magicalimport 0.9.2

importing a module by physical file path

magicalimport

magicalimport is a Python library that provides a flexible way to import modules and symbols directly from their physical file paths.

Motivation

In some cases, you might want to import a Python module that is not part of a standard package or is not located in Python's sys.path. For example:

• Loading a plugin from a user-specified path.
• Using a Python script as a configuration file.
• Dynamically loading modules in a script or a tool.

Standard import mechanisms can be cumbersome in these scenarios. magicalimport simplifies this by allowing you to import modules directly using their file paths.

A key feature of this library is its special handling of .py files. The import_module function can distinguish between a regular module path (like my_package.my_module) and a direct file path (like ./path/to/my_module.py), providing a unified interface for both.

Installation

You can install magicalimport using pip:

pip install magicalimport

Basic Usage

Let's say you have the following directory structure:

.
├── my_app
│   └── main.py
└── external_module
    └── helper.py

And helper.py contains:

# external_module/helper.py
def greet(name):
    return f"Hello, {name}!"

From main.py, you can import helper.py like this:

# my_app/main.py
import os
from magicalimport import import_from_physical_path

# Assuming the script is run from the project root
helper_path = os.path.abspath("../external_module/helper.py")
helper = import_from_physical_path(helper_path)

print(helper.greet("world"))
# => Hello, world!

Special Handling of .py Files

The import_module function is a convenient wrapper that combines Python's standard importlib.import_module with import_from_physical_path. It automatically detects whether the provided path is a file path ending in .py or a regular module path.

from magicalimport import import_module

# Imports a regular module
http_client = import_module("http.client")
print(http_client.HTTPConnection)

# Imports a .py file directly
helper = import_module("./external_module/helper.py")
print(helper.greet("again"))

This allows you to use the same function for both types of imports, simplifying your code.

Importing Symbols

You can also import a specific symbol (a class, function, or variable) from a module using import_symbol. The symbol is specified using a string in the format path/to/module.py:symbol_name.

from magicalimport import import_symbol

# Import the 'greet' function directly
greet_func = import_symbol("./external_module/helper.py:greet")

print(greet_func("from symbol"))
# => Hello, from symbol!

# You can also import from standard libraries
HTTPConnection = import_symbol("http.client:HTTPConnection")
print(HTTPConnection)

API Reference

import_from_physical_path(path, as_=None, here=None, cwd=True)

• path (str): The relative or absolute path to the .py file.
• as_ (str, optional): The name for the module in sys.modules. If not provided, a name is generated from the file path.
• here (str, optional): The base directory to resolve relative paths. If None, it's determined from the caller's file (__file__) or the current working directory.
• cwd (bool): If True and here is None, the current working directory is used as the base.

import_module(module_path, here=None, cwd=True)

• module_path (str): A module path (e.g., my_package.my_module) or a file path (e.g., ./my_module.py).
• here, cwd: Same as in import_from_physical_path.

import_symbol(sym, here=None, sep=":")

• sym (str): The string representing the symbol to import, in the format <module_path>:<symbol_name>.
• here: Same as above.
• sep (str): The separator between the module path and the symbol name.

expose_all_members(module)

• Imports all members (that don't start with _) from the given module into the caller's global scope, similar to from module import *.

expose_members(module, members)

• Imports specified members from the given module into the caller's global scope.

License

This project is licensed under the MIT License - see the LICENSE file for details.