fiber/docs/middleware/keyauth.md

id
keyauth

Keyauth

Key auth middleware provides a key based authentication.

Signatures

func New(config ...Config) fiber.Handler
func TokenFromContext(c fiber.Ctx) string

Examples

package main

import (
	"crypto/sha256"
	"crypto/subtle"
	"github.com/gofiber/fiber/v3"
	"github.com/gofiber/fiber/v3/middleware/keyauth"
)

var (
	apiKey = "correct horse battery staple"
)

func validateAPIKey(c fiber.Ctx, key string) (bool, error) {
	hashedAPIKey := sha256.Sum256([]byte(apiKey))
	hashedKey := sha256.Sum256([]byte(key))

	if subtle.ConstantTimeCompare(hashedAPIKey[:], hashedKey[:]) == 1 {
		return true, nil
	}
	return false, keyauth.ErrMissingOrMalformedAPIKey
}

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

	// note that the keyauth middleware needs to be defined before the routes are defined!
	app.Use(keyauth.New(keyauth.Config{
		KeyLookup:  "cookie:access_token",
		Validator:  validateAPIKey,
	}))

	app.Get("/", func(c fiber.Ctx) error {
		return c.SendString("Successfully authenticated!")
	})

	app.Listen(":3000")
}

Test:

# No api-key specified -> 400 missing 
curl http://localhost:3000
#> missing or malformed API Key

curl --cookie "access_token=correct horse battery staple" http://localhost:3000
#> Successfully authenticated!

curl --cookie "access_token=Clearly A Wrong Key" http://localhost:3000
#>  missing or malformed API Key

For a more detailed example, see also the github.com/gofiber/recipes repository and specifically the fiber-envoy-extauthz repository and the keyauth example code.

Authenticate only certain endpoints

If you want to authenticate only certain endpoints, you can use the Config of keyauth and apply a filter function (eg. authFilter) like so

package main

import (
	"crypto/sha256"
	"crypto/subtle"
	"github.com/gofiber/fiber/v3"
	"github.com/gofiber/fiber/v3/middleware/keyauth"
	"regexp"
	"strings"
)

var (
	apiKey        = "correct horse battery staple"
	protectedURLs = []*regexp.Regexp{
		regexp.MustCompile("^/authenticated$"),
		regexp.MustCompile("^/auth2$"),
	}
)

func validateAPIKey(c fiber.Ctx, key string) (bool, error) {
	hashedAPIKey := sha256.Sum256([]byte(apiKey))
	hashedKey := sha256.Sum256([]byte(key))

	if subtle.ConstantTimeCompare(hashedAPIKey[:], hashedKey[:]) == 1 {
		return true, nil
	}
	return false, keyauth.ErrMissingOrMalformedAPIKey
}

func authFilter(c fiber.Ctx) bool {
	originalURL := strings.ToLower(c.OriginalURL())

	for _, pattern := range protectedURLs {
		if pattern.MatchString(originalURL) {
			return false
		}
	}
	return true
}

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

	app.Use(keyauth.New(keyauth.Config{
		Next:    authFilter,
		KeyLookup: "cookie:access_token",
		Validator: validateAPIKey,
	}))

	app.Get("/", func(c fiber.Ctx) error {
		return c.SendString("Welcome")
	})
	app.Get("/authenticated", func(c fiber.Ctx) error {
		return c.SendString("Successfully authenticated!")
	})
	app.Get("/auth2", func(c fiber.Ctx) error {
		return c.SendString("Successfully authenticated 2!")
	})

	app.Listen(":3000")
}

Which results in this

# / does not need to be authenticated
curl http://localhost:3000
#> Welcome

# /authenticated needs to be authenticated
curl --cookie "access_token=correct horse battery staple" http://localhost:3000/authenticated
#> Successfully authenticated!

# /auth2 needs to be authenticated too
curl --cookie "access_token=correct horse battery staple" http://localhost:3000/auth2
#> Successfully authenticated 2!

Specifying middleware in the handler

package main

import (
	"crypto/sha256"
	"crypto/subtle"
	"github.com/gofiber/fiber/v3"
	"github.com/gofiber/fiber/v3/middleware/keyauth"
)

const (
  apiKey = "my-super-secret-key"
)

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

	authMiddleware := keyauth.New(keyauth.Config{
		Validator:  func(c fiber.Ctx, key string) (bool, error) {
			hashedAPIKey := sha256.Sum256([]byte(apiKey))
			hashedKey := sha256.Sum256([]byte(key))

			if subtle.ConstantTimeCompare(hashedAPIKey[:], hashedKey[:]) == 1 {
				return true, nil
			}
			return false, keyauth.ErrMissingOrMalformedAPIKey
		},
	})

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

	app.Get("/allowed",  authMiddleware, func(c fiber.Ctx) error {
		return c.SendString("Successfully authenticated!")
	})

	app.Listen(":3000")
}

Which results in this

# / does not need to be authenticated
curl http://localhost:3000
#> Welcome

# /allowed needs to be authenticated too
curl --header "Authorization: Bearer my-super-secret-key"  http://localhost:3000/allowed
#> Successfully authenticated!

Config

Property	Type	Description	Default
Next	func(fiber.Ctx) bool	Next defines a function to skip this middleware when returned true.	nil
SuccessHandler	fiber.Handler	SuccessHandler defines a function which is executed for a valid key.	nil
ErrorHandler	fiber.ErrorHandler	ErrorHandler defines a function which is executed for an invalid key.	401 Invalid or expired key
KeyLookup	string	KeyLookup is a string in the form of "<source>:<name>" that is used to extract key from the request.	"header:Authorization"
AuthScheme	string	AuthScheme to be used in the Authorization header.	"Bearer"
Validator	func(fiber.Ctx, string) (bool, error)	Validator is a function to validate the key.	A function for key validation

Default Config

var ConfigDefault = Config{
	SuccessHandler: func(c fiber.Ctx) error {
		return c.Next()
	},
	ErrorHandler: func(c fiber.Ctx, err error) error {
		if err == ErrMissingOrMalformedAPIKey {
			return c.Status(fiber.StatusUnauthorized).SendString(err.Error())
		}
		return c.Status(fiber.StatusUnauthorized).SendString("Invalid or expired API Key")
	},
	KeyLookup:  "header:" + fiber.HeaderAuthorization,
	AuthScheme: "Bearer",
}