Viewing file:  saxutils.py (11.92 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, urllib.parse, urllib.request
import io
import codecs
from . import handler
from . import xmlreader
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.
"""
entities = entities.copy()
entities.update({'\n': ' ', '\r': ' ', '\t':'	'})
data = escape(data, entities)
if '"' in data:
if "'" in data:
data = '"%s"' % data.replace('"', """)
else:
data = "'%s'" % data
else:
data = '"%s"' % data
return data
def _gettextwriter(out, encoding):
if out is None:
import sys
return sys.stdout
if isinstance(out, io.TextIOBase):
# use a text writer as is
return out
if isinstance(out, (codecs.StreamWriter, codecs.StreamReaderWriter)):
# use a codecs stream writer as is
return out
# wrap a binary writer with TextIOWrapper
if isinstance(out, io.RawIOBase):
# Keep the original file open when the TextIOWrapper is
# destroyed
class _wrapper:
__class__ = out.__class__
def __getattr__(self, name):
return getattr(out, name)
buffer = _wrapper()
buffer.close = lambda: None
else:
# 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
buffer.write = out.write
try:
# TextIOWrapper uses this methods to determine
# if BOM (for UTF-16, etc) should be added
buffer.seekable = out.seekable
buffer.tell = out.tell
except AttributeError:
pass
return io.TextIOWrapper(buffer, encoding=encoding,
errors='xmlcharrefreplace',
newline='\n',
write_through=True)
class XMLGenerator(handler.ContentHandler):
def __init__(self, out=None, encoding="iso-8859-1", short_empty_elements=False):
handler.ContentHandler.__init__(self)
out = _gettextwriter(out, encoding)
self._write = out.write
self._flush = out.flush
self._ns_contexts = [{}] # contains uri -> prefix dicts
self._current_context = self._ns_contexts[-1]
self._undeclared_ns_maps = []
self._encoding = encoding
self._short_empty_elements = short_empty_elements
self._pending_start_element = False
def _qname(self, name):
"""Builds a qualified name from a (ns_url, localname) pair"""
if name[0]:
# 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
# self._current_context.
if 'http://www.w3.org/XML/1998/namespace' == name[0]:
return 'xml:' + name[1]
# The name is in a non-empty namespace
prefix = self._current_context[name[0]]
if prefix:
# If it is not the default namespace, prepend the prefix
return prefix + ":" + name[1]
# Return the unqualified name
return name[1]
def _finish_pending_start_element(self,endElement=False):
if self._pending_start_element:
self._write('>')
self._pending_start_element = False
# ContentHandler methods
def startDocument(self):
self._write('<?xml version="1.0" encoding="%s"?>\n' %
self._encoding)
def endDocument(self):
self._flush()
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._finish_pending_start_element()
self._write('<' + name)
for (name, value) in attrs.items():
self._write(' %s=%s' % (name, quoteattr(value)))
if self._short_empty_elements:
self._pending_start_element = True
else:
self._write(">")
def endElement(self, name):
if self._pending_start_element:
self._write('/>')
self._pending_start_element = False
else:
self._write('</%s>' % name)
def startElementNS(self, name, qname, attrs):
self._finish_pending_start_element()
self._write('<' + self._qname(name))
for prefix, uri in self._undeclared_ns_maps:
if prefix:
self._write(' xmlns:%s="%s"' % (prefix, uri))
else:
self._write(' xmlns="%s"' % uri)
self._undeclared_ns_maps = []
for (name, value) in attrs.items():
self._write(' %s=%s' % (self._qname(name), quoteattr(value)))
if self._short_empty_elements:
self._pending_start_element = True
else:
self._write(">")
def endElementNS(self, name, qname):
if self._pending_start_element:
self._write('/>')
self._pending_start_element = False
else:
self._write('</%s>' % self._qname(name))
def characters(self, content):
if content:
self._finish_pending_start_element()
if not isinstance(content, str):
content = str(content, self._encoding)
self._write(escape(content))
def ignorableWhitespace(self, content):
if content:
self._finish_pending_start_element()
if not isinstance(content, str):
content = str(content, self._encoding)
self._write(content)
def processingInstruction(self, target, data):
self._finish_pending_start_element()
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 isinstance(source, str):
source = xmlreader.InputSource(source)
elif hasattr(source, "read"):
f = source
source = xmlreader.InputSource()
if isinstance(f.read(0), str):
source.setCharacterStream(f)
else:
source.setByteStream(f)
if hasattr(f, "name") and isinstance(f.name, str):
source.setSystemId(f.name)
if source.getCharacterStream() is None and 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(urllib.parse.urljoin(base, sysid))
f = urllib.request.urlopen(source.getSystemId())
source.setByteStream(f)
return source
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