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| 2 | #### |
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| 3 | # Copyright 2000,2001 by Timothy O'Malley <timo@alum.mit.edu> |
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| 4 | # |
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| 5 | # All Rights Reserved |
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| 6 | # |
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| 7 | # Permission to use, copy, modify, and distribute this software |
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| 8 | # and its documentation for any purpose and without fee is hereby |
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| 9 | # granted, provided that the above copyright notice appear in all |
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| 10 | # copies and that both that copyright notice and this permission |
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| 11 | # notice appear in supporting documentation, and that the name of |
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| 12 | # Timothy O'Malley not be used in advertising or publicity |
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| 13 | # pertaining to distribution of the software without specific, written |
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| 14 | # prior permission. |
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| 15 | # |
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| 16 | # Timothy O'Malley DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS |
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| 17 | # SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY |
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| 18 | # AND FITNESS, IN NO EVENT SHALL Timothy O'Malley BE LIABLE FOR |
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| 19 | # ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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| 20 | # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, |
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| 21 | # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
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| 22 | # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR |
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| 23 | # PERFORMANCE OF THIS SOFTWARE. |
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| 24 | # |
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| 25 | #### |
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| 26 | |
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| 27 | """Timeout Socket |
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| 28 | |
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| 29 | This module enables a timeout mechanism on all TCP connections. It |
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| 30 | does this by inserting a shim into the socket module. After this module |
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| 31 | has been imported, all socket creation goes through this shim. As a |
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| 32 | result, every TCP connection will support a timeout. |
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| 33 | |
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| 34 | The beauty of this method is that it immediately and transparently |
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| 35 | enables the entire python library to support timeouts on TCP sockets. |
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| 36 | As an example, if you wanted to SMTP connections to have a 20 second |
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| 37 | timeout: |
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| 38 | |
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| 39 | import timeoutsocket |
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| 40 | import smtplib |
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| 41 | timeoutsocket.setDefaultSocketTimeout(20) |
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| 42 | |
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| 43 | |
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| 44 | The timeout applies to the socket functions that normally block on |
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| 45 | execution: read, write, connect, and accept. If any of these |
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| 46 | operations exceeds the specified timeout, the exception Timeout |
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| 47 | will be raised. |
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| 48 | |
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| 49 | The default timeout value is set to None. As a result, importing |
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| 50 | this module does not change the default behavior of a socket. The |
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| 51 | timeout mechanism only activates when the timeout has been set to |
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| 52 | a numeric value. (This behavior mimics the behavior of the |
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| 53 | select.select() function.) |
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| 54 | |
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| 55 | This module implements two classes: TimeoutSocket and TimeoutFile. |
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| 56 | |
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| 57 | The TimeoutSocket class defines a socket-like object that attempts to |
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| 58 | avoid the condition where a socket may block indefinitely. The |
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| 59 | TimeoutSocket class raises a Timeout exception whenever the |
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| 60 | current operation delays too long. |
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| 61 | |
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| 62 | The TimeoutFile class defines a file-like object that uses the TimeoutSocket |
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| 63 | class. When the makefile() method of TimeoutSocket is called, it returns |
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| 64 | an instance of a TimeoutFile. |
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| 65 | |
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| 66 | Each of these objects adds two methods to manage the timeout value: |
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| 67 | |
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| 68 | get_timeout() --> returns the timeout of the socket or file |
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| 69 | set_timeout() --> sets the timeout of the socket or file |
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| 70 | |
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| 71 | |
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| 72 | As an example, one might use the timeout feature to create httplib |
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| 73 | connections that will timeout after 30 seconds: |
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| 74 | |
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| 75 | import timeoutsocket |
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| 76 | import httplib |
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| 77 | H = httplib.HTTP("www.python.org") |
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| 78 | H.sock.set_timeout(30) |
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| 79 | |
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| 80 | Note: When used in this manner, the connect() routine may still |
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| 81 | block because it happens before the timeout is set. To avoid |
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| 82 | this, use the 'timeoutsocket.setDefaultSocketTimeout()' function. |
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| 83 | |
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| 84 | Good Luck! |
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| 85 | |
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| 86 | """ |
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| 87 | |
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| 88 | __version__ = "$Revision: 1.1 $" |
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| 89 | __author__ = "Timothy O'Malley <timo@alum.mit.edu>" |
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| 90 | |
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| 91 | # |
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| 92 | # Imports |
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| 93 | # |
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| 94 | import select, string |
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| 95 | import socket |
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| 96 | if not hasattr(socket, "_no_timeoutsocket"): |
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| 97 | _socket = socket.socket |
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| 98 | else: |
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| 99 | _socket = socket._no_timeoutsocket |
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| 100 | |
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| 101 | |
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| 102 | # |
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| 103 | # Set up constants to test for Connected and Blocking operations. |
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| 104 | # We delete 'os' and 'errno' to keep our namespace clean(er). |
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| 105 | # Thanks to Alex Martelli and G. Li for the Windows error codes. |
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| 106 | # |
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| 107 | import os |
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| 108 | if os.name == "nt": |
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| 109 | _IsConnected = ( 10022, 10056 ) |
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| 110 | _ConnectBusy = ( 10035, ) |
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| 111 | _AcceptBusy = ( 10035, ) |
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| 112 | else: |
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| 113 | import errno |
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| 114 | _IsConnected = ( errno.EISCONN, ) |
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| 115 | _ConnectBusy = ( errno.EINPROGRESS, errno.EALREADY, errno.EWOULDBLOCK ) |
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| 116 | _AcceptBusy = ( errno.EAGAIN, errno.EWOULDBLOCK ) |
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| 117 | del errno |
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| 118 | del os |
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| 119 | |
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| 120 | |
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| 121 | # |
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| 122 | # Default timeout value for ALL TimeoutSockets |
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| 123 | # |
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| 124 | _DefaultTimeout = None |
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| 125 | def setDefaultSocketTimeout(timeout): |
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| 126 | global _DefaultTimeout |
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| 127 | _DefaultTimeout = timeout |
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| 128 | def getDefaultSocketTimeout(): |
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| 129 | return _DefaultTimeout |
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| 130 | |
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| 131 | # |
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| 132 | # Exceptions for socket errors and timeouts |
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| 133 | # |
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| 134 | Error = socket.error |
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| 135 | class Timeout(Exception): |
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| 136 | pass |
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| 137 | |
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| 138 | |
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| 139 | # |
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| 140 | # Factory function |
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| 141 | # |
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| 142 | from socket import AF_INET, SOCK_STREAM |
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| 143 | def timeoutsocket(family=AF_INET, type=SOCK_STREAM, proto=None): |
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| 144 | if family != AF_INET or type != SOCK_STREAM: |
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| 145 | if proto: |
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| 146 | return _socket(family, type, proto) |
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| 147 | else: |
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| 148 | return _socket(family, type) |
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| 149 | return TimeoutSocket( _socket(family, type), _DefaultTimeout ) |
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| 150 | # end timeoutsocket |
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| 151 | |
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| 152 | # |
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| 153 | # The TimeoutSocket class definition |
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| 154 | # |
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| 155 | class TimeoutSocket: |
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| 156 | """TimeoutSocket object |
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| 157 | Implements a socket-like object that raises Timeout whenever |
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| 158 | an operation takes too long. |
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| 159 | The definition of 'too long' can be changed using the |
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| 160 | set_timeout() method. |
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| 161 | """ |
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| 162 | |
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| 163 | _copies = 0 |
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| 164 | _blocking = 1 |
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| 165 | |
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| 166 | def __init__(self, sock, timeout): |
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| 167 | self._sock = sock |
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| 168 | self._timeout = timeout |
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| 169 | # end __init__ |
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| 170 | |
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| 171 | def __getattr__(self, key): |
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| 172 | return getattr(self._sock, key) |
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| 173 | # end __getattr__ |
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| 174 | |
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| 175 | def get_timeout(self): |
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| 176 | return self._timeout |
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| 177 | # end set_timeout |
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| 178 | |
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| 179 | def set_timeout(self, timeout=None): |
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| 180 | self._timeout = timeout |
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| 181 | # end set_timeout |
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| 182 | |
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| 183 | def setblocking(self, blocking): |
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| 184 | self._blocking = blocking |
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| 185 | return self._sock.setblocking(blocking) |
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| 186 | # end set_timeout |
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| 187 | |
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| 188 | def connect_ex(self, addr): |
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| 189 | errcode = 0 |
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| 190 | try: |
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| 191 | self.connect(addr) |
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| 192 | except Error, why: |
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| 193 | errcode = why[0] |
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| 194 | return errcode |
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| 195 | # end connect_ex |
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| 196 | |
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| 197 | def connect(self, addr, port=None, dumbhack=None): |
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| 198 | # In case we were called as connect(host, port) |
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| 199 | if port != None: addr = (addr, port) |
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| 200 | |
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| 201 | # Shortcuts |
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| 202 | sock = self._sock |
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| 203 | timeout = self._timeout |
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| 204 | blocking = self._blocking |
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| 205 | |
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| 206 | # First, make a non-blocking call to connect |
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| 207 | try: |
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| 208 | sock.setblocking(0) |
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| 209 | sock.connect(addr) |
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| 210 | sock.setblocking(blocking) |
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| 211 | return |
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| 212 | except Error, why: |
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| 213 | # Set the socket's blocking mode back |
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| 214 | sock.setblocking(blocking) |
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| 215 | |
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| 216 | # If we are not blocking, re-raise |
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| 217 | if not blocking: |
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| 218 | raise |
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| 219 | |
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| 220 | # If we are already connected, then return success. |
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| 221 | # If we got a genuine error, re-raise it. |
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| 222 | errcode = why[0] |
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| 223 | if dumbhack and errcode in _IsConnected: |
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| 224 | return |
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| 225 | elif errcode not in _ConnectBusy: |
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| 226 | raise |
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| 227 | |
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| 228 | # Now, wait for the connect to happen |
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| 229 | # ONLY if dumbhack indicates this is pass number one. |
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| 230 | # If select raises an error, we pass it on. |
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| 231 | # Is this the right behavior? |
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| 232 | if not dumbhack: |
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| 233 | r,w,e = select.select([], [sock], [], timeout) |
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| 234 | if w: |
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| 235 | return self.connect(addr, dumbhack=1) |
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| 236 | |
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| 237 | # If we get here, then we should raise Timeout |
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| 238 | raise Timeout("Attempted connect to %s timed out." % str(addr) ) |
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| 239 | # end connect |
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| 240 | |
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| 241 | def accept(self, dumbhack=None): |
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| 242 | # Shortcuts |
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| 243 | sock = self._sock |
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| 244 | timeout = self._timeout |
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| 245 | blocking = self._blocking |
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| 246 | |
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| 247 | # First, make a non-blocking call to accept |
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| 248 | # If we get a valid result, then convert the |
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| 249 | # accept'ed socket into a TimeoutSocket. |
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| 250 | # Be carefult about the blocking mode of ourselves. |
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| 251 | try: |
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| 252 | sock.setblocking(0) |
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| 253 | newsock, addr = sock.accept() |
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| 254 | sock.setblocking(blocking) |
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| 255 | timeoutnewsock = self.__class__(newsock, timeout) |
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| 256 | timeoutnewsock.setblocking(blocking) |
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| 257 | return (timeoutnewsock, addr) |
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| 258 | except Error, why: |
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| 259 | # Set the socket's blocking mode back |
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| 260 | sock.setblocking(blocking) |
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| 261 | |
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| 262 | # If we are not supposed to block, then re-raise |
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| 263 | if not blocking: |
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| 264 | raise |
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| 265 | |
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| 266 | # If we got a genuine error, re-raise it. |
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| 267 | errcode = why[0] |
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| 268 | if errcode not in _AcceptBusy: |
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| 269 | raise |
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| 270 | |
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| 271 | # Now, wait for the accept to happen |
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| 272 | # ONLY if dumbhack indicates this is pass number one. |
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| 273 | # If select raises an error, we pass it on. |
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| 274 | # Is this the right behavior? |
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| 275 | if not dumbhack: |
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| 276 | r,w,e = select.select([sock], [], [], timeout) |
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| 277 | if r: |
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| 278 | return self.accept(dumbhack=1) |
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| 279 | |
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| 280 | # If we get here, then we should raise Timeout |
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| 281 | raise Timeout("Attempted accept timed out.") |
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| 282 | # end accept |
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| 283 | |
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| 284 | def send(self, data, flags=0): |
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| 285 | sock = self._sock |
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| 286 | if self._blocking: |
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| 287 | r,w,e = select.select([],[sock],[], self._timeout) |
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| 288 | if not w: |
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| 289 | raise Timeout("Send timed out") |
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| 290 | return sock.send(data, flags) |
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| 291 | # end send |
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| 292 | |
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| 293 | def recv(self, bufsize, flags=0): |
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| 294 | sock = self._sock |
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| 295 | if self._blocking: |
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| 296 | r,w,e = select.select([sock], [], [], self._timeout) |
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| 297 | if not r: |
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| 298 | raise Timeout("Recv timed out") |
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| 299 | return sock.recv(bufsize, flags) |
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| 300 | # end recv |
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| 301 | |
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| 302 | def makefile(self, flags="r", bufsize=-1): |
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| 303 | self._copies = self._copies +1 |
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| 304 | return TimeoutFile(self, flags, bufsize) |
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| 305 | # end makefile |
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| 306 | |
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| 307 | def close(self): |
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| 308 | if self._copies <= 0: |
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| 309 | self._sock.close() |
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| 310 | else: |
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| 311 | self._copies = self._copies -1 |
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| 312 | # end close |
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| 313 | |
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| 314 | # end TimeoutSocket |
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| 315 | |
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| 316 | |
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| 317 | class TimeoutFile: |
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| 318 | """TimeoutFile object |
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| 319 | Implements a file-like object on top of TimeoutSocket. |
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| 320 | """ |
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| 321 | |
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| 322 | def __init__(self, sock, mode="r", bufsize=4096): |
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| 323 | self._sock = sock |
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| 324 | self._bufsize = 4096 |
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| 325 | if bufsize > 0: self._bufsize = bufsize |
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| 326 | if not hasattr(sock, "_inqueue"): self._sock._inqueue = "" |
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| 327 | |
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| 328 | # end __init__ |
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| 329 | |
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| 330 | def __getattr__(self, key): |
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| 331 | return getattr(self._sock, key) |
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| 332 | # end __getattr__ |
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| 333 | |
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| 334 | def close(self): |
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| 335 | self._sock.close() |
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| 336 | self._sock = None |
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| 337 | # end close |
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| 338 | |
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| 339 | def write(self, data): |
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| 340 | self.send(data) |
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| 341 | # end write |
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| 342 | |
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| 343 | def read(self, size=-1): |
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| 344 | _sock = self._sock |
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| 345 | _bufsize = self._bufsize |
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| 346 | while 1: |
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| 347 | datalen = len(_sock._inqueue) |
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| 348 | if datalen >= size >= 0: |
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| 349 | break |
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| 350 | bufsize = _bufsize |
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| 351 | if size > 0: |
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| 352 | bufsize = min(bufsize, size - datalen ) |
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| 353 | buf = self.recv(bufsize) |
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| 354 | if not buf: |
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| 355 | break |
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| 356 | _sock._inqueue = _sock._inqueue + buf |
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| 357 | data = _sock._inqueue |
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| 358 | _sock._inqueue = "" |
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| 359 | if size > 0 and datalen > size: |
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| 360 | _sock._inqueue = data[size:] |
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| 361 | data = data[:size] |
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| 362 | return data |
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| 363 | # end read |
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| 364 | |
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| 365 | def readline(self, size=-1): |
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| 366 | _sock = self._sock |
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| 367 | _bufsize = self._bufsize |
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| 368 | while 1: |
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| 369 | idx = string.find(_sock._inqueue, "\n") |
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| 370 | if idx >= 0: |
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| 371 | break |
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| 372 | datalen = len(_sock._inqueue) |
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| 373 | if datalen >= size >= 0: |
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| 374 | break |
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| 375 | bufsize = _bufsize |
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| 376 | if size > 0: |
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| 377 | bufsize = min(bufsize, size - datalen ) |
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| 378 | buf = self.recv(bufsize) |
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| 379 | if not buf: |
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| 380 | break |
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| 381 | _sock._inqueue = _sock._inqueue + buf |
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| 382 | |
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| 383 | data = _sock._inqueue |
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| 384 | _sock._inqueue = "" |
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| 385 | if idx >= 0: |
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| 386 | idx = idx + 1 |
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| 387 | _sock._inqueue = data[idx:] |
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| 388 | data = data[:idx] |
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| 389 | elif size > 0 and datalen > size: |
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| 390 | _sock._inqueue = data[size:] |
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| 391 | data = data[:size] |
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| 392 | return data |
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| 393 | # end readline |
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| 394 | |
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| 395 | def readlines(self, sizehint=-1): |
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| 396 | result = [] |
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| 397 | data = self.read() |
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| 398 | while data: |
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| 399 | idx = string.find(data, "\n") |
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| 400 | if idx >= 0: |
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| 401 | idx = idx + 1 |
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| 402 | result.append( data[:idx] ) |
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| 403 | data = data[idx:] |
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| 404 | else: |
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| 405 | result.append( data ) |
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| 406 | data = "" |
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| 407 | return result |
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| 408 | # end readlines |
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| 409 | |
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| 410 | def flush(self): pass |
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| 411 | |
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| 412 | # end TimeoutFile |
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| 413 | |
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| 414 | |
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| 415 | # |
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| 416 | # Silently replace the socket() builtin function with |
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| 417 | # our timeoutsocket() definition. |
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| 418 | # |
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| 419 | if not hasattr(socket, "_no_timeoutsocket"): |
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| 420 | socket._no_timeoutsocket = socket.socket |
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| 421 | socket.socket = timeoutsocket |
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| 422 | del socket |
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| 423 | socket = timeoutsocket |
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| 424 | # Finis |
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