cpython/Lib/xml/sax/saxutils.py

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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
_StringTypes = [types.StringType, types.UnicodeType]
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.
"""
data = data.replace("&", "&amp;")
data = data.replace("<", "&lt;")
data = data.replace(">", "&gt;")
for chars, entity in entities.items():
data = data.replace(chars, entity)
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
# ContentHandler methods
def startDocument(self):
self._out.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._out.write('<' + name)
for (name, value) in attrs.items():
self._out.write(' %s="%s"' % (name, escape(value)))
self._out.write('>')
def endElement(self, name):
self._out.write('</%s>' % name)
def startElementNS(self, name, qname, attrs):
name = self._current_context[name[0]] + ":" + name[1]
self._out.write('<' + name)
for pair in self._undeclared_ns_maps:
self._out.write(' xmlns:%s="%s"' % pair)
self._undeclared_ns_maps = []
for (name, value) in attrs.items():
name = self._current_context[name[0]] + ":" + name[1]
self._out.write(' %s="%s"' % (name, escape(value)))
self._out.write('>')
def endElementNS(self, name, qname):
name = self._current_context[name[0]] + ":" + name[1]
self._out.write('</%s>' % name)
def characters(self, content):
self._out.write(escape(content))
def ignorableWhitespace(self, content):
self._out.write(content)
def processingInstruction(self, target, data):
self._out.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."""
# 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.startElement(name, 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):
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)
# --- 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)
source.setByteStream(f)
if source.getByteStream() == None:
sysid = source.getSystemId()
if urlparse.urlparse(sysid)[0] == '':
basehead = os.path.split(os.path.normpath(base))[0]
source.setSystemId(os.path.join(basehead, sysid))
else:
source.setSystemId(urlparse.urljoin(base, sysid))
source.setByteStream(urllib.urlopen(source.getSystemId()))
return source