KeyAuth

The KeyAuth middleware implements API key authentication.

Signatures

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

Examples

Basic example

This example registers KeyAuth with an API key stored in a cookie.

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()

    // Register middleware before the routes that need it
    app.Use(keyauth.New(keyauth.Config{
        Extractor:  keyauth.FromCookie("access_token"),
        Validator:  validateAPIKey,
    }))

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

    app.Listen(":3000")
}

Test:

# No API key specified -> 401 Missing or invalid API Key
curl http://localhost:3000
#> Missing or invalid API Key

# Correct API key -> 200 OK
curl --cookie "access_token=correct horse battery staple" http://localhost:3000
#> Successfully authenticated!

# Incorrect API key -> 401 Missing or invalid API Key
curl --cookie "access_token=Clearly A Wrong Key" http://localhost:3000
#> Missing or invalid API Key

For a more detailed example, see the fiber-envoy-extauthz recipe in the gofiber/recipes repository.

Authenticate only certain endpoints

Use the Next function to run KeyAuth only on selected routes.

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) {
            // Run middleware for protected routes
            return false
        }
    }
    // Skip middleware for non-protected routes
    return true
}

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

    app.Use(keyauth.New(keyauth.Config{
        Next:      authFilter,
        Extractor: keyauth.FromCookie("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")
}

Test:

# / doesn't require authentication
curl http://localhost:3000
#> Welcome

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

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

Apply middleware in the handler

You can apply the middleware to specific routes or groups instead of globally. This example uses the default extractor (FromAuthHeader).

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")
}

Test:

# / doesn't require authentication
curl http://localhost:3000
#> Welcome

# /allowed requires authentication
curl --header "Authorization: Bearer my-super-secret-key"  http://localhost:3000/allowed
#> Successfully authenticated!

Key Extractors

KeyAuth uses an Extractor from the shared extractors package to retrieve the API key from the request. You can specify one or more extractors in the configuration. For a full list of extractors, chaining, and advanced usage, see the Extractors Guide.

Typical Usage

Specify the extractor in the config. For example, to extract from a cookie:

app.Use(keyauth.New(keyauth.Config{
    Extractor: extractors.FromCookie("access_token"),
    Validator: validateAPIKey,
}))

To use the default (Authorization header with Bearer scheme):

app.Use(keyauth.New(keyauth.Config{
    Validator: validateAPIKey, // Extractor defaults to FromAuthHeader("Bearer")
}))

To try multiple sources (header, then query):

app.Use(keyauth.New(keyauth.Config{
    Extractor: extractors.Chain(
        extractors.FromHeader("X-API-Key"),
        extractors.FromQuery("api_key"),
    ),
    Validator: validateAPIKey,
}))

For custom logic, use extractors.FromCustom:

app.Use(keyauth.New(keyauth.Config{
    Extractor: extractors.FromCustom(func(c fiber.Ctx) (string, error) {
        return c.Get("X-My-API-Key"), nil
    }),
    Validator: validateAPIKey,
}))

Refer to the Extractors Guide for details, security notes, and advanced configuration.

Config

Property	Type	Description	Default
Next	func(fiber.Ctx) bool	Next defines a function to skip this middleware when it returns true.	nil
SuccessHandler	fiber.Handler	SuccessHandler defines a function which is executed for a valid key.	c.Next()
ErrorHandler	fiber.ErrorHandler	ErrorHandler defines a function which is executed for an invalid key. By default a 401 response with a WWW-Authenticate challenge is sent.	Default error handler
Validator	func(fiber.Ctx, string) (bool, error)	Required. Validator is a function to validate the key.	nil (panic)
Extractor	extractors.Extractor	Extractor defines how to retrieve the key from the request. Use helper functions from the shared extractors package, e.g. extractors.FromAuthHeader("Bearer") or extractors.FromCookie("access_token").	extractors.FromAuthHeader("Bearer")
Realm	string	Realm specifies the protected area name used in the WWW-Authenticate header.	"Restricted"
Challenge	string	Value of the WWW-Authenticate header when no Authorization scheme is present.	ApiKey realm="Restricted"
Error	string	Error code appended as the error parameter in Bearer challenges. Must be invalid_request, invalid_token, or insufficient_scope.	""
ErrorDescription	string	Human-readable text for the error_description parameter in Bearer challenges. Requires Error.	""
ErrorURI	string	URI identifying a human-readable web page with information about the error in Bearer challenges. Requires Error and must be an absolute URI.	""
Scope	string	Space-delimited list of scopes for the scope parameter in Bearer challenges. Each token must conform to the RFC 6750 scope-token syntax and requires Error set to insufficient_scope.	""

Default Config

var ConfigDefault = Config{
    SuccessHandler: func(c fiber.Ctx) error {
        return c.Next()
    },
    ErrorHandler: func(c fiber.Ctx, _ error) error {
        return c.Status(fiber.StatusUnauthorized).SendString(ErrMissingOrMalformedAPIKey.Error())
    },
    Realm:     "Restricted",
    Extractor: extractors.FromAuthHeader("Bearer"),
}