Class: WebkitRemote::Process

Inherits:
Object
  • Object
show all
Defined in:
lib/webkit_remote/process.rb

Overview

Tracks a Webkit process.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Process

Tracker for a yet-unlaunched process.

Parameters:

  • opts (Hash) (defaults to: {}) —

    tweak the options below

Options Hash (opts):

  • port (Integer) —

    the port used by the remote debugging server; the default port is 9292

  • timeout (Number) —

    number of seconds to wait for the browser to start; the default timeout is 10 seconds

  • window (Hash<Symbol, Number>) —

    set the :left, :top, :width and :height of the browser window; by default, the browser window is 256x256 starting at 0,0.

  • xvfb (Hash<Symbol, Number>, Boolean) —

    use Xvfb instead of a real screen; set the :display, :width, :height, :depth and :dpi of the server, or use the default display number 20, at 1280x1024x32 with 72dpi

  • allow_popups (Boolean) —

    when true, the popup blocker is disabled; this is sometimes necessary when driving a Web UI via JavaScript

  • chrome_binary (String) —

    path to the Chrome binary to be used; by default, the path is automatically detected



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# File 'lib/webkit_remote/process.rb', line 29

def initialize(opts = {})
  @port = opts[:port] || 9292
  @timeout = opts[:timeout] || 10
  @running = false
  @data_dir = Dir.mktmpdir 'webkit-remote'
  @pid = nil
  @xvfb_pid = nil
  if opts[:window]
    @window = opts[:window]
  else
    @window = { }
  end
  if opts[:xvfb]
    @xvfb_cli = xvfb_cli opts
    if opts[:xvfb].respond_to? :[]
      @window[:width] ||= opts[:xvfb][:width]
      @window[:height] ||= opts[:xvfb][:height]
    end
  else
    @xvfb_cli = nil
  end
  @window[:top] ||= 0
  @window[:left] ||= 0
  @window[:width] ||= 256
  @window[:height] ||= 256
  @cli = chrome_cli opts
end

Instance Attribute Details

#port ⇒ Integer (readonly)

Returns port that the process’ remote debugging server listens to.

Returns:

  • (Integer) —

    port that the process’ remote debugging server listens to



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# File 'lib/webkit_remote/process.rb', line 139

def port
  @port
end

#running ⇒ Boolean (readonly) Also known as: running?

Returns true if the Webkit process is running.

Returns:

  • (Boolean) —

    true if the Webkit process is running



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# File 'lib/webkit_remote/process.rb', line 101

def running
  @running
end

Class Method Details

.chrome_binary ⇒ String

Path to a Google Chrome / Chromium binary.

Returns:

  • (String) —

    full-qualified path to a binary that launches Chrome



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# File 'lib/webkit_remote/process.rb', line 268

def self.chrome_binary
  return @chrome_binary unless @chrome_binary == false

  case RUBY_PLATFORM
  when /linux/
    [
      'google-chrome',
      'google-chromium',
    ].each do |binary|
      path = `which #{binary}`
      unless path.empty?
        @chrome_binary = path.strip
        break
      end
    end
  when /darwin/
    [
      '/Applications/Chromium.app/Contents/MacOS/Chromium',
      '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome',
      '/Applications/Google Chrome Canary.app/Contents/MacOS/Google Chrome Canary',
    ].each do |path|
      if File.exist? path
        @chrome_binary = path
        break
      end
    end
  else
    raise "Unsupported platform #{RUBY_PLATFORM}"
  end
  @chrome_binary ||= nil
end

.xvfb_binary ⇒ String

Path to the Xvfb virtual X server binary.

Returns:

  • (String) —

    full-qualified path to a binary that launches Xvfb.



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# File 'lib/webkit_remote/process.rb', line 304

def self.xvfb_binary
  return @xvfb_binary unless @xvfb_binary == false

  path = `which Xvfb`
  unless path.empty?
    @xvfb_binary = path.strip
  end
  @xvfb_binary ||= nil
end

Instance Method Details

#chrome_cli(opts) ⇒ Array<String>

Command-line that launches Google Chrome / Chromium

Parameters:

  • opts (Hash) —

    options passed to the WebkitRemote::Process constructor

Returns:

  • (Array<String>) —

    command line for launching Chrome



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# File 'lib/webkit_remote/process.rb', line 150

def chrome_cli(opts)
  # The Chromium wiki recommends this page for available flags:
  #     http://peter.sh/experiments/chromium-command-line-switches/
  [
    chrome_env(opts),
    opts[:chrome_binary] || self.class.chrome_binary,
  ] + chrome_cli_flags(opts) + [
    "--remote-debugging-port=#{@port}",  # Webkit remote debugging
    "--user-data-dir=#{@data_dir}",  # really ensure a clean slate
    "--window-position=#{@window[:left]},#{@window[:top]}",
    "--window-size=#{@window[:width]},#{@window[:height]}",

    'about:blank',  # don't load the homepage
    {
      chdir: @data_dir,
      in: '/dev/null',
      out: File.join(@data_dir, '.stdout'),
      err: File.join(@data_dir, '.stderr')
    },
  ]
end

#chrome_cli_flags(opts) ⇒ Array<String>

Flags used on the command-line that launches Google Chrome / Chromium.

Parameters:

  • opts (Hash) —

    options passed to the WebkitRemote::Process constructor

Returns:

  • (Array<String>) —

    flags used on the command line for launching Chrome



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# File 'lib/webkit_remote/process.rb', line 176

def chrome_cli_flags(opts)
  flags = [
    '--bwsi',  # disable extensions, sync, bookmarks
    '--disable-default-apps',  # no bundled apps
    '--disable-extensions',  # no extensions
    '--disable-java',  # no plugins
    '--disable-logging',  # don't trash stdout / stderr
    '--disable-plugins',  # no native content
    '--disable-prompt-on-repost',   # no confirmation dialog on POST refresh
    '--disable-sync',  # no talking with the Google servers
    '--disable-translate',  # no Google Translate calls
    '--incognito',  # don't use old state, don't preserve state
    '--homepage=about:blank',  # don't go to Google in new tabs
    '--keep-alive-for-test',  # don't kill process if the last window dies
    '--lang=en-US',  # set a default language
    '--log-level=3',  # FATAL, because there's no setting for "none"
    '--mute-audio',  # don't let the computer make noise
    '--no-default-browser-check',  # don't hang when Chrome isn't default
    '--no-experiments',  # not sure this is useful
    '--no-first-run',  # don't show the help UI
    '--no-js-randomness',  # consistent Date.now() and Math.random()
    '--no-message-box',  # don't let user scripts show dialogs
    '--no-service-autorun',  # don't mess with autorun settings
    '--noerrdialogs',  # don't hang on error dialogs
  ]
  flags << '--disable-popup-blocking' if opts[:allow_popups]
  flags
end

#chrome_env(opts) ⇒ Hash<String, String>

Environment variables set when launching Chrome.

Parameters:

  • opts (Hash) —

    options passed to the WebkitRemote::Process constructor

Returns:

  • (Hash<String, String>) —

    variables to be added to the environment of the Chrome process before launching



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# File 'lib/webkit_remote/process.rb', line 210

def chrome_env(opts)
  if opts[:xvfb]
    if opts[:xvfb].respond_to?(:[]) and opts[:xvfb][:display]
      display = opts[:xvfb][:display]
    else
      display = 20
    end
    { 'DISPLAY' => ":#{display}.0" }
  else
    {}
  end
end

#finalize ⇒ Object

Remove temporary directory if it’s still there at garbage collection time.



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# File 'lib/webkit_remote/process.rb', line 142

def finalize
  PathUtils.rm_rf @data_dir if File.exists?(@data_dir)
end

#start ⇒ WebkitRemote::Browser

Starts the browser process.

Returns:

  • (WebkitRemote::Browser) —

    master session to the started Browser process; the session’s auto_close is set to false so that it can be safely discarded; nil if the launch fails



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# File 'lib/webkit_remote/process.rb', line 62

def start
  return self if running?

  if @xvfb_cli
    unless @xvfb_pid = POSIX::Spawn.spawn(*@xvfb_cli)
      # The Xvfb launch failed.
      return nil
    end
  end

  unless @pid = POSIX::Spawn.spawn(*@cli)
    # The launch failed.
    stop
    return nil
  end

  (@timeout * 20).times do
    # Check if the browser exited.
    begin
      break if status = ::Process.wait(@pid, ::Process::WNOHANG)
    rescue SystemCallError  # no children
      break
    end

    # Check if the browser finished starting up.
    begin
      browser = WebkitRemote::Browser.new process: self
      @running = true
      return browser
    rescue SystemCallError  # most likely ECONNREFUSED
      Kernel.sleep 0.05
    end
  end
  # The browser failed, or was too slow to start.
  stop
  nil
end

#stop ⇒ WebkitRemote::Process

Stops the browser process.

Only call this after you’re done with the process.

Returns:



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# File 'lib/webkit_remote/process.rb', line 109

def stop
  return self unless running?
  if @pid
    begin
      ::Process.kill 'TERM', @pid
      ::Process.wait @pid
    rescue SystemCallError
      # Process died on its own.
    ensure
      @pid = nil
    end
  end

  if @xvfb_pid
    begin
      ::Process.kill 'TERM', @xvfb_pid
      ::Process.wait @xvfb_pid
    rescue SystemCallError
      # Process died on its own.
    ensure
      @xvfb_pid = nil
    end
  end

  FileUtils.rm_rf @data_dir if File.exists?(@data_dir)
  @running = false
  self
end

#xvfb_cli(opts) ⇒ Array<String>

Command-line that launches Xvfb.

Parameters:

  • opts (Hash) —

    options passed to the WebkitRemote::Process constructor

Returns:

  • (Array<String>) —

    command line for launching Xvfb



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# File 'lib/webkit_remote/process.rb', line 227

def xvfb_cli(opts)
  # The OSX man page for Xvfb:
  #     http://developer.apple.com/library/mac/documentation/darwin/reference/manpages/man1/Xvfb.1.html

  xvfb_opts = opts[:xvfb]
  unless xvfb_opts.respond_to? :[]
    xvfb_opts = {}
  end

  display = xvfb_opts[:display] || 20
  width = xvfb_opts[:width] || 1280
  height = xvfb_opts[:height] || 1024
  depth = xvfb_opts[:depth] || 32
  dpi = xvfb_opts[:dpi] || 72

  # https://bugs.freedesktop.org/show_bug.cgi?id=17453
  if depth == 32
    depth = '24+32'
  end

  [
    self.class.xvfb_binary,
    ":#{display}",
    '-screen', '0', "#{width}x#{height}x#{depth}",
    '-auth', File.join(@data_dir, '.Xauthority'),
    '-c',
    '-dpi', dpi.to_s,
    '-terminate',
    '-wr',
    {
      chdir: @data_dir,
      in: '/dev/null',
      out: File.join(@data_dir, '.X_stdout'),
      err: File.join(@data_dir, '.X_stderr'),
    },
  ]
end