1 | # -*- Mode: Python -*- |
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2 | # Id: asyncore.py,v 2.51 2000/09/07 22:29:26 rushing Exp |
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3 | # Author: Sam Rushing <rushing@nightmare.com> |
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4 | |
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5 | # ====================================================================== |
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6 | # Copyright 1996 by Sam Rushing |
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7 | # |
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8 | # All Rights Reserved |
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9 | # |
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10 | # Permission to use, copy, modify, and distribute this software and |
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11 | # its documentation for any purpose and without fee is hereby |
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12 | # granted, provided that the above copyright notice appear in all |
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13 | # copies and that both that copyright notice and this permission |
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14 | # notice appear in supporting documentation, and that the name of Sam |
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15 | # Rushing not be used in advertising or publicity pertaining to |
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16 | # distribution of the software without specific, written prior |
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17 | # permission. |
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18 | # |
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19 | # SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, |
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20 | # INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN |
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21 | # NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR |
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22 | # CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS |
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23 | # OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, |
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24 | # NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
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25 | # CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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26 | # ====================================================================== |
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27 | |
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28 | """Basic infrastructure for asynchronous socket service clients and servers. |
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29 | |
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30 | There are only two ways to have a program on a single processor do "more |
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31 | than one thing at a time". Multi-threaded programming is the simplest and |
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32 | most popular way to do it, but there is another very different technique, |
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33 | that lets you have nearly all the advantages of multi-threading, without |
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34 | actually using multiple threads. it's really only practical if your program |
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35 | is largely I/O bound. If your program is CPU bound, then pre-emptive |
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36 | scheduled threads are probably what you really need. Network servers are |
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37 | rarely CPU-bound, however. |
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38 | |
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39 | If your operating system supports the select() system call in its I/O |
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40 | library (and nearly all do), then you can use it to juggle multiple |
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41 | communication channels at once; doing other work while your I/O is taking |
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42 | place in the "background." Although this strategy can seem strange and |
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43 | complex, especially at first, it is in many ways easier to understand and |
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44 | control than multi-threaded programming. The module documented here solves |
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45 | many of the difficult problems for you, making the task of building |
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46 | sophisticated high-performance network servers and clients a snap. |
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47 | """ |
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48 | |
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49 | import select |
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50 | import socket |
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51 | import sys |
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52 | import time |
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53 | import warnings |
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54 | |
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55 | import os |
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56 | from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, EINVAL, \ |
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57 | ENOTCONN, ESHUTDOWN, EINTR, EISCONN, EBADF, ECONNABORTED, EPIPE, EAGAIN, \ |
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58 | errorcode |
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59 | |
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60 | _DISCONNECTED = frozenset((ECONNRESET, ENOTCONN, ESHUTDOWN, ECONNABORTED, EPIPE, |
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61 | EBADF)) |
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62 | |
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63 | try: |
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64 | socket_map |
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65 | except NameError: |
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66 | socket_map = {} |
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67 | |
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68 | def _strerror(err): |
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69 | try: |
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70 | return os.strerror(err) |
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71 | except (ValueError, OverflowError, NameError): |
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72 | if err in errorcode: |
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73 | return errorcode[err] |
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74 | return "Unknown error %s" %err |
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75 | |
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76 | class ExitNow(Exception): |
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77 | pass |
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78 | |
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79 | _reraised_exceptions = (ExitNow, KeyboardInterrupt, SystemExit) |
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80 | |
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81 | def read(obj): |
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82 | try: |
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83 | obj.handle_read_event() |
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84 | except _reraised_exceptions: |
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85 | raise |
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86 | except: |
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87 | obj.handle_error() |
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88 | |
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89 | def write(obj): |
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90 | try: |
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91 | obj.handle_write_event() |
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92 | except _reraised_exceptions: |
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93 | raise |
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94 | except: |
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95 | obj.handle_error() |
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96 | |
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97 | def _exception(obj): |
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98 | try: |
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99 | obj.handle_expt_event() |
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100 | except _reraised_exceptions: |
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101 | raise |
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102 | except: |
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103 | obj.handle_error() |
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104 | |
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105 | def readwrite(obj, flags): |
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106 | try: |
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107 | if flags & select.POLLIN: |
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108 | obj.handle_read_event() |
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109 | if flags & select.POLLOUT: |
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110 | obj.handle_write_event() |
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111 | if flags & select.POLLPRI: |
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112 | obj.handle_expt_event() |
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113 | if flags & (select.POLLHUP | select.POLLERR | select.POLLNVAL): |
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114 | obj.handle_close() |
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115 | except socket.error, e: |
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116 | if e.args[0] not in _DISCONNECTED: |
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117 | obj.handle_error() |
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118 | else: |
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119 | obj.handle_close() |
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120 | except _reraised_exceptions: |
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121 | raise |
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122 | except: |
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123 | obj.handle_error() |
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124 | |
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125 | def poll(timeout=0.0, map=None): |
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126 | if map is None: |
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127 | map = socket_map |
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128 | if map: |
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129 | r = []; w = []; e = [] |
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130 | for fd, obj in map.items(): |
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131 | is_r = obj.readable() |
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132 | is_w = obj.writable() |
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133 | if is_r: |
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134 | r.append(fd) |
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135 | # accepting sockets should not be writable |
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136 | if is_w and not obj.accepting: |
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137 | w.append(fd) |
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138 | if is_r or is_w: |
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139 | e.append(fd) |
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140 | if [] == r == w == e: |
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141 | time.sleep(timeout) |
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142 | return |
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143 | |
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144 | try: |
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145 | r, w, e = select.select(r, w, e, timeout) |
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146 | except select.error, err: |
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147 | if err.args[0] != EINTR: |
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148 | raise |
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149 | else: |
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150 | return |
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151 | |
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152 | for fd in r: |
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153 | obj = map.get(fd) |
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154 | if obj is None: |
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155 | continue |
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156 | read(obj) |
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157 | |
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158 | for fd in w: |
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159 | obj = map.get(fd) |
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160 | if obj is None: |
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161 | continue |
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162 | write(obj) |
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163 | |
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164 | for fd in e: |
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165 | obj = map.get(fd) |
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166 | if obj is None: |
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167 | continue |
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168 | _exception(obj) |
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169 | |
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170 | def poll2(timeout=0.0, map=None): |
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171 | # Use the poll() support added to the select module in Python 2.0 |
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172 | if map is None: |
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173 | map = socket_map |
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174 | if timeout is not None: |
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175 | # timeout is in milliseconds |
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176 | timeout = int(timeout*1000) |
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177 | pollster = select.poll() |
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178 | if map: |
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179 | for fd, obj in map.items(): |
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180 | flags = 0 |
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181 | if obj.readable(): |
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182 | flags |= select.POLLIN | select.POLLPRI |
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183 | # accepting sockets should not be writable |
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184 | if obj.writable() and not obj.accepting: |
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185 | flags |= select.POLLOUT |
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186 | if flags: |
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187 | # Only check for exceptions if object was either readable |
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188 | # or writable. |
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189 | flags |= select.POLLERR | select.POLLHUP | select.POLLNVAL |
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190 | pollster.register(fd, flags) |
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191 | try: |
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192 | r = pollster.poll(timeout) |
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193 | except select.error, err: |
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194 | if err.args[0] != EINTR: |
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195 | raise |
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196 | r = [] |
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197 | for fd, flags in r: |
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198 | obj = map.get(fd) |
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199 | if obj is None: |
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200 | continue |
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201 | readwrite(obj, flags) |
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202 | |
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203 | poll3 = poll2 # Alias for backward compatibility |
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204 | |
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205 | def loop(timeout=30.0, use_poll=False, map=None, count=None): |
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206 | if map is None: |
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207 | map = socket_map |
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208 | |
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209 | if use_poll and hasattr(select, 'poll'): |
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210 | poll_fun = poll2 |
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211 | else: |
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212 | poll_fun = poll |
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213 | |
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214 | if count is None: |
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215 | while map: |
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216 | poll_fun(timeout, map) |
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217 | |
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218 | else: |
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219 | while map and count > 0: |
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220 | poll_fun(timeout, map) |
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221 | count = count - 1 |
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222 | |
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223 | class dispatcher: |
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224 | |
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225 | debug = False |
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226 | connected = False |
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227 | accepting = False |
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228 | connecting = False |
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229 | closing = False |
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230 | addr = None |
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231 | ignore_log_types = frozenset(['warning']) |
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232 | |
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233 | def __init__(self, sock=None, map=None): |
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234 | if map is None: |
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235 | self._map = socket_map |
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236 | else: |
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237 | self._map = map |
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238 | |
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239 | self._fileno = None |
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240 | |
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241 | if sock: |
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242 | # Set to nonblocking just to make sure for cases where we |
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243 | # get a socket from a blocking source. |
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244 | sock.setblocking(0) |
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245 | self.set_socket(sock, map) |
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246 | self.connected = True |
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247 | # The constructor no longer requires that the socket |
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248 | # passed be connected. |
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249 | try: |
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250 | self.addr = sock.getpeername() |
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251 | except socket.error, err: |
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252 | if err.args[0] in (ENOTCONN, EINVAL): |
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253 | # To handle the case where we got an unconnected |
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254 | # socket. |
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255 | self.connected = False |
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256 | else: |
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257 | # The socket is broken in some unknown way, alert |
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258 | # the user and remove it from the map (to prevent |
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259 | # polling of broken sockets). |
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260 | self.del_channel(map) |
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261 | raise |
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262 | else: |
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263 | self.socket = None |
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264 | |
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265 | def __repr__(self): |
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266 | status = [self.__class__.__module__+"."+self.__class__.__name__] |
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267 | if self.accepting and self.addr: |
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268 | status.append('listening') |
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269 | elif self.connected: |
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270 | status.append('connected') |
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271 | if self.addr is not None: |
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272 | try: |
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273 | status.append('%s:%d' % self.addr) |
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274 | except TypeError: |
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275 | status.append(repr(self.addr)) |
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276 | return '<%s at %#x>' % (' '.join(status), id(self)) |
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277 | |
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278 | __str__ = __repr__ |
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279 | |
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280 | def add_channel(self, map=None): |
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281 | #self.log_info('adding channel %s' % self) |
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282 | if map is None: |
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283 | map = self._map |
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284 | map[self._fileno] = self |
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285 | |
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286 | def del_channel(self, map=None): |
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287 | fd = self._fileno |
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288 | if map is None: |
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289 | map = self._map |
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290 | if fd in map: |
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291 | #self.log_info('closing channel %d:%s' % (fd, self)) |
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292 | del map[fd] |
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293 | self._fileno = None |
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294 | |
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295 | def create_socket(self, family, type): |
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296 | self.family_and_type = family, type |
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297 | sock = socket.socket(family, type) |
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298 | sock.setblocking(0) |
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299 | self.set_socket(sock) |
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300 | |
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301 | def set_socket(self, sock, map=None): |
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302 | self.socket = sock |
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303 | ## self.__dict__['socket'] = sock |
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304 | self._fileno = sock.fileno() |
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305 | self.add_channel(map) |
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306 | |
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307 | def set_reuse_addr(self): |
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308 | # try to re-use a server port if possible |
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309 | try: |
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310 | self.socket.setsockopt( |
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311 | socket.SOL_SOCKET, socket.SO_REUSEADDR, |
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312 | self.socket.getsockopt(socket.SOL_SOCKET, |
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313 | socket.SO_REUSEADDR) | 1 |
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314 | ) |
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315 | except socket.error: |
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316 | pass |
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317 | |
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318 | # ================================================== |
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319 | # predicates for select() |
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320 | # these are used as filters for the lists of sockets |
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321 | # to pass to select(). |
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322 | # ================================================== |
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323 | |
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324 | def readable(self): |
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325 | return True |
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326 | |
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327 | def writable(self): |
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328 | return True |
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329 | |
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330 | # ================================================== |
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331 | # socket object methods. |
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332 | # ================================================== |
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333 | |
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334 | def listen(self, num): |
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335 | self.accepting = True |
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336 | if os.name == 'nt' and num > 5: |
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337 | num = 5 |
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338 | return self.socket.listen(num) |
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339 | |
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340 | def bind(self, addr): |
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341 | self.addr = addr |
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342 | return self.socket.bind(addr) |
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343 | |
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344 | def connect(self, address): |
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345 | self.connected = False |
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346 | self.connecting = True |
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347 | err = self.socket.connect_ex(address) |
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348 | if err in (EINPROGRESS, EALREADY, EWOULDBLOCK) \ |
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349 | or err == EINVAL and os.name in ('nt', 'ce'): |
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350 | self.addr = address |
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351 | return |
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352 | if err in (0, EISCONN): |
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353 | self.addr = address |
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354 | self.handle_connect_event() |
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355 | else: |
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356 | raise socket.error(err, errorcode[err]) |
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357 | |
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358 | def accept(self): |
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359 | # XXX can return either an address pair or None |
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360 | try: |
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361 | conn, addr = self.socket.accept() |
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362 | except TypeError: |
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363 | return None |
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364 | except socket.error as why: |
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365 | if why.args[0] in (EWOULDBLOCK, ECONNABORTED, EAGAIN): |
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366 | return None |
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367 | else: |
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368 | raise |
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369 | else: |
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370 | return conn, addr |
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371 | |
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372 | def send(self, data): |
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373 | try: |
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374 | result = self.socket.send(data) |
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375 | return result |
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376 | except socket.error, why: |
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377 | if why.args[0] == EWOULDBLOCK: |
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378 | return 0 |
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379 | elif why.args[0] in _DISCONNECTED: |
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380 | self.handle_close() |
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381 | return 0 |
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382 | else: |
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383 | raise |
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384 | |
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385 | def recv(self, buffer_size): |
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386 | try: |
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387 | data = self.socket.recv(buffer_size) |
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388 | if not data: |
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389 | # a closed connection is indicated by signaling |
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390 | # a read condition, and having recv() return 0. |
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391 | self.handle_close() |
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392 | return '' |
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393 | else: |
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394 | return data |
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395 | except socket.error, why: |
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396 | # winsock sometimes raises ENOTCONN |
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397 | if why.args[0] in _DISCONNECTED: |
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398 | self.handle_close() |
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399 | return '' |
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400 | else: |
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401 | raise |
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402 | |
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403 | def close(self): |
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404 | self.connected = False |
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405 | self.accepting = False |
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406 | self.connecting = False |
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407 | self.del_channel() |
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408 | try: |
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409 | self.socket.close() |
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410 | except socket.error, why: |
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411 | if why.args[0] not in (ENOTCONN, EBADF): |
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412 | raise |
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413 | |
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414 | # cheap inheritance, used to pass all other attribute |
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415 | # references to the underlying socket object. |
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416 | def __getattr__(self, attr): |
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417 | try: |
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418 | retattr = getattr(self.socket, attr) |
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419 | except AttributeError: |
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420 | raise AttributeError("%s instance has no attribute '%s'" |
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421 | %(self.__class__.__name__, attr)) |
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422 | else: |
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423 | msg = "%(me)s.%(attr)s is deprecated. Use %(me)s.socket.%(attr)s " \ |
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424 | "instead." % {'me': self.__class__.__name__, 'attr':attr} |
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425 | warnings.warn(msg, DeprecationWarning, stacklevel=2) |
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426 | return retattr |
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427 | |
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428 | # log and log_info may be overridden to provide more sophisticated |
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429 | # logging and warning methods. In general, log is for 'hit' logging |
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430 | # and 'log_info' is for informational, warning and error logging. |
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431 | |
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432 | def log(self, message): |
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433 | sys.stderr.write('log: %s\n' % str(message)) |
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434 | |
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435 | def log_info(self, message, type='info'): |
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436 | if type not in self.ignore_log_types: |
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437 | print '%s: %s' % (type, message) |
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438 | |
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439 | def handle_read_event(self): |
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440 | if self.accepting: |
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441 | # accepting sockets are never connected, they "spawn" new |
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442 | # sockets that are connected |
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443 | self.handle_accept() |
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444 | elif not self.connected: |
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445 | if self.connecting: |
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446 | self.handle_connect_event() |
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447 | self.handle_read() |
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448 | else: |
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449 | self.handle_read() |
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450 | |
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451 | def handle_connect_event(self): |
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452 | err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR) |
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453 | if err != 0: |
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454 | raise socket.error(err, _strerror(err)) |
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455 | self.handle_connect() |
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456 | self.connected = True |
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457 | self.connecting = False |
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458 | |
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459 | def handle_write_event(self): |
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460 | if self.accepting: |
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461 | # Accepting sockets shouldn't get a write event. |
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462 | # We will pretend it didn't happen. |
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463 | return |
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464 | |
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465 | if not self.connected: |
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466 | if self.connecting: |
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467 | self.handle_connect_event() |
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468 | self.handle_write() |
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469 | |
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470 | def handle_expt_event(self): |
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471 | # handle_expt_event() is called if there might be an error on the |
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472 | # socket, or if there is OOB data |
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473 | # check for the error condition first |
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474 | err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR) |
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475 | if err != 0: |
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476 | # we can get here when select.select() says that there is an |
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477 | # exceptional condition on the socket |
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478 | # since there is an error, we'll go ahead and close the socket |
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479 | # like we would in a subclassed handle_read() that received no |
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480 | # data |
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481 | self.handle_close() |
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482 | else: |
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483 | self.handle_expt() |
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484 | |
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485 | def handle_error(self): |
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486 | nil, t, v, tbinfo = compact_traceback() |
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487 | |
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488 | # sometimes a user repr method will crash. |
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489 | try: |
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490 | self_repr = repr(self) |
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491 | except: |
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492 | self_repr = '<__repr__(self) failed for object at %0x>' % id(self) |
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493 | |
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494 | self.log_info( |
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495 | 'uncaptured python exception, closing channel %s (%s:%s %s)' % ( |
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496 | self_repr, |
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497 | t, |
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498 | v, |
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499 | tbinfo |
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500 | ), |
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501 | 'error' |
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502 | ) |
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503 | self.handle_close() |
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504 | |
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505 | def handle_expt(self): |
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506 | self.log_info('unhandled incoming priority event', 'warning') |
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507 | |
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508 | def handle_read(self): |
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509 | self.log_info('unhandled read event', 'warning') |
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510 | |
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511 | def handle_write(self): |
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512 | self.log_info('unhandled write event', 'warning') |
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513 | |
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514 | def handle_connect(self): |
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515 | self.log_info('unhandled connect event', 'warning') |
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516 | |
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517 | def handle_accept(self): |
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518 | self.log_info('unhandled accept event', 'warning') |
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519 | |
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520 | def handle_close(self): |
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521 | self.log_info('unhandled close event', 'warning') |
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522 | self.close() |
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523 | |
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524 | # --------------------------------------------------------------------------- |
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525 | # adds simple buffered output capability, useful for simple clients. |
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526 | # [for more sophisticated usage use asynchat.async_chat] |
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527 | # --------------------------------------------------------------------------- |
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528 | |
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529 | class dispatcher_with_send(dispatcher): |
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530 | |
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531 | def __init__(self, sock=None, map=None): |
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532 | dispatcher.__init__(self, sock, map) |
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533 | self.out_buffer = '' |
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534 | |
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535 | def initiate_send(self): |
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536 | num_sent = 0 |
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537 | num_sent = dispatcher.send(self, self.out_buffer[:512]) |
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538 | self.out_buffer = self.out_buffer[num_sent:] |
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539 | |
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540 | def handle_write(self): |
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541 | self.initiate_send() |
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542 | |
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543 | def writable(self): |
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544 | return (not self.connected) or len(self.out_buffer) |
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545 | |
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546 | def send(self, data): |
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547 | if self.debug: |
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548 | self.log_info('sending %s' % repr(data)) |
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549 | self.out_buffer = self.out_buffer + data |
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550 | self.initiate_send() |
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551 | |
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552 | # --------------------------------------------------------------------------- |
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553 | # used for debugging. |
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554 | # --------------------------------------------------------------------------- |
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555 | |
---|
556 | def compact_traceback(): |
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557 | t, v, tb = sys.exc_info() |
---|
558 | tbinfo = [] |
---|
559 | if not tb: # Must have a traceback |
---|
560 | raise AssertionError("traceback does not exist") |
---|
561 | while tb: |
---|
562 | tbinfo.append(( |
---|
563 | tb.tb_frame.f_code.co_filename, |
---|
564 | tb.tb_frame.f_code.co_name, |
---|
565 | str(tb.tb_lineno) |
---|
566 | )) |
---|
567 | tb = tb.tb_next |
---|
568 | |
---|
569 | # just to be safe |
---|
570 | del tb |
---|
571 | |
---|
572 | file, function, line = tbinfo[-1] |
---|
573 | info = ' '.join(['[%s|%s|%s]' % x for x in tbinfo]) |
---|
574 | return (file, function, line), t, v, info |
---|
575 | |
---|
576 | def close_all(map=None, ignore_all=False): |
---|
577 | if map is None: |
---|
578 | map = socket_map |
---|
579 | for x in map.values(): |
---|
580 | try: |
---|
581 | x.close() |
---|
582 | except OSError, x: |
---|
583 | if x.args[0] == EBADF: |
---|
584 | pass |
---|
585 | elif not ignore_all: |
---|
586 | raise |
---|
587 | except _reraised_exceptions: |
---|
588 | raise |
---|
589 | except: |
---|
590 | if not ignore_all: |
---|
591 | raise |
---|
592 | map.clear() |
---|
593 | |
---|
594 | # Asynchronous File I/O: |
---|
595 | # |
---|
596 | # After a little research (reading man pages on various unixen, and |
---|
597 | # digging through the linux kernel), I've determined that select() |
---|
598 | # isn't meant for doing asynchronous file i/o. |
---|
599 | # Heartening, though - reading linux/mm/filemap.c shows that linux |
---|
600 | # supports asynchronous read-ahead. So _MOST_ of the time, the data |
---|
601 | # will be sitting in memory for us already when we go to read it. |
---|
602 | # |
---|
603 | # What other OS's (besides NT) support async file i/o? [VMS?] |
---|
604 | # |
---|
605 | # Regardless, this is useful for pipes, and stdin/stdout... |
---|
606 | |
---|
607 | if os.name == 'posix': |
---|
608 | import fcntl |
---|
609 | |
---|
610 | class file_wrapper: |
---|
611 | # Here we override just enough to make a file |
---|
612 | # look like a socket for the purposes of asyncore. |
---|
613 | # The passed fd is automatically os.dup()'d |
---|
614 | |
---|
615 | def __init__(self, fd): |
---|
616 | self.fd = os.dup(fd) |
---|
617 | |
---|
618 | def recv(self, *args): |
---|
619 | return os.read(self.fd, *args) |
---|
620 | |
---|
621 | def send(self, *args): |
---|
622 | return os.write(self.fd, *args) |
---|
623 | |
---|
624 | def getsockopt(self, level, optname, buflen=None): |
---|
625 | if (level == socket.SOL_SOCKET and |
---|
626 | optname == socket.SO_ERROR and |
---|
627 | not buflen): |
---|
628 | return 0 |
---|
629 | raise NotImplementedError("Only asyncore specific behaviour " |
---|
630 | "implemented.") |
---|
631 | |
---|
632 | read = recv |
---|
633 | write = send |
---|
634 | |
---|
635 | def close(self): |
---|
636 | os.close(self.fd) |
---|
637 | |
---|
638 | def fileno(self): |
---|
639 | return self.fd |
---|
640 | |
---|
641 | class file_dispatcher(dispatcher): |
---|
642 | |
---|
643 | def __init__(self, fd, map=None): |
---|
644 | dispatcher.__init__(self, None, map) |
---|
645 | self.connected = True |
---|
646 | try: |
---|
647 | fd = fd.fileno() |
---|
648 | except AttributeError: |
---|
649 | pass |
---|
650 | self.set_file(fd) |
---|
651 | # set it to non-blocking mode |
---|
652 | flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0) |
---|
653 | flags = flags | os.O_NONBLOCK |
---|
654 | fcntl.fcntl(fd, fcntl.F_SETFL, flags) |
---|
655 | |
---|
656 | def set_file(self, fd): |
---|
657 | self.socket = file_wrapper(fd) |
---|
658 | self._fileno = self.socket.fileno() |
---|
659 | self.add_channel() |
---|