Current File : //usr/lib/python3/dist-packages/twisted/web/domhelpers.py
# -*- test-case-name: twisted.web.test.test_domhelpers -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
A library for performing interesting tasks with DOM objects.
"""
from io import StringIO
from twisted.web import microdom
from twisted.web.microdom import escape, getElementsByTagName, unescape
# These modules are imported here as a shortcut.
escape
getElementsByTagName
class NodeLookupError(Exception):
pass
def substitute(request, node, subs):
"""
Look through the given node's children for strings, and
attempt to do string substitution with the given parameter.
"""
for child in node.childNodes:
if hasattr(child, "nodeValue") and child.nodeValue:
child.replaceData(0, len(child.nodeValue), child.nodeValue % subs)
substitute(request, child, subs)
def _get(node, nodeId, nodeAttrs=("id", "class", "model", "pattern")):
"""
(internal) Get a node with the specified C{nodeId} as any of the C{class},
C{id} or C{pattern} attributes.
"""
if hasattr(node, "hasAttributes") and node.hasAttributes():
for nodeAttr in nodeAttrs:
if str(node.getAttribute(nodeAttr)) == nodeId:
return node
if node.hasChildNodes():
if hasattr(node.childNodes, "length"):
length = node.childNodes.length
else:
length = len(node.childNodes)
for childNum in range(length):
result = _get(node.childNodes[childNum], nodeId)
if result:
return result
def get(node, nodeId):
"""
Get a node with the specified C{nodeId} as any of the C{class},
C{id} or C{pattern} attributes. If there is no such node, raise
L{NodeLookupError}.
"""
result = _get(node, nodeId)
if result:
return result
raise NodeLookupError(nodeId)
def getIfExists(node, nodeId):
"""
Get a node with the specified C{nodeId} as any of the C{class},
C{id} or C{pattern} attributes. If there is no such node, return
L{None}.
"""
return _get(node, nodeId)
def getAndClear(node, nodeId):
"""Get a node with the specified C{nodeId} as any of the C{class},
C{id} or C{pattern} attributes. If there is no such node, raise
L{NodeLookupError}. Remove all child nodes before returning.
"""
result = get(node, nodeId)
if result:
clearNode(result)
return result
def clearNode(node):
"""
Remove all children from the given node.
"""
node.childNodes[:] = []
def locateNodes(nodeList, key, value, noNesting=1):
"""
Find subnodes in the given node where the given attribute
has the given value.
"""
returnList = []
if not isinstance(nodeList, type([])):
return locateNodes(nodeList.childNodes, key, value, noNesting)
for childNode in nodeList:
if not hasattr(childNode, "getAttribute"):
continue
if str(childNode.getAttribute(key)) == value:
returnList.append(childNode)
if noNesting:
continue
returnList.extend(locateNodes(childNode, key, value, noNesting))
return returnList
def superSetAttribute(node, key, value):
if not hasattr(node, "setAttribute"):
return
node.setAttribute(key, value)
if node.hasChildNodes():
for child in node.childNodes:
superSetAttribute(child, key, value)
def superPrependAttribute(node, key, value):
if not hasattr(node, "setAttribute"):
return
old = node.getAttribute(key)
if old:
node.setAttribute(key, value + "/" + old)
else:
node.setAttribute(key, value)
if node.hasChildNodes():
for child in node.childNodes:
superPrependAttribute(child, key, value)
def superAppendAttribute(node, key, value):
if not hasattr(node, "setAttribute"):
return
old = node.getAttribute(key)
if old:
node.setAttribute(key, old + "/" + value)
else:
node.setAttribute(key, value)
if node.hasChildNodes():
for child in node.childNodes:
superAppendAttribute(child, key, value)
def gatherTextNodes(iNode, dounescape=0, joinWith=""):
"""Visit each child node and collect its text data, if any, into a string.
For example::
>>> doc=microdom.parseString('<a>1<b>2<c>3</c>4</b></a>')
>>> gatherTextNodes(doc.documentElement)
'1234'
With dounescape=1, also convert entities back into normal characters.
@return: the gathered nodes as a single string
@rtype: str"""
gathered = []
gathered_append = gathered.append
slice = [iNode]
while len(slice) > 0:
c = slice.pop(0)
if hasattr(c, "nodeValue") and c.nodeValue is not None:
if dounescape:
val = unescape(c.nodeValue)
else:
val = c.nodeValue
gathered_append(val)
slice[:0] = c.childNodes
return joinWith.join(gathered)
class RawText(microdom.Text):
"""This is an evil and horrible speed hack. Basically, if you have a big
chunk of XML that you want to insert into the DOM, but you don't want to
incur the cost of parsing it, you can construct one of these and insert it
into the DOM. This will most certainly only work with microdom as the API
for converting nodes to xml is different in every DOM implementation.
This could be improved by making this class a Lazy parser, so if you
inserted this into the DOM and then later actually tried to mutate this
node, it would be parsed then.
"""
def writexml(
self,
writer,
indent="",
addindent="",
newl="",
strip=0,
nsprefixes=None,
namespace=None,
):
writer.write(f"{indent}{self.data}{newl}")
def findNodes(parent, matcher, accum=None):
if accum is None:
accum = []
if not parent.hasChildNodes():
return accum
for child in parent.childNodes:
# print child, child.nodeType, child.nodeName
if matcher(child):
accum.append(child)
findNodes(child, matcher, accum)
return accum
def findNodesShallowOnMatch(parent, matcher, recurseMatcher, accum=None):
if accum is None:
accum = []
if not parent.hasChildNodes():
return accum
for child in parent.childNodes:
# print child, child.nodeType, child.nodeName
if matcher(child):
accum.append(child)
if recurseMatcher(child):
findNodesShallowOnMatch(child, matcher, recurseMatcher, accum)
return accum
def findNodesShallow(parent, matcher, accum=None):
if accum is None:
accum = []
if not parent.hasChildNodes():
return accum
for child in parent.childNodes:
if matcher(child):
accum.append(child)
else:
findNodes(child, matcher, accum)
return accum
def findElementsWithAttributeShallow(parent, attribute):
"""
Return an iterable of the elements which are direct children of C{parent}
and which have the C{attribute} attribute.
"""
return findNodesShallow(
parent,
lambda n: getattr(n, "tagName", None) is not None and n.hasAttribute(attribute),
)
def findElements(parent, matcher):
"""
Return an iterable of the elements which are children of C{parent} for
which the predicate C{matcher} returns true.
"""
return findNodes(
parent,
lambda n, matcher=matcher: getattr(n, "tagName", None) is not None
and matcher(n),
)
def findElementsWithAttribute(parent, attribute, value=None):
if value:
return findElements(
parent,
lambda n, attribute=attribute, value=value: n.hasAttribute(attribute)
and n.getAttribute(attribute) == value,
)
else:
return findElements(
parent, lambda n, attribute=attribute: n.hasAttribute(attribute)
)
def findNodesNamed(parent, name):
return findNodes(parent, lambda n, name=name: n.nodeName == name)
def writeNodeData(node, oldio):
for subnode in node.childNodes:
if hasattr(subnode, "data"):
oldio.write("" + subnode.data)
else:
writeNodeData(subnode, oldio)
def getNodeText(node):
oldio = StringIO()
writeNodeData(node, oldio)
return oldio.getvalue()
def getParents(node):
l = []
while node:
l.append(node)
node = node.parentNode
return l
def namedChildren(parent, nodeName):
"""namedChildren(parent, nodeName) -> children (not descendants) of parent
that have tagName == nodeName
"""
return [n for n in parent.childNodes if getattr(n, "tagName", "") == nodeName]
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