Added example how to use ulule-limiter with Iris web framework (#2152)

* Added example how to use ulule-limiter with Iris web framework

* format main.go

Signed-off-by: Gerasimos (Makis) Maropoulos <kataras2006@hotmail.com>

---------

Signed-off-by: Gerasimos (Makis) Maropoulos <kataras2006@hotmail.com>
Co-authored-by: Gerasimos (Makis) Maropoulos <kataras2006@hotmail.com>

_examples/request-ratelimit/ulule-limiter/main.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/kataras/iris/v12"
+
+	"github.com/ulule/limiter/v3"
+	"github.com/ulule/limiter/v3/drivers/store/memory"
+)
+
+func main() {
+	app := iris.New()
+	app.Get("/hello", IPRateLimit(), helloWorldHandler) // 3. Use middleware
+	app.Run(iris.Addr(":8080"))
+}
+
+func helloWorldHandler(ctx iris.Context) {
+	err := ctx.StopWithJSON(iris.StatusOK, iris.Map{
+		"message": "Hello World!",
+	})
+	if err != nil {
+		return
+	}
+}
+
+func IPRateLimit() iris.Handler {
+	// 1. Configure
+	rate := limiter.Rate{
+		Period: 2 * time.Second,
+		Limit:  1,
+	}
+	store := memory.NewStore()
+	ipRateLimiter := limiter.New(store, rate)
+
+	// 2. Return middleware handler
+	return func(ctx iris.Context) {
+		ip := ctx.RemoteAddr()
+		limiterCtx, err := ipRateLimiter.Get(ctx.Request().Context(), ip)
+		if err != nil {
+			log.Printf("IPRateLimit - ipRateLimiter.Get - err: %v, %s on %s", err, ip, ctx.Request().URL)
+			ctx.StatusCode(http.StatusInternalServerError)
+			ctx.JSON(iris.Map{
+				"success": false,
+				"message": err,
+			})
+			return
+		}
+
+		ctx.Header("X-RateLimit-Limit", strconv.FormatInt(limiterCtx.Limit, 10))
+		ctx.Header("X-RateLimit-Remaining", strconv.FormatInt(limiterCtx.Remaining, 10))
+		ctx.Header("X-RateLimit-Reset", strconv.FormatInt(limiterCtx.Reset, 10))
+
+		if limiterCtx.Reached {
+			log.Printf("Too Many Requests from %s on %s", ip, ctx.Request().URL)
+			ctx.StatusCode(http.StatusTooManyRequests)
+			ctx.JSON(iris.Map{
+				"success": false,
+				"message": "Too Many Requests on " + ctx.Request().URL.String(),
+			})
+			return
+		}
+		ctx.Next()
+	}
+}