1 | |
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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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