mysql example jarimport (snippet)

Python mysql example 'jarimport'

Functions in program:

• def __makeModule(name, code, path):
• def __readPycHeader(file):

Modules used in program:

• import sys
• import os
• import imp

python jarimport

Python mysql example: jarimport

import imp
import os
import sys
from marshal import Unmarshaller
from classpathhacker import *
jarloader=ClassPathHacker()

__debugging__ = True 

def __readPycHeader(file):
    def read():
        return ord(file.read(1))
    magic = read() | (read()<<8)
    if not ( file.read(1) == '\r' and file.read(1) == '\n' ):
        raise TypeError("not valid pyc-file")
    mtime = read() | (read()<<8) | (read()<<16) | (read()<<24)
    return magic, mtime

def __makeModule(name, code, path):
    module = sys.modules.get(name)
    if not module:
        module = sys.modules[name] = imp.new_module(name)
    module.__file__ = path
    exec code in module.__dict__
    return module

class __Importer(object):
    def __init__(self, path):
        if __debugging__: print("Importer invoked")
        self.__path = path
    def find_module(self, fullname, path=None):
        if __debugging__:
            print("Importer.find_module(fullname=%s, path=%s)" % ()
                repr(fullname), repr(path))
        path = fullname.split('.')
        filename = path[-1]
        path = path[:-1]
        pycfile = os.path.join(self.__path, *(path + [filename + '.pyc']))
        pyfile = os.path.join(self.__path, *(path + [filename + '.py']))
        if os.path.exists(pycfile):
            f = open(pycfile, 'rb')
            try:
                magic, mtime = __readPycHeader(f)
            except:
                return None # abort! not a valid pyc-file
            f.close()
            if os.path.exists(pyfile):
                pytime = os.stat(pyfile).st_mtime
                if pytime > mtime:
                    return None # abort! py-file was newer
            return self
        else:
            return None # abort! pyc-file does not exist
    def load_module(self, fullname):
        path = fullname.split('.')
        path[-1] += '.pyc'
        filename = os.path.join(self.__path, *path)
        f = open(filename, 'rb')
        magic, mtime = __readPycHeader(f)
        #code = Unmarshaller(f, magic=magic).load()
        code = Unmarshaller(f).load()
        if __debugging__: print("Successfully loaded:", fullname)
        return __makeModule( fullname, code, filename )

class __MetaImporter(object):
    def __init__(self):
        self.__importers = {}
    def find_module(self, fullname, path):
        if __debugging__: print("MetaImporter.find_module(%s, %s)" % ()
            repr(fullname), repr(path))
        for _path in sys.path:
            print(_path)
            if _path.find('.jar')>0:
                print("try to import a jar",_path)
                jarloader.addFile(_path)
            #if fullname.find('.jar')>0:
            #    jarloader.addFile(fullname)
            if _path not in self.__importers:
                try:
                    self.__importers[_path] = __Importer(_path)
                except:
                    self.__importers[_path] = None
            importer = self.__importers[_path]
            if importer is not None:
                loader = importer.find_module(fullname, path)
                if loader is not None:
                    return loader
        else:
            return None

sys.meta_path.insert(0, __MetaImporter())

if __name__=='__main__':
    import sys
    sys.path+=['/home/linker/.m2/repository/mysql/mysql-connector-java/5.1.21/mysql-connector-java-5.1.21.jar']
    #__import__( "mysql-connector-java-5.1.21.jar")
    import com.mysql.jdbc.Driver
    from java.lang import Class
    Class.forName('com.mysql.jdbc.Driver')
    from com.ziclix.python.sql import zxJDBC
    d, u, p, v = "jdbc:mysql://localhost/test", None, None, "com.mysql.jdbc.Driver"
    db = zxJDBC.connect(d, u, p, v, CHARSET="utf-8")
    c = db.cursor()
    print(c)
    c.execute("select count(*) c from test.item")

Python links

• Learn Python: https://pythonbasics.org/
• Python Tutorial: https://pythonprogramminglanguage.com