From 22467c9a515002327db55cb7639b35f99c479b52 Mon Sep 17 00:00:00 2001
From: Peleg Rosenthal <peleg@dogparklabs.com>
Date: Mon, 18 May 2020 13:32:16 -0400
Subject: [PATCH] Reinstate CloudFlare support + custom protocol

- Reinstating custom support for CF-VISITOR CloudFlare header +
  options[:protocol]

- Fixing failing tests
  Instead of passing in `X-Forwarded-Proto` to the Rack env, we can now
  safely rely on `HTTP_` env variables which are automatically set. Per
  https://github.com/rack/rack/blob/master/SPEC.rdoc#the-environment-:

      HTTP_ Variables:
      Variables corresponding to the client-supplied HTTP request headers
      (i.e., variables whose names begin with HTTP_). The presence or absence
      of these variables should correspond with the presence or absence of the
      appropriate HTTP header in the request. See RFC3875 section 4.1.18 for
      specific behavior.
---
 lib/prerender_rails.rb      | 9 ++++++++-
 test/lib/prerender_rails.rb | 4 ++--
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/prerender_rails.rb b/lib/prerender_rails.rb
index bcc0d79..3392d02 100644
--- a/lib/prerender_rails.rb
+++ b/lib/prerender_rails.rb
@@ -181,9 +181,16 @@ def get_prerendered_page_response(env)
       end
     end
 
+    def get_cloudflare_scheme(env)
+      match = /"scheme":"(http|https)"/.match(env['CF-VISITOR'])
+      match && match[1]
+    end
+
     def build_api_url(env)
       request_obj = Rack::Request.new(env)
-      url = "#{request_obj.scheme}://#{request_obj.host}#{request_obj.fullpath}"
+      scheme = @options[:protocol] || get_cloudflare_scheme(env) || request_obj.scheme
+      url = "#{scheme}://#{request_obj.host}#{request_obj.fullpath}"
+
       prerender_url = get_prerender_service_url()
       forward_slash = prerender_url[-1, 1] == '/' ? '' : '/'
       "#{prerender_url}#{forward_slash}#{url}"
diff --git a/test/lib/prerender_rails.rb b/test/lib/prerender_rails.rb
index 60d66d9..060f4e2 100644
--- a/test/lib/prerender_rails.rb
+++ b/test/lib/prerender_rails.rb
@@ -200,7 +200,7 @@
 
     # Check X-Forwarded-Proto because Heroku SSL Support terminates at the load balancer
     it "should build the correct api url for the Heroku SSL Addon support with single value" do
-      request = Rack::MockRequest.env_for "http://google.com/search?q=javascript", { 'X-FORWARDED-PROTO' => 'https'}
+      request = Rack::MockRequest.env_for "http://google.com/search?q=javascript", { 'HTTP_X_FORWARDED_PROTO' => 'https'}
       ENV['PRERENDER_SERVICE_URL'] = nil
       assert_equal 'http://service.prerender.io/https://google.com/search?q=javascript', @prerender.build_api_url(request)
     end
@@ -208,7 +208,7 @@
 
     # Check X-Forwarded-Proto because Heroku SSL Support terminates at the load balancer
     it "should build the correct api url for the Heroku SSL Addon support with double value" do
-      request = Rack::MockRequest.env_for "http://google.com/search?q=javascript", { 'X-FORWARDED-PROTO' => 'https,http'}
+      request = Rack::MockRequest.env_for "http://google.com/search?q=javascript", { 'HTTP_X_FORWARDED_PROTO' => 'https,http'}
       ENV['PRERENDER_SERVICE_URL'] = nil
       assert_equal 'http://service.prerender.io/https://google.com/search?q=javascript', @prerender.build_api_url(request)
     end