Viewing file:  saxutils.py (9.04 KB) -rw-r--r--
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"""\
A library of useful helper classes to the SAX classes, for the
convenience of application and driver writers.
"""
import os, urlparse, urllib, types
import handler
import xmlreader
try:
_StringTypes = [types.StringType, types.UnicodeType]
except AttributeError:
_StringTypes = [types.StringType]
# See whether the xmlcharrefreplace error handler is
# supported
try:
from codecs import xmlcharrefreplace_errors
_error_handling = "xmlcharrefreplace"
del xmlcharrefreplace_errors
except ImportError:
_error_handling = "strict"
def __dict_replace(s, d):
"""Replace substrings of a string using a dictionary."""
for key, value in d.items():
s = s.replace(key, value)
return s
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("<", "<")
if entities:
data = __dict_replace(data, entities)
return data
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(">", ">")
if entities:
data = __dict_replace(data, entities)
# must do ampersand last
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
necessary.
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.
"""
data = escape(data, entities)
if '"' in data:
if "'" in data:
data = '"%s"' % data.replace('"', """)
else:
data = "'%s'" % data
else:
data = '"%s"' % data
return data
class XMLGenerator(handler.ContentHandler):
def __init__(self, out=None, encoding="iso-8859-1"):
if out is None:
import sys
out = sys.stdout
handler.ContentHandler.__init__(self)
self._out = out
self._ns_contexts = [{}] # contains uri -> prefix dicts
self._current_context = self._ns_contexts[-1]
self._undeclared_ns_maps = []
self._encoding = encoding
def _write(self, text):
if isinstance(text, str):
self._out.write(text)
else:
self._out.write(text.encode(self._encoding, _error_handling))
# ContentHandler methods
def startDocument(self):
self._write('<?xml version="1.0" encoding="%s"?>\n' %
self._encoding)
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):
self._write('<' + name)
for (name, value) in attrs.items():
self._write(' %s=%s' % (name, quoteattr(value)))
self._write('>')
def endElement(self, name):
self._write('</%s>' % name)
def startElementNS(self, name, qname, attrs):
if name[0] is None:
# if the name was not namespace-scoped, use the unqualified part
name = name[1]
else:
# else try to restore the original prefix from the namespace
name = self._current_context[name[0]] + ":" + name[1]
self._write('<' + name)
for pair in self._undeclared_ns_maps:
self._write(' xmlns:%s="%s"' % pair)
self._undeclared_ns_maps = []
for (name, value) in attrs.items():
name = self._current_context[name[0]] + ":" + name[1]
self._write(' %s=%s' % (name, quoteattr(value)))
self._write('>')
def endElementNS(self, name, qname):
if name[0] is None:
name = name[1]
else:
name = self._current_context[name[0]] + ":" + name[1]
self._write('</%s>' % name)
def characters(self, content):
self._write(escape(content))
def ignorableWhitespace(self, content):
self._write(content)
def processingInstruction(self, target, data):
self._write('<?%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
through."""
def __init__(self, parent = None):
xmlreader.XMLReader.__init__(self)
self._parent = parent
# ErrorHandler methods
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)
# ContentHandler methods
def setDocumentLocator(self, locator):
self._cont_handler.setDocumentLocator(locator)
def startDocument(self):
self._cont_handler.startDocument()
def endDocument(self):
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)
# DTDHandler methods
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)
# EntityResolver methods
def resolveEntity(self, publicId, systemId):
return self._ent_handler.resolveEntity(publicId, systemId)
# XMLReader methods
def parse(self, source):
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)
# XMLFilter methods
def getParent(self):
return self._parent
def setParent(self, parent):
self._parent = parent
# --- Utility functions
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"):
f = source
source = xmlreader.InputSource()
source.setByteStream(f)
if hasattr(f, "name"):
source.setSystemId(f.name)
if source.getByteStream() is None:
sysid = source.getSystemId()
basehead = os.path.dirname(os.path.normpath(base))
sysidfilename = os.path.join(basehead, sysid)
if os.path.isfile(sysidfilename):
source.setSystemId(sysidfilename)
f = open(sysidfilename, "rb")
else:
source.setSystemId(urlparse.urljoin(base, sysid))
f = urllib.urlopen(source.getSystemId())
source.setByteStream(f)
return source
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