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import sys
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import time
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from cStringIO import StringIO
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from session import extract_header, Message
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#-----------------------------------------------------------------------------
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# Stream classes
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#-----------------------------------------------------------------------------
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class OutStream(object):
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"""A file like object that publishes the stream to a 0MQ PUB socket."""
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# The time interval between automatic flushes, in seconds.
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flush_interval = 0.05
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def __init__(self, session, pub_socket, name):
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self.session = session
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self.pub_socket = pub_socket
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self.name = name
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self.parent_header = {}
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self._new_buffer()
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def set_parent(self, parent):
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self.parent_header = extract_header(parent)
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def close(self):
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self.pub_socket = None
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def flush(self):
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if self.pub_socket is None:
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raise ValueError(u'I/O operation on closed file')
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else:
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data = self._buffer.getvalue()
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if data:
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content = {u'name':self.name, u'data':data}
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msg = self.session.msg(u'stream', content=content,
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parent=self.parent_header)
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print>>sys.__stdout__, Message(msg)
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self.pub_socket.send_json(msg)
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self._buffer.close()
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self._new_buffer()
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def isatty(self):
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return False
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def next(self):
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raise IOError('Read not supported on a write only stream.')
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def read(self, size=-1):
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raise IOError('Read not supported on a write only stream.')
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def readline(self, size=-1):
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raise IOError('Read not supported on a write only stream.')
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def write(self, string):
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if self.pub_socket is None:
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raise ValueError('I/O operation on closed file')
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else:
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self._buffer.write(string)
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current_time = time.time()
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if self._start <= 0:
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self._start = current_time
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elif current_time - self._start > self.flush_interval:
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self.flush()
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def writelines(self, sequence):
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if self.pub_socket is None:
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raise ValueError('I/O operation on closed file')
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else:
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for string in sequence:
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self.write(string)
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def _new_buffer(self):
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self._buffer = StringIO()
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self._start = -1
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