add experimental handlers examples

Former-commit-id: 8d8a0d15afce2554dc5926f6b9bd9c42cb95dad0

_examples/experimental-handlers/casbin/middleware/main.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"github.com/kataras/iris"
+
+	"github.com/casbin/casbin/v2"
+	cm "github.com/iris-contrib/middleware/casbin"
+)
+
+// $ go get github.com/casbin/casbin/v2
+// $ go run main.go
+
+// Enforcer maps the model and the policy for the casbin service, we use this variable on the main_test too.
+var Enforcer, _ = casbin.NewEnforcer("casbinmodel.conf", "casbinpolicy.csv")
+
+func newApp() *iris.Application {
+	casbinMiddleware := cm.New(Enforcer)
+
+	app := iris.New()
+	app.Use(casbinMiddleware.ServeHTTP)
+
+	app.Get("/", hi)
+
+	app.Get("/dataset1/{p:path}", hi) // p, alice, /dataset1/*, GET
+
+	app.Post("/dataset1/resource1", hi)
+
+	app.Get("/dataset2/resource2", hi)
+	app.Post("/dataset2/folder1/{p:path}", hi)
+
+	app.Any("/dataset2/resource1", hi)
+
+	return app
+}
+
+func main() {
+	app := newApp()
+	app.Run(iris.Addr(":8080"))
+}
+
+func hi(ctx iris.Context) {
+	ctx.Writef("Hello %s", cm.Username(ctx.Request()))
+}