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This page will contain the activity log of the pyFF+ experiments and endeavours.

Memory profiling

This is the bare import and code usage of using heapy to print heap information while running python code.

from guppy import hpy
import code
hp=hpy()
...
# reset the heap counters
hp.setrelheap()
...

# just print the heap somewhere:
h = hp.heap()
log.debug(f"\nheapy: {h}")

# or possibly interrupt the code execution and inspect the hp object:
code.interact(local=dict(globals(), **locals()))

Un/Pickling etree.ElementTree object

Here we demonstrate that externally parsed etree.ElementTree objects can be pickled (serialized) to be consumed later in pyFF, without the need to parse.

# Create pickled datafile
source = open("edugain.xml", "r", encoding="utf-8")
sink = open("edugain.pkl", "w")

t = objectify.parse(source)
p = pickle.dumps(t).decode('latin1')
sink.write(p)

# Read pickled object back in pyFF
def parse_xml
	return pickle.loads(io.encode('latin1'))

In metadata parser:
t = parse_xml(content) #Instead of parse_xml(unicode_stream(content))

xml.sax etree.ElementTree parser

This code uses the event based xml.sax parser to create an etree.ElementTree object for pyFF, inside pyFF. As of the moment of writing, pyFF refuses validate the result, but it produces correct metadata?
The parsing could be brought outside of pyFF to create a dictionary type of object to be read and parsed as a metadata representation to create the ElementTree object in pyFF instead of parsing XML.

import xml.sax
class XML(xml.sax.handler.ContentHandler):
  def __init__(self):
    self.current = etree.Element("root")
    self.nsmap = {}



  def startElement(self, name, attrs):
    attributes = {}
    for key, value in attrs.items():
        key = key.split(':')
        if len(key) == 2 and key[0] == 'xmlns':
            self.nsmap[key[-1]] = value
        else:
            attributes[key[-1]] = value
    name = name.split(':')
    if len(name) == 2:
        name = f"{{{ self.nsmap.get(name[0], name[0]) }}}{ name[-1] }"
    else:
        name = name[-1]
    self.current = etree.SubElement(self.current, name, attributes, nsmap=self.nsmap)

  def endElement(self, name):
    self.current = self.current.getparent()

  def characters(self, data):
    d = data.strip()
    if d:
      self.current.text = d

def parse_xml(io, base_url=None):
    parser = xml.sax.make_parser()
    handler = XML()
    parser.setContentHandler(handler)
    parser.parse(io)
    return etree.ElementTree(handler.current[0])





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