Jython: Packing several .py on .jar, problem importing .py moduleswithin the .jar

[Gubatron]

Hello all,

I've a problem with Jython and importing .py inside a jar.

I'm putting .class and .py files inside .jar files.

myjar.jar
MyJar\SomeClass.class
MyJar\main.py
MyJar\otherModule.py

So I add the myjar.jar to Jython's sys.path

org.python.core.PySystemState pySys = new
org.python.core.PySystemState();
pySys.path.insert(0,new PyString("/path/to/myjar.jar"));

and execute main.py

//We pass the PythonInterpreter the modified PySystemState
PythonInterpreter i = new PythonInterpreter(null, pySys);

//Find the entry in the jar for the python file and execute it.
//It should be able to find any resource inside the jar.
JarFile jFile = new JarFile("/path/to/myjar.jar");
ZipEntry zipEntry = jFile.getEntry("MyJar/main.py");

InputStream pythonInputStream =
jFile.getInputStream(zipEntry);
i.execfile(pythonInputStream);

main.py will execute fine, it'll be able to do

from MyJar import SomeClass

with no problem

However, If I try to import the other .py in the same jar, it won't
find it:

from otherModule import *

or

from MyJar.otherModule import *

I always get this:

ImportError: no module named otherModule

at org.python.core.Py.ImportError(Unknown Source)
at org.python.core.imp.import_first(Unknown Source)
at org.python.core.imp.import_name(Unknown Source)
at org.python.core.imp.importName(Unknown Source)
at org.python.core.ImportFunction.load(Unknown Source)
at org.python.core.ImportFunction.__call__(Unknown Source)
at org.python.core.PyObject.__call__(Unknown Source)
at org.python.core.__builtin__.__import__(Unknown Source)
at org.python.core.imp.importFromAs(Unknown Source)
at org.python.core.imp.importFrom(Unknown Source)
at org.python.pycode._pyx1.f$0(<iostream>:26)
at org.python.pycode._pyx1.call_function(<iostream>)
at org.python.core.PyTableCode.call(Unknown Source)
at org.python.core.PyCode.call(Unknown Source)
at org.python.core.Py.runCode(Unknown Source)
at org.python.util.PythonInterpreter.execfile(Unknown Source)

I've tried adding more paths to sys.path, with no luck:

pySys.path.insert(0,new PyString("/path/to/myjar.jar/MyJar"));
pySys.path.insert(0,new PyString("file:jar:/path/to/myjar.jar!"));

and nothing works, any ideas would help. I know this has to work,
because I previously had a problem where I couldn't do

import os

and then I added the "Lib/" folder inside jython.jar and now I'm able
to import all those standard jython modules, so, somehow, jython is
able to import .py within a .jar, help would be very much appreciated.

Angel Leon

 

[Gubatron]

I've managed to solve this problem.

I can now run a python script that lives inside a Jar. The python
script is now able to import other scripts within the same jar, and
it's also able to import java classes that live within the jar.

The problem was solved by giving the Jython Interpreter the proper
initialization. This entails:

- Giving it a class loader that has put the Jar on it's class path
- Adding the path of the jar to the interpreter's sys.path

Here's an example:


org.python.core.PySystemState pySys = new
org.python.core.PySystemState();
pySys.setClassLoader(((URLClassLoader) classLoaders.get(jarFile)));

//We also have to pass the jar to JYTHON_PATH (sys.path)
//so that it can properly import inner python modules.
pySys.path.insert(0,new PyString(jarFile));

//We pass the PythonInterpreter the modified PySystemState
PythonInterpreter i = new PythonInterpreter(null, pySys);
i.exec(pythonScriptName);

 

[Gubatron]

cont...

Take in consideration
/** Hashtable of URLClassLoaders for each of the jars loaded */
private Hashtable<String, URLClassLoader> classLoaders;

Here's an example:

org.python.core.PySystemState pySys = new
org.python.core.PySystemState();

//classLoaders is a set that refers to a bunch
of URLClassLoader objects
pySys.setClassLoader(((URLClassLoader)
classLoaders.get(jarFile)));

//We also have to pass the jar to JYTHON_PATH
(sys.path)
//so that it can properly import inner python
modules.
pySys.path.insert(0,new PyString(jarFile));

//We pass the PythonInterpreter the modified
PySystemState
PythonInterpreter i = new PythonInterpreter
(null, pySys);
i.exec(pythonScriptName);


Here's my method to create a classLoader that has a jarFile in its
classpath:

/**
* Adds a given Jar to the Classpath.
* Jython uses both classloaders, and it's JYTHONPATH (sys.path)
* The classloaders help it find Java classes, in this case inside
the jar
* that contains the plugin.
*
* @param jarFile
*
* Where jarFile is the path (String) to the jarFile.
*
* I won't delete it though, in case it might be needed to load
resources from
* the jar. However, I believe the adition to the sys.path of jython
will be enough.
*/
public void addJar2Classpath(String jarFile) throws Exception {
if (jarFile == null)
throw new Exception("PluginLoader.addJar2Classpath() - the jar file
path can't be null");

File f = new File(jarFile);

if (!f.exists()) {
LOG.error("Jar doesn't exist ("+jarFile+")");
throw new Exception("PluginLoader.addJar2Classpath() - The jar file
doesn't exist ("+ jarFile +")");
}

URL jarURL = null;

try {
jarURL = new URL("jar:file:"+jarFile+"!/");
//jarURL = f.toURI().toURL();
LOG.info("The jar as an url " + jarURL);
} catch (Exception e) {
LOG.error("Bad URL for jar ("+jarFile+"):\n"+e.toString()
+" ("+jarURL+")\n");
return;
}

if (loadedJar(jarURL)) {
LOG.info("Jar was already loaded ("+jarURL+")");
return;
}

synchronized (classLoaders) {
getLoadedJars().add((URL) jarURL);
}

//Create a new class loader for this jar.
classLoaders.put(jarFile, URLClassLoader.newInstance(new URL[]
{jarURL}));

LOG.info("Jar loaded ("+jarURL+")");
} //addJar2Classpath


So if we had a Jar like this:

M Filemode Length Date Time File
- ---------- -------- ----------- --------
-------------------------------------
drwxrwxrwx 0 3-Dec-2008 12:46:22 meta-inf/
-rw-rw-rw- 71 3-Dec-2008 12:46:22 meta-inf/manifest.mf
drwxrwxrwx 0 3-Dec-2008 12:46:22 twoScriptsTest/com/
-rw-rw-rw- 491 3-Dec-2008 12:46:22 twoScriptsTest/com/
HelloFromJar.class
drwxrwxrwx 0 3-Dec-2008 12:46:18 twoScriptsTest/guba/
-rw-rw-rw- 0 3-Dec-2008 06:24:22 twoScriptsTest/guba/
__init__.py
-rw-rw-rw- 959 3-Dec-2008 12:46:18 twoScriptsTest/guba/
test.py
-rw-rw-rw- 124 2-Dec-2008 17:50:56 twoScriptsTest/guba/
pleaseWork.py
-rw-rw-rw- 0 3-Dec-2008 12:29:56 twoScriptsTest/
__init__.py
- ---------- -------- ----------- --------
-------------------------------------

When we executed:

i.exec("from guba import test")

if test.py had this code, it'd work perfectly:

#Import and use the Java Object inside the jar
from com import HelloFromJar
h = HelloFromJar()
h.sayHello()

#Import the other python module inside the jar
from pleaseWork import echo
echo("FrostWire")


NOTE: It's very important that you have the __init__.py on the folders
otherwise Jython won't find the modules.