Render a file list from the filesystem (#24)

This MR scans the filesystem in the specified directory. It assembles a list of files from the scan and then presents that entire list to the UI. The UI then renders it.

Resolves: https://www.pivotaltracker.com/story/show/184466979
Co-authored-by: Savanni D'Gerinel <savanni@luminescent-dreams.com>
Reviewed-on: savanni/tools#24

flow/src/lib.rs

@@ -17,7 +17,7 @@ You should have received a copy of the GNU General Public License along with Lum
 //! Where the sled.rs library uses `Result<Result<A, Error>, FatalError>`, these are a little hard to
 //! work with. This library works out a set of utility functions that allow us to work with the
 //! nested errors in the same way as a regular Result.
-use std::error::Error;
+use std::{error::Error, fmt};
 
 /// Implement this trait for the application's fatal errors.
 ///
@@ -110,6 +110,37 @@ impl<A, FE, E> From<Result<A, E>> for Flow<A, FE, E> {
     }
 }
 
+impl<A, FE, E> fmt::Debug for Flow<A, FE, E>
+where
+    A: fmt::Debug,
+    FE: fmt::Debug,
+    E: fmt::Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Flow::Ok(val) => f.write_fmt(format_args!("Flow::Ok {:?}", val)),
+            Flow::Err(err) => f.write_fmt(format_args!("Flow::Err {:?}", err)),
+            Flow::Fatal(err) => f.write_fmt(format_args!("Flow::Fatal {:?}", err)),
+        }
+    }
+}
+
+impl<A, FE, E> PartialEq for Flow<A, FE, E>
+where
+    A: PartialEq,
+    FE: PartialEq,
+    E: PartialEq,
+{
+    fn eq(&self, rhs: &Self) -> bool {
+        match (self, rhs) {
+            (Flow::Ok(val), Flow::Ok(rhs)) => val == rhs,
+            (Flow::Err(_), Flow::Err(_)) => true,
+            (Flow::Fatal(_), Flow::Fatal(_)) => true,
+            _ => false,
+        }
+    }
+}
+
 /// Convenience function to create an ok value.
 pub fn ok<A, FE: FatalError, E: Error>(val: A) -> Flow<A, FE, E> {
     Flow::Ok(val)
@@ -177,43 +208,25 @@ mod test {
         }
     }
 
-    impl PartialEq for Flow<i32, FatalError, Error> {
-        fn eq(&self, rhs: &Self) -> bool {
-            match (self, rhs) {
-                (Flow::Ok(val), Flow::Ok(rhs)) => val == rhs,
-                (Flow::Err(_), Flow::Err(_)) => true,
-                (Flow::Fatal(_), Flow::Fatal(_)) => true,
-                _ => false,
-            }
-        }
-    }
-
-    impl std::fmt::Debug for Flow<i32, FatalError, Error> {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                Flow::Ok(val) => f.write_fmt(format_args!("Flow::Ok {}", val)),
-                Flow::Err(err) => f.write_fmt(format_args!("Flow::Err {:?}", err)),
-                Flow::Fatal(err) => f.write_fmt(format_args!("Flow::Fatal {:?}", err)),
-            }
-        }
-    }
-
     #[test]
     fn it_can_map_things() {
-        let success = ok(15);
+        let success: Flow<i32, FatalError, Error> = ok(15);
         assert_eq!(ok(16), success.map(|v| v + 1));
     }
 
     #[test]
     fn it_can_chain_success() {
-        let success = ok(15);
+        let success: Flow<i32, FatalError, Error> = ok(15);
         assert_eq!(ok(16), success.and_then(|v| ok(v + 1)));
     }
 
     #[test]
     fn it_can_handle_an_error() {
-        let failure = error(Error::Error);
+        let failure: Flow<i32, FatalError, Error> = error(Error::Error);
-        assert_eq!(ok(16), failure.or_else(|_| ok(16)));
+        assert_eq!(
+            ok::<i32, FatalError, Error>(16),
+            failure.or_else(|_| ok(16))
+        );
     }
 
     #[test]

music-player/Makefile

@@ -0,0 +1,9 @@
+
+server-dev:
+	cd server && cargo watch -x run
+
+server-test:
+	cd server && cargo watch -x test
+
+client-dev:
+	cd client && npm run watch

music-player/client/index.html

@@ -24,6 +24,7 @@
             <table>
                 <thead>
                     <tr>
+                        <th> id </th>
                         <th> Track # </th>
                         <th> Title </th>
                         <th> Artist </th>
@@ -33,6 +34,7 @@
                 </thead>
 
                 <tbody>
+                    <!--
                     <tr class="track-list__track-row">
                         <td> 1 </td>
                         <td> Underground </td>
@@ -68,12 +70,13 @@
                         <td> Artemis </td>
                         <td> 3:58 </td>
                     </tr>
+                    -->
                 </tbody>
             </table>
         </div>
     </div>
 
-<script src="./dist/main.js" type="module"></script>
+<script src="./bundle.js" type="module"></script>
 
 </body>
 </html>

music-player/client/package.json

@@ -4,7 +4,7 @@
   "description": "",
   "main": "main.js",
   "scripts": {
-    "build": "browserify src/main.ts -p [ tsify ] > dist/bundle.js",
+    "build": "browserify src/main.ts -p [ tsify ] > dist/bundle.js && cp index.html styles.css dist",
     "test": "echo \"Error: no test specified\" && exit 1",
     "watch": "exa index.html styles.css src/* | entr -s 'npm run build'"
   },
@@ -18,7 +18,6 @@
     "@types/lodash": "^4.14.191",
     "babelify": "^10.0.0",
     "browserify": "^17.0.0",
-    "live-server": "^1.2.2",
     "tsify": "^5.0.4",
     "typescript": "^4.9.4",
     "watchify": "^4.0.0"

music-player/client/src/main.ts

@@ -1,5 +1,13 @@
 import * as _ from "lodash";
 
+interface TrackInfo {
+  id: string;
+  track_number?: number;
+  name?: string;
+  album?: string;
+  artist?: string;
+}
+
 const replaceTitle = () => {
   const title = document.querySelector(".js-title");
   if (title && title.innerHTML) {
@@ -7,21 +15,57 @@ const replaceTitle = () => {
   }
 };
 
-/*
+const getTracks = () => fetch("/api/v1/tracks").then((r) => r.json());
-const checkWeatherService = () => {
+
-    fetch("https://api.weather.gov/")
+const formatTrack = (track: TrackInfo) => {
-        .then((r) => r.json())
+  let row = document.createElement("tr");
-        .then((js) => {
+  row.classList.add("track-list__row");
-            const weather = document.querySelector('.js-weather');
+
-            weather.innerHTML = js.status;
+  let track_id = document.createElement("td");
-        });
+  track_id.appendChild(document.createTextNode(track.id));
-}
+  track_id.classList.add("track-list__cell");
-*/
+
+  let track_number = document.createElement("td");
+  track_number.appendChild(
+    document.createTextNode(track.track_number?.toString() || "")
+  );
+  track_number.classList.add("track-list__cell");
+
+  let name = document.createElement("td");
+  name.appendChild(document.createTextNode(track.name || ""));
+  name.classList.add("track-list__cell");
+
+  let album = document.createElement("td");
+  album.appendChild(document.createTextNode(track.album || ""));
+  album.classList.add("track-list__cell");
+
+  let artist = document.createElement("td");
+  artist.appendChild(document.createTextNode(track.artist || ""));
+  artist.classList.add("track-list__cell");
+
+  let length = document.createElement("td");
+  artist.appendChild(document.createTextNode(""));
+  length.classList.add("track-list__cell");
+
+  row.appendChild(track_id);
+  row.appendChild(track_number);
+  row.appendChild(name);
+  row.appendChild(artist);
+  row.appendChild(album);
+  row.appendChild(length);
+  return row;
+};
+
+const updateTrackList = (tracks: TrackInfo[]) => {
+  const track_list = document.querySelector(".track-list__tracks tbody");
+  if (track_list) {
+    let track_formats = _.map(tracks, formatTrack);
+    _.map(track_formats, (trackinfo) => track_list.appendChild(trackinfo));
+  }
+};
 
 const run = () => {
-  replaceTitle();
+  getTracks().then((tracks) => updateTrackList(tracks));
-  console.log(_.map([4, 8], (x) => x * x));
-  // checkWeatherService();
 };
 
 run();

music-player/client/styles.css

@@ -25,15 +25,18 @@ body {
     list-style: none;
 }
 
-.track-list__track-row {
+.track-list__row {
     background-color: rgb(10, 10, 10);
 }
 
-.track-list__track-row:nth-child(even) {
+.track-list__row:nth-child(even) {
     background-color: rgb(255, 255, 255);
 }
 
-.track-list__track-row:nth-child(odd) {
+.track-list__row:nth-child(odd) {
     background-color: rgb(200, 200, 200);
 }
 
+.track-list__cell {
+    padding: 8px;
+}

music-player/client/tsconfig.json

@@ -6,6 +6,7 @@
       "rootDir": "src",
       "outDir": "./dist",
       "lib": ["es2016", "DOM"],
-      "sourceMap": true
+      "sourceMap": true,
+      "strict": true
   }
 }

music-player/server/src/audio.rs

@@ -10,15 +10,8 @@ Luminescent Dreams Tools is distributed in the hope that it will be useful, but
 You should have received a copy of the GNU General Public License along with Lumeto. If not, see <https://www.gnu.org/licenses/>.
 */
 
-use dbus::ffidisp::Connection;
-use mpris::{FindingError, PlaybackStatus, Player, PlayerFinder, ProgressTick};
 use serde::Serialize;
-use std::{
+use std::time::Duration;
-    path::PathBuf,
-    sync::mpsc::{channel, Receiver, Sender, TryRecvError},
-    thread,
-    time::Duration,
-};
 use thiserror::Error;
 
 pub enum Message {
@@ -27,10 +20,10 @@ pub enum Message {
 
 #[derive(Clone, Debug)]
 pub enum Event {
-    Paused(Track, Duration),
+    Paused(TrackId, Duration),
-    Playing(Track, Duration),
+    Playing(TrackId, Duration),
     Stopped,
-    Position(Track, Duration),
+    Position(TrackId, Duration),
 }
 
 #[derive(Debug)]
@@ -39,17 +32,6 @@ pub struct DeviceInformation {
     pub name: String,
 }
 
-pub fn list_devices(conn: Connection) -> Result<Vec<DeviceInformation>, FindingError> {
-    Ok(PlayerFinder::for_connection(conn)
-        .find_all()?
-        .into_iter()
-        .map(|player| DeviceInformation {
-            address: player.unique_name().to_owned(),
-            name: player.identity().to_owned(),
-        })
-        .collect())
-}
-
 #[derive(Debug, Error)]
 pub enum AudioError {
     #[error("DBus device was not found")]
@@ -113,17 +95,8 @@ impl AsRef<String> for TrackId {
     }
 }
 
-#[derive(Clone, Debug)]
-pub struct TrackInfo {
-    pub track_number: Option<i32>,
-    pub name: Option<String>,
-    pub album: Option<String>,
-    pub artist: Option<String>,
-}
-
 #[derive(Clone, Debug, PartialEq, Serialize)]
-#[serde(rename_all = "camelCase")]
+pub struct TrackInfo {
-pub struct Track {
     pub id: TrackId,
     pub track_number: Option<i32>,
     pub name: Option<String>,
@@ -131,38 +104,20 @@ pub struct Track {
     pub artist: Option<String>,
 }
 
-/*
-impl From<&mpris::Metadata> for Track {
-    fn from(data: &mpris::Metadata) -> Self {
-        Self {
-            id: data.track_id().unwrap(),
-            track_number: data.track_number(),
-            name: data.title().map(|s| s.to_owned()),
-            album: data.album_name().map(|s| s.to_owned()),
-            artist: None,
-        }
-    }
-}
-
-impl From<mpris::Metadata> for Track {
-    fn from(data: mpris::Metadata) -> Self {
-        Self::from(&data)
-    }
-}
-*/
-
 #[derive(Clone, Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub enum State {
-    Playing(Track),
+    Playing(TrackInfo),
-    Paused(Track),
+    Paused(TrackInfo),
     Stopped,
 }
 
+/*
 pub struct CurrentlyPlaying {
-    track: Track,
+    track: TrackInfo,
     position: Duration,
 }
+*/
 
 #[derive(Clone, Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -180,6 +135,7 @@ pub trait AudioPlayer {
     fn play_pause(&self) -> Result<State, AudioError>;
 }
 
+/*
 pub struct GStreamerPlayer {
     url: url::Url,
 }
@@ -201,6 +157,7 @@ impl AudioPlayer for GStreamerPlayer {
         unimplemented!()
     }
 }
+*/
 
 /*
 pub struct MprisDevice {

music-player/server/src/bin/server.rs

@@ -1,72 +1,92 @@
 use flow::Flow;
-use std::{io::stdin, path::PathBuf, sync::Arc, thread, time::Duration};
+use std::{
-// use warp::Filter;
+    net::{IpAddr, Ipv4Addr, SocketAddr},
+    path::PathBuf,
+    sync::Arc,
+};
+use warp::Filter;
 
-use music_player::{core::Core, database::MemoryIndex};
+use music_player::{
+    audio::TrackInfo,
+    core::Core,
+    database::{MemoryIndex, MusicIndex},
+    music_scanner::FileScanner,
+};
 
-/*
+fn tracks(index: &Arc<impl MusicIndex>) -> Vec<TrackInfo> {
-fn tracks() -> Vec<Track> {
+    match index.list_tracks() {
-    vec![
+        Flow::Ok(tracks) => tracks,
-        Track {
+        Flow::Err(err) => panic!("error: {}", err),
-            track_number: Some(1),
+        Flow::Fatal(err) => panic!("fatal: {}", err),
-            name: Some("Underground".to_owned()),
+    }
-            album: Some("Artemis".to_owned()),
+}
-            artist: Some("Lindsey Stirling".to_owned()),
+
-            path: PathBuf::from("/mnt/music/Lindsey Stirling/Artemis/01 - Underground.ogg"),
+enum Bundle {
-        },
+    Index,
-        Track {
+    App,
-            track_number: Some(2),
+    Styles,
-            name: Some("Artemis".to_owned()),
+}
-            album: Some("Artemis".to_owned()),
+
-            artist: Some("Lindsey Stirling".to_owned()),
+impl Bundle {
-            path: PathBuf::from("/mnt/music/Lindsey Stirling/Artemis/02 - Artemis.ogg"),
+    fn read(self, root: PathBuf) -> String {
-        },
+        let mut path = root;
-        Track {
+        match self {
-            track_number: Some(3),
+            Bundle::Index => path.push(PathBuf::from("index.html")),
-            name: Some("Til the Light Goes Out".to_owned()),
+            Bundle::App => path.push(PathBuf::from("bundle.js")),
-            album: Some("Artemis".to_owned()),
+            Bundle::Styles => path.push(PathBuf::from("styles.css")),
-            artist: Some("Lindsey Stirling".to_owned()),
+        };
-            path: PathBuf::from(
+        println!("path: {:?}", path);
-                "/mnt/music/Lindsey Stirling/Artemis/03 - Til the Light Goes Out.ogg",
+        std::fs::read_to_string(path).expect("to find the file")
-            ),
+    }
-        },
-        Track {
-            track_number: Some(4),
-            name: Some("Between Twilight".to_owned()),
-            album: Some("Artemis".to_owned()),
-            artist: Some("Lindsey Stirling".to_owned()),
-            path: PathBuf::from("/mnt/music/Lindsey Stirling/Artemis/04 - Between Twilight.ogg"),
-        },
-        Track {
-            track_number: Some(5),
-            name: Some("Foreverglow".to_owned()),
-            album: Some("Artemis".to_owned()),
-            artist: Some("Lindsey Stirling".to_owned()),
-            path: PathBuf::from("/mnt/music/Lindsey Stirling/Artemis/05 - Foreverglow.ogg"),
-        },
-    ]
 }
-*/
 
 #[tokio::main]
 pub async fn main() {
-    match Core::new(Arc::new(MemoryIndex::new())) {
+    let dev = std::env::var("DEV")
-        Flow::Ok(core) => {
+        .ok()
-            let mut buf = String::new();
+        .and_then(|v| v.parse::<bool>().ok())
-            let _ = stdin().read_line(&mut buf).unwrap();
+        .unwrap_or(false);
-            core.exit();
+    let bundle_root = std::env::var("BUNDLE_ROOT")
+        .map(|b| PathBuf::from(b))
+        .unwrap();
+    let music_root = std::env::var("MUSIC_ROOT")
+        .map(|b| PathBuf::from(b))
+        .unwrap();
+
+    let index = Arc::new(MemoryIndex::new());
+    let scanner = FileScanner::new(vec![music_root.clone()]);
+    let _core = match Core::new(index.clone(), scanner) {
+        Flow::Ok(core) => core,
+        Flow::Err(error) => panic!("error: {}", error),
+        Flow::Fatal(error) => panic!("fatal: {}", error),
+    };
+
+    println!("config: {:?} {:?} {:?}", dev, bundle_root, music_root);
+
+    let root = warp::path!().and(warp::get()).map({
+        let bundle_root = bundle_root.clone();
+        move || {
+            warp::http::Response::builder()
+                .header("content-type", "text/html")
+                .body(Bundle::Index.read(bundle_root.clone()))
         }
-        Flow::Err(err) => println!("non-fatal error: {:?}", err),
+    });
-        Flow::Fatal(err) => println!("fatal error: {:?}", err),
+    let app = warp::path!("bundle.js").and(warp::get()).map({
-    }
+        let bundle_root = bundle_root.clone();
-
+        move || {
-    /*
+            warp::http::Response::builder()
-    let connection = Connection::new_session().expect("to connect to dbus");
+                .header("content-type", "text/javascript")
-
+                .body(Bundle::App.read(bundle_root.clone()))
-    for player in list_players(connection) {
+        }
-        println!("player found: {}", player.identity());
+    });
-    }
+    let styles = warp::path!("styles.css").and(warp::get()).map({
-    */
+        let bundle_root = bundle_root.clone();
+        move || {
+            warp::http::Response::builder()
+                .header("content-type", "text/css")
+                .body(Bundle::Styles.read(bundle_root.clone()))
+        }
+    });
 
     /*
     let devices = warp::path!("api" / "v1" / "devices")
@@ -75,10 +95,14 @@ pub async fn main() {
             let conn = Connection::new_session().expect("to connect to dbus");
             warp::reply::json(&list_devices(conn))
         });
+        */
 
-    let track_list = warp::path!("api" / "v1" / "tracks")
+    let track_list = warp::path!("api" / "v1" / "tracks").and(warp::get()).map({
-        .and(warp::get())
+        let index = index.clone();
-        .map(|| warp::reply::json(&tracks()));
+        move || warp::reply::json(&tracks(&index))
+    });
+
+    /*
     let tracks_for_artist = warp::path!("api" / "v1" / "artist" / String)
         .and(warp::get())
         .map(|_artist: String| warp::reply::json(&tracks()));
@@ -103,6 +127,8 @@ pub async fn main() {
         .or(tracks_for_artist)
         .or(queue)
         .or(playing_status);
+        */
+    let routes = root.or(app).or(styles).or(track_list);
     let server = warp::serve(routes);
     server
         .run(SocketAddr::new(
@@ -110,5 +136,4 @@ pub async fn main() {
             8002,
         ))
         .await;
-        */
 }

music-player/server/src/core.rs

@@ -1,10 +1,8 @@
 use crate::{
-    database::{Database, MemoryIndex, MusicIndex},
+    audio::TrackInfo, database::MusicIndex, music_scanner::MusicScanner, Error, FatalError,
-    Error, FatalError,
 };
-use flow::{error, fatal, ok, return_error, return_fatal, Flow};
+use flow::{ok, Flow};
 use std::{
-    path::{Path, PathBuf},
     sync::{
         mpsc::{channel, Receiver, RecvTimeoutError, Sender},
         Arc,
@@ -14,18 +12,8 @@ use std::{
     time::{Duration, Instant},
 };
 
-#[derive(Debug, Error)]
+fn scan_frequency() -> Duration {
-pub enum ScannerError {
+    Duration::from_secs(60)
-    #[error("Cannot scan {0}")]
-    CannotScan(PathBuf),
-    #[error("IO error {0}")]
-    IO(std::io::Error),
-}
-
-impl From<std::io::Error> for ScannerError {
-    fn from(err: std::io::Error) -> Self {
-        Self::IO(err)
-    }
 }
 
 pub enum ControlMsg {
@@ -33,7 +21,8 @@ pub enum ControlMsg {
 }
 
 pub enum TrackMsg {
-    DbUpdate,
+    UpdateInProgress,
+    UpdateComplete,
 }
 
 pub enum PlaybackMsg {
@@ -45,129 +34,68 @@ pub enum PlaybackMsg {
 
 pub struct Core {
     db: Arc<dyn MusicIndex>,
-    track_handle: JoinHandle<()>,
+    _track_handle: JoinHandle<()>,
-    track_rx: Receiver<TrackMsg>,
+    _track_rx: Receiver<TrackMsg>,
-    playback_handle: JoinHandle<()>,
+    _playback_handle: JoinHandle<()>,
-    playback_rx: Receiver<PlaybackMsg>,
+    _playback_rx: Receiver<PlaybackMsg>,
     control_tx: Sender<ControlMsg>,
 }
 
-fn scan_frequency() -> Duration {
-    Duration::from_secs(60)
-}
-
-pub struct FileScanner {
-    db: Arc<dyn MusicIndex>,
-    control_rx: Receiver<ControlMsg>,
-    tracker_tx: Sender<TrackMsg>,
-    next_scan: Instant,
-    music_directories: Vec<PathBuf>,
-}
-
-impl FileScanner {
-    fn new(
-        db: Arc<dyn MusicIndex>,
-        roots: Vec<PathBuf>,
-        control_rx: Receiver<ControlMsg>,
-        tracker_tx: Sender<TrackMsg>,
-    ) -> Self {
-        Self {
-            db,
-            control_rx,
-            tracker_tx,
-            next_scan: Instant::now(),
-            music_directories: roots,
-        }
-    }
-
-    fn scan(&mut self) {
-        loop {
-            match self.control_rx.recv_timeout(Duration::from_millis(100)) {
-                Ok(ControlMsg::Exit) => return,
-                Err(RecvTimeoutError::Timeout) => (),
-                Err(RecvTimeoutError::Disconnected) => return,
-            }
-            if Instant::now() >= self.next_scan {
-                for root in self.music_directories.iter() {
-                    self.scan_dir(vec![root.clone()]);
-                }
-                self.next_scan = Instant::now() + scan_frequency();
-            }
-        }
-    }
-
-    fn scan_dir(&self, mut paths: Vec<PathBuf>) -> Flow<(), FatalError, ScannerError> {
-        while let Some(dir) = paths.pop() {
-            println!("scanning {:?}", dir);
-            return_error!(self.scan_dir_(&mut paths, dir));
-        }
-        ok(())
-    }
-
-    fn scan_dir_(
-        &self,
-        paths: &mut Vec<PathBuf>,
-        dir: PathBuf,
-    ) -> Flow<(), FatalError, ScannerError> {
-        let dir_iter = return_error!(Flow::from(dir.read_dir().map_err(ScannerError::from)));
-        for entry in dir_iter {
-            match entry {
-                Ok(entry) if entry.path().is_dir() => paths.push(entry.path()),
-                Ok(entry) => {
-                    let _ = return_fatal!(self.scan_file(entry.path()).or_else(|err| {
-                        println!("scan_file failed: {:?}", err);
-                        ok::<(), FatalError, ScannerError>(())
-                    }));
-                    ()
-                }
-                Err(err) => {
-                    println!("scan_dir could not read path: ({:?})", err);
-                }
-            }
-        }
-        ok(())
-    }
-
-    fn scan_file(&self, path: PathBuf) -> Flow<(), FatalError, ScannerError> {
-        ok(())
-    }
-}
-
 impl Core {
-    pub fn new(db: Arc<dyn MusicIndex>) -> Flow<Core, FatalError, Error> {
+    pub fn new(
+        db: Arc<dyn MusicIndex>,
+        scanner: impl MusicScanner + 'static,
+    ) -> Flow<Core, FatalError, Error> {
         let (control_tx, control_rx) = channel::<ControlMsg>();
+        let db = db;
 
-        let (track_handle, track_rx) = {
+        let (_track_handle, _track_rx) = {
             let (track_tx, track_rx) = channel();
             let db = db.clone();
             let track_handle = thread::spawn(move || {
-                FileScanner::new(
+                let mut next_scan = Instant::now();
-                    db,
+                loop {
-                    vec![PathBuf::from("/home/savanni/Music/")],
+                    if Instant::now() >= next_scan {
-                    control_rx,
+                        let _ = track_tx.send(TrackMsg::UpdateInProgress);
-                    track_tx,
+                        for track in scanner.scan() {
-                )
+                            match track {
-                .scan();
+                                Ok(track) => db.add_track(track),
+                                Err(_) => ok(()),
+                            };
+                        }
+                        let _ = track_tx.send(TrackMsg::UpdateComplete);
+                        next_scan = Instant::now() + scan_frequency();
+                    }
+                    match control_rx.recv_timeout(Duration::from_millis(1000)) {
+                        Ok(ControlMsg::Exit) => return,
+                        Err(RecvTimeoutError::Timeout) => (),
+                        Err(RecvTimeoutError::Disconnected) => return,
+                    }
+                }
             });
             (track_handle, track_rx)
         };
 
-        let (playback_handle, playback_rx) = {
+        let (_playback_handle, _playback_rx) = {
-            let (playback_tx, playback_rx) = channel();
+            let (_playback_tx, playback_rx) = channel();
             let playback_handle = thread::spawn(move || {});
             (playback_handle, playback_rx)
         };
 
         ok(Core {
             db,
-            track_handle,
+            _track_handle,
-            track_rx,
+            _track_rx,
-            playback_handle,
+            _playback_handle,
-            playback_rx,
+            _playback_rx,
             control_tx,
         })
     }
 
+    pub fn list_tracks<'a>(&'a self) -> Flow<Vec<TrackInfo>, FatalError, Error> {
+        self.db.list_tracks().map_err(Error::DatabaseError)
+    }
+
     pub fn exit(&self) {
         let _ = self.control_tx.send(ControlMsg::Exit);
         /*
@@ -178,4 +106,49 @@ impl Core {
 }
 
 #[cfg(test)]
-mod test {}
+mod test {
+    use super::*;
+    use crate::{audio::TrackId, database::MemoryIndex, music_scanner::factories::MockScanner};
+    use std::collections::HashSet;
+
+    fn with_example_index<F>(f: F)
+    where
+        F: Fn(Core),
+    {
+        let index = MemoryIndex::new();
+        let scanner = MockScanner::new();
+        match Core::new(Arc::new(index), scanner) {
+            Flow::Ok(core) => {
+                thread::sleep(Duration::from_millis(10));
+                f(core)
+            }
+            Flow::Err(error) => panic!("{:?}", error),
+            Flow::Fatal(error) => panic!("{:?}", error),
+        }
+    }
+
+    #[test]
+    fn it_lists_tracks() {
+        with_example_index(|core| match core.list_tracks() {
+            Flow::Ok(tracks) => {
+                let track_ids = tracks
+                    .iter()
+                    .map(|t| t.id.clone())
+                    .collect::<HashSet<TrackId>>();
+                assert_eq!(track_ids.len(), 5);
+                assert_eq!(
+                    track_ids,
+                    HashSet::from([
+                        TrackId::from("/home/savanni/Track 1.mp3".to_owned()),
+                        TrackId::from("/home/savanni/Track 2.mp3".to_owned()),
+                        TrackId::from("/home/savanni/Track 3.mp3".to_owned()),
+                        TrackId::from("/home/savanni/Track 4.mp3".to_owned()),
+                        TrackId::from("/home/savanni/Track 5.mp3".to_owned()),
+                    ])
+                );
+            }
+            Flow::Fatal(err) => panic!("fatal error: {:?}", err),
+            Flow::Err(err) => panic!("error: {:?}", err),
+        })
+    }
+}

music-player/server/src/database.rs

@@ -1,5 +1,5 @@
 use crate::{
-    audio::{Track, TrackId, TrackInfo},
+    audio::{TrackId, TrackInfo},
     FatalError,
 };
 use flow::{error, ok, Flow};
@@ -11,7 +11,7 @@ use std::{
 };
 use thiserror::Error;
 
-#[derive(Debug, Error)]
+#[derive(Debug, Error, PartialEq)]
 pub enum DatabaseError {
     #[error("database is unreadable")]
     DatabaseUnreadable,
@@ -20,13 +20,14 @@ pub enum DatabaseError {
 }
 
 pub trait MusicIndex: Sync + Send {
-    fn add_track(&mut self, track: &TrackInfo) -> Flow<Track, FatalError, DatabaseError>;
+    fn add_track(&self, track: TrackInfo) -> Flow<(), FatalError, DatabaseError>;
-    fn remove_track(&mut self, id: &TrackId) -> Flow<(), FatalError, DatabaseError>;
+    fn remove_track(&self, id: &TrackId) -> Flow<(), FatalError, DatabaseError>;
-    fn get_track_info(&self, id: &TrackId) -> Flow<Option<Track>, FatalError, DatabaseError>;
+    fn get_track_info(&self, id: &TrackId) -> Flow<Option<TrackInfo>, FatalError, DatabaseError>;
+    fn list_tracks<'a>(&'a self) -> Flow<Vec<TrackInfo>, FatalError, DatabaseError>;
 }
 
 pub struct MemoryIndex {
-    tracks: RwLock<HashMap<TrackId, Track>>,
+    tracks: RwLock<HashMap<TrackId, TrackInfo>>,
 }
 
 impl MemoryIndex {
@@ -38,21 +39,13 @@ impl MemoryIndex {
 }
 
 impl MusicIndex for MemoryIndex {
-    fn add_track(&mut self, info: &TrackInfo) -> Flow<Track, FatalError, DatabaseError> {
+    fn add_track(&self, info: TrackInfo) -> Flow<(), FatalError, DatabaseError> {
-        let id = TrackId::default();
-        let track = Track {
-            id: id.clone(),
-            track_number: info.track_number,
-            name: info.name.clone(),
-            album: info.album.clone(),
-            artist: info.artist.clone(),
-        };
         let mut tracks = self.tracks.write().unwrap();
-        tracks.insert(id, track.clone());
+        tracks.insert(info.id.clone(), info);
-        ok(track)
+        ok(())
     }
 
-    fn remove_track(&mut self, id: &TrackId) -> Flow<(), FatalError, DatabaseError> {
+    fn remove_track(&self, id: &TrackId) -> Flow<(), FatalError, DatabaseError> {
         let mut tracks = self.tracks.write().unwrap();
         tracks.remove(&id);
         ok(())
@@ -61,13 +54,23 @@ impl MusicIndex for MemoryIndex {
     fn get_track_info<'a>(
         &'a self,
         id: &TrackId,
-    ) -> Flow<Option<Track>, FatalError, DatabaseError> {
+    ) -> Flow<Option<TrackInfo>, FatalError, DatabaseError> {
         let track = {
             let tracks = self.tracks.read().unwrap();
             tracks.get(&id).cloned()
         };
         ok(track)
     }
+
+    fn list_tracks<'a>(&'a self) -> Flow<Vec<TrackInfo>, FatalError, DatabaseError> {
+        ok(self
+            .tracks
+            .read()
+            .unwrap()
+            .values()
+            .cloned()
+            .collect::<Vec<TrackInfo>>())
+    }
 }
 
 pub struct ManagedConnection<'a> {
@@ -104,3 +107,35 @@ impl Database {
         pool.push(conn);
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    fn with_memory_index<F>(f: F)
+    where
+        F: Fn(&dyn MusicIndex),
+    {
+        let index = MemoryIndex::new();
+        f(&index)
+    }
+
+    #[test]
+    fn it_saves_and_loads_data() {
+        with_memory_index(|index| {
+            let info = TrackInfo {
+                id: TrackId::from("track_1".to_owned()),
+                track_number: None,
+                name: None,
+                album: None,
+                artist: None,
+            };
+            index.add_track(info.clone());
+
+            assert_eq!(
+                Flow::Ok(Some(info)),
+                index.get_track_info(&TrackId::from("track_1".to_owned()))
+            );
+        });
+    }
+}

music-player/server/src/lib.rs

@@ -1,10 +1,11 @@
 pub mod audio;
 pub mod core;
 pub mod database;
+pub mod music_scanner;
 use database::DatabaseError;
 use thiserror::Error;
 
-#[derive(Debug, Error)]
+#[derive(Debug, Error, PartialEq)]
 pub enum Error {
     #[error("Database error: {0}")]
     DatabaseError(DatabaseError),
@@ -16,7 +17,7 @@ impl From<DatabaseError> for Error {
     }
 }
 
-#[derive(Debug, Error)]
+#[derive(Debug, Error, PartialEq)]
 pub enum FatalError {
     #[error("Unexpected error")]
     UnexpectedError,

music-player/server/src/music_scanner.rs

@@ -0,0 +1,179 @@
+use crate::audio::{TrackId, TrackInfo};
+use std::{
+    fs::{DirEntry, ReadDir},
+    path::PathBuf,
+};
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum ScannerError {
+    #[error("Cannot scan {0}")]
+    CannotScan(PathBuf),
+    #[error("Not found {0}")]
+    NotFound(PathBuf),
+    #[error("IO error {0}")]
+    IO(std::io::Error),
+}
+
+impl From<std::io::Error> for ScannerError {
+    fn from(err: std::io::Error) -> Self {
+        Self::IO(err)
+    }
+}
+
+pub trait MusicScanner: Send {
+    fn scan<'a>(&'a self) -> Box<dyn Iterator<Item = Result<TrackInfo, ScannerError>> + 'a>;
+}
+
+pub struct FileScanner {
+    roots: Vec<PathBuf>,
+}
+
+impl FileScanner {
+    pub fn new(roots: Vec<PathBuf>) -> Self {
+        Self { roots }
+    }
+}
+
+pub struct FileIterator {
+    dirs: Vec<PathBuf>,
+    file_iter: Option<ReadDir>,
+}
+
+impl FileIterator {
+    fn scan_file(&self, path: PathBuf) -> Result<TrackInfo, ScannerError> {
+        Ok(TrackInfo {
+            id: TrackId::from(path.to_str().unwrap().to_owned()),
+            album: None,
+            artist: None,
+            name: None,
+            track_number: None,
+        })
+    }
+}
+
+enum EntryInfo {
+    Dir(PathBuf),
+    File(PathBuf),
+}
+
+impl Iterator for FileIterator {
+    type Item = Result<TrackInfo, ScannerError>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        fn process_entry(entry: DirEntry) -> Result<EntryInfo, ScannerError> {
+            entry
+                .metadata()
+                .map_err(ScannerError::from)
+                .map(|metadata| {
+                    if metadata.is_dir() {
+                        EntryInfo::Dir(entry.path())
+                    } else {
+                        EntryInfo::File(entry.path())
+                    }
+                })
+        }
+
+        let next_file = match &mut self.file_iter {
+            Some(iter) => iter.next(),
+            None => None,
+        };
+
+        match next_file {
+            Some(Ok(entry)) => match process_entry(entry) {
+                Ok(EntryInfo::Dir(path)) => {
+                    self.dirs.push(path);
+                    self.next()
+                }
+                Ok(EntryInfo::File(path)) => Some(self.scan_file(path)),
+                Err(err) => Some(Err(err)),
+            },
+            Some(Err(err)) => Some(Err(ScannerError::from(err))),
+            None => match self.dirs.pop() {
+                Some(dir) => match dir.read_dir() {
+                    Ok(entry) => {
+                        self.file_iter = Some(entry);
+                        self.next()
+                    }
+                    Err(err) => {
+                        if err.kind() == std::io::ErrorKind::NotFound {
+                            Some(Err(ScannerError::NotFound(dir)))
+                        } else {
+                            Some(Err(ScannerError::from(err)))
+                        }
+                    }
+                },
+                None => None,
+            },
+        }
+    }
+}
+
+impl MusicScanner for FileScanner {
+    fn scan<'a>(&'a self) -> Box<dyn Iterator<Item = Result<TrackInfo, ScannerError>> + 'a> {
+        Box::new(FileIterator {
+            dirs: self.roots.clone(),
+            file_iter: None,
+        })
+    }
+}
+
+#[cfg(test)]
+pub mod factories {
+    use super::*;
+    use crate::audio::TrackId;
+
+    pub struct MockScanner {
+        data: Vec<TrackInfo>,
+    }
+
+    impl MockScanner {
+        pub fn new() -> Self {
+            Self {
+                data: vec![
+                    TrackInfo {
+                        id: TrackId::from("/home/savanni/Track 1.mp3".to_owned()),
+                        track_number: Some(1),
+                        name: Some("Track 1".to_owned()),
+                        album: Some("Savanni's Demo".to_owned()),
+                        artist: Some("Savanni".to_owned()),
+                    },
+                    TrackInfo {
+                        id: TrackId::from("/home/savanni/Track 2.mp3".to_owned()),
+                        track_number: Some(2),
+                        name: Some("Track 2".to_owned()),
+                        album: Some("Savanni's Demo".to_owned()),
+                        artist: Some("Savanni".to_owned()),
+                    },
+                    TrackInfo {
+                        id: TrackId::from("/home/savanni/Track 3.mp3".to_owned()),
+                        track_number: Some(3),
+                        name: Some("Track 3".to_owned()),
+                        album: Some("Savanni's Demo".to_owned()),
+                        artist: Some("Savanni".to_owned()),
+                    },
+                    TrackInfo {
+                        id: TrackId::from("/home/savanni/Track 4.mp3".to_owned()),
+                        track_number: Some(4),
+                        name: Some("Track 4".to_owned()),
+                        album: Some("Savanni's Demo".to_owned()),
+                        artist: Some("Savanni".to_owned()),
+                    },
+                    TrackInfo {
+                        id: TrackId::from("/home/savanni/Track 5.mp3".to_owned()),
+                        track_number: Some(5),
+                        name: Some("Track 5".to_owned()),
+                        album: Some("Savanni's Demo".to_owned()),
+                        artist: Some("Savanni".to_owned()),
+                    },
+                ],
+            }
+        }
+    }
+
+    impl MusicScanner for MockScanner {
+        fn scan<'a>(&'a self) -> Box<dyn Iterator<Item = Result<TrackInfo, ScannerError>> + 'a> {
+            Box::new(self.data.iter().map(|t| Ok(t.clone())))
+        }
+    }
+}