SET & GET — The Heart of Redis

Redis is fundamentally a key-value store. The two most important commands are:

• SET key value — store a value under a key
• GET key — retrieve the value, or null if the key doesn't exist

How Redis Stores Data Internally

Under the hood, Redis uses a hash table (dictionary) to map keys to values. This gives O(1) average-case lookup and insertion — the reason Redis is so fast.

In your implementation, you'll use your language's built-in hash map:

• Python: dict
• JavaScript: Map or plain object
• Go: map[string]string
• Rust: HashMap<String, String>

RESP Responses

SET always returns a simple string: +OK\r\n

GET returns a bulk string if the key exists:

$5\r\n
hello\r\n

Or a null bulk string if it doesn't:

$-1\r\n

The -1 length is RESP's way of saying "this value doesn't exist" (like null or nil).

Overwriting

Setting a key that already exists overwrites the previous value silently. There's no error — this is by design. Redis treats SET as an upsert.

SET name Alice    → +OK
SET name Bob      → +OK
GET name          → $3\r\nBob\r\n

Your Task

Add SET and GET to your growing Redis implementation. You'll need a hash map to store the data.