Merge pull request #5958 from avalonmediasystem/tempfile_location

Add setting for alternative rack tempfile directory

config/application.rb

@@ -1,4 +1,5 @@
 require_relative 'boot'
+require_relative '../lib/tempfile_factory'
 
 require 'rails/all'
 require 'resolv-replace'
@@ -56,6 +57,8 @@ class Application < Rails::Application
       end
     end
 
+    config.middleware.insert_before 0, TempfileFactory
+
     config.active_storage.service = (Settings&.active_storage&.service.presence || "local").to_sym
   end
 end

config/settings.yml

@@ -123,3 +123,8 @@ derivative:
   allow_download: true
 # Maximum size for uploaded files in bytes (default is disabled)
 #max_upload_size: 2147483648 # Use :none or comment out to disable limit
+# Rack Multipart creates temporary files when processing multipart form data with a large payload.
+# If the default system /tmp directory is storage constrained, you can define an alternative here. 
+# Leave commented out to use the system default.
+# tempfile:
+#   location: '/tmp'

lib/tempfile_factory.rb

@@ -0,0 +1,30 @@
+# Middleware to override the default Rack::Multipart tempfile factory: 
+# https://www.rubydoc.info/gems/rack/Rack/Multipart/Parser#TEMPFILE_FACTORY-constant
+class TempfileFactory
+  def initialize(app)
+    @app = app
+    return unless Settings.tempfile.present?
+    if Settings.tempfile&.location.present? && File.directory?(Settings.tempfile&.location) && File.writable?(Settings.tempfile&.location)
+      @tempfile_location = Settings.tempfile.location
+    else
+      logger.warn("[Rack::Multipart] [Tempfile] #{Settings.tempfile.location} is not a diretory or not writable. Falling back to #{Dir.tmpdir}.")
+    end
+  end
+
+  def call(env)
+    if @tempfile_location
+      env["rack.multipart.tempfile_factory"] = lambda { |filename, content_type| 
+        extension = ::File.extname(filename.gsub("\0", '%00'))[0, 129]
+        Tempfile.new(["RackMultipart", extension], @tempfile_location)
+      }
+    end
+
+    @app.call(env)
+  end
+
+  private
+
+  def logger
+    @logger ||= Logger.new(File.join(Rails.root, 'log', "#{Rails.env}.log"))
+  end
+end

spec/lib/tempfile_factory_spec.rb

@@ -0,0 +1,79 @@
+# Copyright 2011-2024, The Trustees of Indiana University and Northwestern
+#   University.  Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+# 
+# You may obtain a copy of the License at
+# 
+# http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing, software distributed
+#   under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+#   CONDITIONS OF ANY KIND, either express or implied. See the License for the
+#   specific language governing permissions and limitations under the License.
+# ---  END LICENSE_HEADER BLOCK  ---
+
+require 'rails_helper'
+
+describe TempfileFactory do
+  class MockApp
+    def call(env)
+      [200, {}, env]
+    end
+  end
+
+  let(:file) { fixture_file_upload("videoshort.mp4", "video/mp4") }
+  let(:env) { Rack::MockRequest.env_for('/', method: :post, params: file) }
+  let(:app) { MockApp.new }
+  subject { TempfileFactory.new(app) }
+
+  around do |example|
+    @old_config = Settings.dig(:tempfile, :location)
+    if tempfile_config.present?
+      Settings.tempfile ||= Config::Options.new
+      Settings.tempfile.location = tempfile_config
+    else
+      Settings.tempfile = nil
+    end
+    example.run
+    if @old_config.present?
+      Settings.tempfile ||= Config::Options.new
+      Settings.tempfile.location = @old_config
+    else
+      Settings.tempfile = nil
+    end
+  end
+
+  context "when an alternate directory is defined" do
+    let(:tempfile_config) { Rails.root.join('spec', 'fixtures').to_s }
+
+    it "sets `env['rack.multipart.tempfile_factory']`" do
+      status, headers, response = subject.call(env)
+      expect(response).to include 'rack.multipart.tempfile_factory'
+      expect(response['rack.multipart.tempfile_factory'].call("videoshort.mp4", "video/mp4").path).to start_with(tempfile_config)
+    end
+  end
+
+  context "when an alternate directory is NOT defined" do
+    let(:tempfile_config) { nil }
+
+    it "does not set `env['rack.multipart.tempfile_factory']`" do
+      status, headers, response = subject.call(env)
+      expect(response).to_not include 'rack.multipart.tempfile_factory'
+    end
+  end
+
+  context "when there is a problem with the defined alternate directory" do
+    let(:tempfile_config) { 'does not exist' }
+    let(:logger) { double() }
+
+    before do
+      allow_any_instance_of(TempfileFactory).to receive(:logger).and_return(logger)
+    end
+
+    it "does not set `env['rack.multipart.tempfile_factory']`" do
+      expect(logger).to receive(:warn).with(match("Falling back"))
+      status, headers, response = subject.call(env)
+      expect(response).to_not include 'rack.multipart.tempfile_factory'
+    end
+  end
+end