Send notifications with Matrix

I don't pay enough attention to e-mail notifications any more, since I
no longer get alerts for them on my phone.  I do get Matrix
notifications, though, through Element, and that seems to work well as a
reminder for me.

Matrix is of course a lot more complex than e-mail.  It is a stateful
protocol that requires (at least) keeping authentication and/or session
information on the client.  Technically, clients all have a "device ID,"
which they should use any time they communicate with the server.  I
decided it makes the most sense to keep this value in the same cache
file as the filesystem UUIDs and timestamps.  I prefer reading usernames
and passwords from a configuration file over passing them as
command-line arguments, so I added that ability as well.

Cargo.toml

@@ -15,6 +15,15 @@ serde_json = "1.0"
 version = "0.4"
 features = ["serde"]
 
+[dependencies.matrix-sdk]
+version = "^0.3.0"
+default-features = false
+features = ["markdown", "native-tls"]
+
 [dependencies.serde]
 version = "1.0"
 features = ["derive"]
+
+[dependencies.tokio]
+version = "^1.10.0"
+features = ["rt", "macros"]

src/cache.rs

@@ -1,12 +1,14 @@
-use chrono::Duration;
 use chrono;
+use chrono::Duration;
 use serde::{Deserialize, Serialize};
 use serde_json;
 use std::collections::HashMap;
+use std::env;
 use std::fmt;
 use std::fs;
 use std::io;
 use std::io::prelude::*;
+use std::path::PathBuf;
 
 #[derive(Serialize, Deserialize, Debug)]
 pub struct CacheEntry {
@@ -32,6 +34,7 @@ impl CacheEntry {
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Cache {
     paths: HashMap<String, CacheEntry>,
+    device_id: Option<String>,
 }
 
 #[derive(Debug)]
@@ -71,6 +74,7 @@ impl Cache {
     pub fn new() -> Self {
         Self {
             paths: HashMap::new(),
+            device_id: None,
         }
     }
 
@@ -104,9 +108,41 @@ impl Cache {
     }
 
     pub fn save(&self, path: &str) -> Result<(), Error> {
+        let path = PathBuf::from(path);
+        match path.parent() {
+            Some(p) => {
+                if !p.is_dir() {
+                    fs::create_dir_all(p)?;
+                }
+            },
+            None => {},
+        };
         let mut file = fs::File::create(path)?;
         let contents = serde_json::to_string(&self)?;
         file.write_all(&contents.as_bytes())?;
         Ok(())
     }
+
+    pub fn device_id(&self) -> Option<&str> {
+        match &self.device_id {
+            Some(p) => Some(p),
+            None => None,
+        }
+    }
+
+    pub fn set_device_id(&mut self, device_id: &str) {
+        self.device_id = Some(device_id.into());
+    }
+}
+
+pub fn get_cache_dir() -> PathBuf {
+    let mut dir = match env::var("XDG_CACHE_HOME") {
+        Ok(v) => PathBuf::from(&v),
+        Err(_) => match env::var("HOME") {
+            Ok(v) => [v, ".cache".into()].iter().collect(),
+            Err(_) => ".".into(),
+        },
+    };
+    dir.push(env!("CARGO_PKG_NAME"));
+    dir
 }

src/config.rs

@@ -0,0 +1,95 @@
+use serde::{Deserialize, Serialize};
+use std::env;
+use std::fmt;
+use std::fs;
+use std::io;
+use std::io::prelude::*;
+use std::path::PathBuf;
+
+#[derive(Debug)]
+pub enum ConfigError {
+    Io(io::Error),
+    Json(serde_json::Error),
+}
+
+impl ConfigError {
+    pub fn message(&self) -> String {
+        match *self {
+            Self::Io(ref e) => format!("{}", e),
+            Self::Json(ref e) => format!("{}", e),
+        }
+    }
+}
+
+impl From<io::Error> for ConfigError {
+    fn from(error: io::Error) -> Self {
+        Self::Io(error)
+    }
+}
+
+impl From<serde_json::Error> for ConfigError {
+    fn from(error: serde_json::Error) -> Self {
+        Self::Json(error)
+    }
+}
+
+impl fmt::Display for ConfigError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str(&self.message())
+    }
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct Config {
+    pub ttl: i64,
+    pub homeserver: String,
+    pub username: String,
+    pub password: String,
+    pub room: String,
+}
+
+impl Config {
+    pub fn new() -> Self {
+        Self {
+            ttl: 30,
+            homeserver: "".into(),
+            username: "".into(),
+            password: "".into(),
+            room: "".into(),
+        }
+    }
+
+    pub fn load(path: Option<&str>) -> Result<Self, ConfigError> {
+        let path = match path {
+            Some(p) => PathBuf::from(p),
+            None => {
+                let mut p = get_config_dir();
+                p.push("config.json");
+                p
+            }
+        };
+        if let Ok(mut file) = fs::File::open(path) {
+            let mut contents = String::new();
+            file.read_to_string(&mut contents)?;
+            let config = serde_json::from_str(&contents);
+            match config {
+                Ok(c) => Ok(c),
+                Err(e) => Err(e.into()),
+            }
+        } else {
+            Ok(Self::new())
+        }
+    }
+}
+
+pub fn get_config_dir() -> PathBuf {
+    let mut dir = match env::var("XDG_CONFIG_HOME") {
+        Ok(v) => PathBuf::from(&v),
+        Err(_) => match env::var("HOME") {
+            Ok(v) => [v, ".config".into()].iter().collect(),
+            Err(_) => ".".into(),
+        },
+    };
+    dir.push(env!("CARGO_PKG_NAME"));
+    dir
+}

src/main.rs

@@ -1,29 +1,27 @@
 use chrono::Duration;
 use clap::App;
 use clap::Arg;
+use matrix_sdk::events::room::message::{
+    MessageEventContent, MessageType, TextMessageEventContent,
+};
+use matrix_sdk::events::AnyMessageEventContent;
+use matrix_sdk::identifiers::RoomIdOrAliasId;
+use matrix_sdk::reqwest::Url;
+use matrix_sdk::{Client, ClientConfig, SyncSettings};
+use std::convert::TryFrom;
 use std::env;
-use std::io::prelude::*;
-use std::num::ParseIntError;
-use std::path::PathBuf;
 use std::process;
+use tokio;
 
 mod cache;
+mod config;
 mod error;
 mod mountinfo;
 
 use mountinfo::get_fs_uuid;
 
-const CACHE_FILENAME: &'static str = "mizule.json";
-
-fn validate_int(v: String) -> Result<(), String> {
-    let i: Result<i64, ParseIntError> = v.parse();
-    match i {
-        Ok(_) => Ok(()),
-        Err(e) => Err(format!("Invalid number: {}", e)),
-    }
-}
-
-fn main() {
+#[tokio::main(flavor = "current_thread")]
+async fn main() -> Result<(), matrix_sdk::Error> {
     let matches = App::new("Mizule")
         .version(env!("CARGO_PKG_VERSION"))
         .author(env!("CARGO_PKG_AUTHORS"))
@@ -33,93 +31,115 @@ fn main() {
                 .help("Path to the mounted filesystem to check")
                 .required(true),
         )
-        .arg(
-            Arg::with_name("ttl")
-                .short("t")
-                .long("ttl")
-                .takes_value(true)
-                .validator(validate_int)
-                .default_value("30")
-                .help("Number of days before warning"),
-        )
-        .arg(
-            Arg::with_name("mailto")
-                .short("m")
-                .long("mailto")
-                .alias("mail-to")
-                .takes_value(true)
-                .help("Send warning to this email address"),
-        )
         .get_matches();
 
-    let mountpoint = matches.value_of("mountpoint").unwrap();
-    let ttl: i64 = matches.value_of("ttl").unwrap().parse().unwrap();
-    let ttl = Duration::days(ttl);
-    let mailto = matches.value_of("mailto");
-    match get_fs_uuid(mountpoint) {
-        Ok(uuid) => {
-            check_and_notify(mountpoint, &uuid, ttl, mailto);
-        }
+    let config = match config::Config::load(None) {
+        Ok(c) => c,
         Err(e) => {
-            eprintln!("Error getting filesystem UUID: {}", e);
+            eprintln!("Error loading configuration: {}", e);
             process::exit(1);
         }
-    }
-}
-
-fn check_and_notify(
-    mountpoint: &str,
-    uuid: &str,
-    ttl: Duration,
-    mailto: Option<&str>,
-) {
-    let mut cache_path = match env::var("XDG_CACHE_HOME") {
-        Ok(v) => PathBuf::from(&v),
-        Err(_) => match env::var("HOME") {
-            Ok(v) => [v, ".cache".into()].iter().collect(),
-            Err(_) => ".".into(),
-        },
     };
-    cache_path.push(CACHE_FILENAME);
-    let cache_path = cache_path.to_str().unwrap();
 
-    let cache = cache::Cache::load(cache_path);
-    match cache {
-        Ok(mut cache) => {
-            if let Some(entry) = cache.get(&mountpoint) {
-                if entry.uuid() != uuid {
-                    cache.update(&mountpoint, &uuid);
-                    if let Err(e) = cache.save(&cache_path) {
-                        eprintln!("Failed to save cache: {}", e);
-                    }
-                } else if entry.expired(ttl) {
-                    notify(mountpoint, uuid, entry.changed(), mailto);
-                }
-            } else {
-                cache.update(&mountpoint, &uuid);
-                if let Err(e) = cache.save(&cache_path) {
-                    eprintln!("Failed to save cache: {}", e);
-                }
-            }
-        }
+    let mut cache_path = cache::get_cache_dir();
+    cache_path.push("cache.json");
+    let cache_path = cache_path.to_str().unwrap();
+    let mut cache = match cache::Cache::load(cache_path) {
+        Ok(c) => c,
         Err(e) => {
             eprintln!("Error loading cache: {}", e);
             process::exit(1);
         }
+    };
+
+    let mountpoint = matches.value_of("mountpoint").unwrap();
+    let fsuuid = match get_fs_uuid(mountpoint) {
+        Ok(uuid) => uuid,
+        Err(e) => {
+            eprintln!("Error getting filesystem UUID: {}", e);
+            process::exit(1);
+        }
+    };
+    if check_and_notify(mountpoint, &fsuuid, &config, &mut cache).await {
+        if let Err(e) = cache.save(&cache_path) {
+            eprintln!("Failed to save cache: {}", e);
         }
     }
 
-fn notify(
+    Ok(())
+}
+
+async fn check_and_notify(
+    mountpoint: &str,
+    uuid: &str,
+    config: &config::Config,
+    cache: &mut cache::Cache,
+) -> bool {
+    let mut changed = false;
+    let ttl = Duration::days(config.ttl);
+    if let Some(entry) = cache.get(&mountpoint) {
+        if entry.uuid() != uuid {
+            cache.update(&mountpoint, &uuid);
+            changed = true;
+        } else if entry.expired(ttl) {
+            changed =
+                notify(mountpoint, uuid, entry.changed(), config, cache).await;
+        }
+    } else {
+        cache.update(&mountpoint, &uuid);
+        changed = true;
+    }
+
+    return changed;
+}
+
+async fn notify(
     mountpoint: &str,
     uuid: &str,
     changed: chrono::DateTime<chrono::Utc>,
-    mailto: Option<&str>,
-) {
+    config: &config::Config,
+    cache: &mut cache::Cache,
+) -> bool {
+    let mut cache_changed = false;
+
+    let room_id = RoomIdOrAliasId::try_from(config.room.clone()).unwrap();
+    let server_name = room_id.server_name().to_owned();
+    let server_names = [server_name];
+
+    let clientconfig = ClientConfig::new().store_path(cache::get_cache_dir());
+    let client = Client::new_with_config(
+        Url::parse(&config.homeserver).expect("Invalid homeserver URL"),
+        clientconfig,
+    )
+    .unwrap();
+    let res = client
+        .login(
+            &config.username,
+            &config.password,
+            cache.device_id(),
+            Some(env!("CARGO_PKG_NAME")),
+        )
+        .await
+        .expect("Login failed");
+    if cache.device_id().is_none() {
+        cache.set_device_id(res.device_id.as_str());
+        cache_changed = true;
+    }
+    let res = client
+        .join_room_by_id_or_alias(&room_id, &server_names)
+        .await
+        .expect("Failed to join room");
+    client
+        .sync_once(SyncSettings::default())
+        .await
+        .expect("Failed to sync with Matrix server");
+    let room = client.get_joined_room(&res.room_id).unwrap();
+
     let now = chrono::Utc::now();
     let delta = now - changed;
     let message = format!(
         concat!(
-            "The filesystem mounted at {} (UUID {}) ",
+            "The filesystem mounted at `{}` (UUID {}) ",
             "was last changed on {} ({} days ago)",
         ),
         mountpoint,
@@ -128,37 +148,13 @@ fn notify(
         delta.num_days()
     );
     println!("{}", message);
-    if let Some(mailto) = mailto {
-        println!("Sending notification to {}", mailto);
-        let subject = format!(
-            "{}: {} needs to be changed!",
-            env!("CARGO_PKG_NAME"),
-            mountpoint
-        );
-        if let Err(e) = sendmail(mailto, &subject, &message) {
-            eprintln!("Failed to send email: {}", e);
-        }
-    }
-}
 
-fn sendmail(
-    mailto: &str,
-    subject: &str,
-    message: &str,
-) -> Result<(), std::io::Error> {
-    let mut cmd = process::Command::new("sendmail")
-        .arg("-t")
-        .stdin(process::Stdio::piped())
-        .spawn()?;
-    {
-        let mut stdin = cmd.stdin.take().unwrap();
-        stdin.write_all(format!("To: {}\n", mailto).as_bytes())?;
-        stdin.write_all(format!("Subject: {}\n", subject).as_bytes())?;
-        stdin.write_all("\n".as_bytes())?;
-        stdin.write_all(message.as_bytes())?;
-        stdin.write_all("\n".as_bytes())?;
-        stdin.flush()?;
-    }
-    cmd.wait()?;
-    Ok(())
+    let content =
+        AnyMessageEventContent::RoomMessage(MessageEventContent::new(
+            MessageType::Text(TextMessageEventContent::markdown(message)),
+        ));
+    room.send(content, None)
+        .await
+        .expect("Failed to send Matrix notification");
+    return cache_changed;
 }