text: # Copyright 2014 Google Inc. All rights reserved.
  #
  # Licensed 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.
  
  """Command-line tools for authenticating via OAuth 2.0
  
  Do the OAuth 2.0 Web Server dance for a command line application. Stores the
  generated credentials in a common file that is used by other example apps in
  the same directory.
  """
  
  from __future__ import print_function
  
  import logging
  import socket
  import sys
  
  from six.moves import BaseHTTPServer
  from six.moves import http_client
  from six.moves import input
  from six.moves import urllib
  
  from oauth2client import _helpers
  from oauth2client import client
  
  
  __all__ = ['argparser', 'run_flow', 'message_if_missing']
  
  _CLIENT_SECRETS_MESSAGE = """WARNING: Please configure OAuth 2.0
  
  To make this sample run you will need to populate the client_secrets.json file
  found at:
  
     {file_path}
  
  with information from the APIs Console <https://code.google.com/apis/console>.
  
  """
  
  _FAILED_START_MESSAGE = """
  Failed to start a local webserver listening on either port 8080
  or port 8090. Please check your firewall settings and locally
  running programs that may be blocking or using those ports.
  
  Falling back to --noauth_local_webserver and continuing with
  authorization.
  """
  
  _BROWSER_OPENED_MESSAGE = """
  Your browser has been opened to visit:
  
      {address}
  
  If your browser is on a different machine then exit and re-run this
  application with the command-line parameter
  
    --noauth_local_webserver
  """
  
  _GO_TO_LINK_MESSAGE = """
  Go to the following link in your browser:
  
      {address}
  """
  
  
  def _CreateArgumentParser():
      try:
          import argparse
      except ImportError:  # pragma: NO COVER
          return None
      parser = argparse.ArgumentParser(add_help=False)
      parser.add_argument('--auth_host_name', default='localhost',
                          help='Hostname when running a local web server.')
      parser.add_argument('--noauth_local_webserver', action='store_true',
                          default=False, help='Do not run a local web server.')
      parser.add_argument('--auth_host_port', default=[8080, 8090], type=int,
                          nargs='*', help='Port web server should listen on.')
      parser.add_argument(
          '--logging_level', default='ERROR',
          choices=['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'],
          help='Set the logging level of detail.')
      return parser
  
  
  # argparser is an ArgumentParser that contains command-line options expected
  # by tools.run(). Pass it in as part of the 'parents' argument to your own
  # ArgumentParser.
  argparser = None #_CreateArgumentParser()
  
  
  class ClientRedirectServer(BaseHTTPServer.HTTPServer):
      """A server to handle OAuth 2.0 redirects back to localhost.
  
      Waits for a single request and parses the query parameters
      into query_params and then stops serving.
      """
      query_params = {}
  
  
  class ClientRedirectHandler(BaseHTTPServer.BaseHTTPRequestHandler):
      """A handler for OAuth 2.0 redirects back to localhost.
  
      Waits for a single request and parses the query parameters
      into the servers query_params and then stops serving.
      """
  
      def do_GET(self):
          """Handle a GET request.
  
          Parses the query parameters and prints a message
          if the flow has completed. Note that we can't detect
          if an error occurred.
          """
          self.send_response(http_client.OK)
          self.send_header('Content-type', 'text/html')
          self.end_headers()
          parts = urllib.parse.urlparse(self.path)
          query = _helpers.parse_unique_urlencoded(parts.query)
          self.server.query_params = query
          self.wfile.write(
              b'<html><head><title>Authentication Status</title></head>')
          self.wfile.write(
              b'<body><p>The authentication flow has completed.</p>')
          self.wfile.write(b'</body></html>')
  
      def log_message(self, format, *args):
          """Do not log messages to stdout while running as cmd. line program."""
  
  
  @_helpers.positional(3)
  def run_flow(flow, storage, flags=None, http=None):
      """Core code for a command-line application.
  
      The ``run()`` function is called from your application and runs
      through all the steps to obtain credentials. It takes a ``Flow``
      argument and attempts to open an authorization server page in the
      user's default web browser. The server asks the user to grant your
      application access to the user's data. If the user grants access,
      the ``run()`` function returns new credentials. The new credentials
      are also stored in the ``storage`` argument, which updates the file
      associated with the ``Storage`` object.
  
      It presumes it is run from a command-line application and supports the
      following flags:
  
          ``--auth_host_name`` (string, default: ``localhost``)
             Host name to use when running a local web server to handle
             redirects during OAuth authorization.
  
          ``--auth_host_port`` (integer, default: ``[8080, 8090]``)
             Port to use when running a local web server to handle redirects
             during OAuth authorization. Repeat this option to specify a list
             of values.
  
          ``--[no]auth_local_webserver`` (boolean, default: ``True``)
             Run a local web server to handle redirects during OAuth
             authorization.
  
      The tools module defines an ``ArgumentParser`` the already contains the
      flag definitions that ``run()`` requires. You can pass that
      ``ArgumentParser`` to your ``ArgumentParser`` constructor::
  
          parser = argparse.ArgumentParser(
              description=__doc__,
              formatter_class=argparse.RawDescriptionHelpFormatter,
              parents=[tools.argparser])
          flags = parser.parse_args(argv)
  
      Args:
          flow: Flow, an OAuth 2.0 Flow to step through.
          storage: Storage, a ``Storage`` to store the credential in.
          flags: ``argparse.Namespace``, (Optional) The command-line flags. This
                 is the object returned from calling ``parse_args()`` on
                 ``argparse.ArgumentParser`` as described above. Defaults
                 to ``argparser.parse_args()``.
          http: An instance of ``httplib2.Http.request`` or something that
                acts like it.
  
      Returns:
          Credentials, the obtained credential.
      """
      if flags is None:
          flags = argparser.parse_args()
      logging.getLogger().setLevel(getattr(logging, flags.logging_level))
      if not flags.noauth_local_webserver:
          success = False
          port_number = 0
          for port in flags.auth_host_port:
              port_number = port
              try:
                  httpd = ClientRedirectServer((flags.auth_host_name, port),
                                               ClientRedirectHandler)
              except socket.error:
                  pass
              else:
                  success = True
                  break
          flags.noauth_local_webserver = not success
          if not success:
              print(_FAILED_START_MESSAGE)
  
      if not flags.noauth_local_webserver:
          oauth_callback = 'http://{host}:{port}/'.format(
              host=flags.auth_host_name, port=port_number)
      else:
          oauth_callback = client.OOB_CALLBACK_URN
      flow.redirect_uri = oauth_callback
      authorize_url = flow.step1_get_authorize_url()
  
      if not flags.noauth_local_webserver:
          import webbrowser
          webbrowser.open(authorize_url, new=1, autoraise=True)
          print(_BROWSER_OPENED_MESSAGE.format(address=authorize_url))
      else:
          print(_GO_TO_LINK_MESSAGE.format(address=authorize_url))
  
      code = None
      if not flags.noauth_local_webserver:
          httpd.handle_request()
          if 'error' in httpd.query_params:
              sys.exit('Authentication request was rejected.')
          if 'code' in httpd.query_params:
              code = httpd.query_params['code']
          else:
              print('Failed to find "code" in the query parameters '
                    'of the redirect.')
              sys.exit('Try running with --noauth_local_webserver.')
      else:
          code = input('Enter verification code: ').strip()
  
      try:
          credential = flow.step2_exchange(code, http=http)
      except client.FlowExchangeError as e:
          sys.exit('Authentication has failed: {0}'.format(e))
  
      storage.put(credential)
      credential.set_store(storage)
      print('Authentication successful.')
  
      return credential
  
  
  def message_if_missing(filename):
      """Helpful message to display if the CLIENT_SECRETS file is missing."""
      return _CLIENT_SECRETS_MESSAGE.format(file_path=filename)
  