Implement Line-Delimited Framing (Redis RESP Style) - The Networker

                      TASK
                    

Implementation

Implement line-delimited framing where messages end with \r\n. This is the approach used by Redis RESP, HTTP/1.1 headers, and SMTP.

The challenge: TCP doesn't guarantee that a full line arrives in one read. You must buffer partial reads correctly.

Implement handlers:

Request:  {"type": "line_encode", "msg_id": 1, "message": "PING"}
Response: {"type": "line_encode_ok", "in_reply_to": 1, "encoded": "PING\r\n", "bytes": 6}

Request:  {"type": "line_decode", "msg_id": 2, "buffer": "PING\r\nPONG\r\n"}
Response: {"type": "line_decode_ok", "in_reply_to": 2, "messages": ["PING", "PONG"], "remaining": ""}

Request:  {"type": "line_decode", "msg_id": 3, "buffer": "PING\r\nPON"}
Response: {"type": "line_decode_ok", "in_reply_to": 3, "messages": ["PING"], "remaining": "PON"}

Sample Test Cases

Encode a line messageTimeout: 5000ms

Input

{"src":"c0","dest":"n1","body":{"type":"init","msg_id":1,"node_id":"n1","node_ids":["n1"]}}
{"src":"c1","dest":"n1","body":{"type":"line_encode","msg_id":2,"message":"PING"}}

Expected Output

{"src": "n1", "dest": "c0", "body": {"type": "init_ok", "in_reply_to": 1, "msg_id": 0}}
{"src": "n1", "dest": "c1", "body": {"type": "line_encode_ok", "in_reply_to": 2, "encoded": "PING\r\n", "bytes": 6, "msg_id": 1}}

Decode multiple complete linesTimeout: 5000ms

Input

{"src":"c0","dest":"n1","body":{"type":"init","msg_id":1,"node_id":"n1","node_ids":["n1"]}}
{"src":"c1","dest":"n1","body":{"type":"line_decode","msg_id":2,"buffer":"GET key1\r\nSET key2 val\r\n"}}

Expected Output

{"src": "n1", "dest": "c0", "body": {"type": "init_ok", "in_reply_to": 1, "msg_id": 0}}
{"src": "n1", "dest": "c1", "body": {"type": "line_decode_ok", "in_reply_to": 2, "messages": ["GET key1", "SET key2 val"], "remaining": "", "msg_id": 1}}

Hints

Hint 1▾

Messages are terminated by \r\n (CRLF)

Hint 2▾

Buffer incoming bytes until you find a complete \r\n

Hint 3▾

Handle the case where \r\n is split across two TCP reads

Hint 4▾

This is similar to how Redis RESP protocol works

Hint 5▾

Return an error for messages that exceed a maximum length limit

Resources

Redis Serialization Protocol (RESP)

Redis protocol specification using CRLF-delimited framing

                      OVERVIEW
                    

Theoretical Hub

Concept overview coming soon

Key Concepts

line-delimitedRESP protocolCRLFpartial readsbuffer management

main.py

python