redmirror/handlers.go at master · afif1400/redmirror · GitHub

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package main

import (
	"fmt"
	"strconv"
	"sync"
	"time"
)

var SETs = map[string]string{}
var SETsMu = sync.RWMutex{}

var HSETs = map[string]map[string]string{}
var HSETsMu = sync.RWMutex{}

var Handlers = map[string]func([]Value) Value{
	"PING": ping,
	"ECHO": echo,
	"SET":  set,
	"GET":  get,
	"HSET": hset,
	"HGET": hget,
}

func ping(args []Value) Value {
	return Value{typ: "string", str: "PONG"}
}

func echo(args []Value) Value {
	if len(args) == 0 {
		return Value{typ: "error", str: "echo must have a string"}
	}
	return Value{typ: "string", str: args[0].bulk}
}

func set(args []Value) Value {
	if len(args) < 2 {
		return Value{typ: "error", str: "Err wrong number of arguments for 'set' command"}
	}

	key := args[0].bulk
	value := args[1].bulk

	SETsMu.Lock()
	SETs[key] = value
	SETsMu.Unlock()

	if len(args) > 2 {
		expiryCommand := args[2]
		if expiryCommand.bulk != "px" {
			fmt.Println(expiryCommand)
			return Value{typ: "error", str: "Err incorrect expiry command for 'set'"}
		}
		numberOfMiliseconds, err := strconv.Atoi(args[3].bulk)
		if err != nil {
			return Value{typ: "error", str: "Err incorrect expiry time for 'set'"}
		}
		// set expiration
		go func() {
			<-time.After(time.Duration(numberOfMiliseconds) * time.Millisecond)
			SETsMu.Lock()
			delete(SETs, key)
			SETsMu.Unlock()
		}()
	}

	return Value{typ: "string", str: "OK"}
}

func get(args []Value) Value {
	if len(args) != 1 {
		return Value{typ: "error", str: "ERR wrong number of arguments for 'get' command"}
	}

	key := args[0].bulk

	SETsMu.RLock()
	value, ok := SETs[key]
	SETsMu.RUnlock()

	if !ok {
		return Value{typ: "null"}
	}

	return Value{typ: "bulk", bulk: value}
}

func hset(args []Value) Value {
	if len(args) != 3 {
		return Value{typ: "error", str: "ERR wrong number of arguments for 'hset' command"}
	}

	hash := args[0].bulk
	key := args[1].bulk
	value := args[2].bulk

	HSETsMu.Lock()
	if _, ok := HSETs[hash]; !ok {
		HSETs[hash] = map[string]string{}
	}
	HSETs[hash][key] = value
	HSETsMu.Unlock()

	return Value{typ: "string", str: "OK"}
}

func hget(args []Value) Value {
	if len(args) != 2 {
		return Value{typ: "error", str: "ERR wrong number of arguments for 'hget' command"}
	}

	hash := args[0].bulk
	key := args[1].bulk

	HSETsMu.RLock()
	value, ok := HSETs[hash][key]
	HSETsMu.RUnlock()

	if !ok {
		return Value{typ: "null"}
	}

	return Value{typ: "bulk", bulk: value}
}