Prepare infrastructure for CDP in Ruby

Adds WebSocket support to allow using CDP from Ruby bindings. The
implementation is naive: it simply processes handshake and then writes
to the connection socket and reads from it.

   driver = Selenium::WebDriver.for(:chrome)
   driver.devtools.send('Page.navigate', {url: 'https://google.com'})

There is no built-in CDP commands/types/events support. These will be
added later.

The code relies on websocket gem as it's the only dependency-free
implementation.

rb/lib/selenium/webdriver.rb

@@ -23,6 +23,7 @@
 require 'date'
 require 'json'
 require 'set'
+require 'websocket'
 
 require 'selenium/webdriver/common'
 require 'selenium/webdriver/atoms'
@@ -36,6 +37,7 @@ module WebDriver
     Location  = Struct.new(:latitude, :longitude, :altitude)
 
     autoload :Chrome,     'selenium/webdriver/chrome'
+    autoload :DevTools,   'selenium/webdriver/devtools'
     autoload :Edge,       'selenium/webdriver/edge'
     autoload :EdgeHtml,   'selenium/webdriver/edge'
     autoload :EdgeChrome, 'selenium/webdriver/edge'

rb/lib/selenium/webdriver/chrome/driver.rb

@@ -32,6 +32,7 @@ class Driver < WebDriver::Driver
         include DriverExtensions::HasLocation
         include DriverExtensions::TakesScreenshot
         include DriverExtensions::DownloadsFiles
+        include DriverExtensions::HasDevTools
 
         def browser
           :chrome

rb/lib/selenium/webdriver/common.rb

@@ -62,6 +62,7 @@
 require 'selenium/webdriver/common/driver_extensions/has_debugger'
 require 'selenium/webdriver/common/driver_extensions/uploads_files'
 require 'selenium/webdriver/common/driver_extensions/has_addons'
+require 'selenium/webdriver/common/driver_extensions/has_devtools'
 require 'selenium/webdriver/common/keys'
 require 'selenium/webdriver/common/profile_helper'
 require 'selenium/webdriver/common/options'

rb/lib/selenium/webdriver/common/driver_extensions/has_devtools.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+# Licensed to the Software Freedom Conservancy (SFC) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The SFC licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+module Selenium
+  module WebDriver
+    module DriverExtensions
+      module HasDevTools
+
+        #
+        # Retrieves connection to DevTools.
+        #
+        # @return [DevTools]
+        #
+
+        def devtools
+          @devtools ||= DevTools.new(capabilities['goog:chromeOptions']['debuggerAddress'])
+        end
+
+      end # HasDevTools
+    end # DriverExtensions
+  end # WebDriver
+end # Selenium

rb/lib/selenium/webdriver/devtools.rb

@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+# Licensed to the Software Freedom Conservancy (SFC) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The SFC licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+module Selenium
+  module WebDriver
+    class DevTools
+
+      def initialize(url)
+        @uri = URI("http://#{url}")
+        process_handshake
+      end
+
+      def send(method, **params)
+        data = JSON.generate(id: next_id, method: method, params: params)
+
+        out_frame = WebSocket::Frame::Outgoing::Client.new(version: ws.version, data: data, type: 'text')
+        socket.write(out_frame.to_s)
+
+        in_frame = WebSocket::Frame::Incoming::Client.new(version: ws.version)
+        in_frame << socket.readpartial(4096)
+        JSON.parse(in_frame.next.to_s)
+      end
+
+      private
+
+      def next_id
+        @id ||= 0
+        @id += 1
+      end
+
+      def process_handshake
+        socket.write(ws.to_s)
+        ws << socket.readpartial(1024)
+      end
+
+      def socket
+        @socket ||= TCPSocket.new(ws.host, ws.port)
+      end
+
+      def ws
+        @ws ||= WebSocket::Handshake::Client.new(url: ws_url)
+      end
+
+      def ws_url
+        @ws_url ||= begin
+          urls = JSON.parse(Net::HTTP.get(@uri.hostname, '/json', @uri.port))
+          page = urls.find { |u| u['type'] == 'page' }
+          page['webSocketDebuggerUrl']
+        end
+      end
+
+    end # DevTools
+  end # WebDriver
+end # Selenium

rb/selenium-webdriver.gemspec

@@ -33,6 +33,7 @@ Gem::Specification.new do |s|
 
   s.add_runtime_dependency 'childprocess', ['>= 0.5', '< 4.0']
   s.add_runtime_dependency 'rubyzip', ['>= 1.2.2']
+  s.add_runtime_dependency 'websocket', ['~> 1.0']
 
   # childprocess requires ffi on windows but doesn't declare it in its dependencies
   s.add_development_dependency 'ffi'