httpchain

README

httpchain

Package httpchain

this package provide Chain function to chain multiple middleware into single handler function

Chain function

Chain multiple middleware into single handler function

Middleware is any value that have following type

func(next http.HandlerFunc) http.HandlerFunc

you can pass multiple middleware, slice/array of middleware, or combination of them

this function also accept following type as handler (last function in middleware chain)

http.HandlerFunc
http.Handler
func(*http.Request) http.HandlerFunc

(the last one is from go-handler package)

when you have following code

var h http.HandlerFunc
var m func(http.HandlerFunc) http.HandlerFunc
var ms [2]func(http.HandlerFunc) http.HandlerFunc

then

all := Chain(m, ms, h)

will have same effect as

all := m(ms[0](ms[1](h)))

Documentation

Overview

Package httpchain

this package provide Chain function to chain multiple middleware into single handler function

Index

• func Chain(all ...any) http.HandlerFunc

Examples

• Chain

Functions

func Chain

func Chain(all ...any) http.HandlerFunc

Chain multiple middleware into single handler function

Middleware is any value that have following type

func(next http.HandlerFunc) http.HandlerFunc
func(next http.Handler) http.Handler
func(next http.HandlerFunc) http.Handler
func(next http.Handler) http.HandlerFunc

you can pass multiple middleware, slice/array of middlewares, or combination of them

this function also accept following type as handler (last function in middleware chain)

http.HandlerFunc
http.Handler
func(*http.Request) http.HandlerFunc
func(http.ResponseWriter, *http.Request) error

when you have following code

var h http.HandlerFunc
var m func(http.HandlerFunc) http.HandlerFunc
var ms [2]func(http.HandlerFunc) http.HandlerFunc

then

all := Chain(m, ms, h)

will have same effect as

all := m(ms[0](ms[1](h)))

Example

package main

import (
	"fmt"
	"net/http"
	"net/http/httptest"

	"github.com/payfazz/httpchain"
)

func main() {
	middleware1 := func(next http.HandlerFunc) http.HandlerFunc {
		return func(w http.ResponseWriter, r *http.Request) {
			w.Header().Add("Before", "m1")
			next(w, r)
			w.Header().Add("After", "m1")
		}
	}

	middleware2 := func(next http.HandlerFunc) http.HandlerFunc {
		return func(w http.ResponseWriter, r *http.Request) {
			w.Header().Add("Before", "m2")
			next(w, r)
			w.Header().Add("After", "m2")
		}
	}

	handler := func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprint(w, "x")
	}

	all := httpchain.Chain(
		middleware1,
		middleware2,
		handler,
	)

	res := httptest.NewRecorder()
	req := httptest.NewRequest("GET", "/", nil)
	all(res, req)

	fmt.Printf(
		"%s,%s,%s,%s,%s\n",
		res.Header().Values("Before")[0],
		res.Header().Values("Before")[1],
		res.Body.String(),
		res.Header().Values("After")[0],
		res.Header().Values("After")[1],
	)

}

Output:

m1,m2,x,m2,m1