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Architecture

Source: vignettes/architecture.Rmd
architecture.Rmd
# Verify RDesk is installed correctly
packageVersion("RDesk")
#> [1] '1.0.4'
# Check that the example app is bundled (if existing)
app_path <- system.file("templates/hello", package = "RDesk")
if (nzchar(app_path)) {
  file.exists(app_path)
  list.files(app_path)
}
#> [1] "www"

RDesk is built on a “Source-to-Binary” philosophy that combines the flexibility of R with the security and performance of native Windows APIs.

The Three Components

1. The Native Launcher (launcher.cpp)

A lightweight (66.5kb) C++ application that: - Initializes the WebView2 runtime. - Establishes a Zero-Port IPC bridge using standard input/output (stdin/stdout). - Manages the parent window, native menus, and system tray. - Includes an Anti-Zombie Watchdog that ensures R processes are cleaned up when the UI closes.

2. The R Backend (App.R)

An R6-based event loop that: - Runs a non-blocking service loop to process desktop messages. - Manages the Async Engine for background task execution. - Handles high-level desktop operations (File Dialogs, Clipboard, Notifications).

3. The Web Frontend (www/)

A standard HTML/JS/CSS surface that: - Communicates with R via the global window.rdesk object. - Pushes events to R using rdesk.send(type, payload). - Listens for R updates using rdesk.on(type, callback).

Zero-Port Design

Unlike traditional R web frameworks, RDesk does not open any network ports (httpuv, WebSockets).

  1. Security: No firewall prompts or local network exposure.
  2. Reliability: No “port in use” errors during multi-instance launches.
  3. Performance: Native pipe communication is faster and more reliable than the loopback network stack.

Process Lifecycle

When you run app$run(): 1. R spawns the native launcher as a child process. 2. The launcher opens the Windows window and starts the Chromium-based WebView2. 3. R enters a while(private$.running) loop, servicing the stdin/stdout pipes. 4. When the user closes the window, the launcher signals R to exit, ensuring a clean shutdown of all background worker nodes.