Embedding questions

[Fredrik Lundh]

Olaf Appelt <tholap at compuserve.com> wrote:
> Furthermore I want to avoid having module files lying around in directories.
> The code should be compiled, go into database and later be read from db to
> be executed. All that without going files. Just strings moved between Python
> API and DB.
> 
> Is that possible?

Greg Stein's imputil.py [1] allows you to modify the
import statement so it can pick up code from any
data source.

an example (assuming "db" is a database object which
works pretty much like a code string dictionary).

...

class DatabaseImporter(Importer):
    
    def __init__(self, db):
        self.__db = db

    def get_code(self, parent, modname, fqname):
        # is it a module?
        try:
            code = marshal.loads(self.__db[fqname])
            return 0, code
        except KeyError:
            pass
        # is it a package?
        try:
            fqname = fqname + ".__init__"
            code = marshal.loads(self.__db[fqname])
            return 1, code
        except KeyError:
            pass
        return None # not found in this database

# prepends the database to the import chain
DatabaseImporter(mydb).install()

...

to compile python source code into code strings, use:

    string = marshal.dumps(compile(source, filename, "exec"))

...

hope this helps!

</F>

1) http://www.lyra.org/greg/python/imputil.py