🚀 [Feature]: Casbin: Allow users to use other types of Enforcers

[achmadafriza]

Feature Description

Currently, Casbin supports multiple types of Enforcer:

• Enforcer
• SyncedEnforcer
• CachedEnforcer
• SyncedCachedEnforcer
• DistributedEnforcer

This doesn't deviate from the core functionalities of the Enforcer, which is described in the interface IEnforcer. The types of enforcers acts as a decorator to the actual Enforcer. As such, users should be able to use the middleware with other types of Enforcer.

Additional Context (optional)

No response

Code Snippet (optional)

package main

import (
	c "github.com/casbin/casbin/v2"
	"github.com/gofiber/contrib/casbin"
	"github.com/gofiber/fiber/v2"
)

func main() {
	enforcer, _ := c.NewEnforcer("path/to/basic_model.conf", "path/to/basic_policy.csv")
	//enforcer, _ := c.NewSyncedEnforcer("path/to/basic_model.conf", "path/to/basic_policy.csv") // This fails, but it should work.
	return casbin.New(casbin.Config{
		Enforcer: enforcer,
		Lookup: func(c *fiber.Ctx) string {
			claims, ok := c.UserContext().Value(model.AuthContextKey).(*model.AuthClaims)
			if !ok {
				logger.Error(nil, "failed to get auth claims")
				return ""
			}
			return claims.Role
		},
		Unauthorized: func(c *fiber.Ctx) error {
			return model.Response(c, http.StatusUnauthorized)
		},
		Forbidden: func(c *fiber.Ctx) error {
			return model.Response(c, http.StatusForbidden)
		},
	})
}

Checklist:

• I agree to follow Fiber's Code of Conduct.
• I have checked for existing issues that describe my suggestion prior to opening this one.
• I understand that improperly formatted feature requests may be closed without explanation.

[achmadafriza]

There's a simple fix which just changes /gofiber/casbin.Config.Enforcer type from casbin.*Enforcer to casbin.IEnforcer. However this does not take into account the behavior of DistributedEnforcer, which have another interface casbin.IDistributedEnforcer.

I could submit a PR for it later.