Source code for pykml.factory
'''pyKML Factory Module
The pykml.factory module provides objects and functions that can be used to
create KML documents element-by-element.
The factory module leverages `lxml's ElementMaker factory`_ objects to create
KML objects with the appropriate namespace prefixes.
.. _lxml: http://lxml.de
.. _lxml's ElementMaker factory: http://lxml.de/objectify.html#tree-generation-with-the-e-factory
'''
from lxml import etree, objectify
nsmap={
None: "http://www.opengis.net/kml/2.2",
'atom': "http://www.w3.org/2005/Atom",
'gx': "http://www.google.com/kml/ext/2.2",
}
# create a factory object for creating objects in the KML namespace
KML_ElementMaker = objectify.ElementMaker(
annotate=False,
namespace=nsmap[None],
nsmap=nsmap,
)
# create a factory object for creating objects in the ATOM namespace
ATOM_ElementMaker = objectify.ElementMaker(
annotate=False,
namespace=nsmap['atom'],
nsmap={'atom': nsmap['atom']},
)
# Create a factory object for the KML Google Extension namespace
GX_ElementMaker = objectify.ElementMaker(
annotate=False,
namespace=nsmap['gx'],
nsmap={'gx': nsmap['gx']},
)
[docs]def get_factory_object_name(namespace):
"Returns the correct factory object for a given namespace"
factory_map = {
'http://www.opengis.net/kml/2.2': 'KML',
'http://www.w3.org/2005/Atom': 'ATOM',
'http://www.google.com/kml/ext/2.2': 'GX'
}
if namespace:
if factory_map.has_key(namespace):
factory_object_name = factory_map[namespace]
else:
factory_object_name = None
else:
# use the KML factory object as the default, if no namespace is given
factory_object_name = 'KML'
return factory_object_name
[docs]def write_python_script_for_kml_document(doc):
"Generates a python script that will construct a given KML document"
import StringIO
from pykml.helpers import separate_namespace
output = StringIO.StringIO()
indent_size = 2
# add the etree package so that comments can be handled
output.write('from lxml import etree\n')
# add the namespace declaration section
output.write('from pykml.factory import KML_ElementMaker as KML\n')
output.write('from pykml.factory import ATOM_ElementMaker as ATOM\n')
output.write('from pykml.factory import GX_ElementMaker as GX\n')
output.write('\n')
level = 0
xml = StringIO.StringIO(etree.tostring(doc))
context = etree.iterparse(xml, events=("start", "end", "comment"))
output.write('doc = ')
last_action = None
main_element_processed_flag = False
previous_list = [] # list of comments before the root element
posterior_list = [] # list of comments after the root element
for action, elem in context:
# TODO: remove the following redundant conditional
if action in ('start','end','comment'):
namespace, element_name = separate_namespace(elem.tag)
if action in ('comment'):
indent = ' ' * level * indent_size
if elem.text:
text_list = elem.text.split('\n')
if len(text_list) == 1:
text = repr(elem.text)
else: # len(text_list) > 1
# format and join all non-empty lines
text = '\n' + ''.join(
['{indent}{content}\n'.format(
indent=' '*(len(t)-len(t.lstrip())),
content=repr(t.lstrip())
) for t in text_list if len(t.strip())>0
]
) + indent
else:
text = ''
if level == 0:
# store the comment so that it can be appended later
if main_element_processed_flag:
posterior_list.append("{indent}etree.Comment({comment})".format(
indent = indent,
comment = text,
))
else:
previous_list.append("{indent}etree.Comment({comment})".format(
indent = indent,
comment = text,
))
else:
output.write("{indent}etree.Comment({comment}),\n".format(
indent = indent,
comment = text,
))
elif action in ('start'):
main_element_processed_flag = True
if last_action == None:
indent = ''
else:
indent = ' ' * level * indent_size
level += 1
if elem.text:
# METHOD 1
# # treat all text string the same. this works but gets
# # messy for multi-line test strings
# text = repr(elem.text)
# METHOD 2 - format multiline strings differently
text_list = elem.text.split('\n')
if len(text_list) == 1:
text = repr(elem.text)
else: # len(text_list) > 1
# format and join all non-empty lines
text = '\n' + ''.join(
['{indent}{content}\n'.format(
indent=' '*(len(t)-len(t.lstrip())),
content=repr(t.lstrip())
) for t in text_list if len(t.strip())>0
]
) + indent
else:
text = ''
output.write('{indent}{factory}.{tag}({text}\n'.format(
indent = indent,
factory = get_factory_object_name(namespace),
tag = element_name,
text = text,
))
elif action in ('end'):
level -= 1
if last_action == 'start':
output.pos -= 1
indent = ''
else:
indent = ' ' * level * indent_size
for att,val in elem.items():
output.write('{0} {1}="{2}",\n'.format(indent,att,val))
output.write('{0}),\n'.format(indent))
last_action = action
# remove the last comma
output.pos -= 2
output.truncate()
output.write('\n')
for entry in previous_list:
output.write('doc.addprevious({entry})\n'.format(
entry=entry
))
for entry in posterior_list:
output.write('doc.addnext({entry})\n'.format(
entry=entry
))
# add python code to print out the KML document
output.write('print etree.tostring(etree.ElementTree(doc),pretty_print=True)\n')
return output.getvalue()
