xml.dom.pulldom — Support for building partial DOM trees
Source code: Lib/xml/dom/pulldom.py
xml.dom.pulldom module provides a “pull parser” which can also be asked to produce DOM-accessible fragments of the document where necessary. The basic concept involves pulling “events” from a stream of incoming XML and processing them. In contrast to SAX which also employs an event-driven processing model together with callbacks, the user of a pull parser is responsible for explicitly pulling events from the stream, looping over those events until either processing is finished or an error condition occurs.
xml.dom.pulldom module is not secure against maliciously constructed data. If you need to parse untrusted or unauthenticated data see XML vulnerabilities.
Changed in version 3.7.1: The SAX parser no longer processes general external entities by default to increase security by default. To enable processing of external entities, pass a custom parser instance in:
from xml.dom.pulldom import parse from xml.sax import make_parser from xml.sax.handler import feature_external_ges parser = make_parser() parser.setFeature(feature_external_ges, True) parse(filename, parser=parser)
from xml.dom import pulldom doc = pulldom.parse('sales_items.xml') for event, node in doc: if event == pulldom.START_ELEMENT and node.tagName == 'item': if int(node.getAttribute('price')) > 50: doc.expandNode(node) print(node.toxml())
event is a constant and can be one of:
node is an object of type
Since the document is treated as a “flat” stream of events, the document “tree” is implicitly traversed and the desired elements are found regardless of their depth in the tree. In other words, one does not need to consider hierarchical issues such as recursive searching of the document nodes, although if the context of elements were important, one would either need to maintain some context-related state (i.e. remembering where one is in the document at any given point) or to make use of the
DOMEventStream.expandNode() method and switch to DOM-related processing.
xml.dom.pulldom.parse(stream_or_string, parser=None, bufsize=None)
DOMEventStreamfrom the given input. stream_or_string may be either a file name, or a file-like object. parser, if given, must be an
XMLReaderobject. This function will change the document handler of the parser and activate namespace support; other parser configuration (like setting an entity resolver) must have been done in advance.
If you have XML in a string, you can use the
parseString() function instead:
DOMEventStreamthat represents the (Unicode) string.
Default value for the bufsize parameter to
The value of this variable can be changed before calling
parse()and the new value will take effect.
class xml.dom.pulldom.DOMEventStream(stream, parser, bufsize)
Deprecated since version 3.8: Support for
sequence protocolis deprecated.
Return a tuple containing event and the current node as
xml.dom.minidom.Documentif event equals
xml.dom.minidom.Elementif event equals
xml.dom.minidom.Textif event equals
CHARACTERS. The current node does not contain information about its children, unless
Expands all children of node into node. Example:Python
from xml.dom import pulldom xml = '<html><title>Foo</title> <p>Some text <div>and more</div></p> </html>' doc = pulldom.parseString(xml) for event, node in doc: if event == pulldom.START_ELEMENT and node.tagName == 'p': # Following statement only prints '<p/>' print(node.toxml()) doc.expandNode(node) # Following statement prints node with all its children '<p>Some text <div>and more</div></p>' print(node.toxml())
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