Update

app.go

@@ -558,7 +558,7 @@ func (app *App) init() *App {
 				} else {
 					ctx.err = ErrBadRequest
 				}
-				app.Settings.ErrorHandler(ctx, ctx.err) // ctx.Route() not available
+				app.Settings.ErrorHandler(ctx, ctx.err)
 				app.ReleaseCtx(ctx)
 			},
 		}

ctx.go

@@ -777,6 +777,14 @@ func (ctx *Ctx) Render(name string, bind interface{}) (err error) {
 
 // Route returns the matched Route struct.
 func (ctx *Ctx) Route() *Route {
+	if ctx.route == nil {
+		// Fallback for fasthttp error handler
+		return &Route{
+			Path:     ctx.pathOriginal,
+			Method:   ctx.method,
+			Handlers: make([]Handler, 0),
+		}
+	}
 	return ctx.route
 }
 

middleware/request_id.md

@@ -0,0 +1,71 @@
+# Request ID
+
+Adds an indentifier to the response using the `X-Request-ID` header
+
+
+### Signatures
+```go
+func RequestID(header ...string) fiber.Handler {}
+func RequestIDWithConfig(config RequestIDConfig) fiber.Handler {}
+```
+
+### Config
+```go
+type RequestIDConfig struct {		
+  // Next defines a function to skip this middleware.
+  Next func(ctx *fiber.Ctx) bool
+  
+  // Header is the header key where to get/set the unique ID
+  // Optiona. Defaults: X-Request-ID
+  Header string
+
+  // Generator defines a function to generate the unique identifier.
+  // Optional. Default: func() string {
+  //   return utils.UUID()
+  // }
+  Generator func() string
+}
+```
+### Default Config
+```go
+var RequestIDConfigDefault = RequestIDConfig{
+	Next:   nil,
+	Header: fiber.HeaderXRequestID,
+	Generator: func() string {
+		return utils.UUID()
+	},
+}
+
+```
+### Example
+```go
+package main
+
+import (
+  "github.com/gofiber/fiber"
+  "github.com/gofiber/middleware"
+)
+
+func main() {
+  app := fiber.New()
+
+  // Default
+  app.Use(middleware.RequestID())
+
+  // Custom Header
+  app.Use(middleware.RequestID("X-Custom-Header"))
+  
+  // Custom Config
+  app.Use(middleware.RequestID(middleware.RequestIDConfig{
+    Next: func(ctx *fiber.Ctx) bool {
+      return ctx.Method() != fiber.MethodPost
+    },
+    Header: "X-Custom-Header",
+    Generator: func() string {
+      return "1234567890"
+    }
+  }))
+
+  app.Listen(3000)
+}
+```