treewide: better error handling

Cargo.lock

@@ -67,6 +67,12 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.98"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e16d2d3311acee920a9eb8d33b8cbc1787ce4a264e85f964c2404b969bdcd487"
+
 [[package]]
 name = "autocfg"
 version = "1.4.0"
@@ -369,12 +375,14 @@ dependencies = [
 name = "mrc"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "clap",
  "clap_derive",
  "ipc-channel",
  "native-tls",
  "serde",
  "serde_json",
+ "thiserror",
  "tokio",
  "tokio-native-tls",
  "tracing",
@@ -751,6 +759,26 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "thiserror"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6aaf5339b578ea85b50e080feb250a3e8ae8cfcdff9a461c9ec2904bc923f52"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "thread_local"
 version = "1.1.8"

Cargo.toml

@@ -16,11 +16,13 @@ name = "server"
 path = "src/server.rs"
 
 [dependencies]
+anyhow = "1.0"
 clap = { version = "4.5", features = ["derive"] }
 clap_derive = "4.5"
 ipc-channel = "0.19"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1.0"
+thiserror = "1.0"
 tokio = { version = "1.43", features = ["full"] }
 native-tls = "0.2"
 tokio-native-tls = "0.3"

src/cli.rs

@@ -3,11 +3,10 @@ use mrc::set_property;
 use mrc::SOCKET_PATH;
 use mrc::{
     get_property, loadfile, playlist_clear, playlist_move, playlist_next, playlist_prev,
-    playlist_remove, quit, seek,
+    playlist_remove, quit, seek, MrcError, Result,
 };
 use serde_json::json;
-use std::io::{self, Write};
+use std::{io::{self, Write}, path::PathBuf};
-use std::path::PathBuf;
 use tracing::{debug, error, info};
 
 #[derive(Parser)]
@@ -95,14 +94,17 @@ enum CommandOptions {
 }
 
 #[tokio::main]
-async fn main() -> io::Result<()> {
+async fn main() -> Result<()> {
     tracing_subscriber::fmt::init();
     let cli = Cli::parse();
 
     if !PathBuf::from(SOCKET_PATH).exists() {
         debug!(SOCKET_PATH);
         error!("Error: MPV socket not found. Is MPV running?");
-        return Ok(());
+        return Err(MrcError::ConnectionError(std::io::Error::new(
+            std::io::ErrorKind::NotFound,
+            "MPV socket not found",
+        )));
     }
 
     match cli.command {
@@ -163,7 +165,9 @@ async fn main() -> io::Result<()> {
         CommandOptions::List => {
             info!("Listing playlist items");
             if let Some(data) = get_property("playlist", None).await? {
-                println!("{}", serde_json::to_string_pretty(&data)?);
+                let pretty_json = serde_json::to_string_pretty(&data)
+                    .map_err(MrcError::ParseError)?;
+                println!("{}", pretty_json);
             }
         }
 
@@ -171,7 +175,7 @@ async fn main() -> io::Result<()> {
             if filenames.is_empty() {
                 let e = "No files provided to add to the playlist";
                 error!("{}", e);
-                return Err(io::Error::new(io::ErrorKind::InvalidInput, e));
+                return Err(MrcError::InvalidInput(e.to_string()));
             }
 
             info!("Adding {} files to the playlist", filenames.len());
@@ -206,9 +210,9 @@ async fn main() -> io::Result<()> {
 
             loop {
                 print!("mpv> ");
-                stdout.flush()?;
+                stdout.flush().map_err(MrcError::ConnectionError)?;
                 let mut input = String::new();
-                stdin.read_line(&mut input)?;
+                stdin.read_line(&mut input).map_err(MrcError::ConnectionError)?;
                 let trimmed = input.trim();
 
                 if trimmed.eq_ignore_ascii_case("exit") {
@@ -236,6 +240,7 @@ async fn main() -> io::Result<()> {
                         "set <property> <value>",
                         "Set the specified property to a value",
                     ),
+                    ("help", "Show this help message"),
                     ("exit", "Quit interactive mode"),
                 ];
 
@@ -301,7 +306,9 @@ async fn main() -> io::Result<()> {
                     ["list"] => {
                         info!("Listing playlist items");
                         if let Some(data) = get_property("playlist", None).await? {
-                            println!("{}", serde_json::to_string_pretty(&data)?);
+                            let pretty_json = serde_json::to_string_pretty(&data)
+                                .map_err(MrcError::ParseError)?;
+                            println!("{}", pretty_json);
                         }
                     }
 
@@ -331,7 +338,7 @@ async fn main() -> io::Result<()> {
 
                     _ => {
                         println!("Unknown command: {}", trimmed);
-                        println!("Valid commands: play <index>, pause, stop, next, prev, seek <seconds>, clear, list, add <files>, get <property>, set <property> <value>, exit");
+                        println!("Valid commands: play <index>, pause, stop, next, prev, seek <seconds>, clear, list, add <files>, get <property>, set <property> <value>, help, exit");
                     }
                 }
             }

src/lib.rs

@@ -41,13 +41,65 @@
 //! ## Functions
 
 use serde_json::{json, Value};
-use std::io::{self};
+use std::io;
+use thiserror::Error;
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::UnixStream;
 use tracing::{debug, error};
 
 pub const SOCKET_PATH: &str = "/tmp/mpvsocket";
 
+/// Errors that can occur when interacting with the MPV IPC interface.
+#[derive(Error, Debug)]
+pub enum MrcError {
+    /// Connection to the MPV socket could not be established.
+    #[error("failed to connect to MPV socket: {0}")]
+    ConnectionError(#[from] io::Error),
+    
+    /// Error when parsing a JSON response from MPV.
+    #[error("failed to parse JSON response: {0}")]
+    ParseError(#[from] serde_json::Error),
+    
+    /// Error when a socket operation times out.
+    #[error("socket operation timed out after {0} seconds")]
+    SocketTimeout(u64),
+    
+    /// Error when MPV returns an error response.
+    #[error("MPV error: {0}")]
+    MpvError(String),
+    
+    /// Error when trying to use a property that doesn't exist.
+    #[error("property '{0}' not found")]
+    PropertyNotFound(String),
+    
+    /// Error when the socket response is not valid UTF-8.
+    #[error("invalid UTF-8 in socket response: {0}")]
+    InvalidUtf8(#[from] std::string::FromUtf8Error),
+    
+    /// Error when a network operation fails.
+    #[error("network error: {0}")]
+    NetworkError(String),
+    
+    /// Error when the server connection is lost or broken.
+    #[error("server connection lost: {0}")]
+    ConnectionLost(String),
+    
+    /// Error when a communication protocol is violated.
+    #[error("protocol error: {0}")]
+    ProtocolError(String),
+    
+    /// Error when invalid input is provided.
+    #[error("invalid input: {0}")]
+    InvalidInput(String),
+    
+    /// Error related to TLS operations.
+    #[error("TLS error: {0}")]
+    TlsError(String),
+}
+
+/// A specialized Result type for MRC operations.
+pub type Result<T> = std::result::Result<T, MrcError>;
+
 /// Sends a generic IPC command to the specified socket and returns the parsed response data.
 ///
 /// # Arguments
@@ -59,55 +111,84 @@ pub const SOCKET_PATH: &str = "/tmp/mpvsocket";
 /// A `Result` containing an `Option<Value>` with the parsed response data if successful.
 ///
 /// # Errors
-/// Returns an error if the connection to the socket fails or if the response cannot be parsed.
+/// Returns a `MrcError` if the connection to the socket fails or if the response cannot be parsed.
 pub async fn send_ipc_command(
     command: &str,
     args: &[Value],
     socket_path: Option<&str>,
-) -> io::Result<Option<Value>> {
+) -> Result<Option<Value>> {
     let socket_path = socket_path.unwrap_or(SOCKET_PATH);
     debug!(
         "Sending IPC command: {} with arguments: {:?}",
         command, args
     );
 
-    match UnixStream::connect(socket_path).await {
+    // Add timeout for connection
-        Ok(mut socket) => {
+    let stream = tokio::time::timeout(
-            debug!("Connected to socket at {}", socket_path);
+        std::time::Duration::from_secs(5),
+        UnixStream::connect(socket_path),
+    )
+    .await
+    .map_err(|_| MrcError::SocketTimeout(5))?
+    .map_err(MrcError::ConnectionError)?;
 
-            let mut command_array = vec![json!(command)];
+    let mut socket = stream;
-            command_array.extend_from_slice(args);
+    debug!("Connected to socket at {}", socket_path);
-            let message = json!({ "command": command_array });
-            let message_str = format!("{}\n", serde_json::to_string(&message)?);
-            debug!("Serialized message to send with newline: {}", message_str);
 
-            socket.write_all(message_str.as_bytes()).await?;
+    let mut command_array = vec![json!(command)];
-            socket.flush().await?;
+    command_array.extend_from_slice(args);
-            debug!("Message sent and flushed");
+    let message = json!({ "command": command_array });
+    let message_str = format!("{}\n", serde_json::to_string(&message)?);
+    debug!("Serialized message to send with newline: {}", message_str);
 
-            let mut response = vec![0; 1024];
+    // Write with timeout
-            let n = socket.read(&mut response).await?;
+    tokio::time::timeout(
-            let response_str = String::from_utf8_lossy(&response[..n]);
+        std::time::Duration::from_secs(5),
-            debug!("Raw response: {}", response_str);
+        socket.write_all(message_str.as_bytes()),
+    )
+    .await
+    .map_err(|_| MrcError::SocketTimeout(5))??;
+    
+    // Flush with timeout
+    tokio::time::timeout(
+        std::time::Duration::from_secs(5),
+        socket.flush(),
+    )
+    .await
+    .map_err(|_| MrcError::SocketTimeout(5))??;
+    
+    debug!("Message sent and flushed");
 
-            match serde_json::from_str::<Value>(&response_str) {
+    let mut response = vec![0; 1024];
-                Ok(json_response) => {
+    
-                    debug!("Parsed IPC response: {:?}", json_response);
+    // Read with timeout
-                    Ok(json_response.get("data").cloned())
+    let n = tokio::time::timeout(
-                }
+        std::time::Duration::from_secs(5),
+        socket.read(&mut response),
+    )
+    .await
+    .map_err(|_| MrcError::SocketTimeout(5))??;
+    
+    if n == 0 {
+        return Err(MrcError::ConnectionLost("Socket closed unexpectedly".into()));
+    }
 
-                Err(e) => {
+    let response_str = String::from_utf8(response[..n].to_vec())?;
-                    error!("Failed to parse response: {}", e);
+    debug!("Raw response: {}", response_str);
-                    Ok(None)
-                }
-            }
-        }
 
-        Err(e) => {
+    let json_response = serde_json::from_str::<Value>(&response_str)
-            error!("Failed to connect to MPV socket: {}", e);
+        .map_err(MrcError::ParseError)?;
-            Err(e)
+    
+    debug!("Parsed IPC response: {:?}", json_response);
+    
+    // Check if MPV returned an error
+    if let Some(error) = json_response.get("error").and_then(|e| e.as_str()) {
+        if !error.is_empty() {
+            return Err(MrcError::MpvError(error.to_string()));
         }
     }
+    
+    Ok(json_response.get("data").cloned())
 }
 
 /// Represents common MPV commands.
@@ -179,7 +260,7 @@ pub async fn set_property(
     property: &str,
     value: &Value,
     socket_path: Option<&str>,
-) -> io::Result<Option<Value>> {
+) -> Result<Option<Value>> {
     send_ipc_command(
         MpvCommand::SetProperty.as_str(),
         &[json!(property), value.clone()],
@@ -198,7 +279,7 @@ pub async fn set_property(
 ///
 /// # Errors
 /// Returns an error if the connection to the socket fails or the command execution encounters issues.
-pub async fn playlist_next(socket_path: Option<&str>) -> io::Result<Option<Value>> {
+pub async fn playlist_next(socket_path: Option<&str>) -> Result<Option<Value>> {
     send_ipc_command(MpvCommand::PlaylistNext.as_str(), &[], socket_path).await
 }
 
@@ -212,7 +293,7 @@ pub async fn playlist_next(socket_path: Option<&str>) -> io::Result<Option<Value
 ///
 /// # Errors
 /// Returns an error if the connection to the socket fails or the command execution encounters issues.
-pub async fn playlist_prev(socket_path: Option<&str>) -> io::Result<Option<Value>> {
+pub async fn playlist_prev(socket_path: Option<&str>) -> Result<Option<Value>> {
     send_ipc_command(MpvCommand::PlaylistPrev.as_str(), &[], socket_path).await
 }
 
@@ -227,7 +308,7 @@ pub async fn playlist_prev(socket_path: Option<&str>) -> io::Result<Option<Value
 ///
 /// # Errors
 /// Returns an error if the connection to the socket fails or the command execution encounters issues.
-pub async fn seek(seconds: f64, socket_path: Option<&str>) -> io::Result<Option<Value>> {
+pub async fn seek(seconds: f64, socket_path: Option<&str>) -> Result<Option<Value>> {
     send_ipc_command(MpvCommand::Seek.as_str(), &[json!(seconds)], socket_path).await
 }
 
@@ -241,7 +322,7 @@ pub async fn seek(seconds: f64, socket_path: Option<&str>) -> io::Result<Option<
 ///
 /// # Errors
 /// Returns an error if the connection to the socket fails or the command execution encounters issues.
-pub async fn quit(socket_path: Option<&str>) -> io::Result<Option<Value>> {
+pub async fn quit(socket_path: Option<&str>) -> Result<Option<Value>> {
     send_ipc_command(MpvCommand::Quit.as_str(), &[], socket_path).await
 }
 
@@ -261,7 +342,7 @@ pub async fn playlist_move(
     from_index: usize,
     to_index: usize,
     socket_path: Option<&str>,
-) -> io::Result<Option<Value>> {
+) -> Result<Option<Value>> {
     send_ipc_command(
         MpvCommand::PlaylistMove.as_str(),
         &[json!(from_index), json!(to_index)],
@@ -284,7 +365,7 @@ pub async fn playlist_move(
 pub async fn playlist_remove(
     index: Option<usize>,
     socket_path: Option<&str>,
-) -> io::Result<Option<Value>> {
+) -> Result<Option<Value>> {
     let args = match index {
         Some(idx) => vec![json!(idx)],
         None => vec![json!("current")],
@@ -302,7 +383,7 @@ pub async fn playlist_remove(
 ///
 /// # Errors
 /// Returns an error if the connection to the socket fails or the command execution encounters issues.
-pub async fn playlist_clear(socket_path: Option<&str>) -> io::Result<Option<Value>> {
+pub async fn playlist_clear(socket_path: Option<&str>) -> Result<Option<Value>> {
     send_ipc_command(MpvCommand::PlaylistClear.as_str(), &[], socket_path).await
 }
 
@@ -317,7 +398,7 @@ pub async fn playlist_clear(socket_path: Option<&str>) -> io::Result<Option<Valu
 ///
 /// # Errors
 /// Returns an error if the connection to the socket fails or the command execution encounters issues.
-pub async fn get_property(property: &str, socket_path: Option<&str>) -> io::Result<Option<Value>> {
+pub async fn get_property(property: &str, socket_path: Option<&str>) -> Result<Option<Value>> {
     send_ipc_command(
         MpvCommand::GetProperty.as_str(),
         &[json!(property)],
@@ -342,7 +423,7 @@ pub async fn loadfile(
     filename: &str,
     append: bool,
     socket_path: Option<&str>,
-) -> io::Result<Option<Value>> {
+) -> Result<Option<Value>> {
     let append_flag = if append {
         json!("append-play")
     } else {

src/server.rs

@@ -9,7 +9,7 @@ use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio_native_tls::TlsAcceptor;
 use tracing::{debug, error, info};
 
-use mrc::{get_property, playlist_clear, playlist_next, playlist_prev, quit, seek, set_property};
+use mrc::{get_property, playlist_clear, playlist_next, playlist_prev, quit, seek, set_property, MrcError, Result as MrcResult};
 
 #[derive(Parser)]
 #[command(author, version, about)]
@@ -26,11 +26,13 @@ struct Config {
 async fn handle_connection(
     stream: tokio::net::TcpStream,
     acceptor: Arc<TlsAcceptor>,
-) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+) -> MrcResult<()> {
-    let mut stream = acceptor.accept(stream).await?;
+    let mut stream = acceptor.accept(stream).await
+        .map_err(|e| MrcError::TlsError(e.to_string()))?;
     let mut buffer = vec![0; 2048];
 
-    let n = stream.read(&mut buffer).await?;
+    let n = stream.read(&mut buffer).await
+        .map_err(MrcError::ConnectionError)?;
     let request = String::from_utf8_lossy(&buffer[..n]);
 
     debug!("Received request:\n{}", request);
@@ -87,45 +89,35 @@ async fn handle_connection(
     Ok(())
 }
 
-async fn process_command(command: &str) -> Result<String, String> {
+async fn process_command(command: &str) -> MrcResult<String> {
     match command {
         "pause" => {
             info!("Pausing playback");
-            set_property("pause", &json!(true), None)
+            set_property("pause", &json!(true), None).await?;
-                .await
-                .map_err(|e| format!("Failed to pause: {:?}", e))?;
             Ok("Paused playback\n".to_string())
         }
 
         "play" => {
             info!("Unpausing playback");
-            set_property("pause", &json!(false), None)
+            set_property("pause", &json!(false), None).await?;
-                .await
-                .map_err(|e| format!("Failed to play: {:?}", e))?;
             Ok("Resumed playback\n".to_string())
         }
 
         "stop" => {
             info!("Stopping playback and quitting MPV");
-            quit(None)
+            quit(None).await?;
-                .await
-                .map_err(|e| format!("Failed to stop: {:?}", e))?;
             Ok("Stopped playback\n".to_string())
         }
 
         "next" => {
             info!("Skipping to next item in the playlist");
-            playlist_next(None)
+            playlist_next(None).await?;
-                .await
-                .map_err(|e| format!("Failed to skip to next: {:?}", e))?;
             Ok("Skipped to next item\n".to_string())
         }
 
         "prev" => {
             info!("Skipping to previous item in the playlist");
-            playlist_prev(None)
+            playlist_prev(None).await?;
-                .await
-                .map_err(|e| format!("Failed to skip to previous: {:?}", e))?;
             Ok("Skipped to previous item\n".to_string())
         }
 
@@ -134,55 +126,56 @@ async fn process_command(command: &str) -> Result<String, String> {
             if let Some(seconds) = parts.get(1) {
                 if let Ok(sec) = seconds.parse::<i32>() {
                     info!("Seeking to {} seconds", sec);
-                    seek(sec.into(), None)
+                    seek(sec.into(), None).await?;
-                        .await
-                        .map_err(|e| format!("Failed to seek: {:?}", e))?;
                     return Ok(format!("Seeking to {} seconds\n", sec));
                 }
             }
-            Err("Invalid seek command".to_string())
+            Err(MrcError::InvalidInput("Invalid seek command".to_string()))
         }
 
         "clear" => {
             info!("Clearing the playlist");
-            playlist_clear(None)
+            playlist_clear(None).await?;
-                .await
-                .map_err(|e| format!("Failed to clear playlist: {:?}", e))?;
             Ok("Cleared playlist\n".to_string())
         }
 
         "list" => {
             info!("Listing playlist items");
             match get_property("playlist", None).await {
-                Ok(Some(data)) => Ok(format!(
+                Ok(Some(data)) => {
-                    "Playlist: {}",
+                    let pretty_json = serde_json::to_string_pretty(&data)
-                    serde_json::to_string_pretty(&data).unwrap()
+                        .map_err(MrcError::ParseError)?;
-                )),
+                    Ok(format!("Playlist: {}", pretty_json))
-                Ok(None) => Err("No playlist data available".to_string()),
+                },
-                Err(e) => Err(format!("Failed to fetch playlist: {:?}", e)),
+                Ok(None) => Err(MrcError::PropertyNotFound("playlist".to_string())),
+                Err(e) => Err(e),
             }
         }
-        _ => Err("Unknown command".to_string()),
+        _ => Err(MrcError::InvalidInput(format!("Unknown command: {}", command))),
     }
 }
 
-fn create_tls_acceptor() -> Result<TlsAcceptor, Box<dyn std::error::Error + Send + Sync>> {
+fn create_tls_acceptor() -> MrcResult<TlsAcceptor> {
     let pfx_path = env::var("TLS_PFX_PATH")
-        .map_err(|_| std::io::Error::new(std::io::ErrorKind::NotFound, "TLS_PFX_PATH not set"))?;
+        .map_err(|_| MrcError::InvalidInput("TLS_PFX_PATH not set".to_string()))?;
     let password = env::var("TLS_PASSWORD")
-        .map_err(|_| std::io::Error::new(std::io::ErrorKind::NotFound, "TLS_PASSWORD not set"))?;
+        .map_err(|_| MrcError::InvalidInput("TLS_PASSWORD not set".to_string()))?;
 
-    let mut file = std::fs::File::open(&pfx_path)?;
+    let mut file = std::fs::File::open(&pfx_path)
+        .map_err(MrcError::ConnectionError)?;
     let mut identity = vec![];
-    file.read_to_end(&mut identity)?;
+    file.read_to_end(&mut identity)
+        .map_err(MrcError::ConnectionError)?;
 
-    let identity = Identity::from_pkcs12(&identity, &password)?;
+    let identity = Identity::from_pkcs12(&identity, &password)
-    let native_acceptor = NativeTlsAcceptor::new(identity)?;
+        .map_err(|e| MrcError::TlsError(e.to_string()))?;
+    let native_acceptor = NativeTlsAcceptor::new(identity)
+        .map_err(|e| MrcError::TlsError(e.to_string()))?;
     Ok(TlsAcceptor::from(native_acceptor))
 }
 
 #[tokio::main]
-async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+async fn main() -> MrcResult<()> {
     tracing_subscriber::fmt::init();
     let config = Config::parse();
 
@@ -191,17 +184,23 @@ async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
             "Error: MPV socket not found at '{}'. Is MPV running?",
             config.socket
         );
+        return Err(MrcError::ConnectionError(std::io::Error::new(
+            std::io::ErrorKind::NotFound,
+            format!("MPV socket not found at '{}'", config.socket),
+        )));
     }
 
     info!("Server is starting...");
     match create_tls_acceptor() {
         Ok(acceptor) => {
             let acceptor = Arc::new(acceptor);
-            let listener = tokio::net::TcpListener::bind(&config.bind).await?;
+            let listener = tokio::net::TcpListener::bind(&config.bind).await
+                .map_err(MrcError::ConnectionError)?;
             info!("Server is listening on {}", config.bind);
 
             loop {
-                let (stream, _) = listener.accept().await?;
+                let (stream, _) = listener.accept().await
+                    .map_err(MrcError::ConnectionError)?;
                 info!("New connection accepted.");
 
                 let acceptor = Arc::clone(&acceptor);