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import contextlib

import os

import shutil

import tempfile

import zipfile

import xml.etree.ElementTree as ET

try:

from distutils2.version import NormalizedVersion as Version

except ImportError:

from distutils.version import LooseVersion as Version

MIN_SUPPORTED_VERSION = Version("9.0")

class TableauVersionNotSupportedException(Exception):

pass

class TableauInvalidFileException(Exception):

pass

def xml_open(filename, expected_root=None):

"""Opens the provided 'filename'. Handles detecting if the file is an archive,

detecting the document version, and validating the root tag."""

# Is the file a zip (.twbx or .tdsx)

if zipfile.is_zipfile(filename):

tree = get_xml_from_archive(filename)

else:

tree = ET.parse(filename)

# Is the file a supported version

tree_root = tree.getroot()

file_version = Version(tree_root.attrib.get('version', '0.0'))

if file_version < MIN_SUPPORTED_VERSION:

raise TableauVersionNotSupportedException(file_version)

# Does the root tag match the object type (workbook or data source)

if expected_root and (expected_root != tree_root.tag):

raise TableauInvalidFileException(

"'{}'' is not a valid '{}' file".format(filename, expected_root))

return tree

@contextlib.contextmanager

def temporary_directory(*args, **kwargs):

d = tempfile.mkdtemp(*args, **kwargs)

try:

yield d

finally:

shutil.rmtree(d)

def find_file_in_zip(zip_file):

'''Returns the twb/tds file from a Tableau packaged file format. Packaged

files can contain cache entries which are also valid XML, so only look for

files with a .tds or .twb extension.

'''

candidate_files = filter(lambda x: x.split('.')[-1] in ('twb', 'tds'),

zip_file.namelist())

for filename in candidate_files:

with zip_file.open(filename) as xml_candidate:

try:

ET.parse(xml_candidate)

return filename

except ET.ParseError:

# That's not an XML file by gosh

pass

def get_xml_from_archive(filename):

with zipfile.ZipFile(filename) as zf:

with zf.open(find_file_in_zip(zf)) as xml_file:

xml_tree = ET.parse(xml_file)

return xml_tree

def build_archive_file(archive_contents, zip_file):

"""Build a Tableau-compatible archive file."""

# This is tested against Desktop and Server, and reverse engineered by lots

# of trial and error. Do not change this logic.

for root_dir, _, files in os.walk(archive_contents):

relative_dir = os.path.relpath(root_dir, archive_contents)

for f in files:

temp_file_full_path = os.path.join(

archive_contents, relative_dir, f)

zipname = os.path.join(relative_dir, f)

zip_file.write(temp_file_full_path, arcname=zipname)

def save_into_archive(xml_tree, filename, new_filename=None):

# Saving an archive means extracting the contents into a temp folder,

# saving the changes over the twb/tds in that folder, and then

# packaging it back up into a zip with a very specific format

# e.g. no empty files for directories, which Windows and Mac do by default

if new_filename is None:

new_filename = filename

# Extract to temp directory

with temporary_directory() as temp_path:

with zipfile.ZipFile(filename) as zf:

xml_file = find_file_in_zip(zf)

zf.extractall(temp_path)

# Write the new version of the file to the temp directory

xml_tree.write(os.path.join(

temp_path, xml_file), encoding="utf-8", xml_declaration=True)

# Write the new archive with the contents of the temp folder

with zipfile.ZipFile(new_filename, "w", compression=zipfile.ZIP_DEFLATED) as new_archive:

build_archive_file(temp_path, new_archive)

def _save_file(container_file, xml_tree, new_filename=None):

if new_filename is None:

new_filename = container_file

if zipfile.is_zipfile(container_file):

save_into_archive(xml_tree, container_file, new_filename)

else:

xml_tree.write(new_filename, encoding="utf-8", xml_declaration=True)