importpy 0.1.2

Dynamic, lazy-style module importer for Python.

importpy

Dynamic, lazy-style support importer for Python. It lets you import individual .py files directly at the module level, while still replicating standard package semantics (including automatic __init__.py execution) and resolving relative-import issues in nested directories—no changes to sys.path required. Use it to override Python’s built-in import mechanism only when you need that extra flexibility.

Use Relative Path

root package
    │
    ├─── __init__.py
    │
    ├─── packageA/
    │       │
    │       ├─── __init__.py
    │       ├─── moduleA1.py
    │       └─── moduleA2.py
    │       
    ├─── packageB/
    │       │
    │       ├───── packageC/
    │       │         │
    │       │         ├─── __init__.py
    │       │         ├─── moduleC1.py
    │       │         └─── moduleC2.py
    │       │
    │       ├─── __init__.py
    │       ├─── moduleB1.py
    │       └─── moduleB2.py

Now you can import regardless of path.
For example, you can import moduleB1 of packageB from moduleA1 of packageA as follows.

moduleA1.py of packageA
moduleB1 = importpy('../packageB/moduleB1.py')

likewise, can import moduleA2 of packageA from moduleC2 of packageC as follows.
Of course, absolute paths are also possible.

moduleC2.py of packageC
moduleA1 = importpy('../../packageA/moduleA2.py')
or
moduleA1 = importpy('c:/program files/python/project/test/package_root/packageA/moduleA2.py')

moduleC2.py of packageC
member1, member2, classC = importpy('../../packageA/moduleA2.py', 'member1', 'member2', 'classC')

I came up with this approach because I usually put unit tests in '__main__' of each module.
Additionally, modules imported in this way can be executed independently regardless of the package structure. That's it....

Use URL Path

import Remote Package

remote_package = importpy('file://example.com/remote_package')
remote_package = importpy('http://example.com/remote_package')
remote_package = importpy('https://example.com/remote_package')
remote_package = importpy('ftp://user:[e-mail]/remote_package')
import remote_package # You can use it as a general import.
remote_package.__version__

import Remote Module

remote_module = importpy('file://example.com/remote_module.py')
remote_module = importpy('http://example.com/remote_module.py')
remote_module = importpy('https://example.com/remote_module.py')
remote_module = importpy('ftp://user:[e-mail]/remote_module.py')

import Remote wheel/sdist

pip_package = importpy('https://files.pythonhosted.org/packages/29/a2/d40fb2460e883eca5199c62cfc2463fd261f760556ae6290f88488c362c0/pip-25.1.1-py3-none-any.whl')
pip_package = importpy('https://files.pythonhosted.org/packages/59/de/241caa0ca606f2ec5fe0c1f4261b0465df78d786a38da693864a116c37f4/pip-25.1.1.tar.gz')
import pip # You can use it as a general import.
pip.__version__

import github direct

pip_package = importpy('https://github.com/pypa/pip/tree/main/src/pip')
import pip # You can use it as a general import.
pip.__version__

import module/function with arguments

a, b, c = importpy('file://example.com/remote_package', 'a', 'b', 'c') # member module a,b,c
a, b, c = importpy('file://example.com/remote_module.py', 'a', 'b', 'c') # member function a,b,c

import using custom loader

remote_package = importpy('userdefined://abc/efg/package', CustomMetaFinder())
CustomMetaFinder(AbstractMetaFinder) # See protocol.py for the format of AbstractMetaFinder.
  .
  .
  .

History

2025/07/11 v0.1.0 : initial released
2025/07/13 v0.1.1 : some minor bug fix, support pytest
2025/07/17 v0.1.2 : some minor bug fix, support remote url

Installation (pip install)

python -m pip install importpy
or
python -m pip install git+https://github.com/waveware4ai/importpy

Requirements

Python 3.8+
No external dependencies

Features

• Basic Features
  • importing modules using relative paths
  • importing modules using absolute paths
  • importing package using url paths
  • importing modules using url paths
  • importing member functions from modules
  • support lazy-import avoid circular importing
  • support to import functions from module, like from x import y ...
• Import Logic
  • caller location is traced via inspect
  • relative path is resolved automatically
  • module name is derived from the file path (e.g. utils/web.py → utils.web)
  • result is cached in-memory

Examples

Relative Path

from importpy import loader as importpy
# simple relative import
aaaa = importpy('aaaa.py') # same to below
aaaa = importpy('./aaaa.py')

# wildcard import
bbbb = importpy('../util/test/bbbb.py') # same to below
bbbb = importpy('../util/test/bbbb.py', '*') 

# absolute path
cccc = importpy('/home/user/project/cccc.py')
cccc = importpy('C:/program files/python/project/cccc.py') 

# turn on/off lazy-loading
lazy_on = importpy('lazy_on.py', use_lazy = True) # default action
lazyoff = importpy('lazyoff.py', use_lazy = False)

# import specific attributes
a_member_of_x, b_member_of_x = importpy('./pathto/x.py', 'a_member_of_x', 'b_member_of_x') 
module_x, a_member_of_x, b_member_of_x = importpy('./pathto/x.py', '*', 'a_member_of_x', 'b_member_of_x')  # wildcard include module x self

# class import
ClassA, ClassB = importpy('./pathto/impl.py', 'ClassA', 'ClassB')

The following perform the same role:

import aaaa
aaaa = importpy('aaaa.py')

from x import a_member_of_x, b_member_of_x
a_member_of_x, b_member_of_x = importpy('x.py', 'a_member_of_x', 'b_member_of_x') 

from impl import ClassA, ClassB, funcX
ClassA, ClassB, funcX = importpy('impl.py', 'ClassA', 'ClassB', 'funcX')

URL Path

To do this example, you no longer need pip installed locally. Move it somewhere else or delete it.

def import_pip_test(url: str, custom_finder=None, uselazy:bool = True, isolate=True):
    from importpy import loader as importpy
    pip = importpy(url, custom_finder=custom_finder, uselazy=uselazy, isolate=isolate)
    import pip as PIP # must be the same instance.
    assert id(pip) == id(PIP) 

    print(f"---------- pip-{pip.__version__} from [{pip.__file__}].main(['freeze'])")
    pip.main(["freeze"])
    print(f"---------- pip-{pip.__version__} from [{pip.__file__}].main(['list'])")
    pip.main(["list"])

pypi sdist/wheel remote access test

    import_pip_test("https://files.pythonhosted.org/packages/29/a2/d40fb2460e883eca5199c62cfc2463fd261f760556ae6290f88488c362c0/pip-25.1.1-py3-none-any.whl")
    import_pip_test("https://files.pythonhosted.org/packages/59/de/241caa0ca606f2ec5fe0c1f4261b0465df78d786a38da693864a116c37f4/pip-25.1.1.tar.gz")

pypi sdist/wheel local access test using file://

    import_pip_test("file://[TEST_DIR]/pip-25.1.1-py3-none-any.whl")
    import_pip_test("file://[TEST_DIR]/pip-25.1.1.tar.gz")
    import_pip_test("file://[TEST_DIR]/pip-25.1.1-py3-none-any/pip") # extract to dir

pypi sdist/wheel remote access using ftp://

    import_pip_test("ftp://user:pass@localhost/whl/pip-25.1.1-py3-none-any.whl")
    import_pip_test("ftp://user:pass@localhost/whl/pip-25.1.1.tar.gz")
    import_pip_test("ftp://user:pass@localhost/whl/pip") # extract to dir

pypi sdist/wheel remote access using http/https://

    import_pip_test("http://localhost:1080/whl/pip-25.1.1-py3-none-any.whl")
    import_pip_test("http://localhost:1080/whl/pip-25.1.1.tar.gz")
    import_pip_test("http://localhost:1080/whl/pip") # extract to dir
    import_pip_test("https://localhost:10443/whl/pip-25.1.1-py3-none-any.whl")
    import_pip_test("https://localhost:10443/whl/pip-25.1.1.tar.gz")
    import_pip_test("https://localhost:10443/whl/pip") # extract to dir

github direct access using https://

    import_pip_test("http://github.com/pypa/pip/tree/main/src/pip")

Testing

python -m pytest -v ./importpy/tests
collected 30 items
importpy/tests/test_importpy.py::test_importpy_basic_module PASSED                                       [  3%]
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