Support using bundled WebView2 Runtime without requiring Edge WebView2 installation

[xmha97]

I would like to use OmniGet on Windows without requiring users to install Microsoft Edge WebView2 Runtime separately.

WebView2 supports a Fixed Version Runtime mode, where the WebView2 runtime files can be bundled with the application and loaded locally instead of relying on the system-installed runtime.

I tried placing the WebView2 Fixed Runtime folder next to the OmniGet executable, but the application does not detect or use it and still requires Edge WebView2 to be installed.

Could you please add support for detecting and using a bundled WebView2 Runtime located alongside the application executable?

[tonhowtf]

@xmha97 Implemented — PR #221.

Your diagnosis was right: nothing in the app looked for a runtime next to the executable, so the folder you placed there was simply ignored.

Why it works, and why I checked before promising it. A closely related attempt in this codebase failed for a non-obvious reason — we set WEBVIEW2_USER_DATA_FOLDER for portable mode and it turned out to be dead code, because Tauri resolves the data directory itself before that variable is ever read. So I went to the Tauri source rather than assume this one behaves differently (tauri-2.10.2/src/app.rs:2176):

if let WebviewInstallMode::FixedRuntime { path } = &manager.config.bundle.windows.webview_install_mode {
    std::env::set_var("WEBVIEW2_BROWSER_EXECUTABLE_FOLDER", exe_dir.join(path));
}

Tauri only ever sets this variable, in fixedRuntime bundle mode, and never clears it. So setting it at startup is respected — the opposite of the user-data case.

How to use it. Put the unpacked runtime next to omniget.exe. Either name works:

omniget.exe
Microsoft.WebView2.FixedVersionRuntime.120.0.2210.91.x64/   ← what the Microsoft installer produces
WebView2Runtime/                                            ← short alias, if you prefer

Two deliberate details:

• The folder is only accepted if it actually contains msedgewebview2.exe. Trusting the name alone would let a wrong folder through and the failure would surface later, at window creation — the app would not open at all, which is worse than falling back to the system runtime.
• If you leave several versions side by side, the highest version wins.
• If you already set WEBVIEW2_BROWSER_EXECUTABLE_FOLDER yourself, the app does not touch it.

This also composes with portable mode (#195): a USB stick with the runtime beside the exe runs on a Windows machine with no WebView2 installed and writes nothing to the user profile.

One thing I want to be straight about: I develop on macOS. The discovery logic is pure and covered by six tests that run on any platform, but the line that actually sets the environment variable is behind #[cfg(windows)] and has never executed on a real Windows machine. I'm not going to claim it's confirmed working until someone has seen it. If you're able to test a build once this ships, that would genuinely help — and if it doesn't work, please reopen with what you see.

[xmha97]

Thank you for your explanations and efforts.
It would be great if you could provide a nightly release so that I can test it.

[tonhowtf]

@xmha97 No nightly needed anymore — this shipped in v0.8.0, and the current release is v0.8.3. Grab the installer or portable build from there.

To test: put the unpacked runtime folder next to omniget.exe (either the Microsoft.WebView2.FixedVersionRuntime.<version>.x64 folder the Microsoft installer produces, or a folder named WebView2Runtime), ideally on a machine — or in a state — where the system WebView2 is not installed, and launch. If the window opens, the bundled runtime was picked up; the folder is only accepted if it actually contains msedgewebview2.exe.

As I said when implementing it, that code path has never executed on a real Windows machine — I develop on macOS — so your test is the real one. If it doesn't work, please reopen with what you see.

[xmha97]

Thank you for your guidance and testing instructions. I am pleased to confirm that I tested the build as requested, and everything is working successfully.
You can close this issue.