Create UrlGenerator service

app/services/url_generator.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: false
+
+# Converts strings for use as parts of a URL. The input can contain non-roman/non-UTF8 characters
+# and the output will still be valid (including some transliteration). Examples:
+#
+# "Top Cat!"   -> "top-cat"
+# "Père Noël"  -> "pere-noel"
+# "你好"        -> "ni-hao"
+
+require "stringex/unidecoder"
+
+class UrlGenerator
+  def self.to_url(string)
+    Stringex::Unidecoder.decode(string.to_s).parameterize
+  end
+end

spec/services/url_generator_spec.rb

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+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe UrlGenerator do
+  subject { UrlGenerator }
+
+  describe "#to_url" do
+    it "converts to url-safe strings and removes unusable characters" do
+      expect(subject.to_url("Top Cat!?")).to eq "top-cat"
+    end
+
+    it "handles unusual characters like accents and umlauts" do
+      expect(subject.to_url("Père Noël")).to eq "pere-noel"
+    end
+
+    it "handles transliteration of Chinese characters" do
+      expect(subject.to_url("你好")).to eq "ni-hao"
+    end
+  end
+end