From fcbf9b62a2f7dd2d8a158c565bd68f0d4ada563b Mon Sep 17 00:00:00 2001
From: Sergey Chubaryan <serghio2@yandex.ru>
Date: Sun, 21 Jul 2024 00:39:48 +0300
Subject: [PATCH] =?UTF-8?q?=D0=B4=D0=BE=D0=B1=D0=B0=D0=B2=D0=BB=D0=B5?=
 =?UTF-8?q?=D0=BD=D0=BE=20=D0=BA=D0=B5=D1=88=D0=B8=D1=80=D0=BE=D0=B2=D0=B0?=
 =?UTF-8?q?=D0=BD=D0=B8=D0=B5=20=D1=8E=D0=B7=D0=B5=D1=80=D0=BE=D0=B2?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 main.go            |  1 +
 src/cache_inmem.go | 76 ++++++++++++++++++++++++++++++++++++++++++++++
 src/service.go     | 28 ++++++++++++++---
 3 files changed, 101 insertions(+), 4 deletions(-)
 create mode 100644 src/cache_inmem.go

diff --git a/main.go b/main.go
index ee4376b..ea37104 100644
--- a/main.go
+++ b/main.go
@@ -37,6 +37,7 @@ func main() {
 		Jwt:    jwtUtil,
 		Bcrypt: bcryptUtil,
 		Db:     db,
+		Cache:  src.NewCacheInmem[string, src.UserDTO](60 * 60),
 	})
 
 	r := gin.New()
diff --git a/src/cache_inmem.go b/src/cache_inmem.go
new file mode 100644
index 0000000..57ff597
--- /dev/null
+++ b/src/cache_inmem.go
@@ -0,0 +1,76 @@
+package src
+
+import (
+	"sync"
+	"time"
+)
+
+type Cache[K comparable, V any] interface {
+	Get(key K) (V, bool)
+	Set(key K, value V, ttlSeconds int)
+	Del(key K)
+}
+
+func NewCacheInmem[K comparable, V any](ttlSeconds int) Cache[K, V] {
+	return &cacheInmem[K, V]{
+		m:          &sync.Mutex{},
+		data:       map[K]*cacheInmemItem[V]{},
+		ttlSeconds: ttlSeconds,
+	}
+}
+
+type cacheInmemItem[T any] struct {
+	Value      T
+	Ttl        int64
+	Expiration int64
+}
+
+type cacheInmem[K comparable, V any] struct {
+	m          *sync.Mutex
+	data       map[K]*cacheInmemItem[V]
+	ttlSeconds int
+}
+
+func (c *cacheInmem[K, V]) Get(key K) (V, bool) {
+	c.m.Lock()
+	defer c.m.Unlock()
+
+	item, ok := c.data[key]
+	if !ok {
+		var v V
+		return v, false
+	}
+
+	timestamp := time.Now().Unix()
+	if item.Expiration > timestamp {
+		item.Expiration = timestamp + item.Ttl
+		return item.Value, true
+	}
+
+	delete(c.data, key)
+
+	var v V
+	return v, false
+}
+
+func (c *cacheInmem[K, V]) Set(key K, value V, ttlSeconds int) {
+	c.m.Lock()
+	defer c.m.Unlock()
+
+	ttl := int64(c.ttlSeconds)
+
+	expiration := time.Now().Unix() + ttl
+	item := &cacheInmemItem[V]{
+		Value:      value,
+		Ttl:        ttl,
+		Expiration: expiration,
+	}
+	c.data[key] = item
+}
+
+func (c *cacheInmem[K, V]) Del(key K) {
+	c.m.Lock()
+	defer c.m.Unlock()
+
+	delete(c.data, key)
+}
diff --git a/src/service.go b/src/service.go
index 0abf417..f0f45da 100644
--- a/src/service.go
+++ b/src/service.go
@@ -27,6 +27,7 @@ type UserServiceDeps struct {
 	Db     DB
 	Jwt    JwtUtil
 	Bcrypt BCryptUtil
+	Cache  Cache[string, UserDTO]
 }
 
 type userService struct {
@@ -64,6 +65,8 @@ func (u *userService) CreateUser(ctx context.Context, params UserCreateParams) (
 		return nil, err
 	}
 
+	u.deps.Cache.Set(result.Id, *result, -1)
+
 	return result, nil
 }
 
@@ -85,22 +88,39 @@ func (u *userService) AuthenticateUser(ctx context.Context, login, password stri
 		return "", err
 	}
 
+	u.deps.Cache.Set(user.Id, *user, -1)
+
 	return jwt, nil
 }
 
+func (u *userService) getUserById(ctx context.Context, userId string) (*UserDTO, error) {
+	if user, ok := u.deps.Cache.Get(userId); ok {
+		return &user, nil
+	}
+
+	user, err := u.deps.Db.GetUserById(ctx, userId)
+	if err != nil {
+		return nil, err
+	}
+	if user == nil {
+		return nil, ErrUserNotExists
+	}
+
+	u.deps.Cache.Set(user.Id, *user, -1)
+
+	return user, nil
+}
+
 func (u *userService) ValidateToken(ctx context.Context, tokenStr string) (*UserDTO, error) {
 	payload, err := u.deps.Jwt.Parse(tokenStr)
 	if err != nil {
 		return nil, ErrUserWrongToken
 	}
 
-	user, err := u.deps.Db.GetUserById(ctx, payload.UserId)
+	user, err := u.getUserById(ctx, payload.UserId)
 	if err != nil {
 		return nil, err
 	}
-	if user == nil {
-		return nil, ErrUserNotExists
-	}
 
 	return user, nil
 }