feat: add client get name

Author: Miaxos

app/roster/src/application/server/cmd/client/get_name.rs

@@ -0,0 +1,89 @@
+use super::super::parse::Parse;
+use crate::application::server::connection::WriteConnection;
+use crate::application::server::context::Context;
+use crate::application::server::frame::Frame;
+
+/// The CLIENT GETNAME returns the name of the current connection as set by
+/// CLIENT SETNAME. Since every new connection starts without an associated
+/// name, if no name was assigned a null bulk reply is returned.
+#[derive(Debug, Default)]
+pub struct ClientGetName {}
+
+impl ClientGetName {
+    pub fn new() -> ClientGetName {
+        ClientGetName {}
+    }
+
+    pub(crate) fn parse_frames(
+        parse: &mut Parse,
+    ) -> anyhow::Result<ClientGetName> {
+        parse.finish()?;
+        Ok(ClientGetName::new())
+    }
+
+    pub(crate) async fn apply(
+        self,
+        dst: &mut WriteConnection,
+        ctx: Context,
+    ) -> anyhow::Result<()> {
+        let name = ctx.connection.name().await;
+
+        let response = match name {
+            Some(name) => Frame::Bulk(name.into_bytes()),
+            None => Frame::Null,
+        };
+        dst.write_frame(&response).await?;
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::io::Cursor;
+
+    use bytes::BytesMut;
+    use redis_async::resp::{RespCodec, RespValue};
+    use redis_async::resp_array;
+    use tokio_util::codec::Encoder;
+
+    use crate::application::server::cmd::Command;
+    use crate::application::server::frame::Frame;
+
+    fn parse_cmd(obj: RespValue) -> anyhow::Result<Command> {
+        let mut bytes = BytesMut::new();
+        let mut codec = RespCodec;
+        codec.encode(obj, &mut bytes).unwrap();
+
+        let mut bytes = Cursor::new(bytes.freeze());
+        let frame = Frame::parse(&mut bytes)?;
+        let client_list = Command::from_frame(frame)?;
+        Ok(client_list)
+    }
+
+    #[test]
+    fn ensure_parsing() {
+        let entry: RespValue = resp_array!["CLIENT", "GETNAME"];
+        let client_cmd = parse_cmd(entry).unwrap();
+        insta::assert_debug_snapshot!(client_cmd, @r###"
+        Client(
+            GetName(
+                ClientGetName,
+            ),
+        )
+        "###);
+    }
+
+    #[test]
+    fn ensure_parsing_too_much() {
+        let entry: RespValue = resp_array!["CLIENT", "GETNAME", "BLBL"];
+        let client_cmd = parse_cmd(entry);
+        assert!(client_cmd.is_err());
+        let client_cmd = client_cmd.unwrap_err();
+        insta::assert_debug_snapshot!(client_cmd, @r###"
+        Other(
+            "protocol error; expected end of frame, but there was more",
+        )
+        "###);
+    }
+}

app/roster/src/application/server/cmd/client/mod.rs

@@ -6,6 +6,7 @@ use crate::application::server::connection::WriteConnection;
 use crate::application::server::context::Context;
 use crate::application::server::frame::Frame;
 
+mod get_name;
 mod id;
 mod info;
 mod list;
@@ -16,16 +17,19 @@ mod set_name;
 pub enum Client {
     Help,
     SetInfo(set_info::ClientSetInfo),
+    Info(info::ClientInfo),
     SetName(set_name::ClientSetName),
+    GetName(get_name::ClientGetName),
     List(list::ClientList),
     Id(id::ClientID),
-    Info(info::ClientInfo),
 }
 
 // TODO(@miaxos): This is a simple implementation of the HELP to have the
 // associated test, but the idea is to change it to an autogenerated help based
 // on commands available and the documentation of the structure.
 const HELP_TEXT: &str = r#"CLIENT <subcommand> [<arg> [value] [opt] ...]. subcommands are:
+GETNAME
+    Return the name of the current connection.
 ID
     Return the ID of the current connection.
 INFO
@@ -65,6 +69,9 @@ impl SubcommandRegistry for Client {
             "setname" => Command::Client(Client::SetName(
                 set_name::ClientSetName::parse_frames(&mut parse)?,
             )),
+            "getname" => Command::Client(Client::GetName(
+                get_name::ClientGetName::parse_frames(&mut parse)?,
+            )),
             "id" => Command::Client(Client::Id(id::ClientID::parse_frames(
                 &mut parse,
             )?)),
@@ -120,6 +127,7 @@ impl CommandExecution for Client {
             Client::Help => Client::help(dst, ctx).await,
             Client::SetInfo(cmd) => cmd.apply(dst, ctx).await,
             Client::SetName(cmd) => cmd.apply(dst, ctx).await,
+            Client::GetName(cmd) => cmd.apply(dst, ctx).await,
             Client::Id(cmd) => cmd.apply(dst, ctx).await,
             Client::Info(cmd) => cmd.apply(dst, ctx).await,
             Client::List(cmd) => cmd.apply(dst, ctx).await,

app/roster/tests/client.rs

@@ -31,6 +31,8 @@ pub async fn test_simple_client_help() {
 
     insta::assert_display_snapshot!(joined, @r###"
     CLIENT <subcommand> [<arg> [value] [opt] ...]. subcommands are:
+    GETNAME
+        Return the name of the current connection.
     ID
         Return the ID of the current connection.
     INFO

docs/cmd_list.md

@@ -39,7 +39,7 @@ the command or open an issue.
 - [ ] BZPOPMAX
 - [ ] BZPOPMIN
 - [ ] CLIENT CACHING
-- [ ] CLIENT GETNAME
+- [x] CLIENT GETNAME
 - [ ] CLIENT GETREDIR
 - [x] CLIENT HELP
 - [x] CLIENT ID