Implement LOGOUT

Fixes #21

nut-client/examples/async.rs

@@ -43,5 +43,6 @@ async fn main() -> nut_client::Result<()> {
         }
     }
 
-    Ok(())
+    // Gracefully shut down the connection using the `LOGOUT` command
+    conn.close().await
 }

nut-client/examples/blocking.rs

@@ -1,8 +1,8 @@
+use std::convert::TryInto;
 use std::env;
 
 use nut_client::blocking::Connection;
 use nut_client::{Auth, ConfigBuilder};
-use std::convert::TryInto;
 
 fn main() -> nut_client::Result<()> {
     let host = env::var("NUT_HOST").unwrap_or_else(|_| "localhost".into());
@@ -42,5 +42,6 @@ fn main() -> nut_client::Result<()> {
         }
     }
 
-    Ok(())
+    // Gracefully shut down the connection using the `LOGOUT` command
+    conn.close()
 }

nut-client/src/blocking/mod.rs

@@ -26,6 +26,12 @@ impl Connection {
         Ok(conn)
     }
 
+    /// Gracefully closes the connection.
+    pub fn close(mut self) -> crate::Result<()> {
+        self.logout()?;
+        Ok(())
+    }
+
     /// Sends username and password, as applicable.
     fn login(&mut self, config: &Config) -> crate::Result<()> {
         if let Some(auth) = config.auth.clone() {

nut-client/src/cmd.rs

@@ -15,8 +15,10 @@ pub enum Command<'a> {
     StartTLS,
     /// Queries the network version.
     NetworkVersion,
-    /// Queries the server version
+    /// Queries the server version.
     Version,
+    /// Gracefully shuts down the connection.
+    Logout,
 }
 
 impl<'a> Command<'a> {
@@ -30,6 +32,7 @@ impl<'a> Command<'a> {
             Self::StartTLS => "STARTTLS",
             Self::NetworkVersion => "NETVER",
             Self::Version => "VER",
+            Self::Logout => "LOGOUT",
         }
     }
 
@@ -503,4 +506,9 @@ implement_action_commands! {
     pub(crate) fn set_password(password: &str) {
         Command::SetPassword(password)
     }
+
+    /// Gracefully shuts down the connection.
+    pub(crate) fn logout() {
+        Command::Logout
+    }
 }

nut-client/src/tokio/mod.rs

@@ -27,6 +27,12 @@ impl Connection {
         Ok(conn)
     }
 
+    /// Gracefully closes the connection.
+    pub async fn close(mut self) -> crate::Result<()> {
+        self.logout().await?;
+        Ok(())
+    }
+
     /// Sends username and password, as applicable.
     async fn login(&mut self, config: &Config) -> crate::Result<()> {
         if let Some(auth) = config.auth.clone() {