From a04066148ff2412ad5bcaf6f9f80697f56924ea8 Mon Sep 17 00:00:00 2001
From: Nikita Tokarchuk <nikita@tokarch.uk>
Date: Fri, 3 Dec 2021 03:04:27 +0100
Subject: [PATCH] Implement any-error handler

---
 frontend/renderer/error.go    | 40 +++++++++++++++++++++++++++++++++++
 frontend/renderer/renderer.go |  1 +
 2 files changed, 41 insertions(+)

diff --git a/frontend/renderer/error.go b/frontend/renderer/error.go
index 9e7a183..651b57a 100644
--- a/frontend/renderer/error.go
+++ b/frontend/renderer/error.go
@@ -1,8 +1,12 @@
 package renderer
 
 import (
+	"fmt"
+	"net/http"
+
 	"code.tokarch.uk/mainnika/nikita-tokarch-uk/frontend/content"
 	routing "github.com/jackwhelpton/fasthttp-routing/v2"
+	"github.com/sirupsen/logrus"
 )
 
 // errorNotFound renders http error-404 template
@@ -12,3 +16,39 @@ func (r *Renderer) errorNotFound(c *routing.Context) (err error) {
 
 	return c.Write(errorContent)
 }
+
+// useErrorHandler is the middleware that catch handlers errors and render error template
+func (r *Renderer) useErrorHandler(c *routing.Context) (err error) {
+
+	worker := func() (err error) {
+
+		defer func() {
+			r := recover()
+			if r == nil {
+				return
+			}
+
+			err = routing.NewHTTPError(http.StatusInternalServerError,
+				fmt.Sprintf("panic:\n%v", r))
+		}()
+
+		err = c.Next()
+
+		return
+	}
+
+	err = worker()
+	if err == nil {
+		return
+	}
+
+	c.Abort()
+
+	logrus.Warnf("Cannot process request, %v", err)
+
+	errorContent := content.Error{
+		Message: err.Error(),
+	}
+
+	return c.Write(errorContent)
+}
diff --git a/frontend/renderer/renderer.go b/frontend/renderer/renderer.go
index 79313d5..07d711d 100644
--- a/frontend/renderer/renderer.go
+++ b/frontend/renderer/renderer.go
@@ -29,6 +29,7 @@ func (r *Renderer) init() {
 	router := routing.New()
 
 	router.Use(r.useTemplateWriter)
+	router.Use(r.useErrorHandler)
 	router.NotFound(r.errorNotFound)
 
 	r.router = router