From 77592740e43e7c44e3beeebd5de2d47e8c452b09 Mon Sep 17 00:00:00 2001
From: Alexander Azarov <azarov@osinka.ru>
Date: Tue, 20 Dec 2016 14:23:55 +0200
Subject: [PATCH] Facebook bot

---
 README.md                |  4 +++-
 Rakefile                 |  7 +++++++
 legitbot.gemspec         |  3 +++
 lib/legitbot.rb          |  8 +++++---
 lib/legitbot/facebook.rb | 37 +++++++++++++++++++++++++++++++++++++
 lib/legitbot/version.rb  |  2 +-
 test/facebook_test.rb    | 22 ++++++++++++++++++++++
 7 files changed, 78 insertions(+), 5 deletions(-)
 create mode 100644 lib/legitbot/facebook.rb
 create mode 100644 test/facebook_test.rb

diff --git a/README.md b/README.md
index fc67e6b..317ee85 100644
--- a/README.md
+++ b/README.md
@@ -34,7 +34,9 @@ end
 ## Issues, problems, plans
 
 * Rails middleware
-* Facebook: https://developers.facebook.com/docs/sharing/webmasters/crawler
+* More testing for Facebook
+* Review for thread safety
+* Make it possible to reload Facebook IP ranges
 
 ## License
 
diff --git a/Rakefile b/Rakefile
index 87bdaa8..fc9e3fb 100644
--- a/Rakefile
+++ b/Rakefile
@@ -12,4 +12,11 @@ Rake::TestTask.new do |t|
   t.verbose = true
 end
 
+desc 'Start a console'
+task :console do
+  require 'irb'
+  ARGV.clear
+  IRB.start
+end
+
 task default: %w[test]
diff --git a/legitbot.gemspec b/legitbot.gemspec
index bcd344d..7f13db4 100644
--- a/legitbot.gemspec
+++ b/legitbot.gemspec
@@ -15,6 +15,9 @@ Gem::Specification.new do |spec|
     "made by a real search engine, not a fake"
 
   spec.required_ruby_version = '>= 2.0.0'
+  spec.add_dependency "irrc"
+  spec.add_dependency "segment_tree"
+  spec.add_dependency "concurrent-ruby"
   spec.add_development_dependency "rake"
   spec.add_development_dependency "minitest"
 
diff --git a/lib/legitbot.rb b/lib/legitbot.rb
index 9ba713c..7a3a18a 100644
--- a/lib/legitbot.rb
+++ b/lib/legitbot.rb
@@ -2,8 +2,10 @@
 
 require_relative 'legitbot/legitbot'
 require_relative 'legitbot/botmatch'
-require_relative 'legitbot/google'
-require_relative 'legitbot/yandex'
-require_relative 'legitbot/bing'
+
 require_relative 'legitbot/baidu'
+require_relative 'legitbot/bing'
 require_relative 'legitbot/duckduckgo'
+require_relative 'legitbot/facebook'
+require_relative 'legitbot/google'
+require_relative 'legitbot/yandex'
diff --git a/lib/legitbot/facebook.rb b/lib/legitbot/facebook.rb
new file mode 100644
index 0000000..cb9f92b
--- /dev/null
+++ b/lib/legitbot/facebook.rb
@@ -0,0 +1,37 @@
+require 'segment_tree'
+require 'irrc'
+require 'concurrent'
+
+module Legitbot
+  # https://developers.facebook.com/docs/sharing/webmasters/crawler
+
+  class Facebook < BotMatch
+    AS = 'AS32934'
+    ValidIPs = Concurrent::Delay.new do
+      client = Irrc::Client.new
+      client.query :radb, 'AS32934'
+      results = client.perform
+      Hash[
+        :ipv4 => SegmentTree.new(
+          results[AS][:ipv4][AS].map { |cidr|
+            [IPAddr.new(cidr).to_range, true]
+          }),
+        :ipv6 => SegmentTree.new(
+          results[AS][:ipv6][AS].map { |cidr|
+            [IPAddr.new(cidr).to_range, true]
+          })
+      ]
+    end
+
+    def valid?
+      ip = IPAddr.new(@ip)
+      if ip.ipv4?
+        ValidIPs.value[:ipv4].find(ip)
+      else
+        ValidIPs.value[:ipv6].find(ip)
+      end
+    end
+  end
+
+  rule Legitbot::Facebook, %w(facebookhit facebookexternalhit)
+end
diff --git a/lib/legitbot/version.rb b/lib/legitbot/version.rb
index a38b859..a7f7988 100644
--- a/lib/legitbot/version.rb
+++ b/lib/legitbot/version.rb
@@ -1,3 +1,3 @@
 module Legitbot
-  VERSION = '0.0.1'
+  VERSION = '0.1.0'
 end
diff --git a/test/facebook_test.rb b/test/facebook_test.rb
new file mode 100644
index 0000000..c6b76e2
--- /dev/null
+++ b/test/facebook_test.rb
@@ -0,0 +1,22 @@
+require 'minitest/autorun'
+require 'legitbot'
+
+class FacebookTest < Minitest::Test
+  def test_valid_ip
+    ip = "69.63.186.89"
+    match = Legitbot::Facebook.new(ip)
+    assert match.valid?, msg: "#{ip} is a valid Facebook IP"
+  end
+
+  def test_invalid_ip
+    ip = "127.0.0.1"
+    match = Legitbot::Facebook.new(ip)
+    assert match.fake?, msg: "#{ip} is a fake Facebook IP"
+  end
+
+  def test_user_agent
+    bot = Legitbot.bot("facebookexternalhit/1.1 (+http://www.facebook.com/externalhit_uatext.php)", "31.13.76.56")
+    assert_equal "Facebook", bot.detected_as
+    assert bot.valid?, msg: "A valid Facebook User-agent and IP"
+  end
+end