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.
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
and switch to DOM-related processing.
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.
20.8.1. DOMEventStream Objects¶
DOMEventStream(stream, parser, bufsize)¶
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:
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())