no_context_value.go

package gocontext

import (
	"context"
	"net/http"
)

type SomeMiddleware interface {
	HandleHTTPC(ctx context.Context, rw http.ResponseWriter, req *http.Request, next http.Handler)
}

var FunctionA SomeMiddleware = nil
var FunctionB SomeMiddleware = nil


func makeChain(chain ...SomeMiddleware) http.Handler {return nil}

type AddUserID struct {
	OnUserID func(userID string) http.Handler
}

func (a *AddUserID) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
	userID := req.Header.Get("userid")
	a.OnUserID(userID).ServeHTTP(rw, req)
}

type UseUserID struct {
	UserID string
}

func (u *UseUserID) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
	rw.Write([]byte(u.UserID))
}

type ServerNoAbuseContext struct{}

func (s *ServerNoAbuseContext) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
	req = req.WithContext(context.Background())
	chainWithAuth := func(userID string) http.Handler {
		return makeChain(FunctionA, FunctionA, &UseUserID{
			UserID: userID,
		})
	}
	chainPartOne := &AddUserID{
		OnUserID: chainWithAuth,
	}
	chainPartOne.ServeHTTP(rw, req)
}