Implement LIST CMD

Fixes #18

nut-client/examples/async.rs

@@ -41,6 +41,12 @@ async fn main() -> nut_client::Result<()> {
         for var in conn.list_vars(&name).await? {
             println!("\t\t- {}", var);
         }
+
+        // List UPS commands
+        println!("\t  Commands:");
+        for cmd in conn.list_commands(&name).await? {
+            println!("\t\t- {}", cmd);
+        }
     }
 
     // Gracefully shut down the connection using the `LOGOUT` command

nut-client/examples/blocking.rs

@@ -40,6 +40,12 @@ fn main() -> nut_client::Result<()> {
         for var in conn.list_vars(&name)? {
             println!("\t\t- {}", var);
         }
+
+        // List UPS commands
+        println!("\t  Commands:");
+        for cmd in conn.list_commands(&name)? {
+            println!("\t\t- {}", cmd);
+        }
     }
 
     // Gracefully shut down the connection using the `LOGOUT` command

nut-client/src/cmd.rs

@@ -76,6 +76,10 @@ pub enum Response {
     ///
     /// Params: (client IP)
     Client(String),
+    /// A command (CMD) response.
+    ///
+    /// Params: (command name)
+    Cmd(String),
 }
 
 impl Response {
@@ -196,6 +200,23 @@ impl Response {
                 }?;
                 Ok(Response::Client(ip_address))
             }
+            "CMD" => {
+                let _device = if args.is_empty() {
+                    Err(ClientError::from(NutError::Generic(
+                        "Unspecified CMD device in response".into(),
+                    )))
+                } else {
+                    Ok(args.remove(0))
+                }?;
+                let name = if args.is_empty() {
+                    Err(ClientError::from(NutError::Generic(
+                        "Unspecified CMD name in response".into(),
+                    )))
+                } else {
+                    Ok(args.remove(0))
+                }?;
+                Ok(Response::Cmd(name))
+            }
             _ => Err(NutError::UnknownResponseType(cmd_name).into()),
         }
     }
@@ -243,6 +264,14 @@ impl Response {
             Err(NutError::UnexpectedResponse.into())
         }
     }
+
+    pub fn expect_cmd(&self) -> crate::Result<String> {
+        if let Self::Cmd(name) = &self {
+            Ok(name.to_owned())
+        } else {
+            Err(NutError::UnexpectedResponse.into())
+        }
+    }
 }
 
 /// A macro for implementing `LIST` commands.
@@ -451,7 +480,7 @@ implement_list_commands! {
         )
     }
 
-    /// Queries a list of client IP addresses connected to the given device.
+    /// Queries the list of client IP addresses connected to the given device.
     pub fn list_clients(ups_name: &str) -> Vec<String> {
         (
             { &["CLIENT", ups_name] },
@@ -466,6 +495,14 @@ implement_list_commands! {
             { |row: Response| row.expect_var() },
         )
     }
+
+    /// Queries the list of commands available for the given device.
+    pub fn list_commands(ups_name: &str) -> Vec<String> {
+        (
+            { &["CMD", ups_name] },
+            { |row: Response| row.expect_cmd() },
+        )
+    }
 }
 
 implement_get_commands! {