init of v11.2.0: add context#FullRequestURI and NewConditionalHandler

As requested at: https://github.com/kataras/iris/issues/1167 and https://github.com/kataras/iris/issues/1170


Former-commit-id: 781c92f444b3e362011be886b32cf88f89998589

_examples/routing/conditional-chain/main.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"github.com/kataras/iris"
+)
+
+func main() {
+	app := iris.New()
+	v1 := app.Party("/api/v1")
+
+	myFilter := func(ctx iris.Context) bool {
+		// don't do that on production, use session or/and database calls and etc.
+		ok, _ := ctx.URLParamBool("admin")
+		return ok
+	}
+
+	onlyWhenFilter1 := func(ctx iris.Context) {
+		ctx.Application().Logger().Infof("admin: %s", ctx.Params())
+		ctx.Next()
+	}
+
+	onlyWhenFilter2 := func(ctx iris.Context) {
+		// You can always use the per-request storage
+		// to perform actions like this ofc.
+		//
+		// this handler: ctx.Values().Set("is_admin", true)
+		// next handler: isAdmin := ctx.Values().GetBoolDefault("is_admin", false)
+		//
+		// but, let's simplify it:
+		ctx.HTML("<h1>Hello Admin</h1><br>")
+		ctx.Next()
+	}
+
+	// HERE:
+	// It can be registered anywhere, as a middleware.
+	// It will fire the `onlyWhenFilter1` and `onlyWhenFilter2` as middlewares (with ctx.Next())
+	// if myFilter pass otherwise it will just continue the handler chain with ctx.Next() by ignoring
+	// the `onlyWhenFilter1` and `onlyWhenFilter2`.
+	myMiddleware := iris.NewConditionalHandler(myFilter, onlyWhenFilter1, onlyWhenFilter2)
+
+	v1UsersRouter := v1.Party("/users", myMiddleware)
+	v1UsersRouter.Get("/", func(ctx iris.Context) {
+		ctx.HTML("requested: <b>/api/v1/users</b>")
+	})
+
+	// http://localhost:8080/api/v1/users
+	// http://localhost:8080/api/v1/users?admin=true
+	app.Run(iris.Addr(":8080"))
+}