KeyAuth

The KeyAuth middleware implements API key authentication.

Signatures

func New(config ...Config) fiber.Handler
func TokenFromContext(ctx any) string

TokenFromContext accepts a fiber.CustomCtx, fiber.Ctx, a *fasthttp.RequestCtx, or a context.Context.

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:

bash

# 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:

bash

# / 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).

FromAuthHeader expects a compliant RFC 7235 token68 key value.

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:

bash

# / 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"),
}