PyObjC Framework: BackgroundAssets

Warnings

• breaking PyObjC has dropped support for older Python versions in recent releases. Python 3.9 support was dropped in v12.0, and Python 3.8 support was dropped in v11.0.
  Fix: Ensure your project uses Python 3.10 or later for PyObjC v12.x, or Python 3.9 or later for PyObjC v11.x.
• gotcha PyObjC is a macOS-specific library and will not work on other operating systems. Furthermore, `pyobjc-core` is a compiled extension and requires a compatible Python version and macOS architecture (e.g., Apple Silicon vs. Intel).
  Fix: Develop and run PyObjC projects exclusively on macOS. If encountering installation issues, ensure your Python installation matches your macOS architecture and that Xcode command-line tools are installed (`xcode-select --install`).
• breaking PyObjC 11.1 introduced changes to align Automatic Reference Counting (ARC) behavior for initializer methods with Clang's documentation. This can affect how custom Objective-C classes, or classes subclassed in Python, handle object references during initialization.
  Fix: Review initialization logic for any Python-defined Objective-C classes, especially those overriding `init...` methods, to ensure correct reference counting and object lifetime management.
• gotcha The BackgroundAssets framework, like many macOS background services, typically requires specific application entitlements (e.g., `com.apple.developer.background-downloads`) configured in your Xcode project for full functionality. Without these, downloads may not proceed.
  Fix: When developing a macOS application using BackgroundAssets, ensure the necessary entitlements are added to your application's `Info.plist` or Xcode project settings. Simple Python scripts run without an application bundle may have limited functionality.

Install

• pip install pyobjc-framework-backgroundassets Install package

Imports

• BAManager

  from BackgroundAssets import BAManager

• BAURLDownload

  from BackgroundAssets import BAURLDownload

• BAURLDownloadConfiguration

  from BackgroundAssets import BAURLDownloadConfiguration

• NSURL

  import Foundation

Quickstart

This example demonstrates how to create a `BAURLDownloadConfiguration` and a `BAURLDownload` object using the `BackgroundAssets` framework. Note that actually initiating and managing background downloads requires specific macOS application entitlements and a properly configured application delegate, which are outside the scope of a simple Python script.

import Foundation
from BackgroundAssets import BAManager, BAURLDownload, BAURLDownloadConfiguration, BAURLDownloadNetworkActivityCellular

# Get the shared manager instance
manager = BAManager.sharedManager()

# Create a configuration for the download
config = BAURLDownloadConfiguration.new()
config.setIdentifier_("com.example.mybackgrounddownload") # Unique identifier
config.setDiscretionary_(True) # Allow system to decide when to run
config.setRequiresPower_(False) # Does not require external power
config.setRequiresNetworkActivity_(BAURLDownloadNetworkActivityCellular) # Or BAURLDownloadNetworkActivityAny, BAURLDownloadNetworkActivityWiFi

# Create a URL for the download (replace with a real URL for testing)
download_url_str = "https://example.com/some/large/file.zip"
download_url = Foundation.NSURL.URLWithString_(download_url_str)

# Create the download object
# The last argument is an NSError** pointer; use None for Python in non-error cases
download, error = BAURLDownload.downloadWithURL_configuration_error_(download_url, config, None)

if download:
    print(f"Successfully created BAURLDownload: {download.identifier()}")
    print(f"Download URL: {download.URL().absoluteString()}")
    print(f"Configuration identifier: {download.configuration().identifier()}")
    
    # To actually schedule it, you'd add it to the manager. This often requires
    # specific macOS entitlements and an application lifecycle.
    # For a simple runnable snippet, just creating the objects is sufficient.
    # success, error_add = manager.addDownload_error_(download, None)
    # if success: print(f"Added download to manager.")
    # else: print(f"Failed to add download: {error_add}")
else:
    print(f"Failed to create BAURLDownload: {error}")