Gorm Adapter

In v3.0.3, method NewAdapterByDB creates table named casbin_rules,
we fix it to casbin_rule after that.
If you used v3.0.3 and less, and you want to update it,
you might need to migrate data manually. Find out more at: casbin#78

Gorm Adapter is the Gorm adapter for Casbin. With this library, Casbin can load policy from Gorm supported database or save policy to it.

Based on Officially Supported Databases, The current supported databases are:

• MySQL
• PostgreSQL
• SQL Server
• Sqlite3

gorm-adapter use github.com/glebarez/sqlite instead of gorm official sqlite driver gorm.io/driver/sqlite because the latter needs cgo support. But there is almost no difference between the two driver. If there is a difference in use, please submit an issue.

• other 3rd-party supported DBs in Gorm website or other places.

Installation

go get github.com/casbin/gorm-adapter/v3

Simple Example

package main

import (
	"github.com/casbin/casbin/v2"
	gormadapter "github.com/casbin/gorm-adapter/v3"
	_ "github.com/go-sql-driver/mysql"
)

func main() {
	// Initialize a Gorm adapter and use it in a Casbin enforcer:
	// The adapter will use the MySQL database named "casbin".
	// If it doesn't exist, the adapter will create it automatically.
	// You can also use an already existing gorm instance with gormadapter.NewAdapterByDB(gormInstance)
	a, _ := gormadapter.NewAdapter("mysql", "mysql_username:mysql_password@tcp(127.0.0.1:3306)/") // Your driver and data source.
	e, _ := casbin.NewEnforcer("examples/rbac_model.conf", a)
	
	// Or you can use an existing DB "abc" like this:
	// The adapter will use the table named "casbin_rule".
	// If it doesn't exist, the adapter will create it automatically.
	// a := gormadapter.NewAdapter("mysql", "mysql_username:mysql_password@tcp(127.0.0.1:3306)/abc", true)

	// Load the policy from DB.
	e.LoadPolicy()
	
	// Check the permission.
	e.Enforce("alice", "data1", "read")
	
	// Modify the policy.
	// e.AddPolicy(...)
	// e.RemovePolicy(...)
	
	// Save the policy back to DB.
	e.SavePolicy()
}

Turn off AutoMigrate

New an adapter will use AutoMigrate by default for create table, if you want to turn it off, please use API TurnOffAutoMigrate(db *gorm.DB) *gorm.DB. See example:

db, err := gorm.Open(mysql.Open("root:@tcp(127.0.0.1:3306)/casbin"), &gorm.Config{})
TurnOffAutoMigrate(db)
// a,_ := NewAdapterByDB(...)
// a,_ := NewAdapterByDBUseTableName(...)
a,_ := NewAdapterByDBWithCustomTable(...)

Find out more details at gorm-adapter#162

Customize table columns example

You can change the gorm struct tags, but the table structure must stay the same.

package main

import (
	"github.com/casbin/casbin/v2"
	gormadapter "github.com/casbin/gorm-adapter/v3"
	"gorm.io/gorm"
)

func main() {
	// Increase the column size to 512.
	type CasbinRule struct {
		ID    uint   `gorm:"primaryKey;autoIncrement"`
		Ptype string `gorm:"size:512;uniqueIndex:unique_index"`
		V0    string `gorm:"size:512;uniqueIndex:unique_index"`
		V1    string `gorm:"size:512;uniqueIndex:unique_index"`
		V2    string `gorm:"size:512;uniqueIndex:unique_index"`
		V3    string `gorm:"size:512;uniqueIndex:unique_index"`
		V4    string `gorm:"size:512;uniqueIndex:unique_index"`
		V5    string `gorm:"size:512;uniqueIndex:unique_index"`
	}

	db, _ := gorm.Open(...)

	// Initialize a Gorm adapter and use it in a Casbin enforcer:
	// The adapter will use an existing gorm.DB instnace.
	a, _ := gormadapter.NewAdapterByDBWithCustomTable(db, &CasbinRule{}) 
	e, _ := casbin.NewEnforcer("examples/rbac_model.conf", a)
	
	// Load the policy from DB.
	e.LoadPolicy()
	
	// Check the permission.
	e.Enforce("alice", "data1", "read")
	
	// Modify the policy.
	// e.AddPolicy(...)
	// e.RemovePolicy(...)
	
	// Save the policy back to DB.
	e.SavePolicy()
}

Transaction

You can modify policies within a transaction.See example:

package main

func main() {
	a, err := NewAdapterByDB(db)
	e, _ := casbin.NewEnforcer("examples/rbac_model.conf", a)
	err = e.GetAdapter().(*Adapter).Transaction(e, func(e casbin.IEnforcer) error {
		_, err := e.AddPolicy("jack", "data1", "write")
		if err != nil {
			return err
		}
		_, err = e.AddPolicy("jack", "data2", "write")
		if err != nil {
			return err
		}
		return nil
	})
	if err != nil {
		// handle if transaction failed
		return
	}
}

ConditionsToGormQuery

ConditionsToGormQuery() is a function that converts multiple query conditions into a GORM query statement You can use the GetAllowedObjectConditions() API of Casbin to get conditions, and choose the way of combining conditions through combineType.

ConditionsToGormQuery() allows Casbin to be combined with SQL, and you can use it to implement many functions.

Example: GetAllowedRecordsForUser

• model example: object_conditions_model.conf
• policy example: object_conditions_policy.csv

DataBase example:

id	title	author	publisher	publish_data	price	category_id
1	book1	author1	publisher1	2023-04-09 16:23:42	10	1
2	book2	author1	publisher1	2023-04-09 16:23:44	20	2
3	book3	author2	publisher1	2023-04-09 16:23:44	30	1
4	book4	author2	publisher2	2023-04-09 16:23:45	10	3
5	book5	author3	publisher2	2023-04-09 16:23:45	50	1
6	book6	author3	publisher2	2023-04-09 16:23:46	60	2

type Book struct {
    ID          int
    Title       string
    Author      string
    Publisher   string
    PublishDate time.Time
    Price       float64
    CategoryID  int
}

func TestGetAllowedRecordsForUser(t *testing.T) {
	e, _ := casbin.NewEnforcer("examples/object_conditions_model.conf", "examples/object_conditions_policy.csv")

	conditions, err := e.GetAllowedObjectConditions("alice", "read", "r.obj.")
	if err != nil {
		panic(err)
	}
	fmt.Println(conditions)

	dsn := "root:root@tcp(127.0.0.1:3307)/test?charset=utf8mb4&parseTime=True&loc=Local"
	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})
	if err != nil {
		panic(err)
	}

	fmt.Println("CombineTypeOr")
	rows, err := ConditionsToGormQuery(db, conditions, CombineTypeOr).Model(&Book{}).Rows()
	defer rows.Close()
	var b Book
	for rows.Next() {
		err := db.ScanRows(rows, &b)
		if err != nil {
			panic(err)
		}
		log.Println(b)
	}

	fmt.Println("CombineTypeAnd")
	rows, err = ConditionsToGormQuery(db, conditions, CombineTypeAnd).Model(&Book{}).Rows()
	defer rows.Close()
	for rows.Next() {
		err := db.ScanRows(rows, &b)
		if err != nil {
			panic(err)
		}
		log.Println(b)
	}
}

Context Adapter

gormadapter supports adapter with context, the following is a timeout control implemented using context

ca, _ := NewContextAdapter("mysql", "root:@tcp(127.0.0.1:3306)/", "casbin")
// Limited time 300s
ctx, cancel := context.WithTimeout(context.Background(), 300*time.Microsecond)
defer cancel()
err := ca.AddPolicyCtx(ctx, "p", "p", []string{"alice", "data1", "read"})
if err != nil {
    panic(err)
}

Getting Help

• Casbin

License

This project is under Apache 2.0 License. See the LICENSE file for the full license text.