ikiwiki/plugins/proxy.py

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#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# proxy.py — helper for Python-based external (xml-rpc) ikiwiki plugins
#
# Copyright © martin f. krafft <madduck@madduck.net>
# Released under the terms of the GNU GPL version 2
#
__name__ = 'proxy.py'
__description__ = 'helper for Python-based external (xml-rpc) ikiwiki plugins'
__version__ = '0.1'
__author__ = 'martin f. krafft <madduck@madduck.net>'
__copyright__ = 'Copyright © ' + __author__
__licence__ = 'GPLv2'
import sys
import time
import xmlrpclib
import xml.parsers.expat
from SimpleXMLRPCServer import SimpleXMLRPCDispatcher
class _IkiWikiExtPluginXMLRPCDispatcher(SimpleXMLRPCDispatcher):
def __init__(self, allow_none=False, encoding=None):
try:
SimpleXMLRPCDispatcher.__init__(self, allow_none, encoding)
except TypeError:
# see http://bugs.debian.org/470645
# python2.4 and before only took one argument
SimpleXMLRPCDispatcher.__init__(self)
def dispatch(self, method, params):
return self._dispatch(method, params)
class XMLStreamParser(object):
def __init__(self):
self._parser = xml.parsers.expat.ParserCreate()
self._parser.StartElementHandler = self._push_tag
self._parser.EndElementHandler = self._pop_tag
self._parser.XmlDeclHandler = self._check_pipelining
self._reset()
def _reset(self):
self._stack = list()
self._acc = r''
self._first_tag_received = False
def _push_tag(self, tag, attrs):
self._stack.append(tag)
self._first_tag_received = True
def _pop_tag(self, tag):
top = self._stack.pop()
if top != tag:
raise ParseError, 'expected %s closing tag, got %s' % (top, tag)
def _request_complete(self):
return self._first_tag_received and len(self._stack) == 0
def _check_pipelining(self, *args):
if self._first_tag_received:
raise PipeliningDetected, 'need a new line between XML documents'
def parse(self, data):
self._parser.Parse(data, False)
self._acc += data
if self._request_complete():
ret = self._acc
self._reset()
return ret
class ParseError(Exception):
pass
class PipeliningDetected(Exception):
pass
class _IkiWikiExtPluginXMLRPCHandler(object):
def __init__(self, debug_fn):
self._dispatcher = _IkiWikiExtPluginXMLRPCDispatcher()
self.register_function = self._dispatcher.register_function
self._debug_fn = debug_fn
def register_function(self, function, name=None):
# will be overwritten by __init__
pass
@staticmethod
def _write(out_fd, data):
out_fd.write(str(data))
out_fd.flush()
@staticmethod
def _read(in_fd):
ret = None
parser = XMLStreamParser()
while True:
line = in_fd.readline()
if len(line) == 0:
# ikiwiki exited, EOF received
return None
ret = parser.parse(line)
# unless this returns non-None, we need to loop again
if ret is not None:
return ret
def send_rpc(self, cmd, in_fd, out_fd, *args, **kwargs):
xml = xmlrpclib.dumps(sum(kwargs.iteritems(), args), cmd)
self._debug_fn("calling ikiwiki procedure `%s': [%s]" % (cmd, xml))
_IkiWikiExtPluginXMLRPCHandler._write(out_fd, xml)
self._debug_fn('reading response from ikiwiki...')
xml = _IkiWikiExtPluginXMLRPCHandler._read(in_fd)
self._debug_fn('read response to procedure %s from ikiwiki: [%s]' % (cmd, xml))
if xml is None:
# ikiwiki is going down
self._debug_fn('ikiwiki is going down, and so are we...')
raise _IkiWikiExtPluginXMLRPCHandler._GoingDown
data = xmlrpclib.loads(xml)[0][0]
self._debug_fn('parsed data from response to procedure %s: [%s]' % (cmd, data))
return data
def handle_rpc(self, in_fd, out_fd):
self._debug_fn('waiting for procedure calls from ikiwiki...')
xml = _IkiWikiExtPluginXMLRPCHandler._read(in_fd)
if xml is None:
# ikiwiki is going down
self._debug_fn('ikiwiki is going down, and so are we...')
raise _IkiWikiExtPluginXMLRPCHandler._GoingDown
self._debug_fn('received procedure call from ikiwiki: [%s]' % xml)
params, method = xmlrpclib.loads(xml)
ret = self._dispatcher.dispatch(method, params)
xml = xmlrpclib.dumps((ret,), methodresponse=True)
self._debug_fn('sending procedure response to ikiwiki: [%s]' % xml)
_IkiWikiExtPluginXMLRPCHandler._write(out_fd, xml)
return ret
class _GoingDown:
pass
class IkiWikiProcedureProxy(object):
# how to communicate None to ikiwiki
_IKIWIKI_NIL_SENTINEL = {'null':''}
# sleep during each iteration
_LOOP_DELAY = 0.1
def __init__(self, id, in_fd=sys.stdin, out_fd=sys.stdout, debug_fn=None):
self._id = id
self._in_fd = in_fd
self._out_fd = out_fd
self._hooks = list()
self._functions = list()
self._imported = False
if debug_fn is not None:
self._debug_fn = debug_fn
else:
self._debug_fn = lambda s: None
self._xmlrpc_handler = _IkiWikiExtPluginXMLRPCHandler(self._debug_fn)
self._xmlrpc_handler.register_function(self._importme, name='import')
def rpc(self, cmd, *args, **kwargs):
def subst_none(seq):
for i in seq:
if i is None:
yield IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
else:
yield i
args = list(subst_none(args))
kwargs = dict(zip(kwargs.keys(), list(subst_none(kwargs.itervalues()))))
ret = self._xmlrpc_handler.send_rpc(cmd, self._in_fd, self._out_fd,
*args, **kwargs)
if ret == IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL:
ret = None
return ret
def hook(self, type, function, name=None, id=None, last=False):
if self._imported:
raise IkiWikiProcedureProxy.AlreadyImported
if name is None:
name = function.__name__
if id is None:
id = self._id
def hook_proxy(*args):
# curpage = args[0]
# kwargs = dict([args[i:i+2] for i in xrange(1, len(args), 2)])
ret = function(self, *args)
self._debug_fn("%s hook `%s' returned: [%s]" % (type, name, ret))
if ret == IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL:
raise IkiWikiProcedureProxy.InvalidReturnValue, \
'hook functions are not allowed to return %s' \
% IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
if ret is None:
ret = IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
return ret
self._hooks.append((id, type, name, last))
self._xmlrpc_handler.register_function(hook_proxy, name=name)
def inject(self, rname, function, name=None, memoize=True):
if self._imported:
raise IkiWikiProcedureProxy.AlreadyImported
if name is None:
name = function.__name__
self._functions.append((rname, name, memoize))
self._xmlrpc_handler.register_function(function, name=name)
def getargv(self):
return self.rpc('getargv')
def setargv(self, argv):
return self.rpc('setargv', argv)
def getvar(self, hash, key):
return self.rpc('getvar', hash, key)
def setvar(self, hash, key, value):
return self.rpc('setvar', hash, key, value)
def getstate(self, page, id, key):
return self.rpc('getstate', page, id, key)
def setstate(self, page, id, key, value):
return self.rpc('setstate', page, id, key, value)
def pagespec_match(self, spec):
return self.rpc('pagespec_match', spec)
def error(self, msg):
try:
self.rpc('error', msg)
except IOError, e:
if e.errno != 32:
raise
import posix
sys.exit(posix.EX_SOFTWARE)
def run(self):
try:
while True:
ret = self._xmlrpc_handler.handle_rpc(self._in_fd, self._out_fd)
time.sleep(IkiWikiProcedureProxy._LOOP_DELAY)
except _IkiWikiExtPluginXMLRPCHandler._GoingDown:
return
except Exception, e:
import traceback
self.error('uncaught exception: %s\n%s' \
% (e, traceback.format_exc(sys.exc_info()[2])))
return
def _importme(self):
self._debug_fn('importing...')
for id, type, function, last in self._hooks:
self._debug_fn('hooking %s/%s into %s chain...' % (id, function, type))
self.rpc('hook', id=id, type=type, call=function, last=last)
for rname, function, memoize in self._functions:
self._debug_fn('injecting %s as %s...' % (function, rname))
self.rpc('inject', name=rname, call=function, memoize=memoize)
self._imported = True
return IkiWikiProcedureProxy._IKIWIKI_NIL_SENTINEL
class InvalidReturnValue(Exception):
pass
class AlreadyImported(Exception):
pass