Initial scaffold: Sinatra map app with Tauri desktop shell

Sinatra backend serving a basic Leaflet map, wrapped in a Tauri
desktop shell that starts the same server in a native window.

.gitignore

@@ -0,0 +1,16 @@
+# Ruby / Bundler
+/.bundle/
+/vendor/bundle/
+*.gem
+/log/
+/tmp/
+
+# Rust / Tauri
+/src-tauri/target/
+
+# Editor / OS
+.DS_Store
+*.swp
+
+# Local tooling settings
+.claude/settings.local.json

.ruby-version

@@ -0,0 +1 @@
+4.0.6

Gemfile

@@ -0,0 +1,9 @@
+source "https://rubygems.org"
+
+gem "sinatra", "~> 4.2"
+gem "sinatra-contrib", "~> 4.2"
+gem "puma", "~> 8.0"
+
+group :development do
+  gem "rerun"
+end

Gemfile.lock

@@ -0,0 +1,104 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    base64 (0.3.0)
+    ffi (1.17.4)
+    ffi (1.17.4-aarch64-linux-gnu)
+    ffi (1.17.4-aarch64-linux-musl)
+    ffi (1.17.4-arm-linux-gnu)
+    ffi (1.17.4-arm-linux-musl)
+    ffi (1.17.4-arm64-darwin)
+    ffi (1.17.4-x86-linux-gnu)
+    ffi (1.17.4-x86-linux-musl)
+    ffi (1.17.4-x86_64-darwin)
+    ffi (1.17.4-x86_64-linux-gnu)
+    ffi (1.17.4-x86_64-linux-musl)
+    listen (3.10.0)
+      logger
+      rb-fsevent (~> 0.10, >= 0.10.3)
+      rb-inotify (~> 0.9, >= 0.9.10)
+    logger (1.7.0)
+    multi_json (1.21.1)
+    mustermann (3.1.1)
+    nio4r (2.7.5)
+    puma (8.0.2)
+      nio4r (~> 2.0)
+    rack (3.2.7)
+    rack-protection (4.2.1)
+      base64 (>= 0.1.0)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.1.2)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0)
+    rb-fsevent (0.11.2)
+    rb-inotify (0.11.1)
+      ffi (~> 1.0)
+    rerun (0.14.0)
+      listen (~> 3.0)
+    sinatra (4.2.1)
+      logger (>= 1.6.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.2.1)
+      rack-session (>= 2.0.0, < 3)
+      tilt (~> 2.0)
+    sinatra-contrib (4.2.1)
+      multi_json (>= 0.0.2)
+      mustermann (~> 3.0)
+      rack-protection (= 4.2.1)
+      sinatra (= 4.2.1)
+      tilt (~> 2.0)
+    tilt (2.9.0)
+
+PLATFORMS
+  aarch64-linux-gnu
+  aarch64-linux-musl
+  arm-linux-gnu
+  arm-linux-musl
+  arm64-darwin
+  ruby
+  x86-linux-gnu
+  x86-linux-musl
+  x86_64-darwin
+  x86_64-linux-gnu
+  x86_64-linux-musl
+
+DEPENDENCIES
+  puma (~> 8.0)
+  rerun
+  sinatra (~> 4.2)
+  sinatra-contrib (~> 4.2)
+
+CHECKSUMS
+  base64 (0.3.0) sha256=27337aeabad6ffae05c265c450490628ef3ebd4b67be58257393227588f5a97b
+  bundler (4.0.18) sha256=02d9a17429de1847b4e0c9f27a9ee4b20c0a74c0a641b4e77195d6019e3618ac
+  ffi (1.17.4) sha256=bcd1642e06f0d16fc9e09ac6d49c3a7298b9789bcb58127302f934e437d60acf
+  ffi (1.17.4-aarch64-linux-gnu) sha256=b208f06f91ffd8f5e1193da3cae3d2ccfc27fc36fba577baf698d26d91c080df
+  ffi (1.17.4-aarch64-linux-musl) sha256=9286b7a615f2676245283aef0a0a3b475ae3aae2bb5448baace630bb77b91f39
+  ffi (1.17.4-arm-linux-gnu) sha256=d6dbddf7cb77bf955411af5f187a65b8cd378cb003c15c05697f5feee1cb1564
+  ffi (1.17.4-arm-linux-musl) sha256=9d4838ded0465bef6e2426935f6bcc93134b6616785a84ffd2a3d82bc3cf6f95
+  ffi (1.17.4-arm64-darwin) sha256=19071aaf1419251b0a46852abf960e77330a3b334d13a4ab51d58b31a937001b
+  ffi (1.17.4-x86-linux-gnu) sha256=38e150df5f4ca555e25beca4090823ae09657bceded154e3c52f8631c1ed72cf
+  ffi (1.17.4-x86-linux-musl) sha256=fbeec0fc7c795bcf86f623bb18d31ea1820f7bd580e1703a3d3740d527437809
+  ffi (1.17.4-x86_64-darwin) sha256=aa70390523cf3235096cf64962b709b4cfbd5c082a2cb2ae714eb0fe2ccda496
+  ffi (1.17.4-x86_64-linux-gnu) sha256=9d3db14c2eae074b382fa9c083fe95aec6e0a1451da249eab096c34002bc752d
+  ffi (1.17.4-x86_64-linux-musl) sha256=3fdf9888483de005f8ef8d1cf2d3b20d86626af206cbf780f6a6a12439a9c49e
+  listen (3.10.0) sha256=c6e182db62143aeccc2e1960033bebe7445309c7272061979bb098d03760c9d2
+  logger (1.7.0) sha256=196edec7cc44b66cfb40f9755ce11b392f21f7967696af15d274dde7edff0203
+  multi_json (1.21.1) sha256=e6126a31808e3b4d19f483c775ceac34df190dffa62adfb63a165ee14ba68080
+  mustermann (3.1.1) sha256=4c6170c7234d5499c345562ba7c7dfe73e1754286dcc1abb053064d66a127198
+  nio4r (2.7.5) sha256=6c90168e48fb5f8e768419c93abb94ba2b892a1d0602cb06eef16d8b7df1dca1
+  puma (8.0.2) sha256=c8ed871dfbbe66448ea9ffd46692342d9804d4071522b52b5331b7b6e7b686fb
+  rack (3.2.7) sha256=93e13e1c24f93556671d85d2d79fa228c3485815c50d7e2f265b5330c6528fb7
+  rack-protection (4.2.1) sha256=cf6e2842df8c55f5e4d1a4be015e603e19e9bc3a7178bae58949ccbb58558bac
+  rack-session (2.1.2) sha256=595434f8c0c3473ae7d7ac56ecda6cc6dfd9d37c0b2b5255330aa1576967ffe8
+  rb-fsevent (0.11.2) sha256=43900b972e7301d6570f64b850a5aa67833ee7d87b458ee92805d56b7318aefe
+  rb-inotify (0.11.1) sha256=a0a700441239b0ff18eb65e3866236cd78613d6b9f78fea1f9ac47a85e47be6e
+  rerun (0.14.0) sha256=996a5af2b2b34dcb30146c6c728addab9113e07c119003370daa9bf27feb88fd
+  sinatra (4.2.1) sha256=b7aeb9b11d046b552972ade834f1f9be98b185fa8444480688e3627625377080
+  sinatra-contrib (4.2.1) sha256=10d091c944d268aa910c618ea40a3c3ebe0533e6e32990d84af92235a3d26b4a
+  tilt (2.9.0) sha256=da5735d0280bba96e9a91041bb14aee435ccad5c17b0fa519249ae543d9aa3a5
+
+BUNDLED WITH
+  4.0.18

README.adoc

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+= MapTool
+:toc:
+:toclevels: 2
+:source-highlighter: rouge
+
+A mapping application backend written in Ruby with Sinatra, optionally
+wrapped as a native desktop app with Tauri.
+
+The project's shape is still open — this is the initial scaffold.
+
+== Status
+
+Early scaffold. The web application serves a basic Leaflet map; the
+desktop shell boots the same server inside a native window.
+
+== Requirements
+
+* Ruby (see `.ruby-version`) and Bundler
+* Rust and the Tauri CLI, only if you want to build the desktop shell
+  (see `docs/development.adoc`)
+
+== Getting started
+
+[source,shell]
+----
+bundle install
+bundle exec puma -C config/puma.rb
+----
+
+Then open http://127.0.0.1:4567 in a browser.
+
+== Documentation
+
+* link:docs/architecture.adoc[Architecture]
+* link:docs/development.adoc[Development guide]

app.rb

@@ -0,0 +1,17 @@
+require "sinatra/base"
+require "sinatra/json"
+
+module Maptool
+  class App < Sinatra::Base
+    set :public_folder, File.join(__dir__, "public")
+    set :views, File.join(__dir__, "views")
+
+    get "/" do
+      erb :index
+    end
+
+    get "/api/health" do
+      json status: "ok"
+    end
+  end
+end

config.ru

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+require_relative "app"
+
+run Maptool::App

config/puma.rb

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+bind "tcp://127.0.0.1:#{ENV.fetch('PORT', 4567)}"
+
+environment ENV.fetch("RACK_ENV", "development")
+
+workers 0
+threads 1, 4

docs/architecture.adoc

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+= Architecture
+:toc:
+:toclevels: 2
+
+== Overview
+
+MapTool is a Sinatra web application. The desktop build does not
+reimplement anything natively — it wraps the same Sinatra app in a
+https://tauri.app[Tauri] window, which is the standard way to ship a
+non-JavaScript backend as a desktop app with Tauri: the Rust shell owns
+the native window and starts the web server as a local process; the
+window then simply loads `http://127.0.0.1:4567` as if it were a
+regular page.
+
+[source]
+----
++----------------------------+
+| Tauri window (WebView)     |
+|  loads http://127.0.0.1:PORT
++--------------+-------------+
+               |
+               v
++----------------------------+
+| Sinatra app (Puma)         |
+|  app.rb / config.ru        |
++----------------------------+
+----
+
+== Directory layout
+
+[cols="1,3"]
+|===
+| Path | Purpose
+
+| `app.rb`, `config.ru`
+| Sinatra application and Rack entry point.
+
+| `config/puma.rb`
+| Puma server configuration (binds to `127.0.0.1` only — the app is
+  local-only, not exposed on the network).
+
+| `public/`, `views/`
+| Frontend assets and Sinatra templates. The map view uses Leaflet.
+
+| `src-tauri/`
+| The Tauri (Rust) desktop shell.
+
+| `docs/`
+| Project documentation, in AsciiDoc.
+|===
+
+== Desktop shell (Tauri)
+
+In *development*, `src-tauri/tauri.conf.json` sets `beforeDevCommand`
+to start Puma, and `devUrl` points the window at it. Running the dev
+build (see `docs/development.adoc`) starts both together.
+
+In a *packaged build* there is no `beforeDevCommand` hook, so
+`src-tauri/src/lib.rs` starts the server itself (`bundle exec puma`)
+next to the bundled resources when the app launches, and stops it when
+the window closes.
+
+=== Known limitation: production packaging
+
+The packaged-build server spawn currently assumes a Ruby + Bundler
+installation already present on the machine running the app. That is
+fine for internal or developer builds, but not for a distributable,
+self-contained desktop app.
+
+Shipping a real self-contained build would mean embedding a Ruby
+runtime as a Tauri https://tauri.app/develop/sidecar/[sidecar] binary
+(for example, produced with https://github.com/tebako/tebako[tebako]),
+instead of relying on the system Ruby. That decision — and the
+resulting sidecar build step — is not implemented yet and should be
+revisited before any real distribution build.
+
+== Networking
+
+The Sinatra server only binds to `127.0.0.1`. It is not meant to be
+reachable from other machines; the Tauri window talks to it over
+loopback only.

docs/development.adoc

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+= Development guide
+:toc:
+:toclevels: 2
+
+== Web app only
+
+[source,shell]
+----
+bundle install
+bundle exec puma -C config/puma.rb
+----
+
+Open http://127.0.0.1:4567. For auto-reload during development, run
+via the `rerun` gem instead:
+
+[source,shell]
+----
+bundle exec rerun -- bundle exec puma -C config/puma.rb
+----
+
+== Desktop shell (Tauri)
+
+=== Prerequisites
+
+* Rust (stable) and the Tauri CLI: `cargo install tauri-cli --version "^2"`
+* Ruby + Bundler, with gems installed (`bundle install` in the project
+  root)
+* Platform build tools required by Tauri itself:
+** *Linux*: WebKitGTK and GTK development packages, e.g. on
+   Debian/Ubuntu:
++
+[source,shell]
+----
+sudo apt install libwebkit2gtk-4.1-dev libjavascriptcoregtk-4.1-dev \
+  libgtk-3-dev libsoup-3.0-dev build-essential
+----
+** *macOS*: Xcode command line tools.
+** *Windows*: the WebView2 runtime (preinstalled on current Windows) and
+   the MSVC build tools.
+
+See the upstream https://tauri.app/start/prerequisites/[Tauri
+prerequisites] page for the current package names on your platform.
+
+=== Running in development
+
+[source,shell]
+----
+cd src-tauri
+cargo tauri dev
+----
+
+This runs `beforeDevCommand` (starts Puma on `127.0.0.1:4567`) and
+opens a native window pointed at it, per `src-tauri/tauri.conf.json`.
+
+=== Building
+
+[source,shell]
+----
+cd src-tauri
+cargo tauri build
+----
+
+Requires `Gemfile.lock` to exist (`bundle install` beforehand), since
+the Ruby app files are embedded into the bundle as resources. See
+`docs/architecture.adoc` for the current limitation around this build
+still depending on a system Ruby installation on the target machine.
+
+=== Regenerating icons
+
+Desktop icons live in `src-tauri/icons/`. To regenerate them from a
+new source image (at least 1024x1024 PNG):
+
+[source,shell]
+----
+cd src-tauri
+cargo tauri icon path/to/source.png
+----

public/css/style.css

@@ -0,0 +1,9 @@
+html, body {
+  height: 100%;
+  margin: 0;
+}
+
+#map {
+  height: 100%;
+  width: 100%;
+}

public/js/map.js

@@ -0,0 +1,6 @@
+const map = L.map("map").setView([48.1486, 17.1077], 13);
+
+L.tileLayer("https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png", {
+  maxZoom: 19,
+  attribution: "© OpenStreetMap contributors",
+}).addTo(map);

src-tauri/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "maptool"
+version = "0.1.0"
+description = "Desktop shell for the MapTool mapping application"
+edition = "2021"
+rust-version = "1.77"
+
+[lib]
+name = "maptool_lib"
+crate-type = ["staticlib", "cdylib", "rlib"]
+
+[build-dependencies]
+tauri-build = { version = "2", features = [] }
+
+[dependencies]
+tauri = { version = "2", features = [] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+
+[[bin]]
+name = "maptool"
+path = "src/main.rs"

src-tauri/build.rs

@@ -0,0 +1,3 @@
+fn main() {
+    tauri_build::build()
+}

src-tauri/src/lib.rs

@@ -0,0 +1,59 @@
+#[cfg(not(debug_assertions))]
+use std::process::{Child, Command};
+#[cfg(not(debug_assertions))]
+use std::sync::Mutex;
+
+#[cfg(not(debug_assertions))]
+use tauri::Manager;
+
+#[cfg(not(debug_assertions))]
+struct ServerProcess(Mutex<Option<Child>>);
+
+pub fn run() {
+    let builder = tauri::Builder::default();
+
+    #[cfg(not(debug_assertions))]
+    let builder = builder.setup(|app| {
+        let child = spawn_server(&app.handle())
+            .expect("failed to start the Sinatra server (is Ruby/Bundler installed?)");
+        app.manage(ServerProcess(Mutex::new(Some(child))));
+        Ok(())
+    });
+
+    let app = builder
+        .build(tauri::generate_context!())
+        .expect("error while building the tauri application");
+
+    app.run(|_app_handle, event| {
+        #[cfg(not(debug_assertions))]
+        if let tauri::RunEvent::ExitRequested { .. } = event {
+            if let Some(state) = _app_handle.try_state::<ServerProcess>() {
+                if let Some(mut child) = state.0.lock().unwrap().take() {
+                    let _ = child.kill();
+                }
+            }
+        }
+    });
+}
+
+// In development, `beforeDevCommand` (see tauri.conf.json) already starts the
+// Sinatra server, so the window just points at it. In a packaged build there
+// is no such hook, so the shell starts the server itself, next to the bundled
+// resources, and stops it again when the window closes.
+//
+// NOTE: this assumes a Ruby + Bundler installation on the target machine.
+// Producing a fully self-contained bundle (no external Ruby dependency)
+// requires embedding a Ruby runtime as a sidecar (e.g. via tebako) — see
+// docs/architecture.adoc for the open follow-up.
+#[cfg(not(debug_assertions))]
+fn spawn_server(app: &tauri::AppHandle) -> std::io::Result<Child> {
+    let resource_dir = app
+        .path()
+        .resource_dir()
+        .expect("failed to resolve the resource directory");
+
+    Command::new("bundle")
+        .args(["exec", "puma", "-C", "config/puma.rb"])
+        .current_dir(resource_dir)
+        .spawn()
+}

src-tauri/src/main.rs

@@ -0,0 +1,6 @@
+// Prevents an additional console window on Windows in release builds.
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
+fn main() {
+    maptool_lib::run();
+}

src-tauri/tauri.conf.json

@@ -0,0 +1,45 @@
+{
+  "$schema": "https://schema.tauri.app/config/2",
+  "productName": "MapTool",
+  "version": "0.1.0",
+  "identifier": "net.priesol.maptool",
+  "build": {
+    "beforeDevCommand": "bundle exec puma -C ../config/puma.rb",
+    "devUrl": "http://127.0.0.1:4567",
+    "frontendDist": "http://127.0.0.1:4567"
+  },
+  "app": {
+    "windows": [
+      {
+        "title": "MapTool",
+        "width": 1200,
+        "height": 800,
+        "minWidth": 800,
+        "minHeight": 600
+      }
+    ],
+    "security": {
+      "csp": null
+    }
+  },
+  "bundle": {
+    "active": true,
+    "targets": "all",
+    "icon": [
+      "icons/32x32.png",
+      "icons/128x128.png",
+      "icons/128x128@2x.png",
+      "icons/icon.icns",
+      "icons/icon.ico"
+    ],
+    "resources": {
+      "../Gemfile": "Gemfile",
+      "../Gemfile.lock": "Gemfile.lock",
+      "../app.rb": "app.rb",
+      "../config.ru": "config.ru",
+      "../config/*": "config/",
+      "../public/*": "public/",
+      "../views/*": "views/"
+    }
+  }
+}

views/index.erb

@@ -0,0 +1 @@
+<div id="map"></div>

views/layout.erb

@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>MapTool</title>
+  <link rel="stylesheet" href="https://unpkg.com/leaflet@1.9.4/dist/leaflet.css">
+  <link rel="stylesheet" href="/css/style.css">
+</head>
+<body>
+  <%= yield %>
+  <script src="https://unpkg.com/leaflet@1.9.4/dist/leaflet.js"></script>
+  <script src="/js/map.js"></script>
+</body>
+</html>