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🚀 App

Routing​

Route Handlers​

Registers a route bound to a specific HTTP method.

Signatures
// HTTP methods
func (app *App) Get(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Head(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Post(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Put(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Delete(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Connect(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Options(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Trace(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Patch(path string, handler Handler, middlewares ...Handler) Router

// Add allows you to specify a method as value
func (app *App) Add(method, path string, handler Handler, middlewares ...Handler) Router

// All will register the route on all HTTP methods
// Almost the same as app.Use but not bound to prefixes
func (app *App) All(path string, handler Handler, middlewares ...Handler) Router
Examples
// Simple GET handler
app.Get("/api/list", func(c fiber.Ctx) error {
    return c.SendString("I'm a GET request!")
})

// Simple POST handler
app.Post("/api/register", func(c fiber.Ctx) error {
    return c.SendString("I'm a POST request!")
})
Use

Can be used for middleware packages and prefix catchers. These routes will only match the beginning of each path i.e. /john will match /john/doe, /johnnnnn etc

Signature
func (app *App) Use(args ...any) Router

// Different usage variations
func (app *App) Use(handler Handler, middlewares ...Handler) Router
func (app *App) Use(path string, handler Handler, middlewares ...Handler) Router
func (app *App) Use(paths []string, handler Handler, middlewares ...Handler) Router
func (app *App) Use(path string, app *App) Router
Examples
// Match any request
app.Use(func(c fiber.Ctx) error {
    return c.Next()
})

// Match request starting with /api
app.Use("/api", func(c fiber.Ctx) error {
    return c.Next()
})

// Match requests starting with /api or /home (multiple-prefix support)
app.Use([]string{"/api", "/home"}, func(c fiber.Ctx) error {
    return c.Next()
})

// Attach multiple handlers 
app.Use("/api", func(c fiber.Ctx) error {
    c.Set("X-Custom-Header", random.String(32))
    return c.Next()
}, func(c fiber.Ctx) error {
    return c.Next()
})

// Mount a sub-app
app.Use("/api", api)

Mounting​

You can Mount Fiber instance using the app.Use method similar to express.

Examples
func main() {
    app := fiber.New()
    micro := fiber.New()
    app.Use("/john", micro) // GET /john/doe -> 200 OK

    micro.Get("/doe", func(c fiber.Ctx) error {
        return c.SendStatus(fiber.StatusOK)
    })

    log.Fatal(app.Listen(":3000"))
}

MountPath​

The MountPath property contains one or more path patterns on which a sub-app was mounted.

Signature
func (app *App) MountPath() string
Examples
func main() {
    app := fiber.New()
    one := fiber.New()
    two := fiber.New()
    three := fiber.New()

    two.Use("/three", three)
    one.Use("/two", two)
    app.Use("/one", one)
  
    one.MountPath()   // "/one"
    two.MountPath()   // "/one/two"
    three.MountPath() // "/one/two/three"
    app.MountPath()   // ""
}
caution

Mounting order is important for MountPath. If you want to get mount paths properly, you should start mounting from the deepest app.

Group​

You can group routes by creating a *Group struct.

Signature
func (app *App) Group(prefix string, handlers ...Handler) Router
Examples
func main() {
  app := fiber.New()

  api := app.Group("/api", handler)  // /api

  v1 := api.Group("/v1", handler)   // /api/v1
  v1.Get("/list", handler)          // /api/v1/list
  v1.Get("/user", handler)          // /api/v1/user

  v2 := api.Group("/v2", handler)   // /api/v2
  v2.Get("/list", handler)          // /api/v2/list
  v2.Get("/user", handler)          // /api/v2/user

  log.Fatal(app.Listen(":3000"))
}

Route​

Returns an instance of a single route, which you can then use to handle HTTP verbs with optional middleware.

Similar to Express.

Signature
func (app *App) Route(path string) Register
Click here to see the Register interface
type Register interface {
  All(handler Handler, middleware ...Handler) Register
  Get(handler Handler, middleware ...Handler) Register
  Head(handler Handler, middleware ...Handler) Register
  Post(handler Handler, middleware ...Handler) Register
  Put(handler Handler, middleware ...Handler) Register
  Delete(handler Handler, middleware ...Handler) Register
  Connect(handler Handler, middleware ...Handler) Register
  Options(handler Handler, middleware ...Handler) Register
  Trace(handler Handler, middleware ...Handler) Register
  Patch(handler Handler, middleware ...Handler) Register

  Add(methods []string, handler Handler, middleware ...Handler) Register

  Route(path string) Register
}
Examples
func main() {
  app := fiber.New()

  // use `Route` as chainable route declaration method
  app.Route("/test").Get(func(c fiber.Ctx) error {
    return c.SendString("GET /test")
  })
  
  app.Route("/events").all(func(c fiber.Ctx) error {
    // runs for all HTTP verbs first
    // think of it as route specific middleware!
  })
  .get(func(c fiber.Ctx) error {
    return c.SendString("GET /events")
  })
  .post(func(c fiber.Ctx) error {
    // maybe add a new event...
  })
  
  // combine multiple routes
  app.Route("/v2").Route("/user").Get(func(c fiber.Ctx) error {
    return c.SendString("GET /v2/user")
  })
  
  // use multiple methods
  app.Route("/api").Get(func(c fiber.Ctx) error {
    return c.SendString("GET /api")
  }).Post(func(c fiber.Ctx) error {
    return c.SendString("POST /api")
  })

  log.Fatal(app.Listen(":3000"))
}

HandlersCount​

This method returns the amount of registered handlers.

Signature
func (app *App) HandlersCount() uint32

Stack​

This method returns the original router stack

Signature
func (app *App) Stack() [][]*Route
Examples
var handler = func(c fiber.Ctx) error { return nil }

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

    app.Get("/john/:age", handler)
    app.Post("/register", handler)

    data, _ := json.MarshalIndent(app.Stack(), "", "  ")
    fmt.Println(string(data))

    app.Listen(":3000")
}
Click here to see the result
[
  [
    {
      "method": "GET",
      "path": "/john/:age",
      "params": [
        "age"
      ]
    }
  ],
  [
    {
      "method": "HEAD",
      "path": "/john/:age",
      "params": [
        "age"
      ]
    }
  ],
  [
    {
      "method": "POST",
      "path": "/register",
      "params": null
    }
  ]
]

Name​

This method assigns the name of latest created route.

Signature
func (app *App) Name(name string) Router
Examples
var handler = func(c fiber.Ctx) error { return nil }

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

    app.Get("/", handler)
    app.Name("index")

    app.Get("/doe", handler).Name("home")

    app.Trace("/tracer", handler).Name("tracert")

    app.Delete("/delete", handler).Name("delete")

    a := app.Group("/a")
    a.Name("fd.")

    a.Get("/test", handler).Name("test")

    data, _ := json.MarshalIndent(app.Stack(), "", "  ")
    fmt.Print(string(data))

    app.Listen(":3000")

}
Click here to see the result
[
  [
    {
      "method": "GET",
      "name": "index",
      "path": "/",
      "params": null
    },
    {
      "method": "GET",
      "name": "home",
      "path": "/doe",
      "params": null
    },
    {
      "method": "GET",
      "name": "fd.test",
      "path": "/a/test",
      "params": null
    }
  ],
  [
    {
      "method": "HEAD",
      "name": "",
      "path": "/",
      "params": null
    },
    {
      "method": "HEAD",
      "name": "",
      "path": "/doe",
      "params": null
    },
    {
      "method": "HEAD",
      "name": "",
      "path": "/a/test",
      "params": null
    }
  ],
  null,
  null,
  [
    {
      "method": "DELETE",
      "name": "delete",
      "path": "/delete",
      "params": null
    }
  ],
  null,
  null,
  [
    {
      "method": "TRACE",
      "name": "tracert",
      "path": "/tracer",
      "params": null
    }
  ],
  null
]

GetRoute​

This method gets the route by name.

Signature
func (app *App) GetRoute(name string) Route
Examples
var handler = func(c fiber.Ctx) error { return nil }

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

    app.Get("/", handler).Name("index")
    
    data, _ := json.MarshalIndent(app.GetRoute("index"), "", "  ")
    fmt.Print(string(data))


    app.Listen(":3000")
}
Click here to see the result
{
  "method": "GET",
  "name": "index",
  "path": "/",
  "params": null
}

GetRoutes​

This method gets all routes.

Signature
func (app *App) GetRoutes(filterUseOption ...bool) []Route

When filterUseOption equal to true, it will filter the routes registered by the middleware.

Examples
func main() {
    app := fiber.New()
    app.Post("/", func (c fiber.Ctx) error {
        return c.SendString("Hello, World!")
    }).Name("index")
    data, _ := json.MarshalIndent(app.GetRoutes(true), "", "  ")
    fmt.Print(string(data))
}
Click here to see the result
[
    {
        "method": "POST",
        "name": "index",
        "path": "/",
        "params": null
    }
]

Config​

Config returns the app config as value ( read-only ).

Signature
func (app *App) Config() Config

Handler​

Handler returns the server handler that can be used to serve custom \*fasthttp.RequestCtx requests.

Signature
func (app *App) Handler() fasthttp.RequestHandler

ErrorHandler​

Errorhandler executes the process which was defined for the application in case of errors, this is used in some cases in middlewares.

Signature
func (app *App) ErrorHandler(ctx Ctx, err error) error

NewCtxFunc​

NewCtxFunc allows to customize the ctx struct as we want.

Signature
func (app *App) NewCtxFunc(function func(app *App) CustomCtx)
Examples
type CustomCtx struct {
    DefaultCtx
}

// Custom method
func (c *CustomCtx) Params(key string, defaultValue ...string) string {
    return "prefix_" + c.DefaultCtx.Params(key)
}

app := New()
app.NewCtxFunc(func(app *fiber.App) fiber.CustomCtx {
    return &CustomCtx{
        DefaultCtx: *NewDefaultCtx(app),
    }
})
// curl http://localhost:3000/123
app.Get("/:id", func(c Ctx) error {
    // use custom method - output: prefix_123
    return c.SendString(c.Params("id"))
})

RegisterCustomBinder​

You can register custom binders to use as Bind().Custom("name"). They should be compatible with CustomBinder interface.

Signature
func (app *App) RegisterCustomBinder(binder CustomBinder)
Examples
app := fiber.New()

// My custom binder
customBinder := &customBinder{}
// Name of custom binder, which will be used as Bind().Custom("name")
func (*customBinder) Name() string {
    return "custom"
}
// Is used in the Body Bind method to check if the binder should be used for custom mime types
func (*customBinder) MIMETypes() []string {
    return []string{"application/yaml"}
}
// Parse the body and bind it to the out interface
func (*customBinder) Parse(c Ctx, out any) error {
    // parse yaml body
    return yaml.Unmarshal(c.Body(), out)
}
// Register custom binder
app.RegisterCustomBinder(customBinder)

// curl -X POST http://localhost:3000/custom -H "Content-Type: application/yaml" -d "name: John"
app.Post("/custom", func(c Ctx) error {
    var user User
    // output: {Name:John}
    // Custom binder is used by the name
    if err := c.Bind().Custom("custom", &user); err != nil {
        return err
    }
    // ...
    return c.JSON(user)
})
// curl -X POST http://localhost:3000/normal -H "Content-Type: application/yaml" -d "name: Doe"
app.Post("/normal", func(c Ctx) error {
    var user User
    // output: {Name:Doe}
    // Custom binder is used by the mime type
    if err := c.Bind().Body(&user); err != nil {
        return err
    }
    // ...
    return c.JSON(user)
})

RegisterCustomConstraint​

RegisterCustomConstraint allows to register custom constraint.

Signature
func (app *App) RegisterCustomConstraint(constraint CustomConstraint)

See Custom Constraint section for more information.

SetTLSHandler​

Use SetTLSHandler to set ClientHelloInfo when using TLS with Listener.

Signature
func (app *App) SetTLSHandler(tlsHandler *TLSHandler)

Test​

Testing your application is done with the Test method. Use this method for creating _test.go files or when you need to debug your routing logic. The default timeout is 1s if you want to disable a timeout altogether, pass -1 as a second argument.

Signature
func (app *App) Test(req *http.Request, msTimeout ...int) (*http.Response, error)
Examples
// Create route with GET method for test:
app.Get("/", func(c fiber.Ctx) error {
  fmt.Println(c.BaseURL())              // => http://google.com
  fmt.Println(c.Get("X-Custom-Header")) // => hi

  return c.SendString("hello, World!")
})

// http.Request
req := httptest.NewRequest("GET", "http://google.com", nil)
req.Header.Set("X-Custom-Header", "hi")

// http.Response
resp, _ := app.Test(req)

// Do something with results:
if resp.StatusCode == fiber.StatusOK {
  body, _ := io.ReadAll(resp.Body)
  fmt.Println(string(body)) // => Hello, World!
}

Hooks​

Hooks is a method to return hooks property.

Signature
func (app *App) Hooks() *Hooks

RebuildTree​

The RebuildTree method is designed to rebuild the route tree and enable dynamic route registration. It returns a pointer to the App instance.

Signature
func (app *App) RebuildTree() *App

Note: Use this method with caution. It is not thread-safe and calling it can be very performance-intensive, so it should be used sparingly and only in development mode. Avoid using it concurrently.

Example Usage​

Here’s an example of how to define and register routes dynamically:

app.Get("/define", func(c Ctx) error {  // Define a new route dynamically
    app.Get("/dynamically-defined", func(c Ctx) error {  // Adding a dynamically defined route
        return c.SendStatus(http.StatusOK)
    })

    app.RebuildTree()  // Rebuild the route tree to register the new route

    return c.SendStatus(http.StatusOK)
})

In this example, a new route is defined and then RebuildTree() is called to make sure the new route is registered and available.