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 # Released under the terms of the GNU GPL version 2
   8 #
   9 __name__ = 'proxy.py'
  10 __description__ = 'helper for Python-based external (xml-rpc) ikiwiki plugins'
  11 __version__ = '0.1'
  12 __author__ = 'martin f. krafft <madduck@madduck.net>'
  13 __copyright__ = 'Copyright © ' + __author__
  14 __licence__ = 'GPLv2'
  15
  16 import sys
  17 import time
  18 import xmlrpclib
  19 import xml.parsers.expat
  20 from SimpleXMLRPCServer import SimpleXMLRPCDispatcher
  21
  22 class _IkiWikiExtPluginXMLRPCDispatcher(SimpleXMLRPCDispatcher):
  23
  24     def __init__(self, allow_none=False, encoding=None):
  25         try:
  26             SimpleXMLRPCDispatcher.__init__(self, allow_none, encoding)
  27         except TypeError:
  28             # see http://bugs.debian.org/470645
  29             # python2.4 and before only took one argument
  30             SimpleXMLRPCDispatcher.__init__(self)
  31
  32     def dispatch(self, method, params):
  33         return self._dispatch(method, params)
  34
  35 class _XMLStreamParser(object):
  36
  37     def __init__(self):
  38         self._parser = xml.parsers.expat.ParserCreate()
  39         self._parser.StartElementHandler = self._push_tag
  40         self._parser.EndElementHandler = self._pop_tag
  41         self._parser.XmlDeclHandler = self._check_pipelining
  42         self._reset()
  43
  44     def _reset(self):
  45         self._stack = list()
  46         self._acc = r''
  47         self._first_tag_received = False
  48
  49     def _push_tag(self, tag, attrs):
  50         self._stack.append(tag)
  51         self._first_tag_received = True
  52
  53     def _pop_tag(self, tag):
  54         top = self._stack.pop()
  55         if top != tag:
  56             raise ParseError, 'expected %s closing tag, got %s' % (top, tag)
  57
  58     def _request_complete(self):
  59         return self._first_tag_received and len(self._stack) == 0
  60
  61     def _check_pipelining(self, *args):
  62         if self._first_tag_received:
  63             raise PipeliningDetected, 'need a new line between XML documents'
  64
  65     def parse(self, data):
  66         self._parser.Parse(data, False)
  67         self._acc += data
  68         if self._request_complete():
  69             ret = self._acc
  70             self._reset()
  71             return ret
  72
  73     class ParseError(Exception):
  74         pass
  75
  76     class PipeliningDetected(Exception):
  77         pass
  78
  79 class _IkiWikiExtPluginXMLRPCHandler(object):
  80
  81     def __init__(self, debug_fn):
  82         self._dispatcher = _IkiWikiExtPluginXMLRPCDispatcher()
  83         self.register_function = self._dispatcher.register_function
  84         self._debug_fn = debug_fn
  85
  86     def register_function(self, function, name=None):
  87         # will be overwritten by __init__
  88         pass
  89
  90     @staticmethod
  91     def _write(out_fd, data):
  92         out_fd.write(str(data))
  93         out_fd.flush()
  94
  95     @staticmethod
  96     def _read(in_fd):
  97         ret = None
  98         parser = _XMLStreamParser()
  99         while True:
 100             line = in_fd.readline()
 101             if len(line) == 0:
 102                 # ikiwiki exited, EOF received
 103                 return None
 104
 105             ret = parser.parse(line)
 106             # unless this returns non-None, we need to loop again
 107             if ret is not None:
 108                 return ret
 109
 110     def send_rpc(self, cmd, in_fd, out_fd, *args, **kwargs):
 111         xml = xmlrpclib.dumps(sum(kwargs.iteritems(), args), cmd)
 112         self._debug_fn("calling ikiwiki procedure `%s': [%s]" % (cmd, xml))
 113         _IkiWikiExtPluginXMLRPCHandler._write(out_fd, xml)
 114
 115         self._debug_fn('reading response from ikiwiki...')
 116
 117         xml = _IkiWikiExtPluginXMLRPCHandler._read(in_fd)
 118         self._debug_fn('read response to procedure %s from ikiwiki: [%s]' % (cmd, xml))
 119         if xml is None:
 120             # ikiwiki is going down
 121             return None
 122
 123         data = xmlrpclib.loads(xml)[0][0]
 124         self._debug_fn('parsed data from response to procedure %s: [%s]' % (cmd, data))
 125         return data
 126
 127     def handle_rpc(self, in_fd, out_fd):
 128         self._debug_fn('waiting for procedure calls from ikiwiki...')
 129         xml = _IkiWikiExtPluginXMLRPCHandler._read(in_fd)
 130         if xml is None:
 131             # ikiwiki is going down
 132             self._debug_fn('ikiwiki is going down, and so are we...')
 133             return
 134
 135         self._debug_fn('received procedure call from ikiwiki: [%s]' % xml)
 136         params, method = xmlrpclib.loads(xml)
 137         ret = self._dispatcher.dispatch(method, params)
 138         xml = xmlrpclib.dumps((ret,), methodresponse=True)
 139         self._debug_fn('sending procedure response to ikiwiki: [%s]' % xml)
 140         _IkiWikiExtPluginXMLRPCHandler._write(out_fd, xml)
 141         return ret
 142
 143 class IkiWikiProcedureProxy(object):
 144
 145     # how to communicate None to ikiwiki
 146     _IKIWIKI_NIL_SENTINEL = {'null':''}
 147
 148     # sleep during each iteration
 149     _LOOP_DELAY = 0.1
 150
 151     def __init__(self, id, in_fd=sys.stdin, out_fd=sys.stdout, debug_fn=None):
 152         self._id = id
 153         self._in_fd = in_fd
 154         self._out_fd = out_fd
 155         self._hooks = list()
 156         self._functions = list()
 157         self._imported = False
 158         if debug_fn is not None:
 159             self._debug_fn = debug_fn
 160         else:
 161             self._debug_fn = lambda s: None
 162         self._xmlrpc_handler = _IkiWikiExtPluginXMLRPCHandler(self._debug_fn)
 163         self._xmlrpc_handler.register_function(self._importme, name='import')
 164
 165     def rpc(self, cmd, *args, **kwargs):
 166         def subst_none(seq):
 167             for i in seq:
 168                 if i is None:
 169                     yield IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
 170                 else:
 171                     yield i
 172
 173         args = list(subst_none(args))
 174         kwargs = dict(zip(kwargs.keys(), list(subst_none(kwargs.itervalues()))))
 175         ret = self._xmlrpc_handler.send_rpc(cmd, self._in_fd, self._out_fd,
 176                                             *args, **kwargs)
 177         if ret == IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL:
 178             ret = None
 179         return ret
 180
 181     def hook(self, type, function, name=None, last=False):
 182         if self._imported:
 183             raise IkiWikiProcedureProxy.AlreadyImported
 184
 185         if name is None:
 186             name = function.__name__
 187
 188         def hook_proxy(*args):
 189 #            curpage = args[0]
 190 #            kwargs = dict([args[i:i+2] for i in xrange(1, len(args), 2)])
 191             ret = function(self, *args)
 192             self._debug_fn("%s hook `%s' returned: [%s]" % (type, name, ret))
 193             if ret == IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL:
 194                 raise IkiWikiProcedureProxy.InvalidReturnValue, \
 195                         'hook functions are not allowed to return %s' \
 196                         % IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
 197             if ret is None:
 198                 ret = IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
 199             return ret
 200
 201         self._hooks.append((type, name, last))
 202         self._xmlrpc_handler.register_function(hook_proxy, name=name)
 203
 204     def inject(self, rname, function, name=None, memoize=True):
 205         if self._imported:
 206             raise IkiWikiProcedureProxy.AlreadyImported
 207
 208         if name is None:
 209             name = function.__name__
 210
 211         self._functions.append((rname, name, memoize))
 212         self._xmlrpc_handler.register_function(function, name=name)
 213
 214     def getargv(self):
 215         return self.rpc('getargv')
 216
 217     def setargv(self, argv):
 218         return self.rpc('setargv', argv)
 219
 220     def getvar(self, hash, key):
 221         return self.rpc('getvar', hash, key)
 222
 223     def setvar(self, hash, key, value):
 224         return self.rpc('setvar', hash, key, value)
 225
 226     def getstate(self, page, id, key):
 227         return self.rpc('getstate', page, id, key)
 228
 229     def setstate(self, page, id, key, value):
 230         return self.rpc('setstate', page, id, key, value)
 231
 232     def pagespec_match(self, spec):
 233         return self.rpc('pagespec_match', spec)
 234
 235     def error(self, msg):
 236         try:
 237             self.rpc('error', msg)
 238         except IOError, e:
 239             if e.errno != 32:
 240                 raise
 241
 242         import posix
 243         sys.exit(posix.EX_SOFTWARE)
 244
 245     def run(self):
 246         try:
 247             while True:
 248                 ret = self._xmlrpc_handler.handle_rpc(self._in_fd, self._out_fd)
 249                 if ret is None:
 250                     return
 251                 time.sleep(IkiWikiProcedureProxy._LOOP_DELAY)
 252         except Exception, e:
 253             import traceback
 254             self.error('uncaught exception: %s\n%s' \
 255                        % (e, traceback.format_exc(sys.exc_info()[2])))
 256             import posix
 257             sys.exit(posix.EX_SOFTWARE)
 258
 259     def _importme(self):
 260         self._debug_fn('importing...')
 261         for type, function, last in self._hooks:
 262             self._debug_fn('hooking %s into %s chain...' % (function, type))
 263             self.rpc('hook', id=self._id, type=type, call=function, last=last)
 264         for rname, function, memoize in self._functions:
 265             self._debug_fn('injecting %s as %s...' % (function, rname))
 266             self.rpc('inject', name=rname, call=function, memoize=memoize)
 267         self._imported = True
 268         return IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
 269
 270     class InvalidReturnValue(Exception):
 271         pass
 272
 273     class AlreadyImported(Exception):
 274         pass