refactor string / byte reads from buffer

src/commands/expire.rs

@@ -2,7 +2,7 @@ use std::io::Cursor;
 
 use bytes::{Buf as _, Bytes};
 
-use crate::{Result, connection::Connection, database::Database, errors::AppError};
+use crate::{Result, buffer::try_get_string, connection::Connection, database::Database};
 
 #[derive(Debug, Clone)]
 pub struct Expire {
@@ -22,14 +22,7 @@ impl Expire {
     }
 
     pub fn parse(bytes: &mut Cursor<&[u8]>) -> Result<Self> {
-        let key_length = bytes.try_get_u16()? as usize;
-
-        if bytes.remaining() < key_length {
-            return Err(AppError::IncompleteCommandBuffer);
-        }
-
-        let key = String::from_utf8(bytes.copy_to_bytes(key_length).to_vec())?;
-
+        let key = try_get_string(bytes)?;
         let seconds = bytes.try_get_u64()?;
 
         Ok(Self { key, seconds })