FIX: broken onebox images due to url normalization bugs

normalized_encode in addressable has a number of issues, including sporkmonger/addressable#472

To temporaily work around those issues for the majority of cases, we try parsing with `::URI`. If that fails (e.g. due to non-ascii characters) then we will fall back to addressable.

Hopefully we can simplify this back to `Addressable::URI.normalized_encode` in the future.

This commit also adds support for unicode domain names and emoji domain names with escape_uri.

This removes an unneeded hack checking for pre-signed urls, which are now handled by the general case due to starting off valid and only being minimally normalized. Previous test case continues to pass.

UrlHelper.s3_presigned_url? which was somewhat wide was removed.

lib/url_helper.rb

@@ -60,9 +60,35 @@ def self.secure_proxy_without_cdn(url)
     self.absolute(Upload.secure_media_url_from_upload_url(url), nil)
   end
 
+  # This is a poorly named method. In reality, it **normalizes** the given URL,
+  # and does not escape it. Therefore it's idempotent, and can be used on user
+  # input which includes a mix of escaped and unescaped characters
   def self.escape_uri(uri)
-    return uri if s3_presigned_url?(uri)
-    Addressable::URI.normalized_encode(uri)
+    validated = nil
+    url = uri.to_s
+
+    # Ideally we will jump straight to `Addressable::URI.normalized_encode`. However,
+    # that implementation has some edge-case issues like https://github.com/sporkmonger/addressable/issues/472.
+    # To temporaily work around those issues for the majority of cases, we try parsing with `::URI`.
+    # If that fails (e.g. due to non-ascii characters) then we will fall back to addressable.
+    # Hopefully we can simplify this back to `Addressable::URI.normalized_encode` in the future.
+
+    # edge case where we expect mailto:test%40test.com to normalize to mailto:test@test.com
+    if url.match(/\Amailto:/)
+      return normalize_with_addressable(url)
+    end
+
+    # If it doesn't pass the regexp, it's definitely not gonna parse with URI.parse. Skip
+    # to addressable
+    if !url.match?(/\A#{URI::regexp}\z/)
+      return normalize_with_addressable(url)
+    end
+
+    begin
+      normalize_with_ruby_uri(url)
+    rescue URI::Error
+      normalize_with_addressable(url)
+    end
   end
 
   def self.rails_route_from_url(url)
@@ -72,10 +98,6 @@ def self.rails_route_from_url(url)
     nil
   end
 
-  def self.s3_presigned_url?(url)
-    url[/x-amz-(algorithm|credential)/i].present?
-  end
-
   def self.cook_url(url, secure: false, local: nil)
     is_secure = SiteSetting.secure_media && secure
     local = is_local(url) if local.nil?
@@ -120,4 +142,30 @@ def self.local_cdn_url(url)
     end
   end
 
+  private
+
+  def self.normalize_with_addressable(url)
+    u = Addressable::URI.normalized_encode(url, Addressable::URI)
+
+    if u.host && !u.host.ascii_only?
+      u.host = ::Addressable::IDNA.to_ascii(u.host)
+    end
+
+    u.to_s
+  end
+
+  def self.normalize_with_ruby_uri(url)
+    u = URI.parse(url)
+
+    if u.scheme && u.scheme != u.scheme.downcase
+      u.scheme = u.scheme.downcase
+    end
+
+    if u.host && u.host != u.host.downcase
+      u.host = u.host.downcase
+    end
+
+    u.to_s
+  end
+
 end

spec/lib/final_destination_spec.rb

@@ -26,7 +26,7 @@
         when 'any-subdomain.ihaveawildcard.com' then '104.25.152.11'
         when 'wikipedia.com' then '1.2.3.4'
         else
-          as_ip = IPAddr.new(host)
+          _as_ip = IPAddr.new(host)
           host
         end
       end

spec/lib/url_helper_spec.rb

@@ -86,6 +86,16 @@
   end
 
   describe "#escape_uri" do
+    it "does not double escape %3A (:)" do
+      url = "http://discourse.org/%3A/test"
+      expect(UrlHelper.escape_uri(url)).to eq(url)
+    end
+
+    it "does not double escape %2F (/)" do
+      url = "http://discourse.org/%2F/test"
+      expect(UrlHelper.escape_uri(url)).to eq(url)
+    end
+
     it "doesn't escape simple URL" do
       url = UrlHelper.escape_uri('http://example.com/foo/bar')
       expect(url).to eq('http://example.com/foo/bar')
@@ -107,8 +117,37 @@
     end
 
     it "doesn't escape already escaped chars (hash)" do
-      url = UrlHelper.escape_uri('https://calendar.google.com/calendar/embed?src=en.uk%23holiday%40group.v.calendar.google.com&ctz=Europe%2FLondon')
-      expect(url).to eq('https://calendar.google.com/calendar/embed?src=en.uk%23holiday@group.v.calendar.google.com&ctz=Europe/London')
+      url = 'https://calendar.google.com/calendar/embed?src=en.uk%23holiday@group.v.calendar.google.com&ctz=Europe%2FLondon'
+      escaped = UrlHelper.escape_uri(url)
+      expect(escaped).to eq(url)
+    end
+
+    it "leaves reserved chars alone in edge cases" do
+      skip "see: https://github.com/sporkmonger/addressable/issues/472"
+      url = "https://example.com/ article/id%3A1.2%2F1/bar"
+      expected = "https://example.com/%20article/id%3A1.2%2F1/bar"
+      escaped = UrlHelper.escape_uri(url)
+      expect(escaped).to eq(expected)
+    end
+
+    it "handles emoji domain names" do
+      url = "https://💻.example/💻?computer=💻"
+      expected = "https://xn--3s8h.example/%F0%9F%92%BB?computer=%F0%9F%92%BB"
+      escaped = UrlHelper.escape_uri(url)
+      expect(escaped).to eq(expected)
+    end
+
+    it "handles special-character domain names" do
+      url = "https://éxample.com/test"
+      expected = "https://xn--xample-9ua.com/test"
+      escaped = UrlHelper.escape_uri(url)
+      expect(escaped).to eq(expected)
+    end
+
+    it "performs basic normalization" do
+      url = "http://EXAMPLE.com/a"
+      escaped = UrlHelper.escape_uri(url)
+      expect(escaped).to eq("http://example.com/a")
     end
 
     it "doesn't escape S3 presigned URLs" do

spec/models/upload_spec.rb

@@ -568,27 +568,6 @@ def enable_secure_media
     end
   end
 
-  describe ".signed_url_from_secure_media_url" do
-    before do
-      # must be done so signed_url_for_path exists
-      enable_secure_media
-    end
-
-    it "correctly gives back a signed url from a path only" do
-      secure_url = "/secure-media-uploads/original/1X/c5a2c4ba0fa390f5aac5c2c1a12416791ebdd9e9.png"
-      signed_url = Upload.signed_url_from_secure_media_url(secure_url)
-      expect(signed_url).not_to include("secure-media-uploads")
-      expect(UrlHelper.s3_presigned_url?(signed_url)).to eq(true)
-    end
-
-    it "correctly gives back a signed url from a full url" do
-      secure_url = "http://localhost:3000/secure-media-uploads/original/1X/c5a2c4ba0fa390f5aac5c2c1a12416791ebdd9e9.png"
-      signed_url = Upload.signed_url_from_secure_media_url(secure_url)
-      expect(signed_url).not_to include(Discourse.base_url)
-      expect(UrlHelper.s3_presigned_url?(signed_url)).to eq(true)
-    end
-  end
-
   describe ".secure_media_url_from_upload_url" do
     before do
       # must be done so signed_url_for_path exists