RC Pairing Interview sample (in-memory db)

main.go

package main

import (
	"io"
	"log"
	"net/http"
)

type kvBackend interface {
	addKey(string, string) bool
	delKey(string) bool
	getKey(string) string
}

type kvBackendMemory struct {
	backend map[string]string
}

func (b kvBackendMemory) addKey(k string, v string) bool {
	b.backend[k] = v
	return true
}

func (b kvBackendMemory) delKey(k string) bool {
	return true
}

func (b kvBackendMemory) getKey(k string) string {
	return b.backend[k]
}

func handleSet(key string, value string, kvStore kvBackend) bool {
	success := kvStore.addKey(string(key), string(value))
	return !success
}

func handleGet(key string, kvStore kvBackend) string {
	res := kvStore.getKey(key)
	if res != "" {
		return res
	}
	return "No such key."
}

func main() {
	var kvStore = kvBackendMemory{make(map[string]string)}

	setHandler := func(w http.ResponseWriter, req *http.Request) {
		msg := "There was an internal error setting that key=>value pair."
		values := req.URL.Query()
		if len(values) != 1 {
			msg = "You must set one and only one key=>value pair."
		} else {
			for k, v := range values {
				err := handleSet(k, v[0], kvStore)
				if !err {
					msg = "Successfully set that key=>value pair."
				}
			}
		}
		io.WriteString(w, msg)
	}

	getHandler := func(w http.ResponseWriter, req *http.Request) {
		msg := "There was an internal error getting that key=>value pair."
		values := req.URL.Query()
		searchKey, err := values["key"]

		if !err || len(values) < 1 || len(searchKey) != 1 {
			msg = "Query using the form ?key=searchvalue."
		} else {
			msg = handleGet(searchKey[0], kvStore)
		}
		io.WriteString(w, msg)
	}

	http.HandleFunc("/set", setHandler)
	http.HandleFunc("/get", getHandler)
	log.Fatal(http.ListenAndServe(":4000", nil))
}