Package pyxmpp :: Module xmlextra |
[hide private]

# Source Code for Module pyxmpp.xmlextra

      1  #
      2  # (C) Copyright 2003-2006 Jacek Konieczny <jajcus@jajcus.net>
      3  #
      4  # This program is free software; you can redistribute it and/or modify
      5  # it under the terms of the GNU Lesser General Public License Version
      6  # 2.1 as published by the Free Software Foundation.
      7  #
      8  # This program is distributed in the hope that it will be useful,
      9  # but WITHOUT ANY WARRANTY; without even the implied warranty of
     10  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     11  # GNU Lesser General Public License for more details.
     12  #
     13  # You should have received a copy of the GNU Lesser General Public
     14  # License along with this program; if not, write to the Free Software
     15  # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
     16  #
     17  # pylint: disable-msg=C0103, W0132, W0611
     18
     19  """Extension to libxml2 for XMPP stream and stanza processing"""
     20
     21  __revision__="$Id: xmlextra.py,v 1.15 2004/10/11 18:33:51 jajcus Exp $"
     22  __docformat__="restructuredtext en"
     23
     24  import sys
     25  import libxml2
     26  import threading
     27  import re
     28
     29  from pyxmpp.exceptions import StreamParseError
     30
     31  common_doc = libxml2.newDoc("1.0")
     32  common_root = common_doc.newChild(None,"root",None)
     33  COMMON_NS = "http://pyxmpp.jajcus.net/xmlns/common"
     34  common_ns = common_root.newNs(COMMON_NS, None)
     35  common_root.setNs(common_ns)
     36  common_doc.setRootElement(common_root)
     37
     38 -class StreamHandler:
     39      """Base class for stream handler."""
     40 -    def __init__(self):
     41          pass
     42
     43 -    def _stream_start(self,_doc):
     44          """Process stream start."""
     45          doc=libxml2.xmlDoc(_doc)
     46          self.stream_start(doc)
     47
     48 -    def _stream_end(self,_doc):
     49          """Process stream end."""
     50          doc=libxml2.xmlDoc(_doc)
     51          self.stream_end(doc)
     52
     53 -    def _stanza(self,_doc,_node):
     54          """Process complete stanza."""
     55          doc=libxml2.xmlDoc(_doc)
     56          node=libxml2.xmlNode(_node)
     57          self.stanza(doc,node)
     58
     59 -    def stream_start(self,doc):
     60          """Called when the start tag of root element is encountered
     61          in the stream.
     62
     63          :Parameters:
     64              - `doc`: the document being parsed.
     65          :Types:
     66              - `doc`: `libxml2.xmlDoc`"""
     67          print >>sys.stderr,"Unhandled stream start:",`doc.serialize()`
     68
     69 -    def stream_end(self,doc):
     70          """Called when the end tag of root element is encountered
     71          in the stream.
     72
     73          :Parameters:
     74              - `doc`: the document being parsed.
     75          :Types:
     76              - `doc`: `libxml2.xmlDoc`"""
     77          print >>sys.stderr,"Unhandled stream end",`doc.serialize()`
     78
     79 -    def stanza(self, _unused, node):
     80          """Called when the end tag of a direct child of the root
     81          element is encountered in the stream.
     82
     83          Please note, that node will be removed from the document
     84          and freed after this method returns. If it is needed after
     85          that a copy must be made before the method returns.
     86
     87          :Parameters:
     88              - `_unused`: the document being parsed.
     89              - `node`: the (complete) element being processed
     90          :Types:
     91              - `_unused`: `libxml2.xmlDoc`
     92              - `node`: `libxml2.xmlNode`"""
     93          print >>sys.stderr,"Unhandled stanza",`node.serialize()`
     94
     95 -    def error(self,descr):
     96          """Called when an error is encountered in the stream.
     97
     98          :Parameters:
     99              - `descr`: description of the error
    100          :Types:
    101              - `descr`: `str`"""
    102          raise StreamParseError,descr
    103
    104  try:
    105  #########################################################################
    106  # C-extension based workarounds for libxml2 limitations
    107  #-------------------------------------------------------
    108      from pyxmpp import _xmlextra
    109      from pyxmpp._xmlextra import error
    110
    111      _create_reader = _xmlextra.sax_reader_new
    112
    113 -    def replace_ns(node, old_ns,new_ns):
    114          """Replace namespaces in a whole subtree.
    115
    116          The old namespace declaration will be removed if present on the `node`.
    117
    118          :Parameters:
    119             - `node`: the root of the subtree where namespaces should be replaced.
    120             - `old_ns`: the namespace to replace.
    121             - `new_ns`: the namespace to be used instead of old_ns.
    122          :Types:
    123              - `node`: `libxml2.xmlNode`
    124              - `old_ns`: `libxml2.xmlNs`
    125              - `new_ns`: `libxml2.xmlNs`
    126
    127          Both old_ns and new_ns may be None meaning no namespace set."""
    128          if old_ns is None:
    129              old_ns__o = None
    130          else:
    131              old_ns__o = old_ns._o
    132          if new_ns is None:
    133              new_ns__o = None
    134          else:
    135              new_ns__o = new_ns._o
    136          if node is None:
    137              node__o = None
    138          else:
    139              node__o = node._o
    140          _xmlextra.replace_ns(node__o, old_ns__o, new_ns__o)
    141          if old_ns__o:
    142              _xmlextra.remove_ns(node__o, old_ns__o)
    143
    144      pure_python = False
    145
    146  except ImportError:
    147  #########################################################################
    148  # Pure python implementation (slow workarounds for libxml2 limitations)
    149  #-----------------------------------------------------------------------
    150 -    class error(Exception):
    151          """Exception raised on a stream parse error."""
    152          pass
    153
    154 -    def _escape(data):
    155          """Escape data for XML"""
    156          data=data.replace("&","&amp;")
    157          data=data.replace("<","&lt;")
    158          data=data.replace(">","&gt;")
    159          data=data.replace("'","&apos;")
    160          data=data.replace('"',"&quot;")
    161          return data
    162
    163 -    class _SAXCallback(libxml2.SAXCallback):
    164          """SAX events handler for the python-only stream parser."""
    165 -        def __init__(self, handler):
    166              """Initialize the SAX handler.
    167
    168              :Parameters:
    169                  - `handler`: Object to handle stream start, end and stanzas.
    170              :Types:
    171                  - `handler`: `StreamHandler`
    172              """
    173              self._handler = handler
    174              self._head = ""
    175              self._tail = ""
    176              self._current = ""
    177              self._level = 0
    178              self._doc = None
    179              self._root = None
    180
    181 -        def cdataBlock(self, data):
    182              ""
    183              if self._level>1:
    184                  self._current += _escape(data)
    185
    186 -        def characters(self, data):
    187              ""
    188              if self._level>1:
    189                  self._current += _escape(data)
    190
    191 -        def comment(self, content):
    192              ""
    193              pass
    194
    195 -        def endDocument(self):
    196              ""
    197              pass
    198
    199 -        def endElement(self, tag):
    200              ""
    201              self._current+="</%s>" % (tag,)
    202              self._level -= 1
    203              if self._level > 1:
    204                  return
    205              if self._level==1:
    206                  xml=self._head+self._current+self._tail
    207                  doc=libxml2.parseDoc(xml)
    208                  try:
    209                      node = doc.getRootElement().children
    210                      try:
    211                          node1 = node.docCopyNode(self._doc, 1)
    212                          try:
    213                              self._root.addChild(node1)
    214                              self._handler.stanza(self._doc, node1)
    215                          except:
    216                              node1.unlinkNode()
    217                              node1.freeNode()
    218                              del node1
    219                      finally:
    220                          del node
    221                  finally:
    222                      doc.freeDoc()
    223              else:
    224                  xml=self._head+self._tail
    225                  doc=libxml2.parseDoc(xml)
    226                  try:
    227                      self._handler.stream_end(self._doc)
    228                      self._doc.freeDoc()
    229                      self._doc = None
    230                      self._root = None
    231                  finally:
    232                      doc.freeDoc()
    233
    234 -        def error(self, msg):
    235              ""
    236              self._handler.error(msg)
    237
    238          fatalError = error
    239
    240          ignorableWhitespace = characters
    241
    242 -        def reference(self, name):
    243              ""
    244              self._current += "&" + name + ";"
    245
    246 -        def startDocument(self):
    247              ""
    248              pass
    249
    250 -        def startElement(self, tag, attrs):
    251              ""
    252              s = "<"+tag
    253              if attrs:
    254                  for a,v in attrs.items():
    255                      s+=" %s='%s'" % (a,_escape(v))
    256              s += ">"
    257              if self._level == 0:
    258                  self._head = s
    259                  self._tail = "</%s>" % (tag,)
    260                  xml=self._head+self._tail
    261                  self._doc = libxml2.parseDoc(xml)
    262                  self._handler.stream_start(self._doc)
    263                  self._root = self._doc.getRootElement()
    264              elif self._level == 1:
    265                  self._current = s
    266              else:
    267                  self._current += s
    268              self._level += 1
    269
    270 -        def warning(self):
    271              ""
    272              pass
    273
    274 -    class _PythonReader:
    275          """Python-only stream reader."""
    276 -        def __init__(self,handler):
    277              """Initialize the reader.
    278
    279              :Parameters:
    280                  - `handler`: Object to handle stream start, end and stanzas.
    281              :Types:
    282                  - `handler`: `StreamHandler`
    283              """
    284              self.handler = handler
    285              self.sax = _SAXCallback(handler)
    286              self.parser = libxml2.createPushParser(self.sax, '', 0, 'stream')
    287
    288 -        def feed(self, data):
    289              """Feed the parser with a chunk of data. Apropriate methods
    290              of `self.handler` will be called whenever something interesting is
    291              found.
    292
    293              :Parameters:
    294                  - `data`: the chunk of data to parse.
    295              :Types:
    296                  - `data`: `str`"""
    297              return self.parser.parseChunk(data, len(data), 0)
    298
    299      _create_reader = _PythonReader
    300
    301 -    def _get_ns(node):
    302          """Get namespace of node.
    303
    304          :return: the namespace object or `None` if the node has no namespace
    305          assigned.
    306          :returntype: `libxml2.xmlNs`"""
    307          try:
    308              return node.ns()
    309          except libxml2.treeError:
    310              return None
    311
    312 -    def replace_ns(node, old_ns, new_ns):
    313          """Replace namespaces in a whole subtree.
    314
    315          :Parameters:
    316             - `node`: the root of the subtree where namespaces should be replaced.
    317             - `old_ns`: the namespace to replace.
    318             - `new_ns`: the namespace to be used instead of old_ns.
    319          :Types:
    320              - `node`: `libxml2.xmlNode`
    321              - `old_ns`: `libxml2.xmlNs`
    322              - `new_ns`: `libxml2.xmlNs`
    323
    324          Both old_ns and new_ns may be None meaning no namespace set."""
    325
    326          if old_ns is not None:
    327              old_ns_uri = old_ns.content
    328              old_ns_prefix = old_ns.name
    329          else:
    330              old_ns_uri = None
    331              old_ns_prefix = None
    332
    333          ns = _get_ns(node)
    334          if ns is None and old_ns is None:
    335              node.setNs(new_ns)
    336          elif ns and ns.content == old_ns_uri and ns.name == old_ns_prefix:
    337              node.setNs(new_ns)
    338
    339          p = node.properties
    340          while p:
    341              ns = _get_ns(p)
    342              if ns is None and old_ns is None:
    343                  p.setNs(new_ns)
    344              if ns and ns.content == old_ns_uri and ns.name == old_ns_prefix:
    345                  p.setNs(new_ns)
    346              p = p.next
    347
    348          n = node.children
    349          while n:
    350              if n.type == 'element':
    351                  skip_element = False
    352                  try:
    353                      nsd = n.nsDefs()
    354                  except libxml2.treeError:
    355                      nsd = None
    356                  while nsd:
    357                      if nsd.name == old_ns_prefix:
    358                          skip_element = True
    359                          break
    360                      nsd = nsd.next
    361                  if not skip_element:
    362                      replace_ns(n, old_ns, new_ns)
    363              n = n.next
    364
    365      pure_python = True
    366
    367  ###########################################################
    368  # Common code
    369  #-------------
    370
    371 -def get_node_ns(xmlnode):
    372      """Namespace of an XML node.
    373
    374      :Parameters:
    375          - `xmlnode`: the XML node to query.
    376      :Types:
    377          - `xmlnode`: `libxml2.xmlNode`
    378
    379      :return: namespace of the node or `None`
    380      :returntype: `libxml2.xmlNs`"""
    381      try:
    382          return xmlnode.ns()
    383      except libxml2.treeError:
    384          return None
    385
    386 -def get_node_ns_uri(xmlnode):
    387      """Return namespace URI of an XML node.
    388
    389      :Parameters:
    390          - `xmlnode`: the XML node to query.
    391      :Types:
    392          - `xmlnode`: `libxml2.xmlNode`
    393
    394      :return: namespace URI of the node or `None`
    395      :returntype: `unicode`"""
    396      ns=get_node_ns(xmlnode)
    397      if ns:
    398          return unicode(ns.getContent(),"utf-8")
    399      else:
    400          return None
    401
    402 -def xml_node_iter(nodelist):
    403      """Iterate over sibling XML nodes. All types of nodes will be returned
    404      (not only the elements).
    405
    406      Usually used to iterade over node's children like this::
    407
    408          xml_node_iter(node.children)
    409
    410      :Parameters:
    411          - `nodelist`: start node of the list.
    412      :Types:
    413          - `nodelist`: `libxml2.xmlNode`
    414      """
    415      node = nodelist
    416      while node:
    417          yield node
    418          node = node.next
    419
    420 -def xml_element_iter(nodelist):
    421      """Iterate over sibling XML elements. Non-element nodes will be skipped.
    422
    423      Usually used to iterade over node's children like this::
    424
    425          xml_node_iter(node.children)
    426
    427      :Parameters:
    428          - `nodelist`: start node of the list.
    429      :Types:
    430          - `nodelist`: `libxml2.xmlNode`
    431      """
    432      node = nodelist
    433      while node:
    434          if node.type == "element":
    435              yield node
    436          node = node.next
    437
    438 -def xml_element_ns_iter(nodelist, ns_uri):
    439      """Iterate over sibling XML elements. Only elements in the given namespace will be returned.
    440
    441      Usually used to iterade over node's children like this::
    442
    443          xml_node_iter(node.children)
    444
    445      :Parameters:
    446          - `nodelist`: start node of the list.
    447      :Types:
    448          - `nodelist`: `libxml2.xmlNode`
    449      """
    450      node = nodelist
    451      while node:
    452          if node.type == "element" and get_node_ns_uri(node)==ns_uri:
    453              yield node
    454          node = node.next
    455
    456  evil_characters_re=re.compile(r"[\000-\010\013\014\016-\037]",re.UNICODE)
    457  utf8_replacement_char=u"\ufffd".encode("utf-8")
    458
    459 -def remove_evil_characters(s):
    460      """Remove control characters (not allowed in XML) from a string."""
    461      if isinstance(s,unicode):
    462          return evil_characters_re.sub(u"\ufffd",s)
    463      else:
    464          return evil_characters_re.sub(utf8_replacement_char,s)
    465
    466  bad_nsdef_replace_re=re.compile(r"^([^<]*\<[^><]*\s+)(xmlns=((\"[^\"]*\")|(\'[^\']*\')))")
    467
    468 -def safe_serialize(xmlnode):
    469      """Serialize an XML element making sure the result is sane.
    470
    471      Remove control characters and invalid namespace declarations from the
    472      result string.
    473
    474      :Parameters:
    475          - `xmlnode`: the XML element to serialize.
    476      :Types:
    477          - `xmlnode`: `libxml2.xmlNode`
    478
    479      :return: UTF-8 encoded serialized and sanitized element.
    480      :returntype: `string`"""
    481      try:
    482          ns = xmlnode.ns()
    483      except libxml2.treeError:
    484          ns = None
    485      try:
    486          nsdef = xmlnode.nsDefs()
    487      except libxml2.treeError:
    488          nsdef = None
    489      s=xmlnode.serialize(encoding="UTF-8")
    490      while nsdef:
    491          if nsdef.name is None and (not ns or (nsdef.name, nsdef.content)!=(ns.name, ns.content)):
    492              s = bad_nsdef_replace_re.sub("\\1",s,1)
    493              break
    494          nsdef = nsdef.next
    495      s=remove_evil_characters(s)
    496      return s
    497
    498 -class StreamReader:
    499      """A simple push-parser interface for XML streams."""
    500 -    def __init__(self,handler):
    501          """Initialize `StreamReader` object.
    502
    503          :Parameters:
    504              - `handler`: handler object for the stream content
    505          :Types:
    506              - `handler`: `StreamHandler` derived class
    507          """
    508          self.reader=_create_reader(handler)
    509          self.lock=threading.RLock()
    510          self.in_use=0
    511 -    def doc(self):
    512          """Get the document being parsed.
    513
    514          :return: the document.
    515          :returntype: `libxml2.xmlNode`"""
    516          ret=self.reader.doc()
    517          if ret:
    518              return libxml2.xmlDoc(ret)
    519          else:
    520              return None
    521 -    def feed(self,s):
    522          """Pass a string to the stream parser.
    523
    524          Parameters:
    525              - `s`: string to parse.
    526          Types:
    527              - `s`: `str`
    528
    529          :return: `None` on EOF, `False` when whole input was parsed and `True`
    530              if there is something still left in the buffer."""
    531          self.lock.acquire()
    532          if self.in_use:
    533              self.lock.release()
    534              raise StreamParseError,"StreamReader.feed() is not reentrant!"
    535          self.in_use=1
    536          try:
    537              return self.reader.feed(s)
    538          finally:
    539              self.in_use=0
    540              self.lock.release()
    541
    542
    543  # vi: sts=4 et sw=4
    544