gengitkan/internal/middleware/auth.go

package middleware

import (
	"net/http"

	"github.com/pborman/uuid"

	"forge.cadoles.com/wpetit/gitea-kan/internal/config"
	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/middleware/container"
	"gitlab.com/wpetit/goweb/service"
	"gitlab.com/wpetit/goweb/service/session"
	"golang.org/x/oauth2"
)

const (
	SessionOAuth2AccessToken = "accessToken"
	SessionOAuth2State       = "oauth2State"
)

func Authenticate(next http.Handler) http.Handler {
	fn := func(w http.ResponseWriter, r *http.Request) {
		ctn := container.Must(r.Context())

		sess, err := session.Must(ctn).Get(w, r)
		if err != nil {
			panic(errors.Wrap(err, "could not retrieve session"))
		}

		accessToken, ok := sess.Get(SessionOAuth2AccessToken).(string)

		if !ok || accessToken == "" {

			state := uuid.New()
			sess.Set(SessionOAuth2State, state)
			if err := sess.Save(w, r); err != nil {
				panic(errors.Wrap(err, "could not save session"))
			}

			giteaOAuth2Config := GiteaOAuth2Config(ctn)
			url := giteaOAuth2Config.AuthCodeURL(state)
			http.Redirect(w, r, url, http.StatusSeeOther)

		}

		next.ServeHTTP(w, r)
	}

	return http.HandlerFunc(fn)
}

func GiteaOAuth2Config(ctn *service.Container) *oauth2.Config {
	conf := config.Must(ctn)
	return &oauth2.Config{
		RedirectURL:  conf.Gitea.RedirectURL,
		ClientID:     conf.Gitea.ClientID,
		ClientSecret: conf.Gitea.ClientSecret,
		Scopes:       conf.Gitea.Scopes,
		Endpoint: oauth2.Endpoint{
			AuthURL:   conf.Gitea.AuthURL,
			TokenURL:  conf.Gitea.TokenURL,
			AuthStyle: oauth2.AuthStyleInParams,
		},
	}
}