SideCar/

Spawn.rs

// DEPENDENCY: This module file was created to resolve a missing module error.
// The original Spawn.rs was located at Source/Source/SideCar/Spawn.rs in an
// unusual directory structure. Consider refactoring the directory structure to
// avoid duplicate/confusing module locations.

use std::fs;

use tauri::{AppHandle, Manager};
// Note: Mist crate has lib name "Mist", so we use that for imports
use Mist::dns_port;
// DEPENDENCY: Add tauri-plugin-shell to Cargo.toml dependencies for Tauri 2.x shell support
use tauri_plugin_shell::ShellExt;

const DNS_OVERRIDE:&str = include_str!("../Resource/dns-override.js");

/// Spawns a Node.js sidecar with DNS override configured to use the local
/// Hickory DNS server.
///
/// This function:
/// 1. Creates the app data directory if it doesn't exist
/// 2. Writes the DNS override JavaScript file to the app data directory
/// 3. Configures the sidecar process with NODE_OPTIONS to require the DNS
///    override script
/// 4. Sets the Resolve environment variable with the local DNS server address
/// 5. Spawns the sidecar process
///
/// # Parameters
///
/// * `app` - The Tauri app handle, used to access the app data directory and
///   shell
/// * `sidecar_name` - The name of the sidecar executable to spawn
///
/// # Returns
///
/// Returns `Ok(())` if the sidecar was spawned successfully, or an error if:
/// - The app data directory couldn't be created or accessed
/// - The DNS override file couldn't be written
/// - The sidecar couldn't be found or spawned
///
/// # Example
///
/// ```rust,no_run
/// use tauri::Manager;
/// use SideCar::Spawn::spawn_node_sidecar;
///
/// #[tauri::command]
/// fn launch_sidecar(app:tauri::AppHandle) -> Result<(), String> {
/// 	spawn_node_sidecar(&app, "my-sidecar").map_err(|e| e.to_string())?;
/// 	Ok(())
/// }
/// ```
pub fn spawn_node_sidecar(app:&AppHandle, sidecar_name:&str) -> anyhow::Result<()> {
	// Ensure app data directory exists
	let data_dir = app.path().app_data_dir()?;

	fs::create_dir_all(&data_dir)?;

	// Write DNS override script to app data directory
	let override_path = data_dir.join("dns-override.js");

	fs::write(&override_path, DNS_OVERRIDE)?;

	// Get the DNS server port from Mist module
	let port = dns_port();

	let node_opts = format!("--require {}", override_path.display());

	// Spawn the sidecar with DNS configuration
	app.shell()
		.sidecar(sidecar_name)?
		.env("NODE_OPTIONS", &node_opts)
		.env("Resolve", format!("127.0.0.1:{port}"))
		.spawn()?;

	Ok(())
}