Support URL presign and COPY operation

lib/shrine/storage/google_cloud_storage.rb

@@ -13,16 +13,25 @@ def initialize(bucket:, prefix: nil, host: nil)
         @host = host
       end
 
-      def upload(io, id, shrine_metadata: {}, **options)
+      def upload(io, id, shrine_metadata: {}, **_options)
         # uploads `io` to the location `id`
-        storage_api.insert_object(@bucket, { name: object_name(id) }, content_type: shrine_metadata["mime_type"],
-                                                                      upload_source: io,
-                                                                      options: { uploadType: 'multipart' })
+
+        if copyable?(io)
+          storage_api.copy_object(io.storage.bucket, io.storage.object_name(io.id), @bucket, object_name(id))
+        else
+          storage_api.insert_object(
+            @bucket,
+            { name: object_name(id) },
+            content_type: shrine_metadata["mime_type"],
+            upload_source: io.to_io,
+            options: { uploadType: 'multipart' },
+          )
+        end
       end
 
-      def url(id, **options)
+      def url(id, **_options)
         # URL to the remote file, accepts options for customizing the URL
-        host = @host || "#{@bucket}.storage.googleapis.com"
+        host = @host || "storage.googleapis.com/#{@bucket}"
 
         "https://#{host}/#{object_name(id)}"
       end
@@ -58,6 +67,12 @@ def exists?(id)
       def delete(id)
         # deletes the file from the storage
         storage_api.delete_object(@bucket, object_name(id))
+
+      rescue Google::Apis::ClientError => e
+        # The object does not exist, Shrine expects us to be ok
+        return true if e.status_code == 404
+
+        raise e
       end
 
       def multi_delete(ids)
@@ -89,12 +104,41 @@ def clear!
         batch_delete(ids) unless ids.empty?
       end
 
-      private
+      def presign(id, **options)
+        method = options[:method] || "GET"
+        content_md5 = options[:content_md5] || ""
+        content_type = options[:content_type] || ""
+        expires = (Time.now.utc + (options[:expires] || 300)).to_i
+        headers = nil
+        path = "/#{@bucket}/" + object_name(id)
+
+        to_sign = [method, content_md5, content_type, expires, headers, path].compact.join("\n")
+
+        signing_key = options[:signing_key]
+        signing_key = OpenSSL::PKey::RSA.new(signing_key) unless signing_key.respond_to?(:sign)
+        signature = Base64.strict_encode64(signing_key.sign(OpenSSL::Digest::SHA256.new, to_sign)).delete("\n")
+
+        signed_url = "https://storage.googleapis.com#{path}?GoogleAccessId=#{options[:issuer]}" \
+          "&Expires=#{expires}&Signature=#{CGI.escape(signature)}"
+
+        OpenStruct.new(
+          url: signed_url,
+          fields: {},
+        )
+      end
 
       def object_name(id)
         @prefix ? "#{@prefix}/#{id}" : id
       end
 
+      private
+
+      def copyable?(io)
+        io.is_a?(UploadedFile) &&
+          io.storage.is_a?(Storage::GoogleCloudStorage)
+        # TODO: add a check for the credentials
+      end
+
       def batch_delete(object_names)
         storage_api.batch do |storage|
           object_names.each do |name|

test/gcs_test.rb

@@ -1,5 +1,6 @@
 require_relative "test_helper"
 require "shrine/storage/linter"
+require "date"
 
 describe Shrine::Storage::GoogleCloudStorage do
   def gcs(options = {})
@@ -8,6 +9,28 @@ def gcs(options = {})
     Shrine::Storage::GoogleCloudStorage.new(options)
   end
 
+  def service_account
+    {
+      private_key: "-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----",
+      client_email: 'test-shrine@test.google',
+    }
+  end
+
   before do
     @gcs = gcs
   end
@@ -34,4 +57,25 @@ def gcs(options = {})
       assert @gcs.exists?('pre')
     end
   end
+
+  describe "presign" do
+    it "works on a GET url" do
+      sa = service_account
+
+      storage = Shrine::Storage::GoogleCloudStorage.new(bucket: "shrine-test")
+
+      Time.stub :now, Time.at(1486649900) do
+        presign = storage.presign(
+          'test_presign.txt',
+          method: "GET",
+          expires: 60 * 5,
+          signing_key: sa[:private_key],
+          issuer: sa[:client_email],
+        )
+
+        assert_equal "https://storage.googleapis.com/shrine-test/test_presign.txt?GoogleAccessId=test-shrine@test.google&Expires=1486650200&Signature=O8tYOAJCtk0fXpO9MDhRO7ikVsIRqjALK01naly2rEJBCM2uRHl7meqEaXzu%2Bl9V17zw9P2%2FGb0K2miF%2FyEuZ6mnRIiuH6aI2tg24CV%2FKtuNU5jSqwqMU83iPzuptwakgFNxMGJj73i0SGbB%2F4wodNR7DNQ6KFhSlpJJ1mgD4hI%3D", presign.url
+        assert_equal({}, presign.fields)
+      end
+    end
+  end
 end