[bug] Tauri API not injected into local web server

[cup-dev]

Describe the bug

My app requires spawning a local web server at http://localhost:8080 to function (both for development and production).

Despite setting http://localhost:8080 as the distDir, devPath, and main window URL, the tauri context is not injected when the window is open (i.e. window.__TAURI__ is undefined).

Reproduction

See minimal repro and steps here: https://github.com/cup-dev/tauri-webserver-issue

Expected behavior

I would expect an ability to spawn a local web server as part of my Tauri app and have the Tauri context available within.

Platform and versions

Environment
  › OS: Mac OS 12.4.0 X64
  › Node.js: 16.15.0
  › npm: 8.5.5
  › pnpm: Not installed!
  › yarn: Not installed!
  › rustup: 1.24.3
  › rustc: 1.59.0
  › cargo: 1.59.0
  › Rust toolchain: stable-aarch64-apple-darwin

Packages
  › @tauri-apps/cli [NPM]: 1.0.0
  › @tauri-apps/api [NPM]: 1.0.1
  › tauri [RUST]: 1.0.0,
  › tauri-build [RUST]: 1.0.0,
  › tao [RUST]: 0.11.2,
  › wry [RUST]: 0.18.3,

App
  › build-type: bundle
  › CSP: unset
  › distDir: http://localhost:8080/
  › devPath: http://localhost:8080/

App directory structure
  ├─ dist
  ├─ node_modules
  ├─ src-tauri
  ├─ site
  └─ .git

Stack trace

No response

Additional context

No response

[JonasKruckenberg]

Tauri cannot really do this, we can't inject APIs into apps we don't control/own (doing so would require us to inject code into safari, chrome, firefox etc.).
The Tauri APIs are only available in windows created by Tauri. This is both a feature and fact of life.

(Setting the distDir option to anything else than a local path will not work either)

We do offer a workaround for this though: https://github.com/tauri-apps/tauri-invoke-http
It spawns a localhost server from Rust that can interface with the command system. You can then use fetch to issue commands.
That said it's not very polished or documented yet.