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     29 
     30 
     31 """WebSocket opening handshake processor. This class try to apply available
     32 opening handshake processors for each protocol version until a connection is
     33 successfully established.
     34 """
     35 
     36 
     37 import logging
     38 
     39 from mod_pywebsocket import common
     40 from mod_pywebsocket.handshake import hybi00
     41 from mod_pywebsocket.handshake import hybi
     42 # Export AbortedByUserException, HandshakeException, and VersionException
     43 # symbol from this module.
     44 from mod_pywebsocket.handshake._base import AbortedByUserException
     45 from mod_pywebsocket.handshake._base import HandshakeException
     46 from mod_pywebsocket.handshake._base import VersionException
     47 
     48 
     49 _LOGGER = logging.getLogger(__name__)
     50 
     51 
     52 def do_handshake(request, dispatcher, allowDraft75=False, strict=False):
     53     """Performs WebSocket handshake.
     54 
     55     Args:
     56         request: mod_python request.
     57         dispatcher: Dispatcher (dispatch.Dispatcher).
     58         allowDraft75: obsolete argument. ignored.
     59         strict: obsolete argument. ignored.
     60 
     61     Handshaker will add attributes such as ws_resource in performing
     62     handshake.
     63     """
     64 
     65     _LOGGER.debug('Client\'s opening handshake resource: %r', request.uri)
     66     # To print mimetools.Message as escaped one-line string, we converts
     67     # headers_in to dict object. Without conversion, if we use %r, it just
     68     # prints the type and address, and if we use %s, it prints the original
     69     # header string as multiple lines.
     70     #
     71     # Both mimetools.Message and MpTable_Type of mod_python can be
     72     # converted to dict.
     73     #
     74     # mimetools.Message.__str__ returns the original header string.
     75     # dict(mimetools.Message object) returns the map from header names to
     76     # header values. While MpTable_Type doesn't have such __str__ but just
     77     # __repr__ which formats itself as well as dictionary object.
     78     _LOGGER.debug(
     79         'Client\'s opening handshake headers: %r', dict(request.headers_in))
     80 
     81     handshakers = []
     82     handshakers.append(
     83         ('RFC 6455', hybi.Handshaker(request, dispatcher)))
     84     handshakers.append(
     85         ('HyBi 00', hybi00.Handshaker(request, dispatcher)))
     86 
     87     for name, handshaker in handshakers:
     88         _LOGGER.debug('Trying protocol version %s', name)
     89         try:
     90             handshaker.do_handshake()
     91             _LOGGER.info('Established (%s protocol)', name)
     92             return
     93         except HandshakeException, e:
     94             _LOGGER.debug(
     95                 'Failed to complete opening handshake as %s protocol: %r',
     96                 name, e)
     97             if e.status:
     98                 raise e
     99         except AbortedByUserException, e:
    100             raise
    101         except VersionException, e:
    102             raise
    103 
    104     # TODO(toyoshim): Add a test to cover the case all handshakers fail.
    105     raise HandshakeException(
    106         'Failed to complete opening handshake for all available protocols',
    107         status=common.HTTP_STATUS_BAD_REQUEST)
    108 
    109 
    110 # vi:sts=4 sw=4 et
    111