tauri-runtime-wry

Active contributors: Lucas Fernandes Nogueira, Amr Bashir, Tony

Purpose

crates/tauri-runtime-wry is the default implementation of the tauri-runtime trait set. It wires Tauri to:

• TAO for native windows (via tauri-apps/tao, a fork of winit extended with menu and tray support).
• WRY for webviews (via tauri-apps/wry, which targets WKWebView on macOS/iOS, WebView2 on Windows, WebKitGTK on Linux, and the Android System WebView).

This is the largest single source file in the repository — crates/tauri-runtime-wry/src/lib.rs is 5,383 lines. Most of that is the cross-platform implementation of WindowDispatch/WebviewDispatch and the translation of TAO/WRY events into the backend-agnostic tauri-runtime event types.

Directory layout

crates/tauri-runtime-wry/
├── Cargo.toml          # Re-exports tao + wry; many target_os= deps for GTK / objc2 / windows
├── src/
│   ├── lib.rs          # 5,383 lines: Wry runtime, event loop, dispatchers, message routing
│   ├── undecorated_resizing.rs  # Manual hit-testing for borderless windows
│   ├── util.rs
│   ├── webview.rs
│   ├── dialog/         # Native dialog wrappers
│   ├── monitor/
│   └── window/
└── build.rs

Key abstractions

Type	File	Role
Wry<T>	crates/tauri-runtime-wry/src/lib.rs	The Runtime impl; wraps a TAO EventLoop.
WryHandle<T>	crates/tauri-runtime-wry/src/lib.rs	The RuntimeHandle impl; Send/Sync proxy that posts user events to the loop.
WryWindowDispatcher / WryWebviewDispatcher	crates/tauri-runtime-wry/src/lib.rs	The WindowDispatch / WebviewDispatch impls; send messages to the event loop.
Message<T> / WindowMessage / WebviewMessage / EventLoopWindowTarget	crates/tauri-runtime-wry/src/lib.rs	Internal command enum routed through the event loop.
WindowWrapper, WebContextStore	crates/tauri-runtime-wry/src/lib.rs	Internal bookkeeping: mapping from WindowId/WebviewId to live native objects.
undecorated_resizing::*	crates/tauri-runtime-wry/src/undecorated_resizing.rs	Hit-testing for decorations: false windows so users can still resize from edges.

How it works

The runtime implements TAO's EventLoop::run callback. Every iteration:

1. TAO produces a raw event (WindowEvent, UserEvent, RedrawRequested, Resumed, Suspended, …).
2. The runtime translates it into either:
   • A tauri_runtime::WindowEvent/WebviewEvent and forwards it to the registered Tauri callbacks, or
   • An internal Message<T> it produced itself (e.g. "create new window", "set title") that needs to mutate native state.
3. WRY-side events (page-load, navigation, IPC postMessage) are bridged in via the WRY callbacks set during webview construction.

graph TD
    TAO["TAO EventLoop"] --> RouteEvent["match raw event"]
    RouteEvent -->|window/UI event| Translate["translate to runtime::WindowEvent"]
    Translate --> Core["tauri core callback"]
    RouteEvent -->|user message| Apply["apply WindowMessage / WebviewMessage"]
    Apply --> Native["TAO Window / WRY Webview"]
    WRYIPC["WRY IPC handler"] --> CoreIPC["tauri core IPC entry"]

Custom URI scheme handlers (tauri://, asset://, isolation://) are registered on the WRY WebViewBuilder. The runtime exposes register_uri_scheme_protocol on WindowDispatch so the core crate can install handlers per-webview.

Cargo features

The crate forwards a number of features through to WRY/TAO:

• unstable — turns on WRY's unstable APIs (e.g. multi-webview-per-window).
• x11, dbus, linux-libxdo — Linux subsystems.
• macos-private-api, macos-proxy — macOS-only knobs.
• tracing, devtools, common-controls-v6 — narrower.

Integration points

• Up: consumed by crates/tauri when the wry Cargo feature is enabled (the default). The core crate aliases Wry = tauri_runtime_wry::Wry<EventLoopMessage>.
• Down: depends on tauri-runtime (trait), wry (tauri-apps/wry), tao (tauri-apps/tao) plus a long list of platform deps (gtk, webkit2gtk, objc2, windows, webview2-com, muda, tray-icon).

Entry points for modification

Goal	Start here
Translate a new TAO/WRY event type	crates/tauri-runtime-wry/src/lib.rs (search WindowEvent:: arms)
Implement a new WindowDispatch/WebviewDispatch method	Same file (search match webview_message { / match window_message {)
Tweak hit-testing for borderless windows	crates/tauri-runtime-wry/src/undecorated_resizing.rs
Adjust dialog rendering	crates/tauri-runtime-wry/src/dialog/
Add platform-specific window-creation behaviour	The platform-gated blocks inside Wry::create_window in lib.rs

See tauri-runtime for the trait, tauri for the consumer, and systems/ipc-and-commands for how IPC traverses this layer.