Introduce compressor option to ActiveRecord::Encryption::Encryptor

activerecord/CHANGELOG.md

@@ -1,3 +1,23 @@
+*   `ActiveRecord::Encryption::Encryptor` now supports a `:compressor` option to customize the compression algorithm used.
+
+    ```ruby
+    module ZstdCompressor
+      def self.inflate(data)
+        Zstd.decompress(data)
+      end
+
+      def self.deflate(data)
+        Zstd.compress(data)
+      end
+    end
+
+    class User
+      encrypts :name, encryptor: ActiveRecord::Encryption::Encryptor.new(compressor: ZstdCompressor)
+    end
+    ```
+
+    *heka1024*
+
 *   Added support for recursive common table expressions.
 
     ```ruby

activerecord/lib/active_record/encryption/encryptor.rb

@@ -16,8 +16,11 @@ class Encryptor
       #
       # * <tt>:compress</tt> - Boolean indicating whether records should be compressed before encryption.
       #   Defaults to +true+.
-      def initialize(compress: true)
+      # * <tt>:compressor</tt> - The compressor to use. Defaults to +Zlib+.
+      #   It must respond to +deflate+ and +inflate+.
+      def initialize(compress: true, compressor: Zlib)
         @compress = compress
+        @compressor = compressor
       end
 
       # Encrypts +clean_text+ and returns the encrypted result
@@ -135,7 +138,7 @@ def compress?
         end
 
         def compress(data)
-          Zlib::Deflate.deflate(data).tap do |compressed_data|
+          @compressor.deflate(data).tap do |compressed_data|
             compressed_data.force_encoding(data.encoding)
           end
         end
@@ -149,7 +152,7 @@ def uncompress_if_needed(data, compressed)
         end
 
         def uncompress(data)
-          Zlib::Inflate.inflate(data).tap do |uncompressed_data|
+          @compressor.inflate(data).tap do |uncompressed_data|
             uncompressed_data.force_encoding(data.encoding)
           end
         end

activerecord/test/cases/encryption/encryptor_test.rb

@@ -88,6 +88,22 @@ class ActiveRecord::Encryption::EncryptorTest < ActiveRecord::EncryptionTestCase
     assert_equal Encoding::ISO_8859_1, decrypted_text.encoding
   end
 
+  test "accept a custom compressor" do
+    compressor = Module.new do
+      def self.deflate(data)
+        "compressed #{data}"
+      end
+
+      def self.inflate(data)
+        data.sub(/\Acompressed /, "")
+      end
+    end
+    @encryptor = ActiveRecord::Encryption::Encryptor.new(compressor: compressor)
+    content = SecureRandom.hex(5.kilobytes)
+
+    assert_encrypt_text content
+  end
+
   private
     def assert_encrypt_text(clean_text)
       encrypted_text = @encryptor.encrypt(clean_text)