Direct uploads for S3

Author: David Heinemeier Hansson

Gemfile

@@ -6,6 +6,7 @@ gem 'rake'
 gem 'byebug'
 
 gem 'sqlite3'
+gem 'httparty'
 
 gem 'aws-sdk', require: false
 gem 'google-cloud-storage', require: false

Gemfile.lock

@@ -83,6 +83,8 @@ GEM
       multi_json (~> 1.11)
       os (~> 0.9)
       signet (~> 0.7)
+    httparty (0.15.5)
+      multi_xml (>= 0.5.2)
     httpclient (2.8.3)
     i18n (0.8.4)
     jmespath (1.3.1)
@@ -100,6 +102,7 @@ GEM
     mini_portile2 (2.1.0)
     minitest (5.10.2)
     multi_json (1.12.1)
+    multi_xml (0.6.0)
     multipart-post (2.0.0)
     nokogiri (1.7.2)
       mini_portile2 (~> 2.1.0)
@@ -139,6 +142,7 @@ DEPENDENCIES
   bundler (~> 1.15)
   byebug
   google-cloud-storage
+  httparty
   rake
   sqlite3
 

lib/active_storage/blob.rb

@@ -25,6 +25,10 @@ def build_after_upload(io:, filename:, content_type: nil, metadata: nil)
     def create_after_upload!(io:, filename:, content_type: nil, metadata: nil)
       build_after_upload(io: io, filename: filename, content_type: content_type, metadata: metadata).tap(&:save!)
     end
+
+    def create_before_direct_upload!(filename:, byte_size:, checksum:, content_type: nil, metadata: nil)
+      create! filename: filename, byte_size: byte_size, checksum: checksum, content_type: content_type, metadata: metadata
+    end
   end
 
   # We can't wait until the record is first saved to have a key for it
@@ -40,6 +44,10 @@ def url(expires_in: 5.minutes, disposition: :inline)
     service.url key, expires_in: expires_in, disposition: disposition, filename: filename
   end
 
+  def url_for_direct_upload(expires_in: 5.minutes)
+    service.url_for_direct_upload key, expires_in: expires_in, content_type: content_type, content_length: byte_size
+  end
+
 
   def upload(io)
     self.checksum  = compute_checksum_in_chunks(io)

lib/active_storage/direct_uploads_controller.rb

@@ -0,0 +1,14 @@
+require "action_controller"
+require "active_storage/blob"
+
+class ActiveStorage::DirectUploadsController < ActionController::Base
+  def create
+    blob = ActiveStorage::Blob.create_before_direct_upload!(blob_args)
+    render json: { url: blob.url_for_direct_upload, sgid: blob.to_sgid.to_param }
+  end
+
+  private
+    def blob_args
+      params.require(:blob).permit(:filename, :byte_size, :checksum, :content_type, :metadata).to_h.symbolize_keys
+    end
+end

lib/active_storage/engine.rb

@@ -16,10 +16,11 @@ class Engine < Rails::Engine # :nodoc:
 
     initializer "active_storage.routes" do
       require "active_storage/disk_controller"
+      require "active_storage/direct_uploads_controller"
 
       config.after_initialize do |app|
         app.routes.prepend do
-          get "/rails/blobs/:encoded_key/*filename" => "active_storage/disk#show", as: :rails_disk_blob
+          eval(File.read(File.expand_path("../routes.rb", __FILE__)))
         end
       end
     end

lib/active_storage/routes.rb

@@ -0,0 +1,2 @@
+get  "/rails/active_storage/disk/:encoded_key/*filename" => "active_storage/disk#show", as: :rails_disk_blob
+post "/rails/active_storage/direct_uploads" => "active_storage/direct_uploads#create", as: :rails_direct_uploads

lib/active_storage/service.rb

@@ -78,6 +78,10 @@ def url(key, expires_in:, disposition:, filename:)
     raise NotImplementedError
   end
 
+  def url_for_direct_upload(key, expires_in:, content_type:, content_length:)
+    raise NotImplementedError
+  end
+
   private
     def instrument(operation, key, payload = {}, &block)
       ActiveSupport::Notifications.instrument(

lib/active_storage/service/disk_service.rb

@@ -59,7 +59,7 @@ def url(key, expires_in:, disposition:, filename:)
         if defined?(Rails) && defined?(Rails.application)
           Rails.application.routes.url_helpers.rails_disk_blob_path(verified_key_with_expiration, disposition: disposition, filename: filename)
         else
-          "/rails/blobs/#{verified_key_with_expiration}/#{filename}?disposition=#{disposition}"
+          "/rails/active_storage/disk/#{verified_key_with_expiration}/#{filename}?disposition=#{disposition}"
         end
 
       payload[:url] = generated_url

lib/active_storage/service/s3_service.rb

@@ -56,6 +56,17 @@ def url(key, expires_in:, disposition:, filename:)
     end
   end
 
+  def url_for_direct_upload(key, expires_in:, content_type:, content_length:)
+    instrument :url, key do |payload|
+      generated_url = object_for(key).presigned_url :put, expires_in: expires_in,
+        content_type: content_type, content_length: content_length
+      
+      payload[:url] = generated_url
+      
+      generated_url
+    end
+  end
+
   private
     def object_for(key)
       bucket.object(key)

test/blob_test.rb

@@ -23,6 +23,6 @@ class ActiveStorage::BlobTest < ActiveSupport::TestCase
 
   private
     def expected_url_for(blob, disposition: :inline)
-      "/rails/blobs/#{ActiveStorage::VerifiedKeyWithExpiration.encode(blob.key, expires_in: 5.minutes)}/#{blob.filename}?disposition=#{disposition}"
+      "/rails/active_storage/disk/#{ActiveStorage::VerifiedKeyWithExpiration.encode(blob.key, expires_in: 5.minutes)}/#{blob.filename}?disposition=#{disposition}"
     end
 end