Accessing Briefcase packaging metadata at runtime¶
When Briefcase installs your app, it adds a PEP566 metadata file containing information
about your app, and Briefcase itself. You can retrieve this information at
runtime using the Python builtin library ‘importlib.metadata’.
importlib.metadata
was added in Python 3.8; however, it has been backported
and published on PyPI as ‘importlib_metadata’ for older versions of Python.
To access application metadata at runtime, you can use the following code:
import sys
try:
from importlib import metadata as importlib_metadata
except ImportError:
# Backwards compatibility - importlib.metadata was added in Python 3.8
import importlib_metadata
# Find the name of the module that was used to start the app
app_module = sys.modules['__main__'].__package__
# Retrieve the app's metadata
metadata = importlib_metadata.metadata(app_module)
The metadata
returned by this code will be a dictionary-like object that
contains the following identifying keys:
Metadata-Version - The syntax version of the metadata file itself (as defined in PEP566).
Briefcase-Version - The version of Briefcase used to package the app. The existence of this key in app metadata can be used to identify if your application code is running in a Briefcase container; it will only exist if the app has been packaged by Briefcase.
It will also have the following keys, derived from your application’s
pyproject.toml
configuration:
Name -
app_name
Formal-Name -
formal_name
App-ID -
bundle
andapp_name
, joined with a.
Version -
version
Summary -
description
The metadata may also contain the following keys, if they have been defined
in your app’s pyproject.toml
configuration:
Home-page -
url
Author -
author
Author-email -
author_email
For example, the metadata for the app constructed by the BeeWare Tutorial would contain:
Metadata-Version: 2.1
Briefcase-Version: 0.3.1
Name: helloworld
Formal-Name: Hello World
App-ID: com.example.helloworld
Version: 0.0.1
Home-page: https://example.com/helloworld
Author: Jane Developer
Author-email: jane@example.com
Summary: My first application