From 7b5af13d19cf984a46136d44ebc8d2543cc78bb7 Mon Sep 17 00:00:00 2001
From: Eugen Rochko <eugen@zeonfederated.com>
Date: Fri, 12 May 2017 17:46:44 +0200
Subject: [PATCH] Prepend reblogs' wrapper content with "RT @original_author",
 (#3013)

so that when a reblog parse fails on another instance, it doesn't
look like a misattributed/stolen text
---
 app/lib/atom_serializer.rb |  2 +-
 app/lib/formatter.rb       | 45 +++++++++++++++--------
 spec/lib/formatter_spec.rb | 75 ++++++++++++++++++++++++++------------
 3 files changed, 83 insertions(+), 39 deletions(-)

diff --git a/app/lib/atom_serializer.rb b/app/lib/atom_serializer.rb
index db6bc4dd26..288a9cfadc 100644
--- a/app/lib/atom_serializer.rb
+++ b/app/lib/atom_serializer.rb
@@ -337,7 +337,7 @@ class AtomSerializer
 
   def serialize_status_attributes(entry, status)
     append_element(entry, 'summary', Formatter.instance.format(status.proper, :spoiler_text, false).to_str, 'xml:lang': status.language, type: 'html') if status.spoiler_text?
-    append_element(entry, 'content', Formatter.instance.format(status.proper).to_str, type: 'html', 'xml:lang': status.language)
+    append_element(entry, 'content', Formatter.instance.format(status).to_str, type: 'html', 'xml:lang': status.language)
 
     status.mentions.each do |mentioned|
       append_element(entry, 'link', nil, rel: :mentioned, 'ostatus:object-type': TagManager::TYPES[:person], href: TagManager.instance.uri_for(mentioned.account))
diff --git a/app/lib/formatter.rb b/app/lib/formatter.rb
index 5a1b63c0a2..43d23db963 100644
--- a/app/lib/formatter.rb
+++ b/app/lib/formatter.rb
@@ -10,13 +10,24 @@ class Formatter
   include ActionView::Helpers::TextHelper
 
   def format(status, attribute = :text, paragraphize = true)
+    if status.reblog?
+      prepend_reblog = status.reblog.account.acct
+      status         = status.proper
+    else
+      prepend_reblog = false
+    end
+
     raw_content = status.public_send(attribute)
 
     return '' if raw_content.blank?
     return reformat(raw_content) unless status.local?
 
+    linkable_accounts = status.mentions.map(&:account)
+    linkable_accounts << status.account
+
     html = raw_content
-    html = encode_and_link_urls(html, status.mentions)
+    html = "RT @#{prepend_reblog} #{html}" if prepend_reblog
+    html = encode_and_link_urls(html, linkable_accounts)
     html = simple_format(html, {}, sanitize: false) if paragraphize
     html = html.delete("\n")
 
@@ -52,7 +63,7 @@ class Formatter
     HTMLEntities.new.encode(html)
   end
 
-  def encode_and_link_urls(html, mentions = nil)
+  def encode_and_link_urls(html, accounts = nil)
     entities = Extractor.extract_entities_with_indices(html, extract_url_without_protocol: false)
 
     rewrite(html.dup, entities) do |entity|
@@ -61,7 +72,7 @@ class Formatter
       elsif entity[:hashtag]
         link_to_hashtag(entity)
       elsif entity[:screen_name]
-        link_to_mention(entity, mentions)
+        link_to_mention(entity, accounts)
       end
     end
   end
@@ -69,19 +80,21 @@ class Formatter
   def rewrite(text, entities)
     chars = text.to_s.to_char_a
 
-    # sort by start index
+    # Sort by start index
     entities = entities.sort_by do |entity|
       indices = entity.respond_to?(:indices) ? entity.indices : entity[:indices]
       indices.first
     end
 
     result = []
+
     last_index = entities.reduce(0) do |index, entity|
       indices = entity.respond_to?(:indices) ? entity.indices : entity[:indices]
       result << encode(chars[index...indices.first].join)
       result << yield(entity)
       indices.last
     end
+
     result << encode(chars[last_index..-1].join)
 
     result.flatten.join
@@ -89,26 +102,28 @@ class Formatter
 
   def link_to_url(entity)
     normalized_url = Addressable::URI.parse(entity[:url]).normalize
-    html_attrs = {
-      target: '_blank',
-      rel: 'nofollow noopener',
-    }
+    html_attrs     = { target: '_blank', rel: 'nofollow noopener' }
+
     Twitter::Autolink.send(:link_to_text, entity, link_html(entity[:url]), normalized_url, html_attrs)
   rescue Addressable::URI::InvalidURIError
     encode(entity[:url])
   end
 
-  def link_to_mention(entity, mentions)
+  def link_to_mention(entity, linkable_accounts)
     acct = entity[:screen_name]
-    return link_to_account(acct) unless mentions
-    mention = mentions.find { |item| TagManager.instance.same_acct?(item.account.acct, acct) }
-    mention ? mention_html(mention.account) : "@#{acct}"
+
+    return link_to_account(acct) unless linkable_accounts
+
+    account = linkable_accounts.find { |item| TagManager.instance.same_acct?(item.acct, acct) }
+    account ? mention_html(account) : "@#{acct}"
   end
 
   def link_to_account(acct)
     username, domain = acct.split('@')
-    domain = nil if TagManager.instance.local_domain?(domain)
+
+    domain  = nil if TagManager.instance.local_domain?(domain)
     account = Account.find_remote(username, domain)
+
     account ? mention_html(account) : "@#{acct}"
   end
 
@@ -117,7 +132,7 @@ class Formatter
   end
 
   def link_html(url)
-    url = Addressable::URI.parse(url).display_uri.to_s
+    url    = Addressable::URI.parse(url).display_uri.to_s
     prefix = url.match(/\Ahttps?:\/\/(www\.)?/).to_s
     text   = url[prefix.length, 30]
     suffix = url[prefix.length + 30..-1]
@@ -127,7 +142,7 @@ class Formatter
   end
 
   def hashtag_html(tag)
-    "<a href=\"#{tag_url(tag.downcase)}\" class=\"mention hashtag\">#<span>#{tag}</span></a>"
+    "<a href=\"#{tag_url(tag.downcase)}\" class=\"mention hashtag\" rel=\"tag\">#<span>#{tag}</span></a>"
   end
 
   def mention_html(account)
diff --git a/spec/lib/formatter_spec.rb b/spec/lib/formatter_spec.rb
index 15b4e1d960..1db7f0bc97 100644
--- a/spec/lib/formatter_spec.rb
+++ b/spec/lib/formatter_spec.rb
@@ -7,38 +7,56 @@ RSpec.describe Formatter do
   let(:remote_status) { Fabricate(:status, text: '<script>alert("Hello")</script> Beep boop', uri: 'beepboop', account: account) }
 
   let(:local_text_with_mention) { "@#{account.username} @#{account.username}@example.com #{local_text}?x=@#{account.username} #hashtag" }
-  let(:local_status_with_mention) { Fabricate(:status, text: local_text_with_mention,
-                                              account: account, mentions: [Fabricate(:mention, account: account)]) }
+
+  let(:local_status_with_mention) do
+    Fabricate(
+      :status,
+      text: local_text_with_mention,
+      account: account,
+      mentions: [Fabricate(:mention, account: account)]
+    )
+  end
 
   describe '#format' do
     subject { Formatter.instance.format(local_status) }
 
-    it 'returns a string' do
-      expect(subject).to be_a String
-    end
+    context 'with standalone status' do
+      it 'returns a string' do
+        expect(subject).to be_a String
+      end
 
-    it 'contains plain text' do
-      expect(subject).to match('Hello world')
-    end
+      it 'contains plain text' do
+        expect(subject).to match('Hello world')
+      end
 
-    it 'contains a link' do
-      expect(subject).to match('<a href="http://google.com/" rel="nofollow noopener" target="_blank"><span class="invisible">http://</span><span class="">google.com/</span><span class="invisible"></span></a>')
-    end
+      it 'contains a link' do
+        expect(subject).to match('<a href="http://google.com/" rel="nofollow noopener" target="_blank"><span class="invisible">http://</span><span class="">google.com/</span><span class="invisible"></span></a>')
+      end
 
-    it 'contains a mention' do
-      result = Formatter.instance.format(local_status_with_mention)
-      expect(result).to match "<a href=\"#{TagManager.instance.url_for(account)}\" class=\"u-url mention\">@<span>#{account.username}</span></a></span>"
-      expect(result).to match %r{href=\"http://google.com/\?x=@#{account.username}}
-      expect(result).not_to match "href=\"https://example.com/@#{account.username}"
+      it 'contains a mention' do
+        result = Formatter.instance.format(local_status_with_mention)
+        expect(result).to match "<a href=\"#{TagManager.instance.url_for(account)}\" class=\"u-url mention\">@<span>#{account.username}</span></a></span>"
+        expect(result).to match %r{href=\"http://google.com/\?x=@#{account.username}}
+        expect(result).not_to match "href=\"https://example.com/@#{account.username}"
+      end
+
+      it 'contains a hashtag' do
+        result = Formatter.instance.format(local_status_with_mention)
+        expect(result).to match('/tags/hashtag" class="mention hashtag" rel="tag">#<span>hashtag</span></a>')
+      end
     end
 
-    it 'contains a hashtag' do
-      result = Formatter.instance.format(local_status_with_mention)
-      expect(result).to match("/tags/hashtag\" class=\"mention hashtag\">#<span>hashtag</span></a>")
+    context 'with reblog' do
+      let(:local_status) { Fabricate(:status, account: account, reblog: Fabricate(:status, text: 'Hello world', account: account)) }
+
+      it 'contains credit to original author' do
+        expect(subject).to include("RT <span class=\"h-card\"><a href=\"#{TagManager.instance.url_for(account)}\" class=\"u-url mention\">@<span>#{account.username}</span></a></span> Hello world")
+      end
     end
 
     context 'matches a stand-alone medium URL' do
       let(:local_text) { 'https://hackernoon.com/the-power-to-build-communities-a-response-to-mark-zuckerberg-3f2cac9148a4' }
+
       it 'has valid url' do
         expect(subject).to include('href="https://hackernoon.com/the-power-to-build-communities-a-response-to-mark-zuckerberg-3f2cac9148a4"')
       end
@@ -46,6 +64,7 @@ RSpec.describe Formatter do
 
     context 'matches a stand-alone google URL' do
       let(:local_text) { 'http://google.com' }
+
       it 'has valid url' do
         expect(subject).to include('href="http://google.com/"')
       end
@@ -53,6 +72,7 @@ RSpec.describe Formatter do
 
     context 'matches a stand-alone IDN URL' do
       let(:local_text) { 'https://nic.みんな/' }
+
       it 'has valid url' do
         expect(subject).to include('href="https://nic.xn--q9jyb4c/"')
       end
@@ -64,6 +84,7 @@ RSpec.describe Formatter do
 
     context 'matches a URL without trailing period' do
       let(:local_text) { 'http://www.mcmansionhell.com/post/156408871451/50-states-of-mcmansion-hell-scottsdale-arizona. ' }
+
       it 'has valid url' do
         expect(subject).to include('href="http://www.mcmansionhell.com/post/156408871451/50-states-of-mcmansion-hell-scottsdale-arizona"')
       end
@@ -75,6 +96,7 @@ RSpec.describe Formatter do
 
     context 'matches a URL without exclamation point' do
       let(:local_text) { 'http://www.google.com!' }
+
       it 'has valid url' do
         expect(subject).to include('href="http://www.google.com/"')
       end
@@ -82,6 +104,7 @@ RSpec.describe Formatter do
 
     context 'matches a URL without single quote' do
       let(:local_text) { "http://www.google.com'" }
+
       it 'has valid url' do
         expect(subject).to include('href="http://www.google.com/"')
       end
@@ -89,6 +112,7 @@ RSpec.describe Formatter do
 
     context 'matches a URL without angle brackets' do
       let(:local_text) { 'http://www.google.com>' }
+
       it 'has valid url' do
         expect(subject).to include('href="http://www.google.com/"')
       end
@@ -96,6 +120,7 @@ RSpec.describe Formatter do
 
     context 'matches a URL with a query string' do
       let(:local_text) { 'https://www.ruby-toolbox.com/search?utf8=%E2%9C%93&q=autolink' }
+
       it 'has valid url' do
         expect(subject).to include('href="https://www.ruby-toolbox.com/search?utf8=%E2%9C%93&amp;q=autolink"')
       end
@@ -103,20 +128,23 @@ RSpec.describe Formatter do
 
     context 'matches a URL with parenthesis in it' do
       let(:local_text) { 'https://en.wikipedia.org/wiki/Diaspora_(software)' }
+
       it 'has valid url' do
         expect(subject).to include('href="https://en.wikipedia.org/wiki/Diaspora_(software)"')
       end
     end
 
     context 'contains html (script tag)' do
-        let(:local_text) { '<script>alert("Hello")</script>' }
-        it 'has valid url' do
-            expect(subject).to match '<p>&lt;script&gt;alert(&quot;Hello&quot;)&lt;/script&gt;</p>'
-        end
+      let(:local_text) { '<script>alert("Hello")</script>' }
+
+      it 'has valid url' do
+        expect(subject).to match '<p>&lt;script&gt;alert(&quot;Hello&quot;)&lt;/script&gt;</p>'
+      end
     end
 
     context 'contains html (xss attack)' do
       let(:local_text) { %q{<img src="javascript:alert('XSS');">} }
+
       it 'has valid url' do
         expect(subject).to match '<p>&lt;img src=&quot;javascript:alert(&apos;XSS&apos;);&quot;&gt;</p>'
       end
@@ -124,6 +152,7 @@ RSpec.describe Formatter do
 
     context 'contains invalid URL' do
       let(:local_text) { 'http://www\.google\.com' }
+
       it 'has valid url' do
         expect(subject).to eq '<p>http://www\.google\.com</p>'
       end