The desktop app

CanViewer also runs as a desktop program for Windows, macOS and Linux. It is the same app as the web version, in a window of its own:

• Offline from the start. The app and the Python runtime for non-DBC formats are inside the program. It makes no network requests at all: no telemetry, no update check.
• Every format. DBC with CanViewer's own parser, and ARXML and the other formats through canmatrix, exactly as in the browser.
• Small. The packages are about 11 to 12 MB; the program uses the operating system's own web view (WebView2 on Windows, WebKit on macOS and Linux) instead of bundling a browser.
• Locked down. A strict content security policy allows the window to load only the app's own files. The worker that reads non-DBC formats runs under the same policy, so it cannot reach another host either.

The desktop app is built with Tauri (decision record 0009). CI builds it on all three systems, installs each package the way the install guide says, has the installed app open a DBC and an ARXML file, and uninstalls it again.

The packages

Each release on the repository's GitHub Releases page has:

System	Package	Installs
Windows	CanViewer_<version>_x64-setup.exe	for you alone, in %LOCALAPPDATA%\CanViewer, without administrator rights
Windows	CanViewer_<version>_x64_en-US.msi	for every user of the computer, in C:\Program Files\CanViewer
macOS	CanViewer_<version>_universal.dmg	CanViewer.app, for Apple silicon and Intel
Linux	CanViewer_<version>_amd64.deb	the package can-viewer, with the program /usr/bin/canviewer

Next to them are SHA256SUMS, to check the download, THIRD_PARTY_NOTICES.md, demo.dbc, a sample database to open once the app is installed, and libiconv-1.16.tar.gz and wix3-wix3141rtm.tar.gz, the source code that the licenses of GNU libiconv and the WiX Toolset ask to come with the packages. Every package installs CanViewer's license files (COPYRIGHT, LICENSE and LICENSE-GPL-3.0) and the notices with the app, and its installer shows COPYRIGHT as the license; About CanViewer in the app opens them too. The release notes give each package's size.

The builds are not signed with a paid certificate, so Windows and macOS ask you to confirm the first launch. There is no AppImage: Linux gets the .deb, built and tested on Ubuntu. The install guide walks through checking the download, the first launch, updating and uninstalling on each system.

What is different from the web app

• Exports and files saved as DBC go to your Downloads folder: on Windows the user's Downloads folder, on macOS ~/Downloads, on Linux the XDG Downloads folder named in ~/.config/user-dirs.dirs (or the app's working directory, when that file names none). A name that is taken gets a number rather than overwriting the file.
• The app keeps its data (the last file you opened, the theme, the language) in a folder of its own instead of the browser's storage. Close file in the settings menu forgets the last file; the install guide says where the folder is, and how to remove it.
• No service worker. The web app caches itself for offline use; the desktop app is offline already.
• A self-test. Started with the environment variable CANVIEWER_SMOKE_FILES set to the path of demo.dbc, the app opens the file, prints a report that ends with "passed": true, and quits. The install guide uses it to confirm an install. It starts from a clean profile, so the theme, the language and the last file are reset afterwards.