feature: support cmd decode

Author: samuelj1519

src/cmd/get.rs

@@ -0,0 +1,47 @@
+use crate::cmd::{extract_args, validate_command, CommandError, Executor};
+use crate::{RespArray, RespFrame};
+
+#[allow(dead_code)]
+pub struct Get {
+    key: String,
+}
+
+impl Executor for Get {
+    fn execute(&self) -> Result<RespFrame, CommandError> {
+        todo!()
+    }
+}
+
+// get hello
+// *2\r\n$3\r\nget\r\n$5\r\nhello\r\n
+impl TryFrom<RespArray> for Get {
+    type Error = CommandError;
+
+    fn try_from(value: RespArray) -> Result<Self, Self::Error> {
+        validate_command(&value, &["get"], 1)?;
+
+        let mut args = extract_args(value, 1)?.into_iter();
+        match args.next() {
+            Some(RespFrame::BulkString(key)) => Ok(Get {
+                key: String::from_utf8(key.to_vec())?,
+            }),
+            _ => Err(CommandError::InvalidArgs("Invalid arguments".to_string())),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::RespDecode;
+    use anyhow::Result;
+
+    #[test]
+    fn test_get_command() -> Result<()> {
+        let mut cmd = bytes::BytesMut::from(&b"*2\r\n$3\r\nget\r\n$5\r\nhello\r\n"[..]);
+        let cmd = RespArray::decode(&mut cmd)?;
+        let get = Get::try_from(cmd)?;
+        assert_eq!(get.key, "hello");
+        Ok(())
+    }
+}

src/cmd/hget.rs

@@ -0,0 +1,51 @@
+use crate::cmd::{extract_args, validate_command, CommandError, Executor};
+use crate::{RespArray, RespFrame};
+
+#[allow(dead_code)]
+pub struct HGet {
+    key: String,
+    field: String,
+}
+
+impl Executor for HGet {
+    fn execute(&self) -> Result<RespFrame, CommandError> {
+        todo!()
+    }
+}
+
+// hget map hello
+// *3\r\n$4\r\nhget\r\n$3\r\nmap\r\n$5\r\nhello\r\n
+impl TryFrom<RespArray> for HGet {
+    type Error = CommandError;
+
+    fn try_from(value: RespArray) -> Result<Self, Self::Error> {
+        validate_command(&value, &["hget"], 2)?;
+
+        let mut args = extract_args(value, 1)?.into_iter();
+        match (args.next(), args.next()) {
+            (Some(RespFrame::BulkString(key)), Some(RespFrame::BulkString(field))) => Ok(HGet {
+                key: String::from_utf8(key.to_vec())?,
+                field: String::from_utf8(field.to_vec())?,
+            }),
+            _ => Err(CommandError::InvalidArgs("Invalid arguments".to_string())),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::RespDecode;
+    use anyhow::Result;
+
+    #[test]
+    fn test_hget_command() -> Result<()> {
+        let mut cmd =
+            bytes::BytesMut::from(&b"*3\r\n$4\r\nhget\r\n$3\r\nmap\r\n$5\r\nhello\r\n"[..]);
+        let cmd = RespArray::decode(&mut cmd)?;
+        let get = HGet::try_from(cmd)?;
+        assert_eq!(get.key, "map");
+        assert_eq!(get.field, "hello");
+        Ok(())
+    }
+}

src/cmd/hset.rs

@@ -0,0 +1,68 @@
+use crate::cmd::{extract_args, validate_command, CommandError, Executor};
+use crate::{RespArray, RespFrame};
+
+#[allow(dead_code)]
+pub struct HSet {
+    key: String,
+    field: String,
+    value: RespFrame,
+}
+
+impl Executor for HSet {
+    fn execute(&self) -> Result<RespFrame, CommandError> {
+        todo!()
+    }
+}
+
+// hset map hello world
+// *4\r\n$4\r\nhset\r\n$3\r\nmap\r\n$5\r\nhello\r\n$5\r\nworld\r\n
+impl TryFrom<RespArray> for HSet {
+    type Error = CommandError;
+
+    fn try_from(value: RespArray) -> Result<Self, Self::Error> {
+        validate_command(&value, &["hset"], 3)?;
+
+        let mut args = extract_args(value, 1)?.into_iter();
+        match (args.next(), args.next(), args.next()) {
+            (Some(RespFrame::BulkString(key)), Some(RespFrame::BulkString(field)), Some(value)) => {
+                Ok(HSet {
+                    key: String::from_utf8(key.to_vec())?,
+                    field: String::from_utf8(field.to_vec())?,
+                    value,
+                })
+            }
+
+            _ => Err(CommandError::InvalidArgs("Invalid arguments".to_string())),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{BulkString, RespDecode};
+    use anyhow::Result;
+
+    #[test]
+    fn test_hset_command() -> Result<()> {
+        let mut cmd = bytes::BytesMut::from(
+            &b"*4\r\n$4\r\nhset\r\n$3\r\nmap\r\n$5\r\nhello\r\n$5\r\nworld\r\n"[..],
+        );
+        let cmd = RespArray::decode(&mut cmd)?;
+        let set = HSet::try_from(cmd)?;
+        assert_eq!(set.key, "map");
+        assert_eq!(set.field, "hello");
+        assert_eq!(set.value, BulkString::new(b"world".into()).into());
+        Ok(())
+    }
+
+    #[test]
+    fn test_hset_command_args_not_enough() -> Result<()> {
+        let mut cmd =
+            bytes::BytesMut::from(&b"*3\r\n$4\r\nhset\r\n$5\r\nhello\r\n$5\r\nworld\r\n"[..]);
+        let cmd = RespArray::decode(&mut cmd)?;
+        let set = HSet::try_from(cmd);
+        assert!(set.is_err());
+        Ok(())
+    }
+}

src/cmd/mod.rs

@@ -0,0 +1,122 @@
+use crate::cmd::get::Get;
+use crate::cmd::hget::HGet;
+use crate::cmd::hset::HSet;
+use crate::cmd::set::Set;
+use crate::{RespArray, RespFrame};
+use thiserror::Error;
+
+mod get;
+mod hget;
+mod hset;
+mod set;
+
+pub enum Command {
+    Get(Get),
+    Set(Set),
+    HGet(HGet),
+    HSet(HSet),
+    // HSetAll(hset_all::HSetAll),
+}
+
+#[derive(Error, Debug, PartialEq, Eq)]
+pub enum CommandError {
+    #[error("Invalid frame: {0}")]
+    InvalidFrame(String),
+    #[error("Invalid frame type: {0}")]
+    InvalidCmd(String),
+    #[error("Invalid frame args: {0}")]
+    InvalidArgs(String),
+    #[error("From utf8 error: {0}")]
+    FromUtf8Error(#[from] std::string::FromUtf8Error),
+}
+
+pub trait Executor {
+    fn execute(&self) -> Result<RespFrame, CommandError>;
+}
+
+impl TryFrom<RespFrame> for Command {
+    type Error = CommandError;
+
+    fn try_from(value: RespFrame) -> Result<Self, Self::Error> {
+        let frame = match value {
+            RespFrame::Array(array) => array,
+            _ => return Err(CommandError::InvalidFrame("Invalid frame type".to_string())),
+        };
+
+        match frame.first() {
+            Some(RespFrame::BulkString(cmd)) => match cmd.as_ref() {
+                b"get" => Ok(Command::Get(Get::try_from(frame)?)),
+                b"set" => Ok(Command::Set(Set::try_from(frame)?)),
+                b"hget" => Ok(Command::HGet(HGet::try_from(frame)?)),
+                b"hset" => Ok(Command::HSet(HSet::try_from(frame)?)),
+                // b"hset_all" => Ok(Command::HSetAll(hset_all::HSetAll::new(cmd))),
+                _ => Err(CommandError::InvalidCmd("Invalid command".to_string())),
+            },
+            _ => Err(CommandError::InvalidArgs("Invalid arguments".to_string())),
+        }
+    }
+}
+
+pub(crate) fn validate_command(
+    cmd: &RespArray,
+    names: &[&'static str],
+    args_len: usize,
+) -> Result<(), CommandError> {
+    if cmd.len() < names.len() + args_len {
+        return Err(CommandError::InvalidArgs("Invalid arguments".to_string()));
+    }
+    validate_command_names(names, cmd)?;
+    Ok(())
+}
+
+fn validate_command_names(names: &[&'static str], cmds: &RespArray) -> Result<(), CommandError> {
+    for (name, arg) in names.iter().zip(cmds.iter()) {
+        match arg {
+            RespFrame::BulkString(cmd) => {
+                if cmd.to_ascii_lowercase() != name.as_bytes() {
+                    return Err(CommandError::InvalidCmd(format!(
+                        "Invalid command: expected {}, got {}",
+                        name,
+                        String::from_utf8_lossy(cmd)
+                    )));
+                }
+            }
+            _ => {
+                return Err(CommandError::InvalidArgs(format!(
+                    "Invalid arguments: expected {}, got {:?}",
+                    name, arg
+                )))
+            }
+        }
+    }
+    Ok(())
+}
+
+pub(crate) fn extract_args(value: RespArray, start: usize) -> Result<Vec<RespFrame>, CommandError> {
+    Ok(value
+        .data
+        .into_iter()
+        .skip(start)
+        .collect::<Vec<RespFrame>>())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{BulkString, RespDecode};
+    use anyhow::Result;
+
+    #[test]
+    fn test_extract_args() -> Result<()> {
+        let mut cmd = bytes::BytesMut::from(
+            &b"*4\r\n$4\r\nhset\r\n$3\r\nmap\r\n$5\r\nhello\r\n$5\r\nworld\r\n"[..],
+        );
+        let cmd = RespArray::decode(&mut cmd)?;
+        let args = extract_args(cmd, 1)?;
+        assert_eq!(args.len(), 3);
+        assert_eq!(args[0], BulkString::new(b"map".to_vec()).into());
+        assert_eq!(args[1], BulkString::new(b"hello".to_vec()).into());
+        assert_eq!(args[2], BulkString::new(b"world".to_vec()).into());
+        Ok(())
+    }
+}

src/cmd/set.rs

@@ -0,0 +1,62 @@
+use crate::cmd::{extract_args, validate_command, CommandError, Executor};
+use crate::{RespArray, RespFrame};
+
+#[allow(dead_code)]
+pub struct Set {
+    key: String,
+    value: RespFrame,
+}
+
+impl Executor for Set {
+    fn execute(&self) -> Result<RespFrame, CommandError> {
+        todo!()
+    }
+}
+
+// set hello world
+// *3\r\n$3\r\nset\r\n$5\r\nhello\r\n$5\r\nworld\r\n
+impl TryFrom<RespArray> for Set {
+    type Error = CommandError;
+
+    fn try_from(value: RespArray) -> Result<Self, Self::Error> {
+        validate_command(&value, &["set"], 2)?;
+
+        let mut args = extract_args(value, 1)?.into_iter();
+        match (args.next(), args.next()) {
+            (Some(RespFrame::BulkString(key)), Some(value)) => {
+                let key = String::from_utf8(key.to_vec())?;
+                println!("{:?}", key);
+                println!("{:?}", value);
+                Ok(Set { key, value })
+            }
+            _ => Err(CommandError::InvalidArgs("Invalid arguments".to_string())),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{BulkString, RespDecode};
+    use anyhow::Result;
+
+    #[test]
+    fn test_set_command() -> Result<()> {
+        let mut cmd =
+            bytes::BytesMut::from(&b"*3\r\n$3\r\nset\r\n$5\r\nhello\r\n$5\r\nworld\r\n"[..]);
+        let cmd = RespArray::decode(&mut cmd)?;
+        let set = Set::try_from(cmd)?;
+        assert_eq!(set.key, "hello");
+        assert_eq!(set.value, BulkString::new(b"world".into()).into());
+        Ok(())
+    }
+
+    #[test]
+    fn test_set_command_args_not_enough() -> Result<()> {
+        let mut cmd = bytes::BytesMut::from(&b"*2\r\n$3\r\nset\r\n$5\r\nhello\r\n"[..]);
+        let cmd = RespArray::decode(&mut cmd)?;
+        let set = Set::try_from(cmd);
+        assert!(set.is_err());
+        Ok(())
+    }
+}

src/lib.rs

@@ -1,3 +1,5 @@
 mod resp;
 
+pub mod cmd;
+
 pub use resp::*;