How to modify the headers of a response?

[FlysoftBeta]

I need to set "Access-Control-Allow-Origin" for the response, but I can't find add_WebResourceResponseReceived in ICoreWebView2.

[FabianLars]

The WebResourceResponseReceived event can not be used to modify the Responses, only to monitor them. If you want to modify a Response, you need to listen to the WebResourceResourceRequested event, cancel the request, do your own request stuff (via reqwest for example), modify that response and then send it back to the webview. Example from Microsoft docs: https://learn.microsoft.com/en-us/microsoft-edge/webview2/how-to/webresourcerequested?tabs=dotnet#example-overriding-a-response-to-proactively-replace-it

And the upstream feature request: MicrosoftEdge/WebView2Feedback#2355 - Note that this does not exist on the linux and macos webviews either (but worse because you can't modify requests either).

Also in case it may be helpful for other issues, you need to use the .cast method of the windows-rs crate to cast the ICoreWebView2 to ICoreWebView2_2. Something like this

let core_2 = webview // `webview` is the arg you get in tauri's window.with_webview method.
  .controller()
  .CoreWebView2()
  .unwrap()
  .cast::<ICoreWebView2_2>()
  .unwrap();

[FlysoftBeta]

Thanks!

[MirazMac]

Any plans to include it in the Tauri core? It's cumbersome to worry about CORS in a "native" application. And Tauri's http plugin doesn't even work with thousands of existing popular libraries that use XHR or advanced fetch features like streaming.

[FabianLars]

Not at this point in time, maybe once more platforms have similar capabilities.

[107295472]

Thanks!
Why can't I find the cast?

[107295472]

https://github.com/microsoft/windows-rs/blob/master/crates/libs/core/src/interface.rs

[FabianLars]

Hi 👋 You have to make sure to use the correct package versions, otherwise it won't work. As of Tauri 1.5 (and likely all following 1.x releases) this means webview2-com 0.19 and windows-rs 0.39.
Once the versions match the cast example in my code example above should work again.

[107295472]

webview2-com = "0.26.0"
webview2-com-sys = "0.26.0"
windows = "0.51.1"
windows-sys = "0.48.0"

[FabianLars]

Like i said, those versions have to match what Tauri uses, so 0.19 for webview2-com and 0.39 for windows. If you use the versions you just posted it won't work.

[107295472]

Thank you, I can change it to the version number you mentioned.

[cck190891]

Hello, I also have the same problem. Have you solved it?
this is my tauri info

[✔] Environment
    - OS: Windows 10.0.19045 X64
    ✔ WebView2: 122.0.2365.66
    ✔ MSVC: Visual Studio Build Tools 2022
    ✔ rustc: 1.75.0 (82e1608df 2023-12-21)
    ✔ cargo: 1.75.0 (1d8b05cdd 2023-11-20)
    ✔ rustup: 1.26.0 (5af9b9484 2023-04-05)
    ✔ Rust toolchain: stable-x86_64-pc-windows-msvc (default)
    - node: 20.10.0
    - pnpm: 8.15.1
    - npm: 10.2.3

[-] Packages
    - tauri [RUST]: 2.0.0-beta.8
    - tauri-build [RUST]: 2.0.0-beta.6
    - wry [RUST]: 0.37.0
    - tao [RUST]: 0.26.1
    - @tauri-apps/api [NPM]: 2.0.0-beta.3
    - @tauri-apps/cli [NPM]: 2.0.0-beta.6

[-] App
    - build-type: bundle
    - CSP: unset
    - frontendDist: ../dist
    - devUrl: http://localhost:1420/
    - framework: React
    - bundler: Vite

I've already tried this

webview2-com = "0.19.1"
windows = "0.39.0"

and run this code

let core_2 = webview.controller().CoreWebView2().unwrap()
  .cast::<ICoreWebView2_2>()
  .unwrap();

but still get this

cast method not found in `ICoreWebView2`

I think it's a version problem as mentioned above, but I don't know how to find the corresponding version

[cck190891]

I found this at cargo.toml and tried this version but still get the same error

[target."cfg(windows)".dependencies.webview2-com]
version = "0.28"

[target."cfg(windows)".dependencies.windows]
features = ["Win32_Foundation"]
version = "0.52"

[107295472]

Then I don’t know what the problem is, I’m using 1.x

[cck190891]

I've tried with Tauri 1.6.1 and its corresponding version, it works correctly. But I don't know why it's not working with version 2.0. Still, thank you for your assistance.

[FabianLars]

If you add use windows::core::ComInterface; to your rs file it should work. At least it does for me.

For reference in the versions used for v1 it was use windows::core::Interface;

If that still doesn't work, please cd into the src-tauri dir, run cargo run and show us the full error message.

[cck190891]

Wow, it worked.

I used use windows::core::Interface; before, but it always errored and told me I needed to use use windows_core::com_interface::ComInterface;. I put it in, but it still didn't work for me.

Now, using use windows::core::ComInterface;, it works normally.

Thank you for your help!

[MirazMac]

@FlysoftBeta did you find a solution for this? I'm looking for the same thing