Recover

The Recover middleware for Fiber intercepts panics and forwards them to the central ErrorHandler.

Signatures

func New(config ...Config) fiber.Handler
func DefaultPanicHandler(c fiber.Ctx, r any) error

Examples

Import the middleware package:

import (
    "errors"
    "fmt"

    "github.com/gofiber/fiber/v3"
    recoverer "github.com/gofiber/fiber/v3/middleware/recover"
)

Once your Fiber app is initialized, use the middleware like this:

// Initialize default config
app.Use(recoverer.New())

// Panics in subsequent handlers are caught by the middleware
app.Get("/", func(c fiber.Ctx) error {
    panic("I'm an error")
})

Use PanicHandler to decide which error the central ErrorHandler receives:

// Set up a PanicHandler to hide internals.
app.Use(recoverer.New(recoverer.Config{PanicHandler: func(c fiber.Ctx, r any) error {
    return fiber.ErrInternalServerError
}}))

// You could also just wrap the default handler's error.
app.Use(recoverer.New(recoverer.Config{PanicHandler: func(c fiber.Ctx, r any) error {
    return fmt.Errorf("[RECOVERED]: %w", recoverer.DefaultPanicHandler(c, r))
}}))

In more elaborate scenarios you can create a custom error type that your ErrorHandler handles differently:

// MyCustomRecoveredFromPanicError marks an error that came from a recovered panic.
type MyCustomRecoveredFromPanicError struct {
    Inner error
}

func (e *MyCustomRecoveredFromPanicError) Error() string { return e.Inner.Error() }
func (e *MyCustomRecoveredFromPanicError) Unwrap() error { return e.Inner }

app := fiber.New(fiber.Config{
    ErrorHandler: func(c fiber.Ctx, err error) error {
        var recovered *MyCustomRecoveredFromPanicError
        if errors.As(err, &recovered) {
            // Report the panic here, then answer without its details.
            return c.SendStatus(fiber.StatusInternalServerError)
        }
        return fiber.DefaultErrorHandler(c, err)
    },
})

app.Use(recoverer.New(recoverer.Config{PanicHandler: func(c fiber.Ctx, r any) error {
    return &MyCustomRecoveredFromPanicError{
        Inner: recoverer.DefaultPanicHandler(c, r),
    }
}}))

Config

Property	Type	Description	Default
Next	func(fiber.Ctx) bool	Skip when the function returns true.	nil
PanicHandler	func(fiber.Ctx, any) error	Customize the error returned from a recovered panic. DefaultPanicHandler returns the panic value when it is an error and fmt.Errorf("%v", r) otherwise.	DefaultPanicHandler
EnableStackTrace	bool	Call StackTraceHandler with the recovered value when a panic is caught. The stack trace is not added to the returned error or the response.	false
StackTraceHandler	func(fiber.Ctx, any)	Handle the captured panic when EnableStackTrace is true. The default writes recovered panic: <value> and the stack trace to os.Stderr.	defaultStackTraceHandler

Default Config

var ConfigDefault = recoverer.Config{
    Next:              nil,
    PanicHandler:      DefaultPanicHandler,
    StackTraceHandler: defaultStackTraceHandler,
    EnableStackTrace:  false,
}