Idempotency

Idempotency middleware for Fiber allows for fault-tolerant APIs where duplicate requests — for example due to networking issues on the client-side — do not erroneously cause the same action performed multiple times on the server-side.

Refer to datatracker for a better understanding.

Signatures

func New(config ...Config) fiber.Handler
func IsFromCache(c fiber.Ctx) bool
func WasPutToCache(c fiber.Ctx) bool

Examples

Import the middleware package that is part of the Fiber web framework

import (
    "github.com/gofiber/fiber/v3"
    "github.com/gofiber/fiber/v3/middleware/idempotency"
)

After you initiate your Fiber app, you can use the following possibilities:

Default Config

app.Use(idempotency.New())

Custom Config

app.Use(idempotency.New(idempotency.Config{
    Lifetime: 42 * time.Minute,
    // ...
}))

Config

Property	Type	Description	Default
Next	func(fiber.Ctx) bool	Next defines a function to skip this middleware when returned true.	A function for safe methods
Lifetime	time.Duration	Lifetime is the maximum lifetime of an idempotency key.	30 * time.Minute
KeyHeader	string	KeyHeader is the name of the header that contains the idempotency key.	"X-Idempotency-Key"
KeyHeaderValidate	func(string) error	KeyHeaderValidate defines a function to validate the syntax of the idempotency header.	A function for UUID validation
KeepResponseHeaders	[]string	KeepResponseHeaders is a list of headers that should be kept from the original response.	nil (keep all headers)
Lock	Locker	Lock locks an idempotency key.	An in-memory locker
Storage	fiber.Storage	Storage stores response data by idempotency key.	An in-memory storage

Default Config

var ConfigDefault = Config{
    Next: func(c fiber.Ctx) bool {
        // Skip middleware if the request was done using a safe HTTP method
        return fiber.IsMethodSafe(c.Method())
    },

    Lifetime: 30 * time.Minute,

    KeyHeader: "X-Idempotency-Key",
    KeyHeaderValidate: func(k string) error {
        if l, wl := len(k), 36; l != wl { // UUID length is 36 chars
            return fmt.Errorf("%w: invalid length: %d != %d", ErrInvalidIdempotencyKey, l, wl)
        }

        return nil
    },

    KeepResponseHeaders: nil,

    Lock: nil, // Set in configDefault so we don't allocate data here.

    Storage: nil, // Set in configDefault so we don't allocate data here.
}