From 1be9e5cd7a4ac9baa3c83efdd0bf111a52e69f48 Mon Sep 17 00:00:00 2001
From: Victor Maslov <nakilon@gmail.com>
Date: Wed, 4 Apr 2018 17:09:14 +0300
Subject: [PATCH] better redirect handling

---
 lib/fastimage.rb | 10 +---------
 test/test.rb     |  6 ++++++
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/lib/fastimage.rb b/lib/fastimage.rb
index 777549d..19235c8 100644
--- a/lib/fastimage.rb
+++ b/lib/fastimage.rb
@@ -250,15 +250,7 @@ class FastImage
       if res.is_a?(Net::HTTPRedirection) && @redirect_count < 4
         @redirect_count += 1
         begin
-          newly_parsed_uri = URI.parse(res['Location'])
-          # The new location may be relative - check for that
-          if protocol_relative_url?(res['Location'])
-            @parsed_uri = URI.parse("#{@parsed_uri.scheme}:#{res['Location']}")
-          elsif newly_parsed_uri.scheme != "http" && newly_parsed_uri.scheme != "https"
-            @parsed_uri.path = res['Location']
-          else
-            @parsed_uri = newly_parsed_uri
-          end
+          @parsed_uri = URI.join(@parsed_uri, res['Location'])
         rescue URI::InvalidURIError
         else
           fetch_using_http_from_parsed_uri
diff --git a/test/test.rb b/test/test.rb
index d55d5f6..68b0b19 100644
--- a/test/test.rb
+++ b/test/test.rb
@@ -247,6 +247,12 @@ class FastImageTest < Test::Unit::TestCase
     assert_equal GoodFixtures[GoodFixtures.keys.first][1], FastImage.size(url, :raise_on_failure=>true)
   end
 
+  def test_should_handle_permanent_redirect_with_complex_relative_url
+    register_redirect(TestUrl, "/photo.gne?rb=1&short=Vv4Und")
+    register_redirect("#{TestUrl}photo.gne?rb=1&short=Vv4Und", "/" + GoodFixtures.keys.first)
+    assert_equal GoodFixtures[GoodFixtures.keys.first][1], FastImage.size(TestUrl, :raise_on_failure=>true)
+  end
+
   def register_redirect(from, to)
     resp = Net::HTTPMovedPermanently.new(1.0, 302, "Moved")
     resp['Location'] = to