idempotent

Documentation

Index

• Constants
• Variables
• func FromRequest(req *http.Request, rec Recorder) (key string, seen bool)
• func Header(r *http.Request) string
• func SeenBefore(w http.ResponseWriter)
• type Recorder

Constants

const (

	// HeaderKey is the HTTP header key used to stored idempotency keys
	HeaderKey = "X-Idempotency-Key"
)

Variables

var (
	// ErrSeenBefore is returned when our http ResponseWriter has seen the idempotency key before
	ErrSeenBefore = errors.New("X-Idempotency-Key seen before")
)

Functions

func FromRequest

func FromRequest(req *http.Request, rec Recorder) (key string, seen bool)

FromRequest extracts the idempotency key from HTTP headers and records its presence in the provided Recorder.

A nil Recorder will always return idempotency keys as unseen.

func Header

func Header(r *http.Request) string

Header returns the idempotency key from a http.Request headers

func SeenBefore

func SeenBefore(w http.ResponseWriter)

SeenBefore sets a HTTP response code as an error for previously seen idempotency keys.

Types

type Recorder

type Recorder interface {
	SeenBefore(key string) bool
}

Recorder offers a method to determine if a given key has been seen before or not. Each invocation of SeenBefore needs to record each key found, but there's no minimum duration required.