auto_link: support arbitrary URI schemes like "ftp:" and "file:"

recognizes all URI scheme allowed characters, such as colon and period.

[#3494 state:resolved]

actionpack/lib/action_view/helpers/text_helper.rb

@@ -537,7 +537,7 @@ module ActionView
         end
 
         AUTO_LINK_RE = %r{
-            ( https?:// | www\. )
+            (?: ([\w+.:-]+:)// | www\. )
             [^\s<]+
           }x unless const_defined?(:AUTO_LINK_RE)
 
@@ -548,7 +548,7 @@ module ActionView
         def auto_link_urls(text, html_options = {})
           link_attributes = html_options.stringify_keys
           text.gsub(AUTO_LINK_RE) do
-            href = $&
+            scheme, href = $1, $&
             punctuation = []
             left, right = $`, $'
             # detect already linked URLs and URLs in the middle of a tag
@@ -566,7 +566,7 @@ module ActionView
               end
 
               link_text = block_given?? yield(href) : href
-              href = 'http://' + href unless href =~ %r{^[a-z]+://}i
+              href = 'http://' + href unless scheme
 
               content_tag(:a, h(link_text), link_attributes.merge('href' => href)) + punctuation.reverse.join('')
             end

actionpack/test/template/text_helper_test.rb

@@ -376,17 +376,16 @@ class TextHelperTest < ActionView::TestCase
   end
 
   def test_auto_link_other_protocols
-    silence_warnings do
-      begin
-        old_re_value = ActionView::Helpers::TextHelper::AUTO_LINK_RE
-        ActionView::Helpers::TextHelper.const_set :AUTO_LINK_RE, %r{(ftp://)[^\s<]+}
-        link_raw = 'ftp://example.com/file.txt'
-        link_result = generate_result(link_raw)
-        assert_equal %(Download #{link_result}), auto_link("Download #{link_raw}")
-      ensure
-        ActionView::Helpers::TextHelper.const_set :AUTO_LINK_RE, old_re_value
-      end
-    end
+    ftp_raw = 'ftp://example.com/file.txt'
+    assert_equal %(Download #{generate_result(ftp_raw)}), auto_link("Download #{ftp_raw}")
+    
+    file_scheme   = 'file:///home/username/RomeoAndJuliet.pdf'
+    z39_scheme    = 'z39.50r://host:696/db'
+    chrome_scheme = 'chrome://package/section/path'
+    view_source   = 'view-source:http://en.wikipedia.org/wiki/URI_scheme'
+    assert_equal generate_result(z39_scheme), auto_link(z39_scheme)
+    assert_equal generate_result(chrome_scheme), auto_link(chrome_scheme)
+    assert_equal generate_result(view_source), auto_link(view_source)
   end
 
   def test_auto_link_already_linked