implement mvc HandleError as requested at #1244

Former-commit-id: 58a69f9cffe67c3aa1bab5d9425c5df65e2367ed

_examples/mvc/error-handler/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/kataras/iris"
+
+	"github.com/kataras/iris/mvc"
+)
+
+func main() {
+	app := iris.New()
+	app.Logger().SetLevel("debug")
+
+	mvcApp := mvc.New(app)
+	// To all controllers, it can optionally be overridden per-controller
+	// if the controller contains the `HandleError(ctx iris.Context, err error)` function.
+	//
+	mvcApp.HandleError(func(ctx iris.Context, err error) {
+		ctx.HTML(fmt.Sprintf("<b>%s</b>", err.Error()))
+	})
+	//
+	mvcApp.Handle(new(myController))
+
+	// http://localhost:8080
+	app.Run(iris.Addr(":8080"))
+}
+
+func basicMVC(app *mvc.Application) {
+	// GET: http://localhost:8080
+	app.Handle(new(myController))
+}
+
+type myController struct {
+}
+
+// overriddes the mvcApp.HandleError function.
+// func (c *myController) HandleError(ctx iris.Context, err error) {
+// 	ctx.HTML(fmt.Sprintf("<i>%s</i>", err.Error()))
+// }
+
+func (c *myController) Get() error {
+	return fmt.Errorf("error here")
+}