add accesslog middleware (rel: #1601)

_examples/logging/request-logger/accesslog/access.log.sample

@@ -0,0 +1,6 @@
+2020-08-22 00:44:20|993.3µs|POST|/read_body||200|{"id":10,"name":"Tim","age":22}|{"message":"OK"}|
+2020-08-22 00:44:30|0s|POST|/read_body||400||error(invalid character 'a' looking for beginning of object key string)||
+2020-08-22 03:02:41|1ms|GET|/|a=1 b=2|200||<h1>Hello index</h1>|
+2020-08-22 03:15:29|968.8µs|GET|/public|file=public|404|||
+2020-08-22 03:03:42|0s|GET|/user/kataras|username=kataras|200||Hello, kataras!|
+2020-08-22 03:05:40|0s|GET|/user/kataras|username=kataras a_query_parameter=name|200||Hello, kataras!|

_examples/logging/request-logger/accesslog/main.go

@@ -0,0 +1,47 @@
+package main // See https://github.com/kataras/iris/issues/1601
+
+import (
+	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/middleware/accesslog"
+)
+
+func main() {
+	app := iris.New()
+	ac := accesslog.File("./access.log")
+	defer ac.Close()
+	iris.RegisterOnInterrupt(func() {
+		ac.Close()
+	})
+
+	// Register the middleware (UseRouter to catch http errors too).
+	app.UseRouter(ac.Handler)
+	//
+
+	// Register some routes...
+	app.HandleDir("/", iris.Dir("./public"))
+
+	app.Get("/user/{username}", userHandler)
+	app.Post("/read_body", readBodyHandler)
+	app.Get("/html_response", htmlResponse)
+	//
+
+	app.Listen(":8080")
+}
+
+func readBodyHandler(ctx iris.Context) {
+	var request interface{}
+	if err := ctx.ReadBody(&request); err != nil {
+		ctx.StopWithPlainError(iris.StatusBadRequest, err)
+		return
+	}
+
+	ctx.JSON(iris.Map{"message": "OK", "data": request})
+}
+
+func userHandler(ctx iris.Context) {
+	ctx.Writef("Hello, %s!", ctx.Params().Get("username"))
+}
+
+func htmlResponse(ctx iris.Context) {
+	ctx.HTML("<h1>HTML Response</h1>")
+}

_examples/logging/request-logger/accesslog/public/index.html

@@ -0,0 +1 @@
+<h1>Hello index</h1>