Handle already encoded URLs

Closes #2253

lib/paperclip/io_adapters/http_url_proxy_adapter.rb

@@ -9,7 +9,8 @@ def self.register
     REGEXP = /\Ahttps?:\/\//
 
     def initialize(target, options = {})
-      super(URI(URI.escape(target)), options)
+      escaped = URI.escape(target)
+      super(URI(target == URI.unescape(target) ? escaped : target), options)
     end
   end
 end

spec/paperclip/io_adapters/http_url_proxy_adapter_spec.rb

@@ -107,15 +107,32 @@
   end
 
   context "a url with special characters in the filename" do
-    it "returns a encoded filename" do
+    before do
       Paperclip::HttpUrlProxyAdapter.any_instance.stubs(:download_content).
         returns(@open_return)
-      url = "https://github.com/thoughtbot/paperclip-öäü字´½♥زÈ.png"
-      subject = Paperclip.io_adapters.for(url)
-      filename = "paperclip-%C3%B6%C3%A4%C3%BC%E5%AD%97%C2%B4%C2%BD%E2%99%A5"\
+    end
+
+    let(:filename) do
+      "paperclip-%C3%B6%C3%A4%C3%BC%E5%AD%97%C2%B4%C2%BD%E2%99%A5"\
         "%C3%98%C2%B2%C3%88.png"
+    end
+    let(:url) { "https://github.com/thoughtbot/paperclip-öäü字´½♥زÈ.png" }
+
+    subject { Paperclip.io_adapters.for(url) }
 
+    it "returns a encoded filename" do
       assert_equal filename, subject.original_filename
     end
+
+    context "when already URI encoded" do
+      let(:url) do
+        "https://github.com/thoughtbot/paperclip-%C3%B6%C3%A4%C3%BC%E5%AD%97"\
+        "%C2%B4%C2%BD%E2%99%A5%C3%98%C2%B2%C3%88.png"
+      end
+
+      it "returns a encoded filename" do
+        assert_equal filename, subject.original_filename
+      end
+    end
   end
 end