shekol.go

package main

import (
	"net/http"
)

type MiddlewareFn func(http.HandlerFunc) http.HandlerFunc

type Chain struct {
	middlewares []MiddlewareFn
}

func NewChain(m ...MiddlewareFn) Chain {
	return Chain{append([]MiddlewareFn(nil), m...)}
}

func (c Chain) ThenFunc(fn http.HandlerFunc) http.HandlerFunc {
	idx := len(c.middlewares) - 1
	for i := idx; i >= 0; i-- {
		fn = c.middlewares[i](fn)
	}
	return fn
}

func (c Chain) Append(m ...MiddlewareFn) Chain {
	nc := make([]MiddlewareFn, 0, len(c.middlewares)+len(m))
	nc = append(nc, c.middlewares...)
	return Chain{append(nc, m...)}
}

func (c Chain) Extend(chain Chain) Chain {
	return c.Append(chain.middlewares...)
}