A library of useful helper classes to the SAX classes, for the
convenience of application and driver writers.
import os, urlparse, urllib, types
_StringTypes = [types.StringType, types.UnicodeType]
_StringTypes = [types.StringType]
def __dict_replace(s, d):
"""Replace substrings of a string using a dictionary."""
for key, value in d.items():
s = s.replace(key, value)
def escape(data, entities={}):
"""Escape &, <, and > in a string of data.
You can escape other strings of data by passing a dictionary as
the optional entities parameter. The keys and values must all be
strings; each key will be replaced with its corresponding value.
# must do ampersand first
data = data.replace("&", "&")
data = data.replace(">", ">")
data = data.replace("<", "<")
data = __dict_replace(data, entities)
def unescape(data, entities={}):
"""Unescape &, <, and > in a string of data.
You can unescape other strings of data by passing a dictionary as
the optional entities parameter. The keys and values must all be
strings; each key will be replaced with its corresponding value.
data = data.replace("<", "<")
data = data.replace(">", ">")
data = __dict_replace(data, entities)
return data.replace("&", "&")
def quoteattr(data, entities={}):
"""Escape and quote an attribute value.
Escape &, <, and > in a string of data, then quote it for use as
an attribute value. The \" character will be escaped as well, if
You can escape other strings of data by passing a dictionary as
the optional entities parameter. The keys and values must all be
strings; each key will be replaced with its corresponding value.
entities = entities.copy()
entities.update({'\n': ' ', '\r': ' ', '\t':'	'})
data = escape(data, entities)
data = '"%s"' % data.replace('"', """)
def _gettextwriter(out, encoding):
if isinstance(out, io.RawIOBase):
buffer = io.BufferedIOBase(out)
# Keep the original file open when the TextIOWrapper is
buffer.close = lambda: None
# This is to handle passed objects that aren't in the
# IOBase hierarchy, but just have a write method
buffer = io.BufferedIOBase()
buffer.writable = lambda: True
# TextIOWrapper uses this methods to determine
# if BOM (for UTF-16, etc) should be added
buffer.seekable = out.seekable
# wrap a binary writer with TextIOWrapper
return _UnbufferedTextIOWrapper(buffer, encoding=encoding,
errors='xmlcharrefreplace',
class _UnbufferedTextIOWrapper(io.TextIOWrapper):
super(_UnbufferedTextIOWrapper, self).write(s)
class XMLGenerator(handler.ContentHandler):
def __init__(self, out=None, encoding="iso-8859-1"):
handler.ContentHandler.__init__(self)
out = _gettextwriter(out, encoding)
self._ns_contexts = [{}] # contains uri -> prefix dicts
self._current_context = self._ns_contexts[-1]
self._undeclared_ns_maps = []
self._encoding = encoding
"""Builds a qualified name from a (ns_url, localname) pair"""
# Per http://www.w3.org/XML/1998/namespace, The 'xml' prefix is
# bound by definition to http://www.w3.org/XML/1998/namespace. It
# does not need to be declared and will not usually be found in
if 'http://www.w3.org/XML/1998/namespace' == name[0]:
# The name is in a non-empty namespace
prefix = self._current_context[name[0]]
# If it is not the default namespace, prepend the prefix
return prefix + ":" + name[1]
# Return the unqualified name
self._write(u'<?xml version="1.0" encoding="%s"?>\n' %
def startPrefixMapping(self, prefix, uri):
self._ns_contexts.append(self._current_context.copy())
self._current_context[uri] = prefix
self._undeclared_ns_maps.append((prefix, uri))
def endPrefixMapping(self, prefix):
self._current_context = self._ns_contexts[-1]
del self._ns_contexts[-1]
def startElement(self, name, attrs):
for (name, value) in attrs.items():
self._write(u' %s=%s' % (name, quoteattr(value)))
def endElement(self, name):
self._write(u'</%s>' % name)
def startElementNS(self, name, qname, attrs):
self._write(u'<' + self._qname(name))
for prefix, uri in self._undeclared_ns_maps:
self._write(u' xmlns:%s="%s"' % (prefix, uri))
self._write(u' xmlns="%s"' % uri)
self._undeclared_ns_maps = []
for (name, value) in attrs.items():
self._write(u' %s=%s' % (self._qname(name), quoteattr(value)))
def endElementNS(self, name, qname):
self._write(u'</%s>' % self._qname(name))
def characters(self, content):
if not isinstance(content, unicode):
content = unicode(content, self._encoding)
self._write(escape(content))
def ignorableWhitespace(self, content):
if not isinstance(content, unicode):
content = unicode(content, self._encoding)
def processingInstruction(self, target, data):
self._write(u'<?%s %s?>' % (target, data))
class XMLFilterBase(xmlreader.XMLReader):
"""This class is designed to sit between an XMLReader and the
client application's event handlers. By default, it does nothing
but pass requests up to the reader and events on to the handlers
unmodified, but subclasses can override specific methods to modify
the event stream or the configuration requests as they pass
def __init__(self, parent = None):
xmlreader.XMLReader.__init__(self)
def error(self, exception):
self._err_handler.error(exception)
def fatalError(self, exception):
self._err_handler.fatalError(exception)
def warning(self, exception):
self._err_handler.warning(exception)
def setDocumentLocator(self, locator):
self._cont_handler.setDocumentLocator(locator)
self._cont_handler.startDocument()
self._cont_handler.endDocument()
def startPrefixMapping(self, prefix, uri):
self._cont_handler.startPrefixMapping(prefix, uri)
def endPrefixMapping(self, prefix):
self._cont_handler.endPrefixMapping(prefix)
def startElement(self, name, attrs):
self._cont_handler.startElement(name, attrs)
def endElement(self, name):
self._cont_handler.endElement(name)
def startElementNS(self, name, qname, attrs):
self._cont_handler.startElementNS(name, qname, attrs)
def endElementNS(self, name, qname):
self._cont_handler.endElementNS(name, qname)
def characters(self, content):
self._cont_handler.characters(content)
def ignorableWhitespace(self, chars):
self._cont_handler.ignorableWhitespace(chars)
def processingInstruction(self, target, data):
self._cont_handler.processingInstruction(target, data)
def skippedEntity(self, name):
self._cont_handler.skippedEntity(name)
def notationDecl(self, name, publicId, systemId):
self._dtd_handler.notationDecl(name, publicId, systemId)
def unparsedEntityDecl(self, name, publicId, systemId, ndata):
self._dtd_handler.unparsedEntityDecl(name, publicId, systemId, ndata)
def resolveEntity(self, publicId, systemId):
return self._ent_handler.resolveEntity(publicId, systemId)
self._parent.setContentHandler(self)
self._parent.setErrorHandler(self)
self._parent.setEntityResolver(self)
self._parent.setDTDHandler(self)
self._parent.parse(source)
def setLocale(self, locale):
self._parent.setLocale(locale)
def getFeature(self, name):
return self._parent.getFeature(name)
def setFeature(self, name, state):
self._parent.setFeature(name, state)
def getProperty(self, name):
return self._parent.getProperty(name)
def setProperty(self, name, value):
self._parent.setProperty(name, value)
def setParent(self, parent):
def prepare_input_source(source, base = ""):
"""This function takes an InputSource and an optional base URL and
returns a fully resolved InputSource object ready for reading."""
if type(source) in _StringTypes:
source = xmlreader.InputSource(source)
elif hasattr(source, "read"):
source = xmlreader.InputSource()
source.setSystemId(f.name)
if source.getByteStream() is None:
sysid = source.getSystemId()
basehead = os.path.dirname(os.path.normpath(base))
encoding = sys.getfilesystemencoding()
if isinstance(sysid, unicode):
if not isinstance(basehead, unicode):
basehead = basehead.decode(encoding)
except UnicodeDecodeError:
sysid = sysid.encode(encoding)
if isinstance(basehead, unicode):
sysid = sysid.decode(encoding)
except UnicodeDecodeError:
basehead = basehead.encode(encoding)
sysidfilename = os.path.join(basehead, sysid)
isfile = os.path.isfile(sysidfilename)
source.setSystemId(sysidfilename)
f = open(sysidfilename, "rb")
source.setSystemId(urlparse.urljoin(base, source.getSystemId()))
f = urllib.urlopen(source.getSystemId())