kit/middleware/cors/cors.go

package cors

import (
	"context"
	"git.diulo.com/mogfee/kit/middleware"
	"git.diulo.com/mogfee/kit/transport"
	"net/http"
)

type OptionFunc func(o *option)

func WithDomain(domain string) OptionFunc {
	return func(o *option) {
		o.domain = domain
	}
}
func WithMethod(method string) OptionFunc {
	return func(o *option) {
		o.method = method
	}
}

func WithHeader(header string) OptionFunc {
	return func(o *option) {
		o.headers = header
	}
}

type option struct {
	domain  string
	method  string
	headers string
}

func Cors(ops ...OptionFunc) middleware.Middleware {
	cfg := &option{
		domain:  "*",
		method:  "GET,POST,OPTIONS,PUT,PATCH,DELETE",
		headers: "Content-Type,X-Requested-With,Access-Control-Allow-Credentials,User-Agent,Content-Length,Authorization",
	}
	for _, o := range ops {
		o(cfg)
	}
	return func(handler middleware.Handler) middleware.Handler {
		return func(ctx context.Context, a any) (any, error) {
			if tr, ok := transport.FromServerContext(ctx); ok {
				header := tr.ReplyHeader()
				header.Set("Access-Control-Allow-Origin", cfg.domain)
				header.Set("Access-Control-Allow-Methods", cfg.method)
				header.Set("Access-Control-Allow-Credentials", "true")
				header.Set("Access-Control-Allow-Headers", cfg.headers)
			}
			return handler(ctx, a)
		}
	}
}

func HttpServer() func(http.Handler) http.Handler {
	return func(h http.Handler) http.Handler {
		ch := &cors{h: h}
		ch.h = h
		return ch
	}
}

type cors struct {
	h http.Handler
}

func (ch *cors) ServeHTTP(w http.ResponseWriter, r *http.Request) {

	ch.h.ServeHTTP(w, r)
}