feat: implement info cmd and print error for unrecognized cmd

src/cmd/info.rs

@@ -0,0 +1,33 @@
+use crate::{Backend, CommandError, CommandExecutor, RespArray, RespFrame};
+
+use super::validate_command;
+
+#[derive(Debug)]
+pub struct Info();
+
+impl CommandExecutor for Info {
+    fn execute(self, _: &Backend) -> RespFrame {
+        "Ok".into()
+    }
+}
+
+impl Info {
+    pub fn new() -> Self {
+        Self()
+    }
+}
+
+impl Default for Info {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl TryFrom<RespArray> for Info {
+    type Error = CommandError;
+    fn try_from(value: RespArray) -> Result<Self, Self::Error> {
+        validate_command(&value, &["info"], 0, super::ArgsCheckRule::Equal)?;
+
+        Ok(Info::new())
+    }
+}

src/cmd/mod.rs

@@ -1,6 +1,7 @@
 mod echo;
 mod hmget;
 mod hset;
+pub mod info;
 mod sadd;
 mod sismember;
 mod unrecognized;
@@ -13,7 +14,7 @@ use thiserror::Error;
 use crate::{Backend, RespArray, RespError, RespFrame, SimpleString};
 
 use self::{
-    echo::Echo, hmget::HmGet, hset::HSet, sadd::SAdd, sismember::SisMember,
+    echo::Echo, hmget::HmGet, hset::HSet, info::Info, sadd::SAdd, sismember::SisMember,
     unrecognized::Unrecognized,
 };
 
@@ -42,6 +43,7 @@ pub trait CommandExecutor {
 #[derive(Debug)]
 pub enum Command {
     Echo(Echo),
+    Info(Info),
     SAdd(SAdd),
     SisMember(SisMember),
     HmGet(HmGet),
@@ -76,7 +78,8 @@ impl TryFrom<RespArray> for Command {
                     b"hmget" => Ok(HmGet::try_from(v)?.into()),
                     b"sadd" => Ok(SAdd::try_from(v)?.into()),
                     b"sismember" => Ok(SisMember::try_from(v)?.into()),
-                    _ => Ok(Unrecognized.into()),
+                    b"info" => Ok(Info::try_from(v)?.into()),
+                    _ => Ok(Unrecognized::new(cmd.clone()).into()),
                 },
                 _ => Err(CommandError::InvalidCommand("Command is null".to_string())),
             },

src/cmd/unrecognized.rs

@@ -1,9 +1,20 @@
-use crate::{Backend, CommandExecutor, RespFrame};
+use crate::{Backend, BulkString, CommandExecutor, RespFrame, SimpleError};
 
 #[derive(Debug)]
-pub struct Unrecognized;
+pub struct Unrecognized(pub(crate) BulkString);
+
 impl CommandExecutor for Unrecognized {
     fn execute(self, _: &Backend) -> RespFrame {
-        "OK".into()
+        SimpleError::new(format!(
+            "ERR unknown command '{}', with args beginning with:",
+            self.0
+        ))
+        .into()
+    }
+}
+
+impl Unrecognized {
+    pub fn new(cmd: BulkString) -> Self {
+        Self(cmd)
     }
 }

src/resp/bulk_string.rs

@@ -1,4 +1,4 @@
-use std::ops::Deref;
+use std::{fmt, ops::Deref};
 
 use bytes::{Buf, BytesMut};
 
@@ -31,6 +31,17 @@ use super::{parse_length, CRLF_LEN};
 #[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd)]
 pub struct BulkString(pub(crate) Vec<u8>);
 
+impl fmt::Display for BulkString {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // 使用 from_utf8 检查 Vec<u8> 是否是有效的 UTF-8 序列
+        let str_slice = std::str::from_utf8(&self.0);
+        match str_slice {
+            Ok(s) => write!(f, "{}", s),
+            Err(_) => write!(f, "Invalid UTF-8 sequence"),
+        }
+    }
+}
+
 //
 const NULL_BULK_STRING: &[u8; 5] = b"$-1\r\n";