Onova

⚠️ Project status: maintenance mode (bug fixes only).

Onova is a lightweight auto-update framework for desktop applications. It was primarily designed for updating portable applications that are distributed using archive files, but can be extended for other use cases. Downloaded updates are installed using an embedded external executable, by overwriting files when the application exits. The library requires minimal configuration, doesn't impose any changes to the CI/CD process, and doesn't affect the application's life cycle.

Download

• NuGet: dotnet add package Onova

Features

• Requires minimal configuration
• Supports the following package resolvers:
  • LocalPackageResolver - file system
  • GithubPackageResolver - GitHub releases
  • WebPackageResolver - web version manifest
  • NugetPackageResolver - NuGet feed
  • AggregatePackageResolver - aggregates multiple resolvers
• Supports the following package extractors:
  • ZipPackageExtractor - zip archives
  • NugetPackageExtractor - NuGet packages
• Extendable with custom resolvers and extractors
• Can report progress and supports cancellation
• Allows updating to any available version, not necessarily latest
• Overwrites files in-place using an external executable
• Works with multiple running instances of an application
• Automatically prompts for elevated privileges if necessary
• Fully self-contained and doesn't require additional files
• Supports desktop apps built with .NET Core 3.0+
• Targets .NET Framework 4.6.1+ and .NET Standard 2.0+ (Windows only)
• No external dependencies

Workflow

Package resolving

Packages and their versions are resolved using an implementation of IPackageResolver. Currently there are 5 built-in implementations:

LocalPackageResolver

This implementation looks for files in the specified directory using a predefined pattern. Package versions are extracted from file names, e.g. file named MyProject-v2.1.5.zip corresponds to package version 2.1.5.

GithubPackageResolver

This implementation looks for assets in releases of specified GitHub repository using a predefined pattern. Package versions are extracted from release names, e.g. release named v1.0 corresponds to package version 1.0.

Since .NET assemblies do not support semantic versions, pre-releases are ignored.

WebPackageResolver

This implementation requests a version manifest using the specified URL. The server is expected to respond with a plain-text list of package versions and their URLs, separated by space, one line per package. E.g.:

1.0 https://my.server.com/1.0.zip
2.0 https://my.server.com/2.0.zip

NugetPackageResolver

This implementation resolves packages from the specified NuGet feed.

Since .NET assemblies do not support semantic versions, pre-releases are ignored.

AggregatePackageResolver

This implementation provides aggregation over multiple other IPackageResolver instances. It allows resolving and downloading packages from more than one source.

Package extraction

Downloaded packages are extracted using an implementation of IPackageExtractor. Currently there are 2 built-in implementations:

ZipPackageExtractor

This implementation extracts files from zip-archived packages.

NugetPackageExtractor

This implementation extracts files from NuGet packages, from the specified root directory.

Usage

Basic usage example

The following code checks for updates and installs them if they are available, in a single operation.

// Configure to look for packages in specified directory and treat them as zips
using (var manager = new UpdateManager(
    new LocalPackageResolver("c:\\test\\packages", "*.zip"),
    new ZipPackageExtractor()))
{
    // Check for new version and, if available, perform full update and restart
    await manager.CheckPerformUpdateAsync();
}

Handling intermediate steps manually

To provide users with the most optimal experience, you will probably want to handle intermediate steps manually.

// Check for updates
var result = await manager.CheckForUpdatesAsync();
if (result.CanUpdate)
{
    // Prepare an update by downloading and extracting the package
    // (supports progress reporting and cancellation)
    await manager.PrepareUpdateAsync(result.LastVersion);

    // Launch an executable that will apply the update
    // (can be instructed to restart the application afterwards)
    manager.LaunchUpdater(result.LastVersion);

    // Terminate the running application so that the updater can overwrite files
    Environment.Exit(0);
}

Handling updates with multiple running instances of the application

To prevent conflicts when running multiple instances of the same application, only one instance of UpdateManager (across all processes) is able to prepare updates and launch the updater.

In order to correctly handle cases where multiple instances of the application may try to update at the same time, you need to catch these exceptions:

• LockFileNotAcquiredException - thrown by PrepareUpdateAsync and LaunchUpdater when this instance of UpdateManager cannot acquire a lock file. This means that another instance currently owns the lock file and is probably performing an update.
• UpdaterAlreadyLaunchedException - thrown by PrepareUpdateAsync and LaunchUpdater when an updater executable has already been launched, either by this instance of UpdateManager or another instance that has released the lock file.

The updater will wait until all instances of the application have exited before applying an update, regardless of which instance launched it.

Etymology

The name "Onova" comes from Ukrainian word for "update" (noun).