[IronPython] pyexpat and IronPython

[Mark Rees]

Hi,

Seo has already done a basic pyexpat wrapper. He posted about it in:

http://lists.ironpython.com/pipermail/users-ironpython.com/2005-November/001227.html

And it can be found at:

http://sparcs.kaist.ac.kr/~tinuviel/fepy/old/pyexpat.py

I have used this with ElementTree. There are limitations like iterparse 
doesn't work and if the XML you are parsing contains an empty element 
i.e <doc /> it fails. I have modified Seo's pyexpat.py to handle the 
second limitation and have included the source in this email. I have 
used this for my elementtree requirements but the XML I parse is simple 
so there may be other as yet undiscovered issues.

Regards

Mark

Modified version of pyexpat from 
http://sparcs.kaist.ac.kr/~tinuviel/fepy/old/pyexpat.py


import clr
clr.AddReference("System.Xml")

from System.IO import MemoryStream, SeekOrigin, StreamWriter
from System.Xml import NameTable, XmlNamespaceManager, XmlParserContext, 
XmlSpace
from System.Xml import XmlTextReader, XmlNodeType

def ErrorString(errno):
    if errno > 0:
        return "unknown error"
    else:
        return None
       
def ParserCreate(*args):
    return xmlparser()

class xmlparser:

    __slots__ = [
        "StartElementHandler",
        "EndElementHandler",
        "CharacterDataHandler",
        ]

    returns_unicode = False

    def __init__(self):
        self._stream = MemoryStream()
        self._parser = self._make_parser()

    def Parse(self, data, isfinal=False):
        self._append_stream(data)
        self._parse()
        if isfinal:
            self._stream.Close()

    def _make_parser(self):
        table = NameTable()
        manager = XmlNamespaceManager(table)
        parser = XmlParserContext(table, manager, None, XmlSpace.None)
        return parser

    def _append_stream(self, data):
        stream = self._stream
        position = stream.Position
        stream.Seek(0, SeekOrigin.End)
        writer = StreamWriter(stream)
        writer.Write(data)
        writer.Flush()
        stream.Position = position

    def _parse(self):
        reader = XmlTextReader(self._stream, XmlNodeType.Element, 
self._parser)
        while reader.Read():
            nodetype = reader.NodeType           
            if nodetype == XmlNodeType.Element:
                name = reader.Name
                attributes = {}
                while reader.MoveToNextAttribute():
                    attributes[reader.Name] = reader.Value
                if hasattr(self, "StartElementHandler"):
                    self.StartElementHandler(name, attributes)
                # Create EndElement event as XmlTextReader doesn't
                # do this for empty elements
                if reader.IsEmptyElement:
                    nodetype = XmlNodeType.EndElement
            if nodetype == XmlNodeType.EndElement:
                name = reader.Name
                if hasattr(self, "EndElementHandler"):
                    self.EndElementHandler(name)
            elif nodetype == XmlNodeType.Text:
                data = reader.Value
                if hasattr(self, "CharacterDataHandler"):
                    self.CharacterDataHandler(data)
           





Monty Taylor wrote:
> You could write a Python or C# wrapper around System.XML that behaves
> like pyexpat and contribute it. :)
>
> Monty
>
> On 8/4/06, Bruce Christensen <t-bruch at microsoft.com> wrote:
>   
>> Nope. :) pyexpat relies on Python extension modules written in C, which
>> don't work with IronPython. However, you can use the classes in the .NET
>> System.Xml namespace for parsing XML documents if you're writing new
>> code.
>>
>> --Bruce
>>
>> -----Original Message-----
>> From: users-bounces at lists.ironpython.com
>> [mailto:users-bounces at lists.ironpython.com] On Behalf Of Sridevi
>> Sent: Thursday, August 03, 2006 5:41 AM
>> To: users-ironpython.com at lists.ironpython.com
>> Subject: [IronPython] pyexpat and IronPython
>>
>> Iam unable to run pyexpat from IronPython
>> Is there any files i got to add for it
>>
>> _______________________________________________
>> users mailing list
>> users at lists.ironpython.com
>> http://lists.ironpython.com/listinfo.cgi/users-ironpython.com
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>> users mailing list
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>>
>>     
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