WIP: validate key name

lib/atc/utils/object_key_name_utils.rb

@@ -0,0 +1,47 @@
+require 'pathname'
+module Atc::Utils::ObjectKeyNameUtils
+  # About Cloud Storage objects: https://cloud.google.com/storage/docs/objects
+  # According to the above (and quite probably most Google Cloud Storage documentation),
+  # objects have names
+  # AWS - Creating object key names:
+  # https://docs.aws.amazon.com/AmazonS3/latest/userguide/object-keys.html
+  # As seen in the title for the above page, an object in AWS S3 has a key name (or key)
+  # So fcd1 decided to call this module ObjectKeyNameUtils to try and cover both naming
+  # conventions. However, it's just a name and fcd1 is cool if module is renamed
+
+  # Following method verifies that the given path to file
+  # meets both the requirements for a valid AWS S3 object key name, and the requirements
+  # for a valid Google Cloud Storage object name. So it must meet the more restrictive of the
+  # two requirements, which are the AWS S3 object key name requirements. See above links
+  # QUESTION: Are relative paths valid, as opposed to just absolute paths? Current implementation
+  # allows both for now, but this can be changed.
+  # The path to the filename can only contain, in addition to the '/' delimiter,
+  # the  following characters: a-zA-Z0-9_
+  # In addition to the above characters, the filename (without the path) can also contain
+  # one period, '.', used to delimit the file extension
+  # Method expects an absolute path as its only argument
+  def self.valid_key_name?(path_filename)
+    # Uncomment the following if only absolute paths are valid and relative paths are invalid
+    # return false unless Pathname.new(path_filename).absolute?
+
+    path_to_file, filename = Pathname.new(path_filename).split
+
+    # for filename, get extension (if there is one) and base filename
+    filename_extension = filename.extname
+    base_filename = filename.to_s.delete_suffix(filename_extension)
+
+    # check filename extension
+    if filename_extension
+      return false if (/[^a-zA-Z0-9_]/ =~ filename_extension.delete_prefix('.'))
+    end
+
+    # check base filename
+    return false if (/[^a-zA-Z0-9_]/ =~ base_filename)
+
+    # check each component in the path to the file
+    path_to_file.each_filename do |path_segment|
+      return false if (/[^a-zA-Z0-9_]/ =~ path_segment)
+    end
+    true
+  end
+end

spec/atc/utils/object_key_name_utils_spec.rb

@@ -0,0 +1,39 @@
+# coding: utf-8
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Atc::Utils::ObjectKeyNameUtils do
+  context '.valid_key_name?' do
+    let(:sample_invalid_paths) do
+      [
+        '/top_dîr/sub_dir/file',
+        '/top_dir/sub_dîr/file',
+        '/top_dir/sub_dir/fîle',
+        '/top_dir/sub_dir/fîle.txt',
+        '/top_dir/sub_dir/file.îxt',
+        '/top_dir/sub.dir/file.txt',
+        '/top_dir/sub_dir/file.txt.txt'
+      ]
+    end
+    let(:sample_valid_paths) do
+      [
+        '/top_dir/sub_dir/file',
+        'relative_path/sub_dir/file',
+        '/top_dir/sub_dir/file.txt'
+      ]
+    end
+
+    it 'returns false for all sample invalid paths' do
+      sample_invalid_paths.each do |path|
+        expect(described_class.valid_key_name?(path)).to (be false), lambda { "Test failed on path #{path}." }
+      end
+    end
+
+    it 'returns true for all sample valid paths' do
+      sample_valid_paths.each do |path|
+        expect(described_class.valid_key_name?(path)).to (be true), lambda { "Test failed on path #{path}." }
+      end
+    end
+  end
+end