157 lines
2.5 KiB
Go
157 lines
2.5 KiB
Go
package main
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import (
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"bufio"
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"errors"
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"fmt"
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"io"
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"log"
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"net"
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"strings"
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)
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type RedisCmd struct {
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cmd string
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key string
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val string
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}
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type CommandExec struct {
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*RedisCmd
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Result chan string
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}
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func getCommand(reader io.Reader) (string, error) {
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scanner := bufio.NewScanner(reader)
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for scanner.Scan() {
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str := scanner.Text()
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return str, nil
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}
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return "", scanner.Err()
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}
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func isCommand(str string) bool {
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switch str {
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case "GET":
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fallthrough
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case "SET":
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fallthrough
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case "DEL":
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return true
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default:
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return false
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}
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}
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func parseCmd(line string) (*RedisCmd, error) {
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redisCmd := new(RedisCmd)
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var err error
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parts := strings.Split(line, " ")
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if len(parts) != 2 && len(parts) != 3 {
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err = errors.New("Invalid number of arguments")
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} else {
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for i, part := range parts {
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switch i {
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case 0:
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if isCommand(part) {
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redisCmd.cmd = part
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} else {
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err = errors.New("Unknown command")
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break
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}
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case 1:
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redisCmd.key = part
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case 2:
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if redisCmd.cmd == "SET" {
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redisCmd.val = part
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} else {
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err = errors.New("Invalid number of arguments")
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}
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}
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}
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}
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return redisCmd, err
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}
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func respond(writer io.Writer, ret string) {
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_, err := io.WriteString(writer, ret+"\n")
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if err != nil {
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log.Println(err)
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}
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}
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func main() {
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db := make(map[string]string)
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ln, err := net.Listen("tcp", ":9000")
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if err != nil {
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panic(err)
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}
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defer ln.Close()
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commands := make(chan CommandExec)
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go func() {
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for exec := range commands {
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switch exec.cmd {
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case "DEL":
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log.Println("Deleting", exec.key)
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delete(db, exec.key)
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close(exec.Result)
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case "GET":
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log.Println("Getting", exec.key)
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ret, ok := db[exec.key]
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if ok {
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log.Println("Value found", ret)
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go func() {
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exec.Result <- ret
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}()
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} else {
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log.Println("Unknown key", exec.key)
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close(exec.Result)
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}
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case "SET":
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log.Println("Setting", exec.key)
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db[exec.key] = exec.val
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close(exec.Result)
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}
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}
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}()
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for {
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conn, err := ln.Accept()
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if err != nil {
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panic(err)
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}
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results := make(chan string)
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go func() {
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ret, ok := <-results
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if ok {
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respond(conn, ret)
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}
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defer conn.Close()
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}()
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go func() {
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exec := new(CommandExec)
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exec.Result = results
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line, err := getCommand(conn)
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if err != nil {
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go func() {
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exec.Result <- fmt.Sprint(err)
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}()
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}
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cmd, err := parseCmd(line)
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if err != nil {
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go func() {
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exec.Result <- fmt.Sprint(err)
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}()
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}
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exec.RedisCmd = cmd
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commands <- *exec
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}()
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}
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}
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