From 1f2f3a241c59f467df5bf16fbde872f5083a174f Mon Sep 17 00:00:00 2001
From: omagdy <omar.professional8777@gmail.com>
Date: Wed, 23 Jul 2025 04:06:13 +0300
Subject: feat: Added syncing with empty RDB file

---
 src/lib.rs           |  6 +++---
 src/main.rs          | 48 ++++++++++++++++++++++++++++++++++++++++++++----
 src/resp_commands.rs |  1 +
 3 files changed, 48 insertions(+), 7 deletions(-)

(limited to 'src')

diff --git a/src/lib.rs b/src/lib.rs
index 34a958a..4f3f322 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -67,21 +67,21 @@ fn handshake_process(slave: &RedisServer) -> Result<(), String> {
             // PING
             send_command(&resp_bytes!(array => [resp!(bulk "PING")]))?;
 
-            // REPLCONF listening-port
+            // REPLCONF listening-port <PORT>
             send_command(&resp_bytes!(array => [
                 resp!(bulk "REPLCONF"),
                 resp!(bulk "listening-port"),
                 resp!(bulk slave.port.clone())
             ]))?;
 
-            // REPLCONF capa
+            // REPLCONF capa psync2
             send_command(&resp_bytes!(array => [
                 resp!(bulk "REPLCONF"),
                 resp!(bulk "capa"),
                 resp!(bulk "psync2")
             ]))?;
 
-            // PSYNC
+            // PSYNC <REPL_ID> <REPL_OFFSSET>
             send_command(&resp_bytes!(array => [
                 resp!(bulk "PSYNC"),
                 resp!(bulk "?"),
diff --git a/src/main.rs b/src/main.rs
index 3186b6c..78b9c24 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ use core::time;
 use std::{
     collections::HashMap,
     env,
+    fmt::format,
     io::{Read, Write},
     net::{TcpListener, TcpStream},
     sync::{Arc, Mutex},
@@ -12,6 +13,7 @@ use std::{
 
 use codecrafters_redis::{
     rdb::{KeyExpiry, ParseError, RDBFile, RedisValue},
+    resp_bytes,
     shared_cache::*,
 };
 use codecrafters_redis::{resp_commands::RedisCommands, Config};
@@ -38,6 +40,23 @@ fn spawn_cleanup_thread(cache: SharedCache) {
     });
 }
 
+use base64::{engine::general_purpose, Engine as _};
+
+fn write_rdb_to_stream<W: Write>(writer: &mut W) -> Result<(), Box<dyn std::error::Error>> {
+    let hardcoded_rdb = "UkVESVMwMDEx+glyZWRpcy12ZXIFNy4yLjD6CnJlZGlzLWJpdHPAQPoFY3RpbWXCbQi8ZfoIdXNlZC1tZW3CsMQQAPoIYW9mLWJhc2XAAP/wbjv+wP9aog==";
+
+    let bytes = general_purpose::STANDARD.decode(hardcoded_rdb)?;
+
+    let mut response = format!("${}\r\n", bytes.len()).into_bytes();
+    response.extend_from_slice(&bytes);
+
+    // Write the binary RDB data
+    writer.write_all(&response)?;
+
+    Ok(())
+}
+
+// TODO: This should return a Result to handle the plethora of different errors
 fn handle_client(mut stream: TcpStream, cache: SharedCache, config: SharedConfig) {
     let mut buffer = [0; 512];
 
@@ -48,11 +67,32 @@ fn handle_client(mut stream: TcpStream, cache: SharedCache, config: SharedConfig
             Err(_) => return, // error occurred
         };
 
-        let parsed_resp = parse(&buffer).unwrap();
-        let response = RedisCommands::from(parsed_resp.0).execute(cache.clone(), config.clone());
+        let request = parse(&buffer).unwrap();
+        let response =
+            RedisCommands::from(request.0.clone()).execute(cache.clone(), config.clone());
+
+        let mut request_command = "".to_string();
 
-        // write respose back to the client
-        stream.write(&response).unwrap();
+        // FIXME: Find a solution for this mess!!
+        match &request.0 {
+            RespType::Array(arr) => {
+                if let RespType::BulkString(s) = arr[0].clone() {
+                    request_command = String::from_utf8(s).unwrap();
+                }
+            }
+            _ => {}
+        }
+
+        // if this true immediately write and send back rdb file after response
+        // HACK: This just feels wrong I feel this shouldn't be handled here and should be handled
+        // in the exexute command
+        if request_command.starts_with("PSYNC") {
+            stream.write(&response).unwrap();
+            let _ = write_rdb_to_stream(&mut stream);
+        } else {
+            // write respose back to the client
+            stream.write(&response).unwrap();
+        }
     }
 }
 
diff --git a/src/resp_commands.rs b/src/resp_commands.rs
index 04d304c..3c18b07 100644
--- a/src/resp_commands.rs
+++ b/src/resp_commands.rs
@@ -266,6 +266,7 @@ impl RedisCommands {
                     "FULLRESYNC {} 0",
                     server.master_replid.unwrap_or("".to_string()),
                 );
+
                 resp_bytes!(response)
             }
             RC::Invalid => todo!(),
-- 
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