFedora::File, File, NilClass] Returns the file from the repository or a path to a file on the local file system, if it exists.
       def load_file
         file_reference = params[:file]
         return default_file unless file_reference

spec/controllers/hyrax/downloads_controller_spec.rb

@@ -66,6 +66,48 @@
             expect(ActiveFedora::Base).not_to receive(:find).with(file_set.id)
             get :show, params: { id: file_set, file: 'thumbnail' }
           end
+
+          context "stream" do
+            it "head request" do
+              request.env["HTTP_RANGE"] = 'bytes=0-15'
+              head :show, params: { id: file_set, file: 'thumbnail' }
+              expect(response.headers['Content-Length']).to eq '4218'
+              expect(response.headers['Accept-Ranges']).to eq 'bytes'
+              expect(response.headers['Content-Type']).to start_with 'image/png'
+            end
+
+            it "sends the whole thing" do
+              request.env["HTTP_RANGE"] = 'bytes=0-4217'
+              get :show, params: { id: file_set, file: 'thumbnail' }
+              expect(response.headers["Content-Range"]).to eq 'bytes 0-4217/4218'
+              expect(response.headers["Content-Length"]).to eq '4218'
+              expect(response.headers['Accept-Ranges']).to eq 'bytes'
+              expect(response.headers['Content-Type']).to start_with "image/png"
+              expect(response.headers["Content-Disposition"]).to eq "inline; filename=\"world.png\""
+              expect(response.body).to eq content
+              expect(response.status).to eq 206
+            end
+
+            it "sends the whole thing when the range is open ended" do
+              request.env["HTTP_RANGE"] = 'bytes=0-'
+              get :show, params: { id: file_set, file: 'thumbnail' }
+              expect(response.body).to eq content
+            end
+
+            it "gets a range not starting at the beginning" do
+              request.env["HTTP_RANGE"] = 'bytes=4200-4217'
+              get :show, params: { id: file_set, file: 'thumbnail' }
+              expect(response.headers["Content-Range"]).to eq 'bytes 4200-4217/4218'
+              expect(response.headers["Content-Length"]).to eq '18'
+            end
+
+            it "gets a range not ending at the end" do
+              request.env["HTTP_RANGE"] = 'bytes=4-11'
+              get :show, params: { id: file_set, file: 'thumbnail' }
+              expect(response.headers["Content-Range"]).to eq 'bytes 4-11/4218'
+              expect(response.headers["Content-Length"]).to eq '8'
+            end
+          end
         end
 
         context "that isn't persisted" do