plugins/proxy.py

   1 #!/usr/bin/python
   2 # -*- coding: utf-8 -*-
   3 #
   4 # proxy.py — helper for Python-based external (xml-rpc) ikiwiki plugins
   5 #
   6 # Copyright © martin f. krafft <madduck@madduck.net>
   7 #
   8 #  Redistribution and use in source and binary forms, with or without
   9 # modification, are permitted provided that the following conditions
  10 # are met:
  11 # 1. Redistributions of source code must retain the above copyright
  12 #    notice, this list of conditions and the following disclaimer.
  13 # 2. Redistributions in binary form must reproduce the above copyright
  14 #    notice, this list of conditions and the following disclaimer in the
  15 #    documentation and/or other materials provided with the distribution.
  16 # .
  17 # THIS SOFTWARE IS PROVIDED BY IKIWIKI AND CONTRIBUTORS ``AS IS''
  18 # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  19 # TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  20 # PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION
  21 # OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  22 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  23 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  24 # USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  25 # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  26 # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  27 # OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28 # SUCH DAMAGE.
  29 #
  30 __name__ = 'proxy.py'
  31 __description__ = 'helper for Python-based external (xml-rpc) ikiwiki plugins'
  32 __version__ = '0.1'
  33 __author__ = 'martin f. krafft <madduck@madduck.net>'
  34 __copyright__ = 'Copyright © ' + __author__
  35 __licence__ = 'BSD-2-clause'
  36
  37 import sys
  38 import time
  39 import xmlrpclib
  40 import xml.parsers.expat
  41 from SimpleXMLRPCServer import SimpleXMLRPCDispatcher
  42
  43 class _IkiWikiExtPluginXMLRPCDispatcher(SimpleXMLRPCDispatcher):
  44
  45     def __init__(self, allow_none=False, encoding=None):
  46         try:
  47             SimpleXMLRPCDispatcher.__init__(self, allow_none, encoding)
  48         except TypeError:
  49             # see http://bugs.debian.org/470645
  50             # python2.4 and before only took one argument
  51             SimpleXMLRPCDispatcher.__init__(self)
  52
  53     def dispatch(self, method, params):
  54         return self._dispatch(method, params)
  55
  56 class XMLStreamParser(object):
  57
  58     def __init__(self):
  59         self._parser = xml.parsers.expat.ParserCreate()
  60         self._parser.StartElementHandler = self._push_tag
  61         self._parser.EndElementHandler = self._pop_tag
  62         self._parser.XmlDeclHandler = self._check_pipelining
  63         self._reset()
  64
  65     def _reset(self):
  66         self._stack = list()
  67         self._acc = r''
  68         self._first_tag_received = False
  69
  70     def _push_tag(self, tag, attrs):
  71         self._stack.append(tag)
  72         self._first_tag_received = True
  73
  74     def _pop_tag(self, tag):
  75         top = self._stack.pop()
  76         if top != tag:
  77             raise ParseError, 'expected %s closing tag, got %s' % (top, tag)
  78
  79     def _request_complete(self):
  80         return self._first_tag_received and len(self._stack) == 0
  81
  82     def _check_pipelining(self, *args):
  83         if self._first_tag_received:
  84             raise PipeliningDetected, 'need a new line between XML documents'
  85
  86     def parse(self, data):
  87         self._parser.Parse(data, False)
  88         self._acc += data
  89         if self._request_complete():
  90             ret = self._acc
  91             self._reset()
  92             return ret
  93
  94     class ParseError(Exception):
  95         pass
  96
  97     class PipeliningDetected(Exception):
  98         pass
  99
 100 class _IkiWikiExtPluginXMLRPCHandler(object):
 101
 102     def __init__(self, debug_fn):
 103         self._dispatcher = _IkiWikiExtPluginXMLRPCDispatcher()
 104         self.register_function = self._dispatcher.register_function
 105         self._debug_fn = debug_fn
 106
 107     def register_function(self, function, name=None):
 108         # will be overwritten by __init__
 109         pass
 110
 111     @staticmethod
 112     def _write(out_fd, data):
 113         out_fd.write(str(data))
 114         out_fd.flush()
 115
 116     @staticmethod
 117     def _read(in_fd):
 118         ret = None
 119         parser = XMLStreamParser()
 120         while True:
 121             line = in_fd.readline()
 122             if len(line) == 0:
 123                 # ikiwiki exited, EOF received
 124                 return None
 125
 126             ret = parser.parse(line)
 127             # unless this returns non-None, we need to loop again
 128             if ret is not None:
 129                 return ret
 130
 131     def send_rpc(self, cmd, in_fd, out_fd, *args, **kwargs):
 132         xml = xmlrpclib.dumps(sum(kwargs.iteritems(), args), cmd)
 133         self._debug_fn("calling ikiwiki procedure `%s': [%s]" % (cmd, xml))
 134         _IkiWikiExtPluginXMLRPCHandler._write(out_fd, xml)
 135
 136         self._debug_fn('reading response from ikiwiki...')
 137
 138         xml = _IkiWikiExtPluginXMLRPCHandler._read(in_fd)
 139         self._debug_fn('read response to procedure %s from ikiwiki: [%s]' % (cmd, xml))
 140         if xml is None:
 141             # ikiwiki is going down
 142             self._debug_fn('ikiwiki is going down, and so are we...')
 143             raise _IkiWikiExtPluginXMLRPCHandler._GoingDown
 144
 145         data = xmlrpclib.loads(xml)[0][0]
 146         self._debug_fn('parsed data from response to procedure %s: [%s]' % (cmd, data))
 147         return data
 148
 149     def handle_rpc(self, in_fd, out_fd):
 150         self._debug_fn('waiting for procedure calls from ikiwiki...')
 151         xml = _IkiWikiExtPluginXMLRPCHandler._read(in_fd)
 152         if xml is None:
 153             # ikiwiki is going down
 154             self._debug_fn('ikiwiki is going down, and so are we...')
 155             raise _IkiWikiExtPluginXMLRPCHandler._GoingDown
 156
 157         self._debug_fn('received procedure call from ikiwiki: [%s]' % xml)
 158         params, method = xmlrpclib.loads(xml)
 159         ret = self._dispatcher.dispatch(method, params)
 160         xml = xmlrpclib.dumps((ret,), methodresponse=True)
 161         self._debug_fn('sending procedure response to ikiwiki: [%s]' % xml)
 162         _IkiWikiExtPluginXMLRPCHandler._write(out_fd, xml)
 163         return ret
 164
 165     class _GoingDown:
 166         pass
 167
 168 class IkiWikiProcedureProxy(object):
 169
 170     # how to communicate None to ikiwiki
 171     _IKIWIKI_NIL_SENTINEL = {'null':''}
 172
 173     # sleep during each iteration
 174     _LOOP_DELAY = 0.1
 175
 176     def __init__(self, id, in_fd=sys.stdin, out_fd=sys.stdout, debug_fn=None):
 177         self._id = id
 178         self._in_fd = in_fd
 179         self._out_fd = out_fd
 180         self._hooks = list()
 181         self._functions = list()
 182         self._imported = False
 183         if debug_fn is not None:
 184             self._debug_fn = debug_fn
 185         else:
 186             self._debug_fn = lambda s: None
 187         self._xmlrpc_handler = _IkiWikiExtPluginXMLRPCHandler(self._debug_fn)
 188         self._xmlrpc_handler.register_function(self._importme, name='import')
 189
 190     def rpc(self, cmd, *args, **kwargs):
 191         def subst_none(seq):
 192             for i in seq:
 193                 if i is None:
 194                     yield IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
 195                 else:
 196                     yield i
 197
 198         args = list(subst_none(args))
 199         kwargs = dict(zip(kwargs.keys(), list(subst_none(kwargs.itervalues()))))
 200         ret = self._xmlrpc_handler.send_rpc(cmd, self._in_fd, self._out_fd,
 201                                             *args, **kwargs)
 202         if ret == IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL:
 203             ret = None
 204         return ret
 205
 206     def hook(self, type, function, name=None, id=None, last=False):
 207         if self._imported:
 208             raise IkiWikiProcedureProxy.AlreadyImported
 209
 210         if name is None:
 211             name = function.__name__
 212
 213         if id is None:
 214             id = self._id
 215
 216         def hook_proxy(*args):
 217 #            curpage = args[0]
 218 #            kwargs = dict([args[i:i+2] for i in xrange(1, len(args), 2)])
 219             ret = function(self, *args)
 220             self._debug_fn("%s hook `%s' returned: [%s]" % (type, name, ret))
 221             if ret == IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL:
 222                 raise IkiWikiProcedureProxy.InvalidReturnValue, \
 223                         'hook functions are not allowed to return %s' \
 224                         % IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
 225             if ret is None:
 226                 ret = IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
 227             return ret
 228
 229         self._hooks.append((id, type, name, last))
 230         self._xmlrpc_handler.register_function(hook_proxy, name=name)
 231
 232     def inject(self, rname, function, name=None, memoize=True):
 233         if self._imported:
 234             raise IkiWikiProcedureProxy.AlreadyImported
 235
 236         if name is None:
 237             name = function.__name__
 238
 239         self._functions.append((rname, name, memoize))
 240         self._xmlrpc_handler.register_function(function, name=name)
 241
 242     def getargv(self):
 243         return self.rpc('getargv')
 244
 245     def setargv(self, argv):
 246         return self.rpc('setargv', argv)
 247
 248     def getvar(self, hash, key):
 249         return self.rpc('getvar', hash, key)
 250
 251     def setvar(self, hash, key, value):
 252         return self.rpc('setvar', hash, key, value)
 253
 254     def getstate(self, page, id, key):
 255         return self.rpc('getstate', page, id, key)
 256
 257     def setstate(self, page, id, key, value):
 258         return self.rpc('setstate', page, id, key, value)
 259
 260     def pagespec_match(self, spec):
 261         return self.rpc('pagespec_match', spec)
 262
 263     def error(self, msg):
 264         try:
 265             self.rpc('error', msg)
 266         except IOError, e:
 267             if e.errno != 32:
 268                 raise
 269         import posix
 270         sys.exit(posix.EX_SOFTWARE)
 271
 272     def run(self):
 273         try:
 274             while True:
 275                 ret = self._xmlrpc_handler.handle_rpc(self._in_fd, self._out_fd)
 276                 time.sleep(IkiWikiProcedureProxy._LOOP_DELAY)
 277         except _IkiWikiExtPluginXMLRPCHandler._GoingDown:
 278             return
 279
 280         except Exception, e:
 281             import traceback
 282             self.error('uncaught exception: %s\n%s' \
 283                        % (e, traceback.format_exc(sys.exc_info()[2])))
 284             return
 285
 286     def _importme(self):
 287         self._debug_fn('importing...')
 288         for id, type, function, last in self._hooks:
 289             self._debug_fn('hooking %s/%s into %s chain...' % (id, function, type))
 290             self.rpc('hook', id=id, type=type, call=function, last=last)
 291         for rname, function, memoize in self._functions:
 292             self._debug_fn('injecting %s as %s...' % (function, rname))
 293             self.rpc('inject', name=rname, call=function, memoize=memoize)
 294         self._imported = True
 295         return IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
 296
 297     class InvalidReturnValue(Exception):
 298         pass
 299
 300     class AlreadyImported(Exception):
 301         pass