JSaxonPy
jsaxonpy - the python package to be used for your Java Saxon XSLT transformations in your python applications.
Installation
pip install jsaxonpy
Quick overview
>>> from jsaxonpy import Xslt
>>> t = Xslt()
>>> xml = "<root><child>text</child></root>"
>>> xsl = """
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:copy-of select="."/>
</xsl:template>
</xsl:stylesheet>
"""
>>> t.transform(xml, xsl)
'<?xml version="1.0" encoding="UTF-8"?><root><child>text</child></root>'You can supply params if you needed as python dictioary with keys & values as strings (str type).
>>> params = {"param1": "value1", "param2": "value2"}
>>> out = t.transform(xml, xsl, params)
xml and xsl arguments could be either string documents (str type) or
files names wrapped into pathlib.Path(...) class, before being passed.
Also you can run transformations using threads or multiple processes using
concurrent.futures or multiprocessing modules. The only known limitation is
not to run transformations (using Xslt class) using multi-processing in parent
process, you can successfully run it in children. If you try to run in parent process and in children processes, then you application would hang. With threading instantiation of Xslt class works both in main thread and in children threads.
Examples
Plain
from pathlib import Path
from jsaxonpy import Xslt
t = Xslt()
xml = Path("file.xml")
xsl = Path("file.xsl")
print(t.transform(xml, xsl))would produce:
<?xml version="1.0" encoding="UTF-8"?><root><child>text</child></root>
Threads
from concurrent.futures import ThreadPoolExecutor
from pathlib import Path
from jsaxonpy import Xslt
def func(args):
xml, xsl = args
t = Xslt()
out = t.transform(xml, xsl)
return out
xsl_path = Path('file.xsl')
worker_args = []
with ThreadPoolExecutor(max_workers=3) as executor:
for xml_path in map(lambda f: Path(f), ["file1.xml", ..., "fileN.xml"]):
worker_args.append((xml_path, xsl_path))
for out in executor.map(func, worker_args):
assert out == xmlProcesses
from concurrent.futures import ProcessPoolExecutor
from pathlib import Path
from jsaxonpy import Xslt
def func(args):
xml, xsl = args
t = Xslt()
out = t.transform(xml, xsl)
return out
xsl_path = Path('file.xsl')
worker_args = []
with ProcessPoolExecutor(max_workers=3) as executor:
for xml_path in map(lambda f: Path(f), ["file1.xml", ..., "fileN.xml"]):
worker_args.append((xml_path, xsl_path))
for out in executor.map(func, worker_args):
assert out == xmlGCP Functions
import os, threading
from timeit import default_timer as timer
import functions_framework
from jdk4py import JAVA, JAVA_HOME, JAVA_VERSION
from saxonhe4py import SAXON_HE_JAR
from jsaxonpy import Xslt
# following env variable must be defined, otherwise pyjnius would fail
os.environ["JAVA_HOME"] = str(JAVA_HOME)
os.environ["JDK_HOME"] = str(JAVA_HOME)
# to find the location of Saxon HE
os.environ["CLASSPATH"] = str(SAXON_HE_JAR)
# setup JVM options
os.environ["JVM_OPTIONS"] = "-Xmx64m"
@functions_framework.http
def transform(request):
#
thread_id = threading.get_native_id()
process_id = os.getpid()
#
timer_xslt_started = timer()
t = Xslt() # do not move this from function.
timer_xslt_ended = timer()
#
xml = "<p>Paragraph text</p>"
xsl = """
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:copy-of select="."/>
</xsl:template>
</xsl:stylesheet>
"""
#
timer_transform_started = timer()
output=t.transform(xml, xsl)
timer_transform_ended = timer()
return (
f"{output}\n"
f"timer(Xslt) = {timer_xslt_ended - timer_xslt_started:.6f}\n"
f"timer(transform) = {timer_transform_ended - timer_transform_started:.6f}\n"
f"thread_id={thread_id} process_id={process_id}\n"
)Notes
Supported and tested versions of Saxon are 9, 10, 11.
Catalog resolution is supported only if you run on Saxon 11.
Before executing you application it is expected you set your java related
environment variables, including the CLASSPATH to point to your Java Saxon
installation.
You can use JVM_OPTIONS environment variable to set java virtual environment,
see example below.
export JVM_OPTIONS="-Xrs -Xmx4096m -XX:ActiveProcessorCount=24";
export CLASSPATH=/usr/local/Saxon-J/saxon-he-11.4.jar;
your_python_app.pyWhen you pass the same xsl path it is actually being compiled once for the time of the life of the process/thread, which means you do not need to do any special steps to compile those to speed up transformations.
API
class JVM
1 Help on class JVM in module jsaxonpy.jvm:
2
3 class JVM(builtins.object)
4 | JVM(*args, **kwargs)
5 |
6 | Methods defined here:
7 |
8 | __init__(self)
9 | Initialize self. See help(type(self)) for accurate signature.
10 |
class Xslt
1 Help on class Xslt in module jsaxonpy.xslt:
2
3 class Xslt(InterfaceXslt)
4 | Xslt(catalog: Optional[pathlib.Path] = None, jvm: Optional[jsaxonpy.jvm.JVM] = None, licensed_edition: bool = False)
5 |
6 | Xslt class exposes transformations based on Java Saxon transform() method of
7 | net.sf.saxon.s9api.XsltTransformer class.
8 |
9 | Notes:
10 | If you plan to use multiprocessing, then do not instantiate Xslt class
11 | in parent process because saxon compiler hangs if parent process has jnius
12 | JVM machine running already.
13 |
14 | Method resolution order:
15 | Xslt
16 | InterfaceXslt
17 | abc.ABC
18 | builtins.object
19 |
20 | Methods defined here:
21 |
22 | __init__(self, catalog: Optional[pathlib.Path] = None, jvm: Optional[jsaxonpy.jvm.JVM] = None, licensed_edition: bool = False)
23 | Initializer for Xslt class.
24 |
25 | Args:
26 | @catalog (Optional[Path], optional):
27 | Path to catalog file, optional. Defaults to None.
28 | @jvm (Optional[JVM], optional):
29 | optional instance of `JVM` class. Defaults to None.
30 | @licensed_edition (bool, optional):
31 | Indicate if you run on Licensed edition. Defaults to False.
32 |
33 | transform(self, xml: Union[pathlib.Path, str], xsl: Union[pathlib.Path, str], params: Dict[str, str] = {}, pretty: bool = False) -> str
34 | `transform` method executes the transformation of the input XML string
35 | or file with provided XSL code and optional XSL parameters.
36 | You can pass Stylesheet Export File (SEF) in place of `xsl` argument instead
37 | of regular XSL file path.
38 |
39 | Args:
40 | @xml (InputSource):
41 | XML markup (string) or file pathlib.Path("path/to/file.xml")
42 | @xsl (InputSource):
43 | XSL code (string) or file pathlib.Path("path/to/file.xsl")
44 | @params (XsltParams, optional):
45 | XSL parameters. Defaults to {}.
46 | @pretty (bool, optional):
47 | Format output pretty. Defaults to False.
48 |
49 | Returns:
50 | str: The output of the transformation
51 |
52 | Notes:
53 | The following types `InputSource`, `XsltParams` are defined as following:
54 |
55 | InputSource = Union[Path, str]
56 | XsltParams = Dict[str, str]
57 |
58 | ----------------------------------------------------------------------
59 | Readonly properties defined here:
60 |
61 | is_catalog_supported
62 |
63 | saxon_major_version
64 |
65 | saxon_version
66 |
