Implemented query marshalling to help with remote caching (#7)

* Implemented query marshalling to help with remote caching

* Improved query marshalling, and prepared version 3 as API has changed

README.md

@@ -127,17 +127,128 @@ func main() {
 }
 ```
 
-## Cacher Example
+## Cacher Example (Redis)
 
 ```go
 package main
 
 import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/go-gorm/caches/v3"
+	"github.com/redis/go-redis/v9"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+)
+
+type UserRoleModel struct {
+	gorm.Model
+	Name string `gorm:"unique"`
+}
+
+type UserModel struct {
+	gorm.Model
+	Name   string
+	RoleId uint
+	Role   *UserRoleModel `gorm:"foreignKey:role_id;references:id"`
+}
+
+type redisCacher struct {
+	rdb *redis.Client
+}
+
+func (c *redisCacher) Get(ctx context.Context, key string, q *caches.Query[any]) (*caches.Query[any], error) {
+	res, err := c.rdb.Get(ctx, key).Result()
+	if err == redis.Nil {
+		return nil, nil
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	if err := q.Unmarshal([]byte(res)); err != nil {
+		return nil, err
+	}
+
+	return q, nil
+}
+
+func (c *redisCacher) Store(ctx context.Context, key string, val *caches.Query[any]) error {
+	res, err := val.Marshal()
+	if err != nil {
+		return err
+	}
+
+	c.rdb.Set(ctx, key, res, 300*time.Second) // Set proper cache time
+	return nil
+}
+
+func main() {
+	db, _ := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{})
+
+	cachesPlugin := &caches.Caches{Conf: &caches.Config{
+		Cacher: &redisCacher{
+			rdb: redis.NewClient(&redis.Options{
+				Addr:     "localhost:6379",
+				Password: "",
+				DB:       0,
+			}),
+		},
+	}}
+
+	_ = db.Use(cachesPlugin)
+
+	_ = db.AutoMigrate(&UserRoleModel{})
+	_ = db.AutoMigrate(&UserModel{})
+
+	db.Delete(&UserRoleModel{})
+	db.Delete(&UserModel{})
+
+	adminRole := &UserRoleModel{
+		Name: "Admin",
+	}
+	db.Save(adminRole)
+
+	guestRole := &UserRoleModel{
+		Name: "Guest",
+	}
+	db.Save(guestRole)
+
+	db.Save(&UserModel{
+		Name: "ktsivkov",
+		Role: adminRole,
+	})
+
+	db.Save(&UserModel{
+		Name: "anonymous",
+		Role: guestRole,
+	})
+
+	q1User := &UserModel{}
+	db.WithContext(context.Background()).Find(q1User, "Name = ?", "ktsivkov")
+	q2User := &UserModel{}
+	db.WithContext(context.Background()).Find(q2User, "Name = ?", "ktsivkov")
+
+	fmt.Println(fmt.Sprintf("%+v", q1User))
+	fmt.Println(fmt.Sprintf("%+v", q2User))
+}
+```
+
+## Cacher Example (Memory)
+
+```go
+package main
+
+import (
+	"context"
 	"fmt"
 	"sync"
 
-	"github.com/go-gorm/caches"
-	"gorm.io/driver/mysql"
+	"github.com/go-gorm/caches/v3"
+	"gorm.io/driver/sqlite"
 	"gorm.io/gorm"
 )
 
@@ -153,77 +264,83 @@ type UserModel struct {
 	Role   *UserRoleModel `gorm:"foreignKey:role_id;references:id"`
 }
 
-type dummyCacher struct {
+type memoryCacher struct {
 	store *sync.Map
 }
 
-func (c *dummyCacher) init() {
+func (c *memoryCacher) init() {
 	if c.store == nil {
 		c.store = &sync.Map{}
 	}
 }
 
-func (c *dummyCacher) Get(key string) *caches.Query {
+func (c *memoryCacher) Get(ctx context.Context, key string, q *caches.Query[any]) (*caches.Query[any], error) {
 	c.init()
 	val, ok := c.store.Load(key)
 	if !ok {
-		return nil
+		return nil, nil
 	}
 
-	return val.(*caches.Query)
+	if err := q.Unmarshal(val.([]byte)); err != nil {
+		return nil, err
+	}
+
+	return q, nil
 }
 
-func (c *dummyCacher) Store(key string, val *caches.Query) error {
+func (c *memoryCacher) Store(ctx context.Context, key string, val *caches.Query[any]) error {
 	c.init()
-	c.store.Store(key, val)
+	res, err := val.Marshal()
+	if err != nil {
+		return err
+	}
+
+	c.store.Store(key, res)
 	return nil
 }
 
 func main() {
-	db, _ := gorm.Open(
-		mysql.Open("DATABASE_DSN"),
-		&gorm.Config{},
-	)
+	db, _ := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{})
 
 	cachesPlugin := &caches.Caches{Conf: &caches.Config{
-		Cacher: &dummyCacher{},
+		Cacher: &memoryCacher{},
 	}}
 
 	_ = db.Use(cachesPlugin)
 
 	_ = db.AutoMigrate(&UserRoleModel{})
-
 	_ = db.AutoMigrate(&UserModel{})
 
+	db.Delete(&UserRoleModel{})
+	db.Delete(&UserModel{})
+
 	adminRole := &UserRoleModel{
 		Name: "Admin",
 	}
-	db.FirstOrCreate(adminRole, "Name = ?", "Admin")
+	db.Save(adminRole)
 
 	guestRole := &UserRoleModel{
 		Name: "Guest",
 	}
-	db.FirstOrCreate(guestRole, "Name = ?", "Guest")
+	db.Save(guestRole)
 
 	db.Save(&UserModel{
 		Name: "ktsivkov",
 		Role: adminRole,
 	})
+
 	db.Save(&UserModel{
 		Name: "anonymous",
 		Role: guestRole,
 	})
 
-	var (
-		q1Users []UserModel
-		q2Users []UserModel
-	)
+	q1User := &UserModel{}
+	db.WithContext(context.Background()).Find(q1User, "Name = ?", "ktsivkov")
+	q2User := &UserModel{}
+	db.WithContext(context.Background()).Find(q2User, "Name = ?", "ktsivkov")
 
-	db.Model(&UserModel{}).Joins("Role").Find(&q1Users, "Role.Name = ? AND Sleep(1) = false", "Admin")
-	fmt.Println(fmt.Sprintf("%+v", q1Users))
-
-	db.Model(&UserModel{}).Joins("Role").Find(&q2Users, "Role.Name = ? AND Sleep(1) = false", "Admin")
-	fmt.Println(fmt.Sprintf("%+v", q2Users))
+	fmt.Println(fmt.Sprintf("%+v", q1User))
+	fmt.Println(fmt.Sprintf("%+v", q2User))
 }
 ```
 

cacher.go

@@ -1,6 +1,14 @@
 package caches
 
+import (
+	"context"
+)
+
 type Cacher interface {
-	Get(key string) *Query
-	Store(key string, val *Query) error
+	// Get impl should check if a specific key exists in the cache and return its value
+	// look at Query.Marshal
+	Get(ctx context.Context, key string, q *Query[any]) (*Query[any], error)
+	// Store is supposed to store a cached representation of the val param
+	// look at Query.Unmarshal
+	Store(ctx context.Context, key string, val *Query[any]) error
 }

cacher_test.go

@@ -1,6 +1,7 @@
 package caches
 
 import (
+	"context"
 	"errors"
 	"sync"
 )
@@ -15,42 +16,38 @@ func (c *cacherMock) init() {
 	}
 }
 
-func (c *cacherMock) Get(key string) *Query {
+func (c *cacherMock) Get(_ context.Context, key string, _ *Query[any]) (*Query[any], error) {
 	c.init()
 	val, ok := c.store.Load(key)
 	if !ok {
-		return nil
+		return nil, nil
 	}
 
-	return val.(*Query)
+	return val.(*Query[any]), nil
 }
 
-func (c *cacherMock) Store(key string, val *Query) error {
+func (c *cacherMock) Store(_ context.Context, key string, val *Query[any]) error {
 	c.init()
 	c.store.Store(key, val)
 	return nil
 }
 
-type cacherStoreErrorMock struct {
-	store *sync.Map
+type cacherStoreErrorMock struct{}
+
+func (c *cacherStoreErrorMock) Get(context.Context, string, *Query[any]) (*Query[any], error) {
+	return nil, nil
 }
 
-func (c *cacherStoreErrorMock) init() {
-	if c.store == nil {
-		c.store = &sync.Map{}
-	}
+func (c *cacherStoreErrorMock) Store(context.Context, string, *Query[any]) error {
+	return errors.New("store-error")
 }
 
-func (c *cacherStoreErrorMock) Get(key string) *Query {
-	c.init()
-	val, ok := c.store.Load(key)
-	if !ok {
-		return nil
-	}
+type cacherGetErrorMock struct{}
 
-	return val.(*Query)
+func (c *cacherGetErrorMock) Get(context.Context, string, *Query[any]) (*Query[any], error) {
+	return nil, errors.New("get-error")
 }
 
-func (c *cacherStoreErrorMock) Store(string, *Query) error {
-	return errors.New("store-error")
+func (c *cacherGetErrorMock) Store(context.Context, string, *Query[any]) error {
+	return nil
 }

caches.go

@@ -87,7 +87,7 @@ func (c *Caches) ease(db *gorm.DB, identifier string) {
 		return
 	}
 
-	q := Query{
+	q := Query[any]{
 		Dest:         db.Statement.Dest,
 		RowsAffected: db.Statement.RowsAffected,
 	}
@@ -96,7 +96,15 @@ func (c *Caches) ease(db *gorm.DB, identifier string) {
 
 func (c *Caches) checkCache(db *gorm.DB, identifier string) bool {
 	if c.Conf.Cacher != nil {
-		if res := c.Conf.Cacher.Get(identifier); res != nil {
+		res, err := c.Conf.Cacher.Get(db.Statement.Context, identifier, &Query[any]{
+			Dest:         db.Statement.Dest,
+			RowsAffected: db.Statement.RowsAffected,
+		})
+		if err != nil {
+			_ = db.AddError(err)
+		}
+
+		if res != nil {
 			res.replaceOn(db)
 			return true
 		}
@@ -106,7 +114,7 @@ func (c *Caches) checkCache(db *gorm.DB, identifier string) bool {
 
 func (c *Caches) storeInCache(db *gorm.DB, identifier string) {
 	if c.Conf.Cacher != nil {
-		err := c.Conf.Cacher.Store(identifier, &Query{
+		err := c.Conf.Cacher.Store(db.Statement.Context, identifier, &Query[any]{
 			Dest:         db.Statement.Dest,
 			RowsAffected: db.Statement.RowsAffected,
 		})