1 files changed, 38 insertions, 0 deletions
diff --git a/app/validators/json_schema_validator.rb b/app/validators/json_schema_validator.rb
new file mode 100644
index 00000000000..f8c1727035c
--- /dev/null
+++ b/app/validators/json_schema_validator.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+#
+# JsonSchemaValidator
+#
+# Custom validator for json schema.
+# Create a json schema within the json_schemas directory
+#
+#   class Project < ActiveRecord::Base
+#     validates :data, json_schema: { filename: "file" }
+#   end
+#
+class JsonSchemaValidator < ActiveModel::EachValidator
+  FILENAME_ALLOWED = /\A[a-z0-9_-]*\Z/.freeze
+  FilenameError = Class.new(StandardError)
+
+  def initialize(options)
+    raise ArgumentError, "Expected 'filename' as an argument" unless options[:filename]
+    raise FilenameError, "Must be a valid 'filename'" unless options[:filename].match?(FILENAME_ALLOWED)
+
+    super(options)
+  end
+
+  def validate_each(record, attribute, value)
+    unless valid_schema?(value)
+      record.errors.add(attribute, "must be a valid json schema")
+    end
+  end
+
+  private
+
+  def valid_schema?(value)
+    JSON::Validator.validate(schema_path, value)
+  end
+
+  def schema_path
+    Rails.root.join('app', 'validators', 'json_schemas', "#{options[:filename]}.json").to_s
+  end
+end