finalizer

README

Finalizer is a Go package that implements an HTTP Middleware with a callback that gets called at the end of every request. Typically used to implement HTTP logging.

The code in this package has been adapted from the Go-Kit http server code.

Documentation

Overview

Package finalizer implements an HTTP Middleware with a callback that's executed at the end of the HTTP request.

Index

• func Header(ctx context.Context) (http.Header, bool)
• func Middleware(finalizer ServerFinalizerFunc, next http.Handler) http.Handler
• func ResponseSize(ctx context.Context) (int, bool)
• type ServerFinalizerFunc

Examples

• Middleware

Functions

func Header

func Header(ctx context.Context) (http.Header, bool)

Header returns the HTTP Response headers from a ServerFinalizerFunc context.

func Middleware

func Middleware(finalizer ServerFinalizerFunc, next http.Handler) http.Handler

Middleware calls the ServerFinalizerFunc at the end of an HTTP Request.

Example

//finalizer is executed at the end of the HTTP request in Middleware.
finalizer := func(ctx context.Context, code int, r *http.Request) {
	header, _ := Header(ctx)
	size, _ := ResponseSize(ctx)
	contentType := header.Get("Content-Type")

	fmt.Printf("status=%d, contentType=%s, responseSize=%d\n", code, contentType, size)
}

handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(http.StatusTeapot)
	w.Header().Set("Content-Type", "message/teapot")
	w.Write([]byte("I brew Tea"))
})

// wrap the handler with the finalizer middleware.
wrappedHandler := Middleware(finalizer, handler)

srv := httptest.NewServer(wrappedHandler)
defer srv.Close()

if _, err := http.Get(srv.URL); err != nil {
	panic(err)
}

Output:

status=418, contentType=message/teapot, responseSize=0

func ResponseSize

func ResponseSize(ctx context.Context) (int, bool)

ResponseSize returns the written response size from a ServerFinalizerFunc context.

Types

type ServerFinalizerFunc

type ServerFinalizerFunc func(ctx context.Context, code int, r *http.Request)

ServerFinalizerFunc is a function executed at the end of an HTTP request.