chrome/test/data/native_messaging/native_hosts/echo.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 # A simple native client in python.
   7 # All this client does is echo the text it receives back at the extension.
   8
   9 import os
  10 import platform
  11 import sys
  12 import struct
  13
  14 def WriteMessage(message):
  15   try:
  16     sys.stdout.write(struct.pack("I", len(message)))
  17     sys.stdout.write(message)
  18     sys.stdout.flush()
  19     return True
  20   except IOError:
  21     return False
  22
  23 def Main():
  24   message_number = 0
  25
  26   caller_url = None
  27   parent_window = None
  28
  29   if len(sys.argv) < 2:
  30     sys.stderr.write("URL of the calling application is not specified.\n")
  31     return 1
  32   # TODO(sergeyu): Use argparse module to parse the arguments (not available in
  33   # Python 2.6).
  34   for arg in sys.argv[1:]:
  35     if arg.startswith('--'):
  36       if arg.startswith('--parent-window='):
  37         parent_window = long(arg[len('--parent-window='):])
  38     elif caller_url == None:
  39       caller_url = arg
  40
  41   if platform.system() == 'Windows':
  42     import win32gui
  43     if parent_window and not win32gui.IsWindow(parent_window):
  44       sys.stderr.write('Invalid --parent-window.\n')
  45       return 1
  46
  47   while 1:
  48     # Read the message type (first 4 bytes).
  49     text_length_bytes = sys.stdin.read(4)
  50
  51     if len(text_length_bytes) == 0:
  52       break
  53
  54     # Read the message length (4 bytes).
  55     text_length = struct.unpack('i', text_length_bytes)[0]
  56
  57     # Read the text (JSON object) of the message.
  58     text = sys.stdin.read(text_length).decode('utf-8')
  59
  60     # bigMessage() test sends a special message that is sent to verify that
  61     # chrome rejects messages that are too big. Try sending a message bigger
  62     # than 1MB after receiving a message that contains 'bigMessageTest'.
  63     if 'bigMessageTest' in text:
  64       text = '{"key": "' + ("x" * 1024 * 1024) + '"}'
  65
  66     # "stopHostTest" verifies that Chrome properly handles the case when the
  67     # host quits before port is closed. When the test receives response it
  68     # will try sending second message and it should fail becasue the stdin
  69     # pipe will be closed at that point.
  70     if 'stopHostTest' in text:
  71       # Using os.close() here because sys.stdin.close() doesn't really close
  72       # the pipe (it just marks it as closed, but doesn't close the file
  73       # descriptor).
  74       os.close(sys.stdin.fileno())
  75       WriteMessage('{"stopped": true }')
  76       sys.exit(0)
  77
  78     message_number += 1
  79
  80     message = '{{"id": {0}, "echo": {1}, "caller_url": "{2}"}}'.format(
  81           message_number, text, caller_url).encode('utf-8')
  82     if not WriteMessage(message):
  83       break
  84
  85 if __name__ == '__main__':
  86   sys.exit(Main())