＃请求定义
[request_definition]
r = sub, obj, act
#策略定义
[policy_definition]
p = sub, obj, act
#角色定义
[role_definition]
g = _, _
[policy_effect]
e = some(where (p.eft == allow))
[matchers]
m = g(r.sub, p.sub) && r.obj == p.obj && r.act == p.act

p, xiaomt, data1, read
p, xiaomt, data2, write

package main
import (
   "fmt"
   "log"
   "github.com/casbin/casbin"
   xd "github.com/casbin/xorm-adapter"
   "github.com/gin-gonic/gin"
   _ "github.com/go-sql-driver/mysql"
)
// myAuth 拦截器
func myAuth(e *casbin.Enforcer) gin.HandlerFunc {
   return func(c *gin.Context) {
      obj := c.Request.URL.RequestURI()
      // 获取方法
      act := c.Request.Method
      sub := "root"
      // 判断策略是否已经存在了
      if ok := e.Enforce(sub, obj, act); ok {
         log.Println("Check successfully")
         c.Next()
      } else {
         log.Println("sorry , Check failed")
         c.Abort()
      }
   }
}
func main() {
   // 使用自己定义rbac_db
   // 最后的一个参数咱们写true ，否则默认为false,使用缺省的数据库名casbin,不存在则创建
   a := xd.NewAdapter("mysql", "root:123456@tcp(127.0.0.1:3306)/mycasbin?charset=utf8", true)
   e := casbin.NewEnforcer("./rbac_models.conf", a)
   //从DB中 load 策略
   e.LoadPolicy()
   //new 一个路由
   r := gin.New()
   r.POST("/api/v1/add", func(c *gin.Context) {
      log.Println("add a policy")
      if ok := e.AddPolicy("root", "/api/v1/hello", "GET"); !ok {
         log.Println("The strategy already exists")
      } else {
         log.Println("add successfully ...")
      }
   })
   //使用自定义拦截器中间件，每一个接口的访问，都会通过这个拦截器
   r.Use(myAuth(e))
   //创建请求
   r.GET("/api/v1/hello", func(c *gin.Context) {
      fmt.Println("hello wolrd")
   })
   // 监听 127。0.0.1:8888
   r.Run(":8888")
}

// NewAdapter is the constructor for Adapter.
// dbSpecified is an optional bool parameter. The default value is false.
// It's up to whether you have specified an existing DB in dataSourceName.
// If dbSpecified == true, you need to make sure the DB in dataSourceName exists.
// If dbSpecified == false, the adapter will automatically create a DB named "casbin".
func NewAdapter(driverName string, dataSourceName string, dbSpecified ...bool) *Adapter {
   a := &Adapter{}
   a.driverName = driverName
   a.dataSourceName = dataSourceName
   if len(dbSpecified) == 0 {
      a.dbSpecified = false
   } else if len(dbSpecified) == 1 {
      a.dbSpecified = dbSpecified[0]
   } else {
      panic(errors.New("invalid parameter: dbSpecified"))
   }
   // Open the DB, create it if not existed.
   a.open()
   // Call the destructor when the object is released.
   runtime.SetFinalizer(a, finalizer)
   return a
}

// e := casbin.NewEnforcer("path/to/basic_model.conf", "path/to/basic_policy.csv")
// MySQL DB:
// a := mysqladapter.NewDBAdapter("mysql", "mysql_username:mysql_password@tcp(127.0.0.1:3306)/")
// e := casbin.NewEnforcer("path/to/basic_model.conf", a)

func NewEnforcer(params ...interface{}) *Enforcer {
   e := &Enforcer{}
   parsedParamLen := 0
   // 判断参数个数
   if len(params) >= 1 {
      enableLog, ok := params[len(params)-1].(bool)
      if ok {
         e.EnableLog(enableLog)
         parsedParamLen++
      }
   }
   // 省略 部分代码
   return e
}