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🎣 Hooks

Fiber lets you run custom callbacks at specific points in the routing lifecycle. Available hooks include:

Constants​

// Handlers define functions to create hooks for Fiber.
type OnRouteHandler = func(Route) error
type OnNameHandler = OnRouteHandler
type OnGroupHandler = func(Group) error
type OnGroupNameHandler = OnGroupHandler
type OnListenHandler = func(ListenData) error
type OnForkHandler = func(int) error
type OnPreShutdownHandler  = func() error
type OnPostShutdownHandler = func(error) error
type OnMountHandler = func(*App) error

OnRoute​

Runs after each route is registered. The callback receives the route so you can inspect its properties.

Signature
func (h *Hooks) OnRoute(handler ...OnRouteHandler)

OnName​

Runs when a route is named. The callback receives the route.

caution

OnName only works with named routes, not groups.

Signature
func (h *Hooks) OnName(handler ...OnNameHandler)
package main

import (
    "fmt"

    "github.com/gofiber/fiber/v3"
)

func main() {
    app := fiber.New()

    app.Get("/", func(c fiber.Ctx) error {
        return c.SendString(c.Route().Name)
    }).Name("index")

    app.Hooks().OnName(func(r fiber.Route) error {
        fmt.Print("Name: " + r.Name + ", ")
        return nil
    })

    app.Hooks().OnName(func(r fiber.Route) error {
        fmt.Print("Method: " + r.Method + "\n")
        return nil
    })

    app.Get("/add/user", func(c fiber.Ctx) error {
        return c.SendString(c.Route().Name)
    }).Name("addUser")

    app.Delete("/destroy/user", func(c fiber.Ctx) error {
        return c.SendString(c.Route().Name)
    }).Name("destroyUser")

    app.Listen(":5000")
}

// Results:
// Name: addUser, Method: GET
// Name: destroyUser, Method: DELETE

OnGroup​

Runs after each group is registered. The callback receives the group.

Signature
func (h *Hooks) OnGroup(handler ...OnGroupHandler)

OnGroupName​

Runs when a group is named. The callback receives the group.

caution

OnGroupName only works with named groups, not routes.

Signature
func (h *Hooks) OnGroupName(handler ...OnGroupNameHandler)

OnListen​

Runs when the app starts listening via Listen, ListenTLS, or Listener.

Signature
func (h *Hooks) OnListen(handler ...OnListenHandler)
package main

import (
    "log"
    "os"

    "github.com/gofiber/fiber/v3"
    "github.com/gofiber/fiber/v3/log"
)

func main() {
    app := fiber.New(fiber.Config{
        DisableStartupMessage: true,
    })

    app.Hooks().OnListen(func(listenData fiber.ListenData) error {
        if fiber.IsChild() {
            return nil
        }
        scheme := "http"
        if listenData.TLS {
            scheme = "https"
        }
        log.Println(scheme + "://" + listenData.Host + ":" + listenData.Port)
        return nil
    })

    app.Listen(":5000")
}

OnFork​

Runs in the child process after a fork.

Signature
func (h *Hooks) OnFork(handler ...OnForkHandler)

OnPreShutdown​

Runs before the server shuts down.

Signature
func (h *Hooks) OnPreShutdown(handler ...OnPreShutdownHandler)

OnPostShutdown​

Runs after the server shuts down.

Signature
func (h *Hooks) OnPostShutdown(handler ...OnPostShutdownHandler)

OnMount​

Fires after a sub-app is mounted on a parent. The parent app is passed to the callback and it works for both app and group mounts.

Signature
func (h *Hooks) OnMount(handler ...OnMountHandler)
package main

import (
    "fmt"

    "github.com/gofiber/fiber/v3"
)

func main() {
    app := fiber.New()
    app.Get("/", testSimpleHandler).Name("x")

    subApp := fiber.New()
    subApp.Get("/test", testSimpleHandler)

    subApp.Hooks().OnMount(func(parent *fiber.App) error {
        fmt.Print("Mount path of parent app: " + parent.MountPath())
        // Additional custom logic...
        return nil
    })

    app.Mount("/sub", subApp)
}

func testSimpleHandler(c fiber.Ctx) error {
    return c.SendString("Hello, Fiber!")
}

// Result:
// Mount path of parent app: /sub
caution

OnName, OnRoute, OnGroup, and OnGroupName are mount-sensitive. When you mount a sub-app that registers these hooks, route and group paths include the mount prefix.